The present invention relates to a method for visualizing image data, in particular image data having at least one piece of additional information. In addition, the present invention relates to a computer program including program code for performing all the steps of the method and a computer program product including program code stored in a computer-readable medium to perform the method according to the present invention. The present invention also relates to a device for visualizing image data, in particular image data having at least one piece of additional information. In addition, the present invention relates to a system for visualizing image data having at least one piece of additional information.
The present invention is directed to a method, a device, a computer program, a computer program product and a system for visualizing image data. The objects of the present invention are also driver assistance systems, monitoring camera systems, camera systems for an aircraft, camera systems for a watercraft or a submarine vehicle or the like in which image data are represented.
German Patent Application No. DE 102 53 509 A1 describes a method and a device for warning the driver of a motor vehicle. A visual warning is generated via a signaling component within the field of vision of the driver in the direction of at least one object in the vehicle surroundings, the visual warning occurring at least before the object becomes visible to the driver. The visual warning is at least one light spot and/or at least one warning symbol, at least the duration of the display being variable. In this approach, objects are recognized and a signal is generated in the form of symbols for the object. The signal is transmitted to the driver, e.g., acoustically or visually.
The method, device, system and computer program according to the present invention as well as the computer program product according to the present invention for visualizing image data, may have the advantage that the image data or an image data image generated therefrom, enriched, in particular superimposed, by appropriate additional information such as, for example, distance information, is transmitted to a user.
The user is able to directly recognize the relevance of the image data, objects and the like from this additional information, such as distance information or other information, for example, to fulfill a driving task (braking, accelerating, following, etc.). The user may thus comprehend the additional information more rapidly through the superimposed display of additional information (distance information, etc.) and image data. Relevant data, inference, etc., for example, in fulfilling a task, for example, a driving task, may thus be eliminated in a suitable manner so that the user is able to perceive this task intuitively and respond appropriately even when confronted with an increased information density. Visualization is possible without recognizing objects because additional information is displayed generally for each pixel or all image data. A more rapid visualization is thus implemented. Not lastly, an aesthetically attractive display of relevant information is possible.
It is advantageous in particular that the additional information is displayed classified, in particular through a difference in coloration, texture, brightness, darkening, sharpening, magnification, increased contrast, reduced contrast, omission, virtual illumination, inversion, distortion, abstraction, with contours, in a chronologically variable manner (moving, flashing, vibrating, wobbling) and the like both individually and in combination, depending on the classification. The classification allows the relevant information to be displayed superimposed over the image data image in a manner that is easier for the user to comprehend. The classification also permits a faster and simpler processing of the combination of image data and additional information. Problems, details or additional information may be derived from the appropriate classes, so that it is superfluous to search in all the image data, in particular to search visually, so that the processing rate is increased and/or the visual detection is accelerated.
It is another advantage of the present invention that the additional information is additionally displayed in a processed representation at least partially above and/or next to the image data, in particular as a histogram or the like. The variety of information (image, distance and other information) may thus be represented in a compressed form in which it is easily comprehensible for the user and in particular also for further processing.
The additional information and/or the image data is/are preferably represented in a smoothed form in which the classified information is represented showing fuzzy borders between the neighboring classes. This is advantageous in particular in the case of image points where there is a substantial jump from one class to another. A fluid emphasis or representation may be implemented in this way. Thus a soft transition, for example, a visually soft transition, is implemented in the representation. The additional information may be smoothed prior to enrichment of or superpositioning on the image. This also makes it possible to average out errors in an advantageous manner. Smoothing may be performed with regard to time or place or both time and place. Smoothing allows the information content to be reduced to a suitable extent. To minimize or prevent an impression of fuzziness associated with smoothing, additional lines and/or contours, for example, object edges, object contours, etc., may be represented by using a Canny algorithm, for example, which finds and provides dominant edges of the camera image, for example.
It is advantageous that transitions, for example, edges of objects, are represented for a sharp localization of fuzzy additional information. Clear, sharp visualizations are generated in this way, despite fuzziness, in colors, for example.
The device and system according to the present invention for visualizing image data may have the advantage that rapid and easily comprehensible information processing is implementable with an aesthetically appealing execution for the user through the use and/or implementation of the method according to the present invention.
It is also advantageous that a display device is included, which is designed to display further information such as additional information and the like in enriched form and/or superimposed with respect to the image data. The additional information includes all information, including information relating to distance, for example. Information derived therefrom is also to be included here. For example, this may include changes in distance over time, for example, distance divided by changes in distance (also TTC—time to collision), and the like. This information may in general also include other data, for example, which is displayed in a suitable form superimposed on the image data.
It may be advantageous in particular if the device or the system has at least one interface for coupling to system components that are to be connected such as a driver assistance system, a motor vehicle, additional sensors, and the like. This yields numerous possible uses for optimized approaches to suitably supported tasks.
