The present invention relates to a movable body spectrum measuring apparatus for discriminating a measuring object on the basis of spectrum data regarding the measuring object as measured by a spectrum sensor mounted on a movable body such as a vehicle, in particular, an automobile.
In recent years, vehicles such as automobiles have been often provided with a drive assisting device that recognizes the state of a pedestrian, a traffic light or the like, which dynamically varies around the vehicle, and assists driving and decision making for the driver. Most of such apparatuses take an image of the state of a traffic light, a pedestrian or the like by use of a CCD camera, processes the taken image in real time to recognize the state and uses the recognition result for the above-mentioned assistance for driving. However, since the shape of a pedestrian generally varies depending on size, orientation or presence or absence of his/her belongings, it is difficult to correctly recognize the existence of a pedestrian on the basis of the shape obtained by the above-mentioned image processing. Although traffic lights are highly standardized in size and color, the shapes disadvantageously vary depending on the viewing angle, and shape recognition through the above-mentioned image processing has its limits.
Patent Document 1 describes a remote sensing technique using spectrum data collected by a spectrum sensor as one technique for recognizing a measuring object. According to this technique, measuring objects such as woods, agricultural fields and urban areas, which are difficult to be recognized only by a visible light region, are discriminated by classifying and characterizing multi-spectrum image data also including invisible light regions photographed by the spectrum sensor mounted on an airplane, an artificial satellite, or the like.
Since a spectrum sensor observes a brightness value (light intensity) of each wavelength range also including the invisible light region, characteristics of the measuring object can be found by comparing brightness values of wavelengths with each other and furthermore, allowing the measuring object to be discriminated. In addition, in recent years, a hyper spectrum sensor having a wide imageable bandwidth and a high resolution of a few nm to a dozens of nm has been put into practical use as the above-mentioned spectrum sensor (refer to Patent Document 2).
Thus, it has been recently considered that such a spectrum sensor mounted on a vehicle such as an automobile, and various measuring objects around the vehicle are discriminated on the basis of spectrum data taken by the spectrum sensor. However, in the case where such a spectrum sensor is applied to a movable body such as a vehicle, the spectrum of even an identical measuring object varies due to the influence of ambient light, including weather and the degree of sunshine, the brightness of street lamps, and road environment. For this reason, even when spectrum data regarding the measuring object is acquired by the spectrum sensor, lowering of recognition accuracy due to such influences from ambient light is inevitable.
Accordingly, it is an objective of the present invention to provide a movable body spectrum measuring apparatus that reduces the influence of ambient light on data captured by the spectrum sensor mounted on a movable body such as a vehicle, thereby enabling discrimination of a measuring object with higher reliability.
To achieve the foregoing objective, a movable body spectrum measuring apparatus according to the present invention is provided with a spectrum sensor mounted on a movable body. The spectrum sensor is capable of measuring wavelength information and light intensity information. The spectrum measuring apparatus discriminates a measuring object around the movable body on the basis of spectrum data regarding observation light detected by the spectrum sensor. The apparatus includes a feature value varying device and a controller. The feature value varying device varies a feature value of at least one of a wavelength range of the observation light and a light intensity at each wavelength of the observation light. The controller controls a feature value varying mode of the feature value varying device on the basis of a control value corresponding to an environment element.
As with the above-mentioned configuration, if the feature value varying device varies the feature value of at least one of the wavelength range and the light intensity at each wavelength of the observation light, which is detected by the spectrum sensor, according to the environment element at each time, for example, even when the ambient light varies, the wavelength range and the light intensity at each wavelength of the observation light can be adequately compensated for so as to reduce the influence from ambient light. Thereby, in discriminating the measuring object on the basis of detection of the observation light, the discrimination can be achieved with high accuracy.
According to one aspect of the present invention, an illumination device is provided as the feature value varying device. The illumination device radiates reference light. At least one of the wavelength range and the light intensity at each wavelength of the reference light is changeable. The controller controls at least one of the wavelength range and the light intensity at each wavelength of the reference light radiated from the illumination device on the basis of the control value, thereby varying the feature value of the observation light.
With the above-mentioned configuration, by adjusting at least one of the wavelength range and the light intensity at each wavelength of the reference light radiated toward the measuring object, the wavelength range and the light intensity at each wavelength of light reflected from the measuring object irradiated with the reference light, that is, the feature value of the observation light detected by the spectrum sensor can be adjusted. For this reason, in discriminating the measuring object on the basis of the spectrum data detected by the spectrum sensor, the spectrum data corresponding to the ambient light radiated toward the measuring object can be acquired, resulting in that discrimination on the attribute and the like of the measuring object can be achieved with high accuracy.
In accordance with one aspect of the present invention, the controller is configured to be capable of controlling blinking of reference light radiated from the illumination device.
With the above-mentioned configuration, by blinking of the reference light radiated toward the measuring object, each of the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light can be acquired. For this reason, the measuring object can be discriminated on the basis of each of the spectrum data regarding the measuring object that is irradiated with the reference light and the spectrum data regarding the measuring object that is not irradiated with the reference light.
In accordance with one aspect of the present invention, an illumination device is provided as the feature value varying device. The illumination device radiates reference light toward the measuring object. The controller controls blinking of the reference light radiated from the illumination device on the basis of the control value, thereby varying the feature value of the observation light.
