JP2011254289A - Moving body locus display device, and moving body locus display program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display a locus of a moving body on a photographed image that is available by photographing means whose photographing region is variable, on the photographed image.SOLUTION: When a moving body 100 appears on a photographed image available using a PTZ camera as photographing means, operations of panning/tilting/zooming of the camera are so controlled as to automatically track the moving body 100. A current position mark 120 representing a current position of the moving body 100 is attached to the gravity center position of the moving body 100, obtained by the camera which is automatically tracking, on the photographed image. Every time the photographed image is updated by M frames, a locus mark 130 representing past positions which the current position mark 120 has travelled is attached, and, with the current position mark 120 as a top, a locus line 140 is so attached as to sequentially connect the locus marks 130 in time series. In short, the locus of the moving body 100 is displayed on the photographed image available with the camera which is automatically tracking.

Description

  The present invention relates to a mobile object trajectory display device and a mobile object trajectory display program, and in particular, a mobile object that displays a trajectory of a mobile object on a video composed of a plurality of frame images sequentially obtained by imaging means having a variable imaging area. The present invention relates to a trajectory display device and a moving object trajectory display program.

  Conventionally, particularly in the surveillance field, when a moving body such as an intruder (strictly, an image of a moving body) appears in a captured image obtained from a surveillance camera as an imaging means, the trajectory of the moving body is displayed in the captured image. Various display techniques have been proposed. For example, Patent Document 1 discloses a technique for displaying a center of gravity of a detected person as a moving body and an arrow indicating the moving direction of the detected person on a captured image obtained from a so-called fixed camera with a fixed shooting area. Are disclosed. Patent Document 2 discloses a moving object mark indicating a current position of a moving object and a moving path of the moving object on a map image simulating a plan view of the entire site to be monitored, not a captured image itself. A technique for displaying a trajectory line is disclosed.

Japanese Patent Laid-Open No. 11-41589 (paragraph 0098 and FIG. 29) JP2009-210331A (paragraph 0023 and FIG. 6)

  However, in the past, a captured image obtained from a movable camera having a variable photographing area such as a PTZ (Pan-Tilt-Zoom) camera, in particular, a movable state in which pan / tilt / zoom operations are performed so as to automatically track a moving object. There is no technique for displaying the trajectory of a moving object on a captured image obtained from a camera. If such a technique is applied to the monitoring field, it is expected that more accurate, effective and novel monitoring will be realized.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a novel technique capable of displaying the trajectory of a moving body on a photographed image obtained by photographing means having a variable photographing area such as a PTZ camera.

  In order to achieve this object, the present invention provides a moving object trajectory display device for displaying a trajectory of a moving object on a video composed of a plurality of frame images sequentially obtained by imaging means having a variable imaging area. Position detecting means for detecting the position of the moving body in each of the plurality of frame images is provided. And the position conversion means which converts the detection position by this position detection means into the position in the newest frame image is also provided. Furthermore, output image generation means for generating an output image for output by superimposing the symbol of the moving object on the position converted by the position conversion means on the latest frame image is provided.

  That is, according to the present invention, a plurality of frame images are sequentially obtained by an imaging means having a variable imaging area, for example, a PTZ camera. The plurality of frame images form a captured video as a so-called moving image. Here, the position of the moving body in each frame image is detected by the position detection means. The position detected by the position detection means, that is, the position of the moving body in each frame image is converted to the position in the latest (most recent) frame image by the position conversion means. Further, the output image in which the symbol of the moving object is superimposed on the position after the conversion by the position converting means on the latest frame image, that is, the position of the moving object in each frame image replaced on the latest frame image. Is generated by the output image generating means. The symbol on the output image represents the past position that the moving body has traced, that is, the locus of the moving body.

  The present invention can also be applied to the photographing means itself. In particular, when the photographing unit is, for example, a PTZ camera including a CPU (Central Processing Unit) called a combination camera, the present invention can be mounted on the combination camera itself as the photographing unit.

  In the present invention, specifying means for specifying a portion including the moving body in each frame image based on the detection position by the position detection means may be provided. In this case, it is desirable that the output image generation unit superimposes the image of the portion including the moving body specified by the specifying unit on the latest frame image as a symbol. According to this configuration, the trajectory of the moving body is displayed by the image of the moving body itself.

  Furthermore, the output image generation means may change the display mode of the symbol corresponding to each frame image according to the time-series order of each frame image. According to this configuration, the order of the positions followed by the mobile object can be recognized from the symbol display mode.