The method is advantageously implemented as a computer program and/or a computer program product. This includes all computer units, in particular also integrated circuits such as FPGAs (field programmable gate arrays), ASICs (application specific integrated circuits), ASSPs (application specific standard products), DSPs (digital signal processors) and the like, as well as hardwired computer modules.
A suitable method for faster image processing is preferably used for the method, the device, the computer program, the computer program product and the system. A suitable method may be a method for visualizing image data based on disparities. More specifically, a method for processing image data of a disparity image, in particular a disparity image obtained in a stereo video-based system and produced by stereo video-based raw image data, present in at least two raw image data images, at least one corresponding piece of distance information, in particular disparity information being present for at least one data point of the image data. To perform an image data-dependent task, the method includes the steps: transmitting the image data to a processing unit and processing the image data, so that generally all image data are classified before being processed with respect to their distance information in order to reduce the complexity for further processing based on the classification of pixels. This has the advantage that (image) data or an image data image generated therefrom may be processed directly, i.e., without object grouping or object transformation. The processing is performed with respect to distance information available for individual pieces of image data or raw image data available with respect to the image data. Distance information is generally available for each pixel, preferably a disparity. A disparity is understood in general to refer to the offset resulting when using a stereo video camera system in comparison with the pixels resulting for a space-time point on the different camera images, each pixel and/or disparity having a clear-cut relationship to the particular distance of the space-time point from the camera. For example, the disparity may be based on the focal length of the cameras and may be expressed as the quotient of the offset of the pixels corresponding to a space-time point expressed in image coordinates, and the focal length of the camera. This disparity is the reciprocal of the distance of the space-time point from a reference location such as a reference point, a reference area (e.g., in the case of a rectified camera), a reference surface and the like and may be expressed as the following ratio, for example, by taking into account the basic spacing of the cameras among one another, i.e., the distance of the cameras from one another: the quotient of disparity and camera focal length corresponds to the quotient of the basic width and the distance from the space-time point. The space-time point corresponds to the actual point of an object in the surroundings. The pixels represent the space-time point detected by sensors in a camera image or an image data image, for example, a pixel image, which is defined by x and y coordinates in the pixel image. All the image data are preferably located in a Cartesian coordinate system in accordance with their disparity and their position, given in x coordinates and y coordinates, preferably in a Cartesian coordinate system, where they are assigned to a class, i.e., are classified, in particular being characterized in the same way, and are thus displayed for a user and/or transmitted to a further processing unit. This makes it possible to implement faster classification and thus faster processing of (raw) data. Furthermore, the two-dimensional representation on a display gains information content by additionally showing the depth direction, which cannot be represented per se, by superpositioning. This method is applicable to image data of a disparity image. Raw image data for creating a camera image, for example, may be used after being processed appropriately to form a disparity image, may be discarded after processing or may be used in combination with the disparity image. In this method, the classification is performed in such a way that the (raw) image data are subdivided/organized into multiple classes, preferably into at least two classes, more preferably into at least three classes. The following conclusions are easily reached on the basis of the classification into two or more classes, for example, three classes, in the case of a driver assistance system, for example, in which disparity information or distance information is assigned to pixels from vehicle surroundings: the corresponding pixel corresponds to a real point or a space-time point, which belongs generally to a plane, a surface or a roadway, for example, or to a tolerance range thereto in which a user such as a vehicle is situated and/or moving. In other words, this space-time point is in a reference class or in a reference plane. The real roadway surface corresponds only approximately to a plane. It is in fact more or less curved. The term reference plane is therefore also understood to be a reference surface or reference area designed generally, i.e., approximately, to be planar. If the vehicle is moving on this reference plane or reference surface or is situated in or on this reference plane, there is no risk of collision between the vehicle and the points classified as belonging to the reference plane. In addition, the pixel may correspond to a space-time point which is situated outside, in particular above or below, the reference plane or reference class. The point may be at such a height or distance from the reference plane that there is the possibility of a collision with the point. The corresponding space-time point is thus a part of an obstacle. After appropriate processing of the data, a warning may be output or other corresponding measures may be initiated. The pixel may also correspond to a space-time point, which is situated at a distance from the reference plane, so there is no possibility of a collision or interference. These situations may thus change according to a chronological sequence and/or movement sequence, so that repeated classifications of the image data are performed. This method according to the present invention does not require any training phases. The classification is performed without any knowledge of the appearance of objects. No advance information about properties such as size, color, texture, shape, etc. is required, so it is possible to respond quickly to new situations in the surroundings.
