Patent Publication Number: US-2023143262-A1

Title: Context based separation of on-/off- vehicle points of interest in videos

Description:
BACKGROUND 
     Tracking pixels on a moving object between frames have numerous applications in computer vision, including accurate velocity estimation of the target vehicle, estimation of rotation of the target vehicle, matching vehicles between frames. 
     However, the problem of pixel tracking (“find the same pixel in both frames”) is inherently ill-defined. For example, a pixel on the edge of the vehicle in the source frame might be considered to belong to the vehicle or it might be considered to belong to the background. These choices might lead to two different pixels in the target frame that could be rightfully matched to this source frame pixel. 
     There is a growing need to accurately separate background pixels from a moving vehicle pixels. 
     SUMMARY 
     There is provided a method, a system and/or a non-transitory computer readable medium for providing a context based separation of on-/off- vehicle points of interest in videos. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments of the disclosure will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
         FIG.  1    illustrates an example of a method; 
         FIG.  2    illustrates an example of a vehicle and a 2D bounding box; 
         FIG.  3    illustrates an example of a vehicle and a 3D bounding box; 
         FIG.  4    is an example of a first and second images; and 
         FIG.  5    illustrates an example of a vehicle. 
     
    
    
     DESCRIPTION OF EXAMPLE EMBODIMENTS 
     In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention. 
     The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings. 
     It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. 
     Because the illustrated embodiments of the present invention may for the most part, be implemented using electronic components and circuits known to those skilled in the art, details will not be explained in any greater extent than that considered necessary as illustrated above, for the understanding and appreciation of the underlying concepts of the present invention and in order not to obfuscate or distract from the teachings of the present invention. 
     Any reference in the specification to a method should be applied mutatis mutandis to a device or system capable of executing the method and/or to a non-transitory computer readable medium that stores instructions for executing the method. 
     Any reference in the specification to a system or device should be applied mutatis mutandis to a method that may be executed by the system, and/or may be applied mutatis mutandis to non-transitory computer readable medium that stores instructions executable by the system. 
     Any reference in the specification to a non-transitory computer readable medium should be applied mutatis mutandis to a device or system capable of executing instructions stored in the non-transitory computer readable medium and/or may be applied mutatis mutandis to a method for executing the instructions. 
     Any combination of any module or unit listed in any of the figures, any part of the specification and/or any claims may be provided. 
     Any one of the units may be implemented in hardware and/or code, instructions and/or commands stored in a non-transitory computer readable medium, may be included in a vehicle, outside a vehicle, in a mobile device, in a server, and the like. 
     The vehicle may be any type of vehicle that a ground transportation vehicle, an airborne vehicle, and a water vessel. 
     The specification and/or drawings may refer to an image. An image is an example of a media unit. Any reference to an image may be applied mutatis mutandis to a media unit. A media unit may be an example of sensed information. Any reference to a media unit may be applied mutatis mutandis to any type of natural signal such as but not limited to signal generated by nature, signal representing human behavior, signal representing operations related to the stock market, a medical signal, financial series, geodetic signals, geophysical, chemical, molecular, textual and numerical signals, time series, and the like. Any reference to a media unit may be applied mutatis mutandis to sensed information. The sensed information may be of any kind and may be sensed by any type of sensors - such as a visual light camera, an audio sensor, a sensor that may sense infrared, radar imagery, ultrasound, electro-optics, radiography, LIDAR (light detection and ranging), etc. The sensing may include generating samples (for example, pixel, audio signals) that represent the signal that was transmitted, or otherwise reach the sensor. 
     The specification and/or drawings may refer to a processor. The processor may be a processing circuitry. The processing circuitry may be implemented as a central processing unit (CPU), and/or one or more other integrated circuits such as application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), full-custom integrated circuits, etc., or a combination of such integrated circuits. 
     Any combination of any steps of any method illustrated in the specification and/or drawings may be provided. 
     Any combination of any subject matter of any of claims may be provided. 
     Any combinations of systems, units, components, processors, sensors, illustrated in the specification and/or drawings may be provided. 
     The term obtaining may include at least one of receiving, retrieving, requesting and getting, being fed by, generating, or receiving a partially processed result and completing the process. 
     There may be provided a method, a system and/or a non-transitory computer readable medium for context based separation between vehicle pixels and background pixels. 
       FIG.  1    illustrates method  100  for context based separation between vehicle pixels and background pixels. 
     Method  100  may start by step  110  of receiving a first image and a second image, the first image and the second images may be of temporarily adjacent to each other and capture a same vehicle and background content. While the vehicle is the same vehicle - the background content may change - due to the time difference between the images and/or due to differences in acquisition parameters (optical axis changes, illumination changes, focus changes) of the images. 
     Adjacent - may be consecutive images or images spaced apart by up to 1, 2, 3, 4, 5, seconds, and the like. 
     Step  110  may be followed by step  120  of obtaining:
     (a) a first bounding box that surrounds at least a part of the vehicle within the first image, wherein the first bounding has a first width and a first height.   (b) a second bounding box that surrounds at least the part of the vehicle within the second image; wherein the second bounding box has a second width and a second height.   (c) a mapping between pairs of initially matched pixels, wherein each pair may include a first pixel and a second pixel that correspond to same entity portion (are initially tagged or determined to belong to the captured entity portion within the first and second image respectively), wherein the entity portion may be a portion of the vehicle or of the background content.   