  The present invention also provides a moving object trajectory display program. That is, the moving object locus display program according to the present invention detects a position of a moving object in each of a plurality of frame images sequentially obtained by imaging means having a variable imaging area, and a detection position by this position detection procedure. A position conversion procedure for converting to a position in the latest frame image, and an output image generation procedure for generating an output image by superimposing the symbol of the moving object on the position after conversion by the position conversion procedure on the latest frame image To be executed.

  As described above, according to the present invention, the trajectory of the moving object is displayed on the captured image by the imaging means having a variable imaging area such as the PTZ camera, and more specifically, the moving object is located at the past position that the moving object has traced. The symbol is displayed. Therefore, for example, in the monitoring field, more accurate, effective and novel monitoring which cannot be expected by the conventional techniques disclosed in Patent Documents 1 and 2 is realized.

1 is a block diagram schematically showing a configuration of a monitoring system according to an embodiment of the present invention. It is an illustration figure which shows the monitoring object in the embodiment roughly. It is an illustration figure which shows the initial state in which the mobile body appeared in the monitoring object of FIG. It is an illustration figure which shows the display image of the display in the state of FIG. It is an illustration figure which shows the display image of the display in the state of FIG. It is an illustration figure which shows the display image of the display following FIG. It is an illustration figure which shows transition of the display video of the display containing FIG. It is an illustration figure for demonstrating the content of the process by the conversion type | formula calculating part in the embodiment. It is a flowchart which shows the flow of the concrete operation | movement of the personal computer for comprising the same conversion type | formula calculating part. It is an illustration figure which shows another example of the display image of the display in the same embodiment. It is an illustration figure which shows the example further different from FIG. FIG. 12 is an illustrative view showing another example different from FIG. 11. It is an illustration figure for demonstrating the specific aspect of the example of FIG. FIG. 13 is an illustrative view showing another example different from FIG. 12.

  An embodiment of the present invention will be described by taking the monitoring system 10 shown in FIG. 1 as an example.

  As shown in the figure, a monitoring system 10 according to the present embodiment includes a dome-shaped PTZ camera (hereinafter simply referred to as a camera) 12 as a photographing unit and a personal computer (hereinafter referred to as a camera) to which the camera 12 is connected. 14 for short).

  The PC 14 executes a control program installed in itself, in particular, an automatic tracking program as a subprogram constituting the control program, so that a moving body 100 described later appears in a captured image obtained from the camera 12. The camera 12 functions as a camera control device that controls the pan angle / tilt angle / zoom magnification (view angle) of the camera 12 to automatically track this. In addition, the PC 14 executes a moving object locus display program as another subprogram constituting the control program, thereby displaying a moving object locus display device that displays the locus of the moving object 100 on the captured image from the camera 12. Also works. In addition, the specific aspect of PC14 for implement | achieving these functions is demonstrated in detail later. The control program installed in the PC 14 is supplied via a storage medium such as a CD-ROM (Compact Disc ROM) or DVD (Digital Versatile Disc) (not shown), or via an electric communication line such as the Internet. Is done. Further, the PC 14 is connected to a display 16 as information output means for displaying various types of information including a photographed image from the camera 12. In addition, command input means such as a mouse and a keyboard (not shown) for inputting various commands to the PC 14 are also connected.

  Assume that the monitoring system 10 is monitoring the area where the house 200, the tree 300, the pond 400 and the automobile 500 are present as shown in FIG. Then, in this monitoring target, as shown in FIG. 3, a moving body 100 such as a human appears in the vicinity of the house 200, and this moving body 100 is in the vicinity of the house 200 as indicated by an arrow 600 in FIG. It is assumed that the vehicle moves from the tree 300 to the pond 400 toward the automobile 500.

  In this case, until just before the moving object 100 appears in the monitoring target, that is, in the state shown in FIG. 2, the pan angle / tilt angle / The zoom magnification is controlled. In other words, the camera 12 is in an initial state (home position) for performing wide-angle shooting. Then, the captured image from the camera 12 in this initial state is displayed on the display 16 as shown in FIG.

  Subsequently, when the moving body 100 appears on the monitoring target as shown in FIG. 3, the moving body 100 naturally appears on the captured video displayed on the display 16 as shown in FIG. Then, the moving body 100 on the captured image is detected by a known moving body detection method such as a frame difference method or a background difference method, and is locked-on. A rectangular frame 110 is displayed on the captured image so as to surround (inscribe) the mobile body 100 that is locked on in order to express the fact that the lock is turned on. The rectangular frame 110 is indicated by a broken line in FIG. 5, but is actually indicated by a red solid line. Of course, the rectangular frame 110 may be displayed in other modes (colors and diagrams). Further, separately from the rectangular frame 110, a current position mark 120, for example, a red circle representing the current position of the moving body 100 is displayed at a predetermined position, for example, the center of gravity position of the moving body 100 on the captured image. The current position mark 120 may also be displayed in a manner other than this.