With the above-mentioned configuration, by blinking the reference light radiated toward the measuring object, for example, at predetermined cycles, the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light can be acquired in real time. Thus, the measuring object can be discriminated on the basis of each of the spectrum data regarding the measuring object that is irradiated with the reference light and the spectrum data regarding the measuring object that is not irradiated with the reference light. Further, by controlling blinking the reference light, the wavelength range and the light intensity at each wavelength of light reflected from the measuring object irradiated with the reference light, that is, the feature value of the observation light detected by the spectrum sensor can be also adjusted. Thereby, in discriminating the measuring object on the basis of the spectrum data detected by the spectrum sensor, the spectrum data corresponding to the ambient light radiated toward the measuring object can be acquired, resulting in that discrimination on the attribute and the like of the measuring object can be achieved with high accuracy.
In accordance with one aspect of the present invention, the measuring object is discriminated by computing the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light on the basis of control of blinking of the reference light by the controller.
For the spectrum data regarding the measuring object that is irradiated with the reference light and the spectrum data regarding the measuring object that is not irradiated with the reference light, which are acquired through control of the above-mentioned blinking, a difference between the pieces of spectrum data regarding objects other than the light source such as a self-luminous body becomes remarkable. Then, as with the above-mentioned configuration, the measuring object can be easily discriminated on the basis of the computation of each of the spectrum data regarding the measuring object that is irradiated with the reference light and the spectrum data regarding the measuring object that is not irradiated with the reference light.
In accordance with one aspect of the present invention, in computing the two pieces of spectrum data regarding the observation light, the difference or the ratio between the pieces of spectrum data is acquired.
As with the above-mentioned configuration, by discriminating the measuring object based on the difference or the ratio between the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light, which are acquired during blinking of the reference light, it becomes possible to further reduce and suppress the influence of the ambient light such as electric light and sunlight, which is radiated toward the measuring object, separately from the reference light radiated from the illumination device. Thereby, in discriminating the measuring object on the basis of such detection of the spectrum data, the measuring object can be discriminated with higher accuracy.
In accordance with one aspect of the present invention, the discrimination of the measuring object is discrimination on whether or not the measuring object is a self-luminous body on the basis of a differential computation between the pieces of the spectrum data regarding the observation light.
For example, when the reference light is radiated from the illumination device to a reflector having a high reflectance, reference light reflected once by the reflector is detected as the observation light by the spectrum sensor. Meanwhile, since the reflector itself does not emit light during non-radiation of the reference light, light reflected from ambient light or the like is detected as the observation light by the spectrum sensor. For this reason, when an object irradiated with the reference light is a reflector, the difference between the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light becomes large.
When the reference light is radiated from the illumination device to a self-luminous body, light emitted from the self-luminous body and the reference light radiated from the illumination device are detected by the wavelength sensor. Meanwhile, during non-radiation of the reference light, the light emitted from the self-luminous body and the ambient light are detected by the spectrum sensor. For this reason, when the object irradiated with the reference light is a reflector, the difference between the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light is reduced by the light emitted from the self-luminous body.
By discriminating the measuring object on the basis of the difference between the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light in this manner, it is possible to determine whether or not the measuring object is a self-luminous body, or whether or not the measuring object is a reflector.
In accordance with one aspect of the present invention, ambient light of the measuring object is light from an electric lamp lit with power supplied from a commercial AC power source. A blinking cycle of the blinking control of the reference light by the controller is set so as to be in sync with a cycle using an AC frequency of the commercial AC power source as a reference.
A light-emitting basic cycle of an electric lamp such as a fluorescent lamp lit with power supplied from a commercial AC power source is, for example in Japan, a “100 Hz standard” in the Kanto area and a “120 Hz standard” in the Kansai area. As with the above-mentioned configuration, when the ambient light is from an electric lamp, by blinking the reference light in sync with the light-emitting basic cycle, influence from the ambient light due to radiation of the reference light can be reliably eliminated.
In accordance with one aspect of the present invention, the movable body is provided with a drive assistance system for periodically computing various information supporting driving of the movable body. A blinking cycle of the blinking control of the reference light by the controller is set so as to be equal to or smaller than a computation cycle of the drive assistance system.
When the movable body is an automobile, the computation cycle of the drive assistance system (microcomputer) is, for example, “100 msec”. As with the above-mentioned configuration, by setting the blinking cycle of the reference light so as to be equal to or smaller than the computation cycle of the drive assistance system, the measuring object can be monitored in real time and reliability of drive assistance of the movable body on the basis of discrimination of the monitored measuring object can be improved.
In accordance with one aspect of the present invention, the illumination device is configured to be capable of changing light distribution, which is a radiation position of the reference light. The controller controls light distribution of the reference light by the illumination device according to the discriminated measuring object.
With the above-mentioned configuration, distribution of the reference light radiated from the illumination device is adjusted according to the measuring object discriminated on the basis of detection of the spectrum data. Thereby, discrimination of the measuring object can be stably achieved with high accuracy.
In accordance with one aspect of the present invention, 11. The illumination device uses an LED luminous body as a source of the reference light.
As with the above-mentioned configuration, by using the LED luminous body as the source of the reference light, the wavelength range and the light intensity at each wavelength as the reference light can be adjusted more easily and with high accuracy.
In accordance with one aspect of the present invention, the LED luminous body includes a plurality of LED light-emitting elements that emit light components having different wavelengths and are arranged in a row or a matrix. The controller selectively drives the LED light-emitting elements to control the wavelength range of the reference light, and adjusts the value of a current supplied to the selected LED light-emitting element or the duty cycle of a pulse voltage applied to the selected LED light-emitting element to control the light intensity at each wavelength of the reference light or to control blinking.
With the above-mentioned configuration, through radiation/non-radiation of the reference light by the LED light-emitting elements having different wavelengths, which configure the LED luminous body, the wavelength range of the reference light can be adjusted, and adjustment of the feature value of the observation light detected by the spectrum sensor can be performed more easily and with a simpler configuration.
In accordance with one aspect of the present invention, the illumination device uses a halogen lamp as a source for the reference light.