The (raw) image data may be classified in intermediate classes according to a suitable method if the (raw) image data are classifiable in different classes, for example, if a disparity value is close to a corresponding decision threshold for a classification, i.e., if no definite classification is possible, sufficient information is not available, interference occurs, or the limits are not sharply defined. Even if a space-time point is represented only on one image data image, then this image data value may be assigned to an intermediate class. Thus, instead of a sharp separation of the predetermined classes, a soft separation may also be performed. The separation may be soft, i.e., continuous, or it may be stepwise in one or more classes. Furthermore, the (raw) image data may be classified in classes relevant for solving a driving problem, in particular selected from the group of classes including: risk of collision, no risk of collision, flat, steep, obstacle, within an area of a reference, below a reference, above a reference, at the side of a reference, relevant, irrelevant, unknown, unclassifiable and the like. This allows extremely fast processing of the (raw) image data which may be made accessible to the driver in an easily comprehensible manner, for example, by display. Classification permits a reduction in information, so that only the relevant data need be processed for faster and further processing and it is possible to respond rapidly accordingly. In addition, the (raw) image data images may be at least partially rectified prior to the disparity determination and/or classification. In particular it is advantageous if an epipolar rectification is performed. The rectification is performed in such a way that the pixels of a second image data image, for example, of a second camera, corresponding to a pixel in a row y of a first image data image, for example, of a first camera, is situated in the same row y in the image data image of the second image, so it is assumed here without any restriction on general validity that the cameras are situated side by side. The distance of the space-time point from the cameras may then be determined from a calculation of the displacement of the so-called disparities of the two points along the x axis, and corresponding distance information may be generated for each pixel. It is advantageous in particular if a full rectification is performed, so that the relationship between the disparity and the distance is the same for all pixels. Furthermore, the classification with respect to the distance information may include classification with regard to a distance from a reference in different directions in space. It is thus possible to calculate a disparity space on the basis of which a suitable classification of the image data of the real surroundings may be easily performed. The disparity space may be spanned by the different directions in space, which may be selected to be any desired directions. The directions in space are preferably selected according to a suitable coordinate system, for example, a system spanned by an x axis, a y axis and a d axis (disparity axis), but other suitable coordinate systems may also be selected. Furthermore, at least one reference from the following group of references may be selected from the image data: a reference point, a reference plane, a reference area, a reference surface, a reference space, a reference half-space and the like, in particular a reference area or a reference plane. A tolerance range is preferably determined next to the reference plane. Pixels situated in this tolerance range are determined as belonging to the reference plane. The reference plane or reference area in particular is ascertained as any reference plane with regard to its orientation, position, curvature and combinations thereof and the like. For example, a reference plane may stand vertically or horizontally in the world. In this way, objects in a driving tube or a driving path, for example, may be separated from objects offset therefrom, for example, to the right and left. The reference planes may be combined in any way, for example, a horizontal reference plane and a vertical reference plane. Likewise, oblique reference planes may also be determined, for example, to separate a step or an inclination from corresponding objects on the step or inclination. It is also possible to use surfaces having any curvature as the reference plane. For example, relevant or interesting objects and persons on a hill or an embankment may be easily differentiated from objects or persons not relevant or not of interest, for example, at a distance therefrom. This method may be implemented as a computer program and/or a computer program product. This includes all computer units, in particular also integrated circuits such as FPGAs (field programmable gate arrays), ASICs (application specific integrated circuits), ASSPs (application specific standard products), DSPs (digital signal processors) and the like as well as hardwired computer modules.
Exemplary embodiments of the present invention are shown in the figures and explained in greater detail below.
In
The classifications of the image data or the particular objects in the image according to
In addition to main classes 16, 17 and 18, additional classes (e.g., “low”) or intermediate classes 19, which are characterized by hues of color in between, may be determined.
The visualization in which only the points where there is an obstacle (class II 17, preferably shown in red) is now shown advantageously in particular as superimposed on the camera image. The non-collision-relevant classes are not superimposed, i.e., only camera image 11, preferably shown without coloration, is visible there. Accordingly, classes up to a maximum distance upper limit may be represented and classes having additional information 2 outside of the range are not emphasized. The distance range may vary as a function of the driving situation, for example, with respect to speed. In a parking maneuver, for example, only the distance range in the immediate vicinity of the host vehicle is relevant. However, ranges at a greater distance are also relevant when driving on a highway. On the basis of the available distance information, it is possible to decide whether this is inside or outside of the relevant distance range for each pixel.
The coloring will not be explained again with reference to
A corresponding system may be designed, for example, as a stereo camera system using analog and/or digital cameras, CCD or CMOS cameras or other high-resolution imaging sensors using two or more cameras/imagers/optics, as a system based on two or more individual cameras, and/or as a system using only one imager and suitable mirror optics. The imaging sensors or imaging units may be designed as any visually imaging device. For example, an imager is a sensor chip which may be part of a camera and is located in the interior of the camera behind its optics. Appropriate imagers convert light intensities into the appropriate signals.
In addition, at least one image processing computer is required. Processing of the image data may be performed within camera 25 (in the case of so-called “smart cameras”), in a dedicated image processing computer or on available computer platforms, for example, a navigation system. It is also possible for the computation operations to be distributed among multiple subsystems. The configuration of the camera system may vary as illustrated in
Number | Date | Country | Kind |
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10 2008 002 560.7 | Jun 2008 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP08/65748 | 11/18/2008 | WO | 00 | 3/17/2011 |