  In this way, when the moving body 100 is locked on the captured image, the pan angle / tilt of the camera 12 is so captured that the locked-on moving body 100 is captured by the camera 12 with an appropriate composition and size. The angle / zoom magnification is controlled, and so-called zoom-up is performed. As a result, as shown in FIG. 6, a captured image in which the moving body 100 is appropriately zoomed up is displayed on the display 16. The rectangular frame 110 and the current position mark 120 are also displayed on the zoomed-up shot video. Note that the size of the rectangular frame 110 changes according to the size of the moving body 100 before and after zooming up, but the size of the current position mark 120 is unchanged.

  When the moving body 100 moves as indicated by an arrow 600 in FIG. 3, the pan angle / tilt angle / zoom magnification of the camera 12 is automatically controlled so as to follow the moving body, that is, automatically by the camera 12. Tracking is performed. Accordingly, the captured video from the camera 12 displayed on the display 16 changes as shown in (a) to (l) of FIG. FIG. 7A shows the same image as shown in FIG. Further, the rectangular frame 110 and the current position mark 120 are also displayed in the captured video that changes every moment. In addition, as shown in FIGS. 7B to 7L in particular, circular locus marks 130 representing the locus of the moving body 100 are sequentially displayed at past positions that the current position mark 120 has followed. At the same time, a linear trajectory line 140 is attached so that the trajectory marks 130 are sequentially connected in time series with the current position mark 120 as the head. Specifically, the captured video from the camera 12 is updated at a frame rate of 30 frames per second, but each time the captured video is updated by M (M; an integer of 1 or more) frames, the rectangular frame 110 and The display with the current position mark 120 is revised. Similarly, the display of the trajectory mark 130 and the trajectory line 140 is revised.

  The display number Q of the trajectory marks 130 may be infinite (strictly, as long as the moving body 100 exists in an area that can be photographed by the camera 12), but is limited in this embodiment. For example, Q is about 10 to 20 at the maximum. Of course, it is not limited to this value. The trace mark 130 is displayed in a different manner between the new one and the old one. For example, the new one is displayed in a whitish color (high luminance), and the old one is displayed in a blackish color (low luminance).

  When the moving body 100 disappears from the captured image (strictly, within the area that can be captured by the camera 12), the lock-on for the moving body 100 is released, and the automatic tracking by the camera 12 ends. Accordingly, the display of the rectangular frame 110, the current position mark 120, the locus mark 130, and the locus line 140 is also terminated. Then, the camera 12 returns to the initial state.

  As described above, according to the present embodiment, the current position mark 120 representing the current position of the moving body 100 and the position where the current position mark 120 has traced are displayed on the captured image from the camera 12 that is automatically tracking. The trajectory mark 130 to be displayed and the trajectory line 140 connecting the trajectory marks 130 with the current position mark 120 as the head are displayed, that is, the trajectory of the moving body 100 is displayed. And the moving direction of the said mobile body 100 is known from the locus | trajectory of this mobile body 100. FIG. In particular, the moving speed of the moving body 100 can be determined from the distance between the current position mark 120 and each locus mark 130, in other words, from the length dimension of each locus line 140. Therefore, more accurate, effective, and novel monitoring that cannot be expected with the conventional techniques disclosed in Patent Documents 1 and 2 described above is realized.

  In order to exhibit such a function, the PC 14 in the present embodiment has the following configuration by executing the above-described control program.

  That is, referring again to FIG. 1, the PC 14 forms an image input unit 22 that accepts an input of a photographed video (video signal) from the camera 12, specifically accepts an input of a frame image that constitutes the photographed video. . The image input unit 22 converts an analog frame image input from the camera 12 into a digital mode. Then, the frame image converted into the digital form is input to the output image generation unit 26 as output image generation means.

  When the moving body 100 does not exist in the frame image input thereto, the output image generation unit 26 sends the frame image to the image output unit 26 as it is. The image output unit 26 converts the frame image from the output image generation unit 26 into an analog form. Then, the frame image converted into the analog form by the image output unit 26 is output to the outside, and then input to the display 16. As a result, a captured video as a moving image is displayed on the display 16.