With the above-mentioned configuration, by using the halogen lamp as the source of the illumination device, the illumination device can be configured more simply.
In accordance with one aspect of the present invention, the illumination device includes a plurality of optical filters having different wavelength characteristics and transmittances, which cover the halogen lamp. Through selection of the optical filters, the controller controls at least one of the wavelength range and the light intensity at each wavelength of the reference light or controls blinking.
With the above-mentioned configuration, the reference light radiated from the halogen lamp is radiated toward the measuring object through the filter selected from a plurality of filters having different wavelength characteristics and transmittances. In other words, the wavelength range and the light intensity at each wavelength of the reference light are adjusted according to the wavelength characteristic and the transmittance of the filter. Thereby, an illumination device that can adjust the feature value of the detected observation light can be configured from a very versatile light source such as a halogen lamp.
In accordance with one aspect of the present invention, the illumination device is provided with a spectroscope for separating light radiated from the halogen lamp according to wavelength. Through adjustment of the phase of the light separated according to wavelength, the controller controls at least one of the wavelength range and the light intensity at each wavelength of the reference light or controls blinking.
With the above-mentioned configuration, the intensity and the wavelength range of the reference light radiated toward the measuring object can be adjusted through phase adjustment of the reference light radiated from the halogen light source. Also in this case, an illumination device that can adjust the feature value of the detected observation light can be configured from a very versatile light source such as the halogen lamp.
In accordance with one aspect of the present invention, the illumination device is provided with a spectroscope for separating light radiated from the halogen lamp according to wavelength. Through selective transmission or restriction of the light separated according to wavelength, the controller controls at least one of the wavelength range and the light intensity at each wavelength of the reference light or controls blinking.
With the above-mentioned configuration, the light radiated from the halogen light source is separated by the spectroscope according to wavelength and the amount of the separated light is adjusted according to wavelength. For this reason, the wavelength range and the light intensity of the reference light radiated from the illumination device can be adjusted through the amount of light according to wavelength. Also in this case, an illumination device that can adjust the feature value of the detected observation light can be configured from a very versatile light source such as the halogen lamp.
In accordance with one aspect of the present invention, the reference light radiated from the illumination device is light having wavelength in a nonvisible region.
With the above-mentioned configuration, by adopting light having wavelengths in the invisible region as the reference light radiated from the illumination device, even when the spectrum data regarding the measuring object such as a pedestrian and a vehicle is detected, the reference light can be radiated without exerting an influence on walking by the pedestrian and driving of the vehicle.
In accordance with one aspect of the present invention, the feature value varying device includes a spectral characteristic varying part for varying an imaging spectral characteristic of the mounted spectrum sensor. The controller controls the imaging spectral characteristic by the spectral characteristic varying part on the basis of the control value, thereby varying the feature value of the observation light.
With the above-mentioned configuration, by adjusting the imaging spectral characteristic of the spectrum sensor, the feature value of the observation light detected by the spectrum sensor can be adjusted. For this reason, in discriminating the measuring object on the basis of the spectrum data detected by the spectrum sensor, the spectrum data corresponding to the attribute of the measuring object or the ambient light to the measuring object can be acquired, resulting in that the measuring object can be discriminated with high accuracy. By using the spectral characteristic varying part (spectrum sensor) and the above-mentioned illumination device concurrently as the feature value varying device, the degree in adjusting the feature value of the observation light as well as the degree of flexibility in adjustment are significantly improved.
In accordance with one aspect of the present invention, the mounted spectrum sensor is a spectrum sensor provided with a CMOS image sensor as an imaging element. The feature value varying device includes a pixel driver of the CMOS image sensor as the spectral characteristic varying part. The controller controls the imaging spectral characteristic by adjusting gain at each pixel of the CMOS image sensor, which corresponds to each light separated according to wavelength, thereby varying the feature value of the observation light.
With the above-mentioned configuration, by adjusting the gain of each row of the CMOS image sensor configuring the hyper spectrum sensor, imaging spectrum, that is, the feature value of the observation light can be adjusted. Thereby, the feature value of the observation light detected from the measuring object can be electrically adjusted and furthermore, an increase in size of the spectrum sensor is prevented.
In accordance with one aspect of the present invention, the mounted spectrum sensor is a multi-spectrum sensor for capturing the observation light into each of a plurality of imaging elements through optical filters having different wavelength characteristics and transmittances. The feature value varying device includes the optical filters having different wavelength characteristics and transmittances as the spectral characteristic varying part. The controller controls the imaging spectral characteristic by synthesizing the observation light captured into each of the imaging element through the optical filters, thereby varying the feature value of the observation light.
With the above-mentioned configuration, by capturing the observation light radiated toward the imaging elements of the multi-spectrum sensor through the optical filters having different wavelength characteristics and transmittances, the observation light, the feature value of which is adjusted according to the wavelength characteristics and transmittances of the optical filters, can be detected. Thus, the feature value of the observation light detected from the measuring object can be easily adjusted.
In accordance with one aspect of the present invention, the mounted spectrum sensor is a multi-spectrum sensor for directing the observation light to each of a plurality of imaging elements having different wavelength ranges. The feature value varying device includes a driver for each of the imaging elements as the spectral characteristic varying part. The controller controls the imaging spectral characteristic by adjusting a gain of each of the imaging elements, thereby varying the feature value of the observation light.
With the above-mentioned configuration, by adjusting the gain of each of the imaging elements configuring the multi-spectrum sensor, the feature value of the observation light detected by the multi-spectrum sensor can be adjusted. Also in this case, the feature value of the observation light is detected from the measuring object can be easily adjusted.
In accordance with one aspect of the present invention, the controller determines the control value corresponding to the environment element on the basis of a detection result of the spectrum sensor.
