Patent Application
20210144348
The present disclosure relates to a projector apparatus, a method for controlling a projector apparatus, a program, and a recording medium.
The following technology is known in the field of projector apparatuses. The intensity per unit area of projection light is high in the vicinity of a projection aperture of a projection unit of a projector. Thus, there is a demand for a further enhancement of safety for users. Accordingly, a distance-measuring unit is provided in a projector so as to measure the distance from a projection aperture of a projection unit to an object to be measured, and when the measured distance is equal to or smaller than a safe distance, it is determined to be an unsafe area. When an object to be measured is located in the unsafe area, the intensity of projection light is reduced, or the projection light is turned off (Japanese Unexamined Patent Application Publication No. 2014-174194 (published Sep. 22, 2014)).
In recent years, a technology for using a projector in projection mapping has been developed. When the optical axis of projection light emitted from a projector is not perpendicular to a projection surface, an image that is projected on the projection surface is distorted, and thus, distortion correction is performed. More specifically, the image distortion is corrected by calculating the distance to the projection surface (Japanese Unexamined Patent Application Publication No. 2019-20439 (published Feb. 7, 2019)).
However, in Japanese Unexamined Patent Application Publication No. 2014-174194, a projected image is enlarged when the distance from the projection unit of the projector to an object to be measured increases. In this case, there is a problem in that the brightness per unit area of the projected image decreases.
In addition, in Japanese Unexamined Patent Application Publication No. 2019-20439, there is a problem in that unevenness in the brightness of a projected image is generated because, in projection mapping, the brightness per unit area of a projected image differs between a portion of a projection surface that is spaced apart from a projection unit by a small distance and a portion of the projection surface that is spaced apart from the projection unit by a large distance.
If the luminance of a projection unit of a projector is increased in order to address the above problems, there is a possibility that projection light may affect the safety of users.
The present disclosure provides a projector apparatus capable of suppressing a decrease in the brightness of a projected image and ensuring safety for users even if the distance from a projection unit of the projector apparatus to a projection surface increases.
According to a first aspect of the present disclosure, there is provided a projector apparatus including a projection unit that projects an image on a projection target, a distance-measuring unit that measures a distance from an emitting end of the projection unit to the projection target, and a control unit that sets a luminance of projection light to a predetermined constant value when a distance measured by the distance-measuring unit is equal to or smaller than a predetermined distance and increases the luminance of the projection light such that the luminance does not exceed a set luminance of the projection light corresponding to the measured distance when the distance measured by the distance-measuring unit is larger than the predetermined distance.
According to a second aspect of the present disclosure, there is provided a method for controlling a projector apparatus including projecting an image on a projection target, measuring a distance from an emitting end of a projection unit, which is used in the projecting, to the projection target, and setting a luminance of projection light to a predetermined constant value when a distance measured in the measuring is equal to or smaller than a predetermined distance and increasing the luminance of the projection light such that the luminance does not exceed a set luminance of the projection light corresponding to the distance measured in the projecting when the measured distance is larger than the predetermined distance.
Before specifically describing an embodiment of the present application, a reference technology and a preliminary configuration will be described as a supplementary explanation of the above-mentioned related art.
In a projector apparatus that projects an image onto a projection target by using a projection unit, it is necessary to ensure the safety of users against projection light of the projector. Accordingly, the international electrotechnical commission (IEC) has established safety class standards. A detector for evaluation is installed, on the basis of the standards, at a location that is spaced apart from an emitting end of the projection unit by a certain distance. The light output of the projection unit is set to be equal to or less than a maximum exposure emission standard set for each class, and the luminance of the projection unit of the projector is set accordingly.
The luminance of the projection unit of the projector is usually set to be constant and does not vary in accordance with the distance from the projection unit to a projection target.
A first embodiment of the present disclosure will now be described in detail with reference to
The first embodiment will be described in order to embody the concept of the present disclosure, and the present disclosure is not limited to the first embodiment and the other embodiments, which will be described later.