  Further, the frame image converted into the digital form by the image input unit 22 is also input to the conversion formula calculation unit 28 as the conversion formula calculation unit and the moving body detection unit 30 as the position detection unit. Among these, the moving body detection unit 30 detects the moving body 100 when the moving body 100 appears in the frame image input from the image input unit 22 by the known moving body detection method described above. Find the center of gravity (coordinates). Then, the obtained center of gravity position is transmitted to the camera control unit 32. The camera control unit 32 zooms in on the moving body 100 based on the position of the center of gravity of the moving body 100 transmitted from the moving body detection unit 30 and automatically pans / tilts / zooms the camera 12 so as to track automatically. Control the magnification.

  Further, the center of gravity position of the moving body 100 obtained by the moving body detection unit 30, in other words, the current position of the moving body 100 is stored in a current position storage unit 34, which will be described later, as current position storage means. In addition, the conversion formula calculation unit 28 is informed that the center of gravity of the mobile unit 100 has been obtained by the mobile unit detection unit 30, in other words, that automatic tracking has started.

When the conversion formula calculation unit 28 is informed that the automatic tracking is started from the moving body detection unit 30, the conversion type calculation unit 28 stores the frame image for every M frames (every M-1 frames) described above. Specifically, the conversion formula calculation unit 28 has a storage area for two frames (not shown), and in the storage area for two frames, a so-called FIFO (First-In / First-Out) method is used. A frame image is stored every M frames. Then, feature points as feature portions corresponding to each other between the latest frame image stored most recently, that is, the current frame image, and the frame image stored before the M frame, that is, the previous frame image, are obtained. Extract. More specifically, N (N: integer greater than or equal to 1) feature points are obtained for the previous frame image by using, for example, a known Harris method (Harris Corner Detector). At this time, the N feature points are obtained in descending order of so-called feature point likelihood. Then, where the N feature points in the previous frame image are located on the current frame image, for example, a known KLT method (Kanade-Lucas
Estimate using Feature Tracker). As a result, N ′ (N ′; an integer greater than or equal to 1) feature points corresponding to each other between the previous frame image and the current frame image are extracted. Note that the number of N ′ feature points corresponding to each other between the frame images is equal to or less than the number of N feature points extracted for the previous frame image (N ′ ≦ N). This is because, out of the N feature points extracted for the previous frame image, there is a possibility that when the feature point is replaced on the current frame image, it is out of the current frame image. In addition, estimation errors also cause this. For this reason, the number N of feature points extracted for the previous frame image is relatively large, for example, several tens to several hundreds, and N = 100 to 200 is appropriate.

  Further, the conversion formula calculation unit 28 converts the coordinate X of an arbitrary point in the previous frame image to the coordinate Y in the current frame image based on the positional relationship of the N ′ feature points corresponding to each other between the frame images. A coordinate conversion expression expressed by the following expression 1 for converting to is obtained. In addition, this Formula 1 is expressed simply for convenience of explanation, and is actually a generally known projective transformation formula, for example. Further, in this equation 1, the left side coordinate Y and the right side coordinate X are expressed by one symbol Y and X, respectively, but in reality, a two-dimensional coordinate value (horizontal coordinate value and vertical coordinate value). Coordinate value). In addition, the equation 1 includes 8 conversion coefficients.

<< Formula 1 >>
Y = f (X)

  This will be described in more detail. For example, as shown exaggeratedly in FIG. 8, each feature point X1, X2,... In the previous frame image in (a) is represented by Y1, in the current frame image in (b). It corresponds to each feature point Y2,. It is assumed that there are N ′ combinations in total. For these N ′ combinations, the conversion formula calculation unit 28 calculates the mutual relationship between the coordinates of the feature points X1, X2,... In the previous frame image and the coordinates of the feature points Y1, Y2,. The relational expression is assembled as the following expression 2 in accordance with the above expression 1.

<< Formula 2 >>
Y1 = f (X1)
Y2 = f (X2)
:
YN '= f (XN')

  Then, the conversion formula calculation unit 28 is included in the above formula 1 by an appropriate regression analysis method such as a least square method using the N ′ (set) coordinate relational expressions represented by the formula 2. Eight conversion coefficients are obtained as unknowns. Then, by substituting these conversion coefficients into Equation 1, Equation 1 for converting the coordinate X in the previous frame image to the coordinate Y in the current frame image is obtained. In addition, although detailed description here is abbreviate | omitted, when the said conversion factor is substituted to Formula 1, it may be assumed that those validity is confirmed in an appropriate way.