With the above-mentioned configuration, by determining the control value of the controller that can vary the feature value of the observation light on the basis of the detection result of the spectrum sensor, the feature value of the observation light can be adjusted in a recursive manner. For this reason, even in the situation where the ambient light gradually varies with movement of the movable body, the reference light corresponding to the ambient light can be appropriately radiated toward the measuring object, and the spectrum data can be acquired more desirably.
In accordance with one aspect of the present invention, the movable body is further provided with an environment information sensor for detecting surrounding environment information of the movable body. The controller determines the control value corresponding to the environment element on the basis of a detection result of the environment information sensor.
The spectrum data detected from the measuring object varies depending on, for example, an atmospheric state caused by change in weather, sunlight radiation degree and the like. With the above-mentioned configuration, the environment information sensor can monitor the atmospheric state and the sunlight radiation degree, and the control value determined according to the monitored environment element, that is, the feature value of the observation light can be adjusted. Thus, even when surrounding environment of the movable body varies, the measuring object can be discriminated with influence from the surrounding environment being reduced.
In accordance with one aspect of the present invention, the environment information sensor is an image sensor for acquiring a surrounding image of the movable body.
With the above-mentioned configuration, the image sensor for acquiring the surrounding image of the movable body can monitor the surrounding environment information of the movable body with high accuracy. This can determine the control value of the controller according to the environment element of the movable body, and adjust the feature value of the observation light according to the surrounding environment of the movable body with high accuracy.
In accordance with one aspect of the present invention, the environment information sensor is a radar device for detecting presence or absence of an object in the surroundings of the movable body and the distance from the object on the basis of a reception mode of a reflected wave of a transmitted radio wave.
With the above-mentioned configuration, the radar device can detect the presence or absence of objects surrounding the movable body as the measuring object. This can set the control value corresponding to an object in the surroundings of the movable body, and adjust the feature value of the observation light according to the surrounding environment of the movable body with high accuracy.
In accordance with one aspect of the present invention, the movable body is an automobile moving on a road surface.
The present invention with the above-mentioned configuration is especially effective for the automobile as the movable body provided with the spectrum sensor, and enables very reliable acquisition of discrimination information of the measuring object, which is necessary for supporting driving of the automobile.
a) is a block diagram schematically showing the configuration of a movable body spectrum measuring apparatus according to a first embodiment of the present invention;
b) is a diagram showing an example of a control value map for an illumination controller and a sensor controller;
a) is a graph showing an example of spectrum shape of reference light radiated from an illumination device in the first embodiment;
b) is a graph showing an example of spectrum data regarding a measuring object, which is detected by a spectrum sensor;
a) to 3(d) are graphs showing examples of shift of the spectrum data regarding sunlight as ambient light over time;
a) and 4(b) are views showing examples of the control value map for the illumination controller in the apparatus according to the first embodiment;
a) to 6(d) are graphs showing examples of shift of a wavelength range and the light intensity at each wavelength of the reference light generated by the illumination controller in the apparatus according to the first embodiment over time;
a) is a graph showing relationship between a supplied current and the light intensity of the LED light-emitting element configuring the illumination device shown in
b) is a time chart showing an example of shift of time and an applied pulse voltage in the case of pulse width modulation-controlling the light intensity of the LED light-emitting element configuring the illumination device (duty cycle control);
a) is a graph showing an example of the wavelength characteristic and transmittance of the optical filter;
b) is a graph showing relationship between an light intensity and a current supplied to a halogen lamp configuring the illumination device shown in
a) and 17(b) are partial perspective views schematically showing the configuration of an illumination device adopted in a movable body spectrum measuring apparatus according to a fourth embodiment of the present invention;
a) is a block diagram showing the configuration of a gain adjusting part of each CCD image sensor configuring the spectrum sensor shown in
b) is a graph showing an example of a gain adjusting mode of the CCD image sensors;
a) is a diagram schematically showing an example of an external environment element to the vehicle during non-radiation of the reference light in a movable body spectrum measuring apparatus according to a ninth embodiment of the present invention;
b) is a graph showing an example of the spectrum data detected by the spectrum sensor during non-radiation of the reference light in this embodiment;
a) is a diagram schematically showing an example of the external environment element to the vehicle during radiation of the reference light in the ninth embodiment;
b) is a graph showing an example of the spectrum data detected by the spectrum sensor during radiation of the reference light;
a) is a time chart showing an example of a blinking cycle of an electric lamp as a source of the ambient light in the movable body spectrum measuring apparatus according to a tenth embodiment of the present invention;
b) is a time chart showing an example of the blinking cycle of the reference light radiated from the illumination device in this embodiment;
a) is a diagram schematically showing an example of the external environment element to the vehicle during non-radiation of the reference light from the illumination device in a movable body spectrum measuring apparatus according to an eleventh embodiment of the present invention;
b) is a graph showing an example of the spectrum data detected by the spectrum sensor during radiation of the reference light in this embodiment;
a) is a diagram schematically showing an example of the external environment element to the vehicle during non-radiation of the reference light from the illumination device of the apparatus according to the eleventh embodiment
b) is a diagram showing an example of difference between the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light;
a) is a graph showing an example of the spectrum shape of the reference light radiated from the illumination device of the apparatus according to the eleventh embodiment
b) is a graph showing an example of the spectrum data detected by the measuring object during radiation of the reference light together with a discrimination condition;
c) is a graph showing an example of difference between the spectrum data during radiation and the spectrum data during non-radiation together with the discrimination condition;
As shown in
Further, in the spectrum sensor S, the sensor controller 140 can vary the imaging spectral characteristic according to the control value map of the control value calculator 100, thereby varying the feature value of the detected observation light. When the spectrum sensor S detects the spectrum data regarding the measuring object, then the spectrum data is captured into a detector 150, and it is discriminated whether the measuring object is a pedestrian, traffic light or an obstacle on the basis of the feature value of the spectrum data. Then, discriminating information of the measuring object is recursively captured into the control value calculator 100. The discriminating information of the measuring object is also captured into a drive assistance system 160 that cyclically operates various types of information for supporting driving of the vehicle to supply drive assistance such as navigation and auto-cruise control to the driver, and also serves as driving assistance by the system 160.