     The first bounding box may be obtained before the acquisition of the second image. 
     The mapping may be provided by a temporal compressor, or another entity. 
     The first bounding box and the second bounding box may be provided by an object detector. 
     The first bounding box and the second bounding box may be two dimensional (2D) or three dimensional (3D). Their vertices and their edges may be represented in a physical (for example X,Y,Z) coordinate system. The pairs of pixels may be provided in a pixel coordinate system. The pixel coordinate system represents locations of pixels within the image - for example - the (m,n)’th pixel is located within the n’th column and the m’th row of pixels. 
     The method may include coordinate system conversions - for example from the pixel coordinate system to the physical coordinate system. 
     A part of an object may not be flat - but it may be bounded by a flat 2D bounding box - or by a flat facet of a 3D bounding box. This difference should be taken into account. 
     Accordingly - a first normalized relative location of the first pixel may be calculated based on an estimate of a shape and size of the part of the vehicle and/or on an estimate of a deviation from flatness of the part of the vehicle. 
     The shapes of different parts of different vehicles can be provided to the method - or may be learnt in any manner. 
     Step  120  may be followed by step  130  of determining, for each pair of at least some of the pairs, a first normalized relative location (α) of a first pixel of the pair within the first bounding box and a second normalized relative location (β) of a second pixel of the pair within the second bounding box. 
     Step  130  may be applied on all pixels of the images or only on some. The latter may save energy and time. 
     The at least some pairs that are relevant to step  130  may include (a) only some of the first pixels within the first bounding box, (b) all first pixels within the first bounding box, (c) or first pixels located in a predefined proximity to an estimated edge of the vehicle. The estimates edge of the vehicle may be provided from an object detector or another entity. 
     The at least some pairs that are relevant to step  130  may include (a) only some of the second pixels within the second bounding box, (b) all second pixels within the second bounding box, (c) or second pixels located in a predefined proximity to an estimated edge of the vehicle. The estimates edge of the vehicle may be provided from an object detector or another entity. 
     The normalized location takes into account the location of the pixel and the dimensions of the bounding boxes. 
     The first normalized relative location of the first pixel may be calculated within a pixel coordinate system. 
     Step  130  may include calculating the first normalized relative location of the first pixel based on (a) a first axis distance from a certain vertex of the first bounding box, (b) the first width, (c) a second axis distance from the certain vertex of the first bounding box, and (d) the first height. 
     Step  130  may include calculating the first normalized relative location of the first pixel by calculating a first ratio between the first axis distance from the certain vertex of the first bounding box, and the first width, and a second ratio between the second axis distance from the certain vertex of the first bounding box, and the first height. 
     Step  130  may be followed by step  140  of determining for the each pair whether the pair is a vehicle related pair (belongs to the captured vehicle) or a background content pair (belongs to the captured environment). 
     Step  140  may include determining that a pair may be the vehicle related based on a distance between the first and second normalized relative locations. Especially -comparing the distance to a certain threshold - and when exceeding the threshold -the pair belongs to the vehicle. 
     The threshold can be determined or received in any manner - using a machine learning process, using a rule based decision, and the like. 
     The threshold may depend on at least one of - location difference between the vehicle in the first and second images (may be a function of time between images, speed of the vehicle), image capture accuracy (lower accuracy - larger threshold), desired false positive rate, desired false negative rate, desired true positive rate or desired true negative rate, and the like. 
       FIGS.  2  and  3    illustrate various calculations. The calculations should be done of a first image of a pair and on a second image of a pair. These example refer to three points of the vehicle  11 ,  12  and  13  - but may be applied on any number of pixels within the bounding box - see, for example, the pixels on which step  130  is applied. The normalized distances may be calculated in relation to any vertex or reference point of the bounding box. 
     Referring to  FIG.  2   . This figure illustrates a 2D dimensional bounding box 25 that has four 2D vertexes - Vertex2D(u1,v1) 24(1,1), Vertex2D(u2,v2) 24(2,2), Vertex2D(u3,v3) 24(3,3), and Vertex2D(u4,v4) 24(4,4) (whereas u1, v1, u2, v2, u3, v3, u4 and v4 are their pixel coordinates). 
     Assuming that the distance is calculated in relation to Vertex2D(u1,v1). 
     The normalized relative locations of three different pixels of the vehicle  11 ,  12  and  13  (located at pixel coordinates (u( 11 ), v( 11 )), (u( 12 ), v( 12 )) and (u( 13 ), v( 13 ))) are: 
     