A projection surface of the projection target 3 is positioned so as to be substantially perpendicular to the optical axis of the projection light 2. In addition, the projection surface of the projection target 3 is a flat surface.
More specifically, the distance-measuring unit 4 (distance-measuring sensor 20) is built in the projection unit 1. In the first embodiment, the projection unit 1 forms part of the projector apparatus that employs a laser-beam scanning system and that projects an image by scanning laser beams.
The optical modules accommodated in the housing 10 include a red-laser emitter 11, a first collimator lens 12, a green-laser emitter 13, a second collimator lens 14, a blue-laser emitter 15, a third collimator lens 16, a first beam splitter 17, a second beam splitter 18, and a micro electro mechanical system (MEMS) mirror 19 that is movable in two axial directions, which are a horizontal direction and/or a vertical direction.
The laser driver 25 includes a red-laser control unit 21, a green-laser control unit 22, and a blue-laser control unit 23. The red-laser emitter 11 emits a red laser beam by receiving power controlled by the red-laser control unit 21. The green-laser emitter 13 emits a green laser beam by receiving power controlled by the green-laser control unit 22. The blue-laser emitter 15 emits a blue laser beam by receiving power controlled by the blue-laser control unit 23.
The first collimator lens 12 causes the red laser beam emitted by the red-laser emitter 11 to become collimated light, and the collimated light passes through the first beam splitter 17 and the second beam splitter 18 and is incident on the MEMS mirror 19.
The second collimator lens 14 causes the green laser beam emitted by the green-laser emitter 13 to become collimated light, and the collimated light is reflected by the first beam splitter 17, passes through the second beam splitter 18, and is incident on the MEMS mirror 19.
The third collimator lens 16 causes the blue laser beam emitted by the blue-laser emitter 15 to become collimated light, and the collimated light is reflected by the second beam splitter 18 and is incident on the MEMS mirror 19.
The optical axes of the red laser beam, the green laser beam, and the blue laser beam, which are incident on the MEMS mirror 19, are optically aligned so as to coincide with one another, and the MEMS mirror 19 is caused to scan by the control unit 24, so that an image can be projected onto a projection target.
Although not particularly illustrated, an image processing unit that is included in the projector apparatus performs conversion processing so as to convert image data input from the outside into data items of three colors of red (R), green (G), and blue (B), and each of the converted data items is transmitted to a corresponding one of the red-laser control unit 21, the green-laser control unit 22, and the blue-laser control unit 23.
The description of the first embodiment will be continued below. In the first embodiment, the following configuration is employed in order to achieve both suppression of a decrease in the brightness of a projected image that is projected on the projection target 3 and ensuring of user safety. The distance-measuring sensor 20 measures the distance from the emitting end of the projection unit 1 (the right-hand end of the projection unit 1 in
In contrast, when the distance from the emitting end of the projection unit 1 to the projection target 3 is increased to be larger than the reference distance, the projected image is enlarged. Along with the enlargement of the projected image, the brightness per unit area of the projected image decreases. If the luminance of the projection light 2 emitted by the projection unit 1 is increased in order to suppress a decrease in the brightness of the projected image, there is a possibility that the safety of users against the projection light 2 may be reduced.
Accordingly, in the first embodiment, when the distance from the emitting end of the projection unit 1 to the projection target 3 is larger than the reference distance, the control unit 24 calculates a maximum allowable luminance that corresponds to the measured distance and increases the luminance of the projection light 2 emitted by the projection unit 1 to be less than the maximum allowable luminance (a set luminance). As a result, even when the distance from the emitting end of the projection unit 1 to the projection target 3 is increased, suppression of a decrease in the brightness per unit area of the projected image projected on the projection target 3 and ensuring of the user safety can be both achieved.