In addition to the spectrum data regarding the measuring object, which is detected by the spectrum sensor S, information detected by an environment information sensor 170 formed of, for example, an image sensor for acquiring positional information of the vehicle by GPS and images surrounding the vehicle or a radar device for detecting presence or absence of an object surrounding the vehicle and distance from the object on the basis of the reception mode of the reflected wave of the transmitted radio wave is captured into the control value calculator 100. Thus, it becomes possible to monitor the environment elements such as the atmospheric state (weather) and the obstacle surrounding the vehicle, which can exert an influence in discriminating the measuring object on the basis of the spectrum data.
As described above, the control value calculator 100 determines the control value in order to radiate the appropriate reference light to the measuring object according to discriminating information of the measuring object from the detector 150 or various environment information from the environment information sensor 170, and to detect the appropriate attribute of the measuring object from the spectrum sensor S.
In this embodiment, first, an example of adjusting the reference light on the basis of solar radiation information among the environment elements, that is, adjusting the feature value of the observation light will be described.
a) to 3(b) show examples of shift of the light intensity at each wavelength of sunlight as the ambient light in Japan.
As shown in
First, a mode of adjusting the reference light will be described with reference to
First, as shown in
As shown in
Next, an example of the illumination device 120 will be described with reference to
As shown in
By control of the current supplied to each LED light-emitting element, that is, adjustment of the light intensity, as shown in
Next, a reference light control mode performed by the control value calculator 100 and the illumination controller 110 on the assumption of the above-mentioned description will be described with reference to
First, when the spectrum data regarding the measuring object is acquired on the basis of detection by the spectrum sensor S, it is determined whether or not the acquired spectrum data has sufficient intensity required to discriminate the measuring object or more (Steps S100, S101). When it is determined that the intensity of the spectrum data falls below the required intensity, the wavelength range and the intensity in each wavelength range of the reference light at this time is acquired from the control value map (
Thus, even when the intensity of the spectrum data falls below the required intensity due to influence of sunlight, by radiating the reference light to the measuring object so as to compensate sunlight, the measuring object can be discriminated with high reliability without being influenced by sunlight.
As described above, the movable body spectrum measuring apparatus according to this embodiment can obtain the following advantages.
(1) By radiating the reference light to the measuring object in acquiring the spectrum data regarding the measuring object, light reflected from the measuring object is detected as the observation light of the measuring object by the spectrum sensor S. Thereby, even in an environment in which reference light such as sunlight does not exist, the spectrum sensor can measure the spectrum of the measuring object.
(2) The wavelength range and the light intensity at each wavelength of the reference light radiated from the illumination device 120 are adjusted in the mode to compensate change in the wavelength range and the light intensity at each wavelength of sunlight in the ambient light, that is, the feature value. Thereby, in discriminating the measuring object on the basis of the spectrum data regarding the measuring object, which is detected by the spectrum sensor S, influence of sunlight, that is, influence of the ambient light can be reduced, enabling discrimination of the measuring object with higher reliability.
(3) The LED luminous body configured of a plurality of LED light-emitting elements that are arranged in a matrix and emit light having different wavelengths is used as a light source of the illumination device 120. Thereby, the wavelength range and the light intensity at each wavelength of the reference light can be controlled with high accuracy and with high degree of flexibility by controlling the value of the current supplied to each LED light-emitting element or duty cycle of the pulse voltage applied to each LED light-emitting element.
A movable body spectrum measuring apparatus according to a second embodiment of the present invention will be described below with reference to
That is, as shown in
Ta>Tb>Tc.
The reference light passes through the optical filters 122A to 122C, so that the spectrum shape is converted according to each of the transmittances Ta to Tc, thereby varying the wavelength range and the light intensity at each wavelength of the reference light. The intensity of the halogen lamp 121 is, as shown in
As described above, the illumination device 120A can also vary the wavelength range and the light intensity at each wavelength of the reference light on the basis of the control value map according to the environment element. Thus, even when the ambient light changes, the reference light can be radiated in the mode to compensate the change and accordingly, the spectrum data can be acquired while being less influenced by the ambient light.
As described above, the movable body spectrum measuring apparatus according to the second embodiment can obtain advantages similar to the advantages (1) and (2) in the first embodiment, and the following advantage in place of the advantage (3).
(4) The illumination device 120A is configured of the halogen lamp 121 and the optical filter varying plate 122 including the optical filters 122A to 122H having different wavelength characteristics and transmittances. Thus, in adjusting the wavelength range and the light intensity at each wavelength of the reference light radiated toward the measuring object, the illumination device can be configured of a very versatile light source such as a halogen lamp.
A movable body spectrum measuring apparatus according to a third embodiment of the present invention will be described below with reference to
That is, an illumination device 120B adopted in this embodiment includes, as shown in
As shown in
As described above, the movable body spectrum measuring apparatus according to the third embodiment can obtain advantages similar to the advantages (1) and (2) obtained in the first embodiment, and the following advantage in place of the advantage (3).