       
         
           
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     Referring to  FIG.  3   . This figure illustrates a  23  dimensional bounding box  20  that has eight vertexes (seven vertices are shown) and multiple facets (three are shown). The 3D vertices of facet  22 ( 2 ) are shown and include Vertex3D(u1,v1)  21 ( 1 , 1 ), Vertex3D(u2,v2)  21 ( 2 , 2 ), Vertex3D(u3,v3)  21 ( 3 , 3 ), and Vertex2D(u4,v4)  21 ( 4 , 4 ). The coordinates of the fours 3D vertices are (u1, v1), (u2, v2), (u3, v3), and (u4 and v4) in the pixel coordinate system and (x1,y1,z1), (x2,y2,z2), (x3,y3,z3) and (x4, y4,z4) in a physical coordinate system. 
     The normalized relative locations of three different pixels of the vehicle  11 ,  12  and  13  (located at pixel coordinates (u( 11 ), v( 11 )), (u( 12 ), v( 12 )) and (u( 13 ), v( 13 ))) are: 
     
       
         
           
             
               
                 
                   
                     
                       
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       FIG.  4    illustrates an example of a video stream  80 , a first image  61 , a second image  62  - both images capture a vehicle  75  and its environment - the environment includes a road and a sign  71 . The first and second images belong to the video stream  80  and are relatively close to each other (from a time of acquisition point of time). 
       FIG.  5    illustrates metadata a vehicle  201  that include system  200 . 
     System  200  may include visual sensor  220  such as a camera (illustrated as outputting sensed image  308 ), controller  230 , processing unit  240 , man machine interface such as display  250 , memory unit  260 , autonomous driving module  270  and ADAS module  280 . 
     The autonomous driving module  270 , and ADAS module  280  may respond to lane boundary information generated by the processing unit  240 . 
     The controller  230  may control the operation of the system  200 . 
     System  200  may be configured to execute method  100 . Alternatively - remote computerized system  400  may execute method  100 . 
     System  200  (or remote computerized system  400 ) may include a first module  201  for obtaining information and/or mappings related to steps  110 , and  120 , and may also include a second module for executing steps  130  and  140 . 
     In the foregoing specification, the invention has been described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein without departing from the broader spirit and scope of the invention as set forth in the appended claims. 
     Moreover, the terms “front,” “back,” “top,” “bottom,” “over,” “under” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. 
     Furthermore, the terms “assert” or “set” and “negate” (or “deassert” or “clear”) are used herein when referring to the rendering of a signal, status bit, or similar apparatus into its logically true or logically false state, respectively. If the logically true state is a logic level one, the logically false state is a logic level zero. And if the logically true state is a logic level zero, the logically false state is a logic level one. 
     Those skilled in the art will recognize that the boundaries between logic blocks are merely illustrative and that alternative embodiments may merge logic blocks or circuit elements or impose an alternate decomposition of functionality upon various logic blocks or circuit elements. Thus, it is to be understood that the architectures depicted herein are merely exemplary, and that in fact many other architectures may be implemented which achieve the same functionality. 
     Any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality may be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected,” or “operably coupled,” to each other to achieve the desired functionality. 
     Furthermore, those skilled in the art will recognize that boundaries between the above described operations merely illustrative. The multiple operations may be combined into a single operation, a single operation may be distributed in additional operations and operations may be executed at least partially overlapping in time. Moreover, alternative embodiments may include multiple instances of a particular operation, and the order of operations may be altered in various other embodiments. 
     Also for example, in one embodiment, the illustrated examples may be implemented as circuitry located on a single integrated circuit or within a same device. Alternatively, the examples may be implemented as any number of separate integrated circuits or separate devices interconnected with each other in a suitable manner. 
     However, other modifications, variations and alternatives are also possible. The specifications and drawings are, accordingly, to be regarded in an illustrative rather than in a restrictive sense. 
     In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word ‘comprising’ does not exclude the presence of other elements or steps then those listed in a claim. Furthermore, the terms “a” or “an,” as used herein, are defined as one or more than one. Also, the use of introductory phrases such as “at least one” and “one or more” in the claims should not be construed to imply that the introduction of another claim element by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an.” The same holds true for the use of definite articles. Unless stated otherwise, terms such as “first” and “second” are used to arbitrarily distinguish between the elements such terms describe. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage. 
     While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention. 
     It is appreciated that various features of the embodiments of the disclosure which are, for clarity, described in the contexts of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features of the embodiments of the disclosure which are, for brevity, described in the context of a single embodiment may also be provided separately or in any suitable subcombination. 
     It will be appreciated by persons skilled in the art that the embodiments of the disclosure are not limited by what has been particularly shown and described hereinabove. Rather the scope of the embodiments of the disclosure is defined by the appended claims and equivalents thereof.