(Relationship Between Luminance of Projection Unit and Distance from Projection Unit to Projection Target)
When a distance that is measured by the distance-measuring unit 4 is larger than the reference distance, in the projector apparatus that employs a laser scanning system, the maximum allowable luminance of the projection light 2 corresponding to the above measured distance is obtained by calculating a maximum allowable exposure light output of a laser beam for each distance and calculating the maximum allowable luminance of the projection unit 1 corresponding thereto. The set luminance of the projection unit 1 may be set to be lower than the maximum allowable luminance so as to allow some leeway (e.g., by multiplying it by a predetermined coefficient). In the first embodiment, the set luminance for each measured distance larger than the reference distance is set to be 10% lower than the maximum allowable luminance for the corresponding measured distance and to be, at a maximum, 90% of the maximum allowable luminance.
In a projector of the related art, the luminance of a projection unit is set, regardless of a distance, in such a manner that the maximum allowable luminance is lower than 11 lumens at an evaluation distance of 100 mm based on the safety standards for laser products (see
In contrast, in the projector apparatus according to the first embodiment, when a distance that is measured by the distance-measuring unit 4 after the reference distance has been determined increases, the set luminance is set for each distance as illustrated in
In the first embodiment, as illustrated in
A second embodiment of the present disclosure will now be described in detail with reference to
In the second embodiment, the case of using a projector apparatus in projection mapping will be described.
As illustrated in
In this case, in the projection region 106, which is spaced apart from the projection unit 101 by the larger distance, the safety of users can be ensured by setting the set luminance to be lower than the maximum luminance of the projection light 102 emitted by the projection unit 101, the maximum luminance being determined by the maximum allowable exposure light output corresponding to the distance from the projection unit 101.
In the second embodiment, effects similar to those of the first embodiment can be obtained.
A third embodiment of the present disclosure will now be described in detail with reference to
As illustrated in
Here, the distance-measuring unit 204 measures the distance from the emitting end of the projection unit 201 to each portion of the projection surface of the projection target 203, and a shortest distance L21 is set. The luminance of the projection unit 201 is adjusted in such a manner that the output of the projection light 202 becomes a level at which safety can be ensured with respect to the shortest distance L21.
More specifically, the luminance of the projection light 202 to be projected onto a portion that is spaced apart from the projection unit 201 by a distance that is measured by the distance-measuring unit 204 and that is larger than the shortest distance L21 is increased by the control unit 24 (see
Thus, by increasing the luminance of the projection light 202 to be projected onto a portion that is spaced apart from the projection unit 201 by a distance larger than the shortest distance L21 such that the luminance does not exceed the set luminance of the projection light 202, a projector apparatus capable of ensuring the safety of the projection light 202 to be projected onto a portion that is spaced apart from the projection unit 201 by a distance larger than the shortest distance L21 can be provided.
A fourth embodiment of the present disclosure will now be described in detail with reference to
The difference between the fourth embodiment and the above-described embodiments is that a distance-measuring unit 304 is disposed near a projection unit 301.
As illustrated in
Thus, by increasing the luminance of the projection light 302 to be projected onto a portion that is spaced apart from the projection unit 301 by a distance larger than the shortest distance L31 such that the luminance does not exceed the set luminance of the projection light 302, a projector apparatus capable of ensuring the safety of the projection light 302 to be projected onto a portion that is spaced apart from the projection unit 301 by a distance larger than the shortest distance L31 can be provided.
In addition, since the distance-measuring unit 304 and the projection unit 301 can be arranged independently of each other, it is not necessary to change the structure of the projection unit 301 and the structure of the distance-measuring unit 304, and thus, the system can be constructed relatively easily.
A fifth embodiment of the present disclosure will now be described in detail with reference to
The differences between the fifth embodiment and the above-described embodiments are that irregularities are formed on a projection surface of the projection target 403 and that a plurality of distance-measuring units are arranged near a projection unit 401. Here, as an example, a distance-measuring unit 404 and a distance-measuring unit 405 are arranged on opposite sides of the projection unit 401.