(5) The wavelength range and the light intensity at each wavelength of the reference light radiated from the illumination device 120B can be phase-adjusted by the phase plates 124 configuring the illumination device 120B. Thus, in adjusting the wavelength range and the light intensity at each wavelength of the reference light radiated toward the measuring object, the illumination device can be configured of the very versatile light source such as the halogen lamp.
A spectrum measuring apparatus according to a fourth embodiment of the present invention will be described below with reference to
That is, in an illumination device 120C adopted in this embodiment, as shown in
The shielding plates 128 (128A to 128D) are, as shown in
By performing selective transmission and restriction of the light La to Ld separated according to wavelength through the shielding plates 128, as shown in
As described above, the illumination device 120C can also vary the wavelength range and the light intensity at each wavelength of the reference light on the basis of the control value map according to the environment element. Thus, even when the ambient light changes, the reference light can be radiated so as to compensate for the change and accordingly, the spectrum data can be acquired while being less influenced by the ambient light.
As described above, the movable body spectrum measuring apparatus according to the fourth embodiment can obtain advantages similar to the advantages (1) and (2) in the first embodiment, and the following advantage in place of the advantage (3).
(6) The light radiated from the halogen lamp 121 is separated according to wavelength, and the wavelength range and the light intensity at each wavelength of the reference light radiated from the illumination device 120C are adjusted through selective transmission and restriction of the separated light. Thus, in adjusting the wavelength range and the light intensity at each wavelength of the reference light radiated toward the measuring object, the illumination device can be configured of a very versatile light source such as the halogen lamp.
A spectrum measuring apparatus according to a fifth embodiment of the present invention will be described below with reference to
First, as shown in
As shown in
In the CMOS image sensor 203, the light wavelengths L2 separated by “5 nm” are spread for each pixel. Then, by adjusting a gain of each pixel of the CMOS image sensor 203 by using the sensor controller 140, the feature value of the observation light wavelengths L2 spread by, for example, “5 nm” is adjusted.
As shown in
Next, a mode of controlling the sensitivity characteristic of the CMOS image sensor 203 by the control value calculator 100 and the sensor controller 140 on the assumption of the above-mentioned situation will be described with reference to
First, when the spectrum data regarding the measuring object is acquired on the basis of the spectrum sensor S, it is determined whether or not the intensity of the acquired spectrum data is an intensity required to discriminate the measuring object or larger (Steps S200, S201). When it is determined that the intensity of the spectrum data is smaller than the required intensity, wavelength range and the intensity in each wavelength range of the reference light at this time are acquired from the control value map (
The CMOS image sensor 203, the sensitivity characteristic of which is adjusted, appropriately detects the spectrum data regarding the measuring object (image formation). Thereby, even when the intensity of the spectrum data falls below the required intensity due to influence of the ambient light, the feature value of the observation light is adjusted in the mode to compensate influence of the ambient light, and through this adjustment, the measuring object can be discriminated with higher reliability without being influenced by the ambient light.
As described above, the movable body spectrum measuring apparatus according to the fifth embodiment can obtain the following advantages.
(7) Basically, only through control of each pixel driver of the COMS image sensor 203 configuring the imaging element of the spectrum sensor S (hyper spectrum sensor), the feature value of the observation light detected from the measuring object can be adjusted.
(8) Since the feature value of the observation light is performed in a purely electrical manner, an increase in size of the spectrum sensor S is prevented.
(9) The illumination controller 110 and the illumination device 120 in
A movable body spectrum measuring apparatus according to a sixth embodiment of the present invention will be described below with reference to
That is, as shown in
The spectral characteristic varying part 210 with such a configuration can adjust the imaging spectral characteristic according to the wavelength characteristics and transmittances of the optical filters 213A to 213C, that is, adjust the feature value of the observation light L1.
As described above, the movable body spectrum measuring apparatus according to the sixth embodiment can obtain the following advantages.
(10) The spectral characteristic varying part 210 that can vary the feature value of the observation light is configured of the optical filters 213A to 213C having different wavelength characteristics and transmittances, and the spectrum data regarding the measuring object is acquired by synthesizing the observation light captured into the imaging elements 214A to 214C through the optical filters 213A to 213C. Thereby, the feature value of the observation light detected from the measuring object can be adjusted so as to reduce influence of the ambient light.
(11) The illumination controller 110 and the illumination device 120 in
A movable body spectrum measuring apparatus according to a seventh embodiment of the present invention will be described below with reference to
That is, as shown in
As described above, the movable body spectrum measuring apparatus according to the seventh embodiment can obtain advantages similar to the advantages (10) and (11) obtained in the sixth embodiment as well as the following advantage.
(12) The spectral characteristic varying part 220 that can vary the feature value of the observation light is configured of the filter varying plate 215 including the optical filters 215A to 215H having different wavelength characteristics and transmittances. The spectrum data regarding the measuring object is acquired by synthesizing the images of the observation light formed on the imaging elements 214A to 214C through the selectively used optical filters 215A to 215H. As a result, the feature value of the observation light can be adjusted with a higher degree of flexibility and therefore, the measuring object can be discriminated with higher accuracy.
A movable body spectrum measuring apparatus according to an eighth embodiment of the present invention will be described below with reference to
That is, as shown in
When the observation light L1 is captured into the imaging elements 233A to 233C, as shown in
The spectral characteristic varying part 230 with such a configuration can adjust the gain (sensitivity) in each wavelength range of the observation light captured into each of the imaging elements 233A to 233C, and thus, can adjust the feature value of the observation light.
As described above, the movable body spectrum measuring apparatus according to the eighth embodiment can obtain the following advantages.
(13) The spectral characteristic varying part 230 that can vary the feature value of the observation light is configured to include the drivers for the imaging elements 233A to 233C, and acquires the spectrum data regarding the measuring object by synthesizing the observation light captured into the imaging elements 233A to 233C. Thereby, the feature value of the observation light, which is detected from the measuring object, can be adjusted in the mode to reduce influence of the ambient light.
(14) The illumination controller 110 and the illumination device 120 in
A movable body spectrum measuring apparatus according to a ninth embodiment of the present invention will be described below with reference to
a) shows the influence of ambient light on a measuring object TG in the case where the reference light from the illumination device 120 is turned “off”, and
As shown in
For this reason, the spectrum data detected by the spectrum sensor S at this time includes, as shown in
As shown in
Then, in this embodiment, the ambient light radiated from the illumination device 120 is controlled to blink, and influence of the ambient light is eliminated through computation of the spectrum data detected during radiation of the reference light and the spectrum data detected during non-radiation of the reference light by the detector 150. The information path indicating “during radiation/non-radiation” of the reference light, which is supplied from the illumination controller 110 to the detector 150, is represented by the broken line arrow in
First, given that the spectrum data detected by the spectrum sensor S during non-radiation of the reference light is A(λ) and the spectrum data detected by the spectrum sensor S during radiation of the reference light is B(λ), the spectrum data regarding the measuring object TG(λ) is calculated according to the following equation (1).
TG(λ)=B(λ)−A(λ) (1)
When the spectrum data regarding the measuring object TG(λ) is calculated according to the equation (1) in this manner, reflectance Rtg of the measuring object TG is calculated based on TG(λ) and a spectrum D(λ) of the reference light radiated from the illumination device 120 according to the following equation (2).
Rtg=TG(λ)/D(λ) (2)
When the reflectance Rtg of the measuring object TG is calculated according to the equation (2) in this manner, the measuring object is discriminated on the basis of the reflectance Rtg.
As shown in
For this reason, the spectrum change by only radiation of the reference light can be determined based on the ratio of the spectrum data A(λ) during non-radiation of the reference light to the spectrum data B(λ) during radiation of the reference light. Therefore, the measuring object can be discriminated without being influenced by the ambient light.
In this embodiment, control of blinking of the reference light by the illumination device 120 is performed in a cycle of “100 msec” as the computation cycle of the drive assistance system 160 for the vehicle or smaller. As a result, even when the source of the ambient light varies with movement of the vehicle, the measuring object can be discriminated in real time without being influenced by the ambient light at each time.
Also in this embodiment, the first to fourth embodiments, or the fifth to eighth embodiments combined with any one of the first to fourth embodiments can be used concurrently, and through such concurrent use, the measuring object can be performed with higher reliability.
As described above, the movable body spectrum measuring apparatus according to the ninth embodiment can obtain the following advantages.
(15) The reference light radiated from the illumination device 120 is controlled to blink, and the measuring object is discriminated on the basis of the difference or the ratio between the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light. Thus, the measuring object can be discriminated on the basis of the spectrum data without being influenced by the ambient light with higher reliability.
(16) The blinking cycle of the reference light radiated from the illumination device 120 is set to “100 msec” as the computation cycle of the drive assistance system 160 or smaller. Thereby, in mounting the spectrum measuring apparatus on the vehicle, the measuring object can be discriminated with high accuracy and in real time.
A movable body spectrum measuring apparatus according to a tenth embodiment of the present invention will be described with reference to
Generally, an electric lamp such as a street lamp as a source of the ambient light for the vehicle especially in night is lit by power supplied from a commercial AC power source. Such an electric lamp is, as shown in
Thus, in this embodiment, as shown in
Also in this embodiment, the first to fourth embodiments, or the fifth to eighth embodiments combined with any one of the first to fourth embodiments can be used concurrently, and through such concurrent use, the discrimination of measuring object can be performed with higher reliability.
As described above, the movable body spectrum measuring apparatus according to the tenth embodiment can obtain the following advantage.
(17) The blinking cycle of the reference light radiated from the illumination device 120 is synchronized with the blinking cycle of the electric lamp such as the street lamp as the source of the ambient light. Thus, in eliminating influence of the ambient light through control of blinking of the reference light, reliability is further improved.
A movable body spectrum measuring apparatus according to an eleventh embodiment of the present invention will be described below with reference to
a) shows influence of the ambient light on the measuring object TG in the case where the reference light by the illumination device 120 is turned “off”, and
First, as shown in
Given that the reference light is radiated from the illumination device 120 to the measuring object, light radiated from the self-luminous bodies 311 to 313 and reference light reflected from the high reflectors 321 and 322 are detected as the observation light by the spectrum sensor S.
Thus, since the reflectance of the reflector 321 is high, as represented by a curve Lr1 in
Meanwhile, during non-radiation of the reference light, as shown in
For this reason, as represented by a solid line Lr2 indicating the spectrum data regarding the reflector 321 during non-radiation of the reference light and by a broken line Lr1 indicating the spectrum data regarding the reflector 321 during radiation of the reference light in
Thus, in this embodiment, it is discriminated whether or not the measuring object is a self-luminous body on the basis of the difference between the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light. In this embodiment, in an object that absorbs light in the whole wavelength band, in consideration of the characteristic that the difference between the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light is small, the above-mentioned discrimination is performed according to the difference in the spectrum data on the basis of the light intensity of the spectrum data.
Next, a mode for discriminating whether or not the measuring object is a self-luminous body will be described with reference to
First, as shown in
Given that a reference light having the spectrum shape shown in
Further, as shown in
As a result of determination between the light intensity I0 and the difference D of the detected spectrum data, and the determining standards A and B, when it is determined as
I0>A, D<B,
the measuring object is determined as the “self-luminous body” on the basis of the determining standard shown in
Further, when the above-mentioned determining result indicates
I0>A, D>B,
the measuring object is determined as the “high reflector” on the basis of the determining standard.