Projection light 402 that is emitted from an emitting end of the projection unit 401 is projected on the projection target 403. Here, the distance-measuring unit 404 measures a shortest distance L41 from the distance-measuring unit 404 to the projection target 403, and the distance-measuring unit 405 measures a shortest distance L42 from the distance-measuring unit 405 to the projection target 403. The luminance of the projection unit 401 is adjusted in such a manner that the output of the projection light 402 becomes a level at which safety can be ensured with respect to the shortest distance L42, which is smaller than the shortest distance L41.
Thus, by increasing the luminance of the projection light 402 to be projected onto a portion that is spaced apart from the projection unit 401 by a distance larger than the shortest distance L42 such that the luminance does not exceed the set luminance of the projection light 402, a projector apparatus capable of ensuring the safety of the projection light 402 to be projected onto a portion that is spaced apart from the projection unit 401 by a distance larger than the shortest distance L42 can be provided.
By providing a plurality of distance-measuring units, the shortest distance to a projection target can be calculated from a plurality of distance data items, and thus, an improvement in the accuracy of distance measurement can be achieved. In addition, by using distance-measuring sensors employing different methods in a plurality of distance-measuring units and by selecting an optimum distance-measuring sensor in accordance with the surface profile or the surface state of the projection target 403, an improvement in the accuracy of distance measurement can be achieved.
A sixth embodiment of the present disclosure will now be described in detail with reference to
As illustrated in
In the above-described first embodiment, an optical triangulation sensor or a time of flight (TOF) sensor is applicable to the distance-measuring sensor 20 of the distance-measuring unit.
Although a projector apparatus that employs a laser-beam scanning system has been described in each of the above-described embodiments, a projector apparatus that employs a spatial modulation system is also applicable within the scope of the present disclosure.
In addition, as described above, the projector apparatuses described in the above embodiments can be used for image projection and projection mapping. [Implementation Example with Software]
A control block (particularly the control unit 24) of the projector apparatus may be fabricated by using a logic circuit (hardware) formed in, for example, an integrated circuit (an IC chip) or may be fabricated by using software.
In the latter case, the projector apparatus includes a computer that executes an instruction of a program, which is software that implements each function. The computer includes, for example, at least one processor (control device) and at least one computer-readable recording medium in which the above-mentioned program is stored. In the above-mentioned computer, the processor reads the above-mentioned program from the above-mentioned recording medium and runs the program, so that an object of the present disclosure is achieved. As the above-mentioned processor, for example, a central processing unit (CPU) can be used. As the recording medium, a “non-transitory tangible medium” such as, for example, a read only memory (ROM), a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. The computer may further include, for example, random access memory (RAM) into which the program is expanded. In addition, the program may be provided to the computer through an arbitrary transmission medium (such as a communication network or a broadcast wave) that is capable of transmitting the program. Note that an aspect of the present disclosure can also be implemented in the form of a data signal embedded in a carrier wave in which the program is embodied by electronic transmission.
The projector apparatus according to the first aspect of the present disclosure includes the projection unit (1, 101, 201, 301, 401, 501) that projects an image onto the projection target (3, 103, 203, 303, 403, 503), the distance-measuring unit (4, 104, 204, 304, 404, 405, 504) that measures the distance from the emitting end of the projection unit to the projection target, and the control unit (24) that sets the luminance of the projection light (2, 102, 202, 302, 402, 502) to a predetermined constant value when the distance measured by the distance-measuring unit is equal to or smaller than a predetermined distance and increases the luminance of the projection light such that the luminance does not exceed the set luminance of the projection light corresponding to the measured distance when the distance measured by the distance-measuring unit is larger than the predetermined distance.
According to the above-described configuration, a projector apparatus capable of suppressing a decrease in the brightness of a projected image and ensuring safety for users even when the distance from the projection unit of the projector apparatus increases can be provided.