Furthermore, when the above-mentioned determining result indicates
I0<A, D<B,
the measuring object is determined as the “absorber” on the basis of the determining standard.
Finally, when the above-mentioned determining result indicates
I0<A, D>B,
the measuring object is determined as the “low reflector” on the basis of the determining standard.
As described above, the measuring object can be determined as one of a “self-luminous body”, a “high reflector”, an “absorber” or a “low reflector” on the basis of the light intensity I1 in the spectrum data and the spectrum difference D between the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light.
Also in this embodiment, the first to fourth embodiments, or the fifth to eighth embodiments combined with any one of the first to fourth embodiments can be used concurrently, and through such concurrent use, the measuring object can be performed with higher reliability.
As described above, the movable body spectrum measuring apparatus according to the eleventh embodiment can obtain the following advantage.
(8) The measuring object is discriminated on the basis of the light intensity I1 of the spectrum data detected during radiation of the reference light and the difference D between the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light. Thus, the measuring object can be discriminated on the basis of the spectrum data detected by the spectrum sensor S with higher accuracy.
A movable body spectrum measuring apparatus according to a twelfth embodiment of the present invention will be described below with reference to
That is, as shown in
Next, a mode for distributing the reference light performed on the assumption of above-mentioned situation will be described with reference to
As shown in
Priority of danger assessment degree for the vehicle is determined based on the discriminating information. For example, when the priority of danger assessment degree of the pedestrian 404 is determined as highest, the illumination controller 110 sets distribution of the reference light radiated from the illumination device 120 so as to lean toward the pedestrian 404 as shown in
Also in this embodiment, the first to fourth embodiments, or the fifth to eighth embodiments combined with any one of the first to fourth embodiments can be used concurrently, and through such concurrent use, the measuring object can be performed with higher reliability.
As described above, the movable body spectrum measuring apparatus according to the twelfth embodiment can obtain the following advantage.
(19) Distribution of the reference light radiated from the illumination device 120 can be varied according to the discriminated measuring object. Thus, in discriminating the measuring object on the basis of the spectrum data detected by the spectrum sensor S, the measuring object can be discriminated selectively and with higher accuracy.
Each of the above-mentioned embodiments can be implemented as follows.
In the eleventh embodiment, the measuring object is discriminated on the basis of the difference between the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light, and the light intensity in the spectrum data regarding the measuring object detected during radiation of the reference light. The present invention is not limited to this, and when the object that absorbs light in the whole wavelength band can be determined, the measuring object may be discriminated on the basis of only the difference between the spectrum data during radiation of the reference light and the spectrum data during non-radiation of the reference light.
Although the illumination device has a structure that can vary light distribution as the radiation position of the reference light in the twelfth embodiment, such a structure may be omitted when an illumination region necessary for acquiring the spectrum data regarding the measuring object from the reference light radiated from the illumination device can be ensured.
Although the feature value of the observation light is adjusted on the basis of the sunshine degree in the first and fifth embodiments, the feature value of the observation light may be adjusted on the basis of the atmospheric state such as weather detected by the environment information sensor 170, positional information of the vehicle and obstacles, the environment element for the vehicle and the like. Further, the feature value of the observation light may be adjusted according to an instruction of the user.
Although the wavelength range of the reference light radiated from the illumination device is set to “400 nm” to “1000 nm” in the first embodiment, the wavelength range may be any wavelength range that enables discrimination of the measuring object on the basis of the spectrum data acquired by the spectrum sensor. In addition, in acquiring the characteristic spectrum shape from the observation light, it is desired that the wavelength range of the reference light is a visible light region or a near-infrared ray region. Further, when the spectrum sensor is used as a passive sensor for detecting the pedestrian during day and night, it is desired that the wavelength range of the reference light is a far-infrared ray region.
Although the LED light-emitting elements configuring the illumination device 120 are arranged in a matrix in the first embodiment, the LED light-emitting elements may be arranged in any adequate manner, for example, merely in a row. Further, as long as the different LED light-emitting elements having different wavelengths can adjust the wavelength range of the reference light, the wavelength characteristics of the LED light-emitting elements and the arrangement order of the LED light-emitting element are optional.
Although the feature value of the observation light is adjusted by adjusting the wavelength range and the light intensity at each wavelength of the reference light radiated from the illumination device 120 in the first to fourth embodiments, the advantage (1) in the first embodiment can be obtained only by radiating the reference light from the illumination device 120. In this regard, even with the configuration having only the device for radiating the reference light, the feature values of the wavelength range and the light intensity at each wavelength of the observation light, which are detected by the spectrum sensor S, can be varied.
When it is only required that only a certain feature value of the wavelength range and the light intensity at each wavelength of the observation light, which are detected by the spectrum sensor S, can be varied, there is no need to feed the discrimination result of the measuring object and the environment information to the control value calculator 100, and as feed-forward configuration, a configuration having only the control value calculator 100, the illumination controller 110 and the illumination device 120, or configuration having only the control value calculator 100 and the sensor controller 140 may be adopted.
Although a vehicle such as an automobile is assumed as the movable body that mounts the spectrum sensor thereon in each of the above-mentioned embodiments, the movable body may be a two-wheeled motor vehicle, a robot or the like. The present invention is not limited to this, the present invention can be applied as long as the movable body mounts the spectrum sensor thereon and discriminates the measuring object on the basis of the spectrum data detected by the spectrum sensor.
Although the feature values of wavelength range of the observation light and the light intensity at each wavelength are adjusted in each of the above-mentioned embodiments, at least one of the wavelength range of the observation light and the light intensity at each wavelength may be adjusted.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2009/059914 | 5/29/2009 | WO | 00 | 1/20/2012 |