In the projector apparatus according to the second aspect of the present disclosure, in the above-described first aspect, the distance-measuring unit may measure the distance to each portion of the projection target, and the control unit may increase the luminance of the projection light that is projected onto a portion of the projection target, the portion being spaced apart from the emitting end of the projection unit by a distance that is measured by the distance-measuring unit and that is larger than the predetermined distance, such that the luminance does not exceed the set luminance of the projection light.
According to the above-described configuration, an effect similar to that of the first aspect is obtained.
In the projector apparatus according to the third aspect of the present disclosure, in the above-described first or second aspect, the predetermined distance may be 300 mm or larger and 400 mm or smaller.
According to the above-described configuration, the set luminance is set to be constant when the distance from the projection unit of the projector apparatus to the projection target is equal to or smaller than the predetermined distance, and the luminance of the projection light is increased when the distance from the projection unit of the projector apparatus to the projection target is larger than the predetermined distance, so that an effect similar to that of the first aspect is obtained.
In the projector apparatus according to the fourth aspect of the present disclosure, in any one of the above-described first to third aspect, an increase rate at which the control unit increases the luminance of the projection light for a distance larger than the predetermined distance may be 0.02 lumens/mm or greater and 0.03 lumens/mm or less.
According to the above-described configuration, an effect similar to that of the third aspect is obtained.
In the projector apparatus according to the fifth aspect of the present disclosure, in any one of the above-described first to fourth aspect, the control unit may set a set luminance of the projection light for each distance corresponding to a distance that is measured by the distance-measuring unit and that is larger than the predetermined distance to be, at a maximum, 90% of a maximum allowable luminance that is larger than the set luminance for the distance.
According to the above-described configuration, a projector apparatus capable of suppressing a decrease in the brightness of a projected image and ensuring safety for users with higher certainty even when the distance from the projection unit of the projector apparatus increases can be provided.
In the projector apparatus according to the sixth aspect of the present disclosure, in any one of the above-described first to fourth aspect, when a shielding object is interposed between the emitting end and the projection target, the control unit may set the set luminance that corresponds to the shortest distance from the emitting end to the shielding object. when the shielding object is removed, and the image is projected on the projection target, the control unit may increase the luminance of the projection light such that the luminance does not exceed the set luminance corresponding to the distance to the projection target.
According to the above-described configuration, an effect similar to that of the first aspect is obtained.
In the projector apparatus according to the seventh aspect of the present disclosure, in any one of the above-described first to sixth aspect, the projector apparatus may be a projector apparatus that employs a laser-beam scanning system.
In the projector apparatus according to the eighth aspect of the present disclosure, in any one of the above-described first to seventh aspect, the projection unit and the distance-measuring unit may be arranged close to each other.
In the projector apparatus according to the ninth aspect of the present disclosure, in any one of the above-described first to eighth aspect, the distance-measuring unit may be one of a plurality of distance-measuring units included in the projector apparatus.
A method for controlling a projector apparatus according to the tenth aspect of the present disclosure includes projecting an image on a projection target, measuring a distance from an emitting end of a projection unit, which is used in the projecting, to the projection target, and setting a luminance of projection light to a predetermined constant value when a distance measured in the measuring is equal to or smaller than a predetermined distance and increasing the luminance of the projection light such that the luminance does not exceed a set luminance of the projection light corresponding to the distance measured in the projecting when the measured distance is larger than the predetermined distance.
According to the above-described configuration, an effect similar to that of the first aspect is obtained.
The present disclosure is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. Embodiments that are obtained by suitably combining the technical measures disclosed in the different embodiments are also within the technical scope of the present disclosure. In addition, a new technical feature can be obtained by combining the technical measures disclosed in the embodiments.
The present disclosure contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2019-203449 filed in the Japan Patent Office on Nov. 8, 2019, the entire contents of which are hereby incorporated by reference.
It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-203449 | Nov 2019 | JP | national |