  Further, when storing the next new frame image, in other words, when the current frame image is used as a new previous frame image, the conversion formula calculation unit 28 sets the number N ′ of feature points of the new previous frame image. Is less than the prescribed number N (N ′ <N), the deficiency (= N−N ′) is newly extracted by the Harris method described above and added. As a result, N feature points are also determined for the new previous frame image. However, immediately after the automatic tracking is started, only one frame image is obtained. Therefore, the conversion formula calculation unit 28 stores the first one frame image as the previous frame image, and N pieces of the previous frame image are stored. The feature points are extracted, and Equation 1 is not obtained (it cannot be obtained strictly).

  Returning to FIG. 1, when the equation 1 is obtained by the conversion equation calculator 28 as described above, the equation 1 is given to the coordinate converter 36 serving as a position converter. On the other hand, as described above, the current position of the moving body 100 detected by the moving body detection unit 30 is stored in the current position storage unit 34, and the current position of the moving body 100 stored in the current position storage unit 34 is stored. Strictly speaking, the current position is stored for each M frame in synchronization with the storage timing of the frame image for each M frame by the conversion formula calculation unit 28 described above. Each time a new current position is stored in the current position storage unit 34, the original current position stored in the current position storage unit 34 until then represents the position of the moving body 100 before M frames. In other words, it is stored as the previous position in the previous position storage unit 38 that forms the previous position storage means. The coordinate conversion unit 36 acquires the previous position from the previous position storage unit 38, and converts the coordinates of the previous position into coordinates in the current frame image based on Expression 1 given from the conversion expression calculation unit 28. The coordinates after conversion by the coordinate conversion unit 36 are stored in the post-conversion position storage unit 40.

  The post-conversion coordinates stored in the post-conversion position storage unit 40 are taken into the output image generation unit 24. In addition, the output image generation unit 24 acquires the current position from the current position storage unit 34. Further, the frame image is input from the image input unit 22 to the output image generation unit 24 as described above. The output image generation unit 24 superimposes the above-described current position mark 120 on the current position on the frame image input from the image input unit 22, that is, on the current frame image, and is indicated by the converted coordinates. The locus mark 130 is superimposed on the position. Further, the output image generation unit 24 also superimposes the locus line 140 so as to connect the current position mark 120 and the locus mark 130. The current frame image in which the current position mark 120, the trajectory mark 130, and the trajectory line 140 are superimposed in this manner is input to the image output unit 26 as an output frame image, and is displayed on the display 16 as a result.

  Immediately after the automatic tracking is started, there is no post-conversion coordinate, so that the current position mark 120 is displayed on the display 16 as shown in FIGS. 6 and 7A. The locus line 140 is not displayed. Then, when the converted coordinates are obtained for the first time, one locus mark 130 and one locus line 140 are displayed together with the current position mark 120 as shown in FIG. 7B.

  Further, the coordinates after conversion by the coordinate conversion unit 36 are stored in the previous position storage unit 38 again. Specifically, the post-conversion position stored in the previous position storage unit 38 is stored in the previous position storage unit 38 as a position before (past) the previous position stored via the current position storage unit 34. The In the next conversion, the coordinate conversion unit 36 acquires all previous positions from the previous position storage unit 38 and performs the conversion for all these previous positions. Note that time series information representing each time series order is attached to each previous position. Of course, the time-series information is also attached to the current position.

  As a result, the images shown in FIGS. 7C to 7L are sequentially displayed on the display 16. In other words, the current position mark 120 is attached to the current position of the moving body 100, and the trajectory mark 130 is attached to each previous position that the current position mark 120 has traced. A trajectory line 140 is attached so as to connect the trajectory marks 130 in time series. Note that the order of the trajectory marks 130 connected by the trajectory line 140 is based on the time-series information described above. Also, based on this time series information, as described above, the new trajectory mark 130 is displayed in a whitish color, and the old trajectory mark 130 is displayed in a blackish color.

  Note that the number of front positions of the moving body 100 stored in the front position storage unit 38 is not infinite and is limited to Q. When the number of storages of Q is exceeded, the previous positions stored in the previous position storage unit 38 are discarded in order from the oldest one. As a result, the number of trajectory marks 130 displayed on the display 16 is limited to the number Q as described above. The maximum number of Q stored at the previous position can be arbitrarily set by the above-described command input means (not shown). Further, instead of limiting the maximum storage number Q in this way, the number Q of trajectory marks 130 displayed by the output image generation unit 24 may be limited.

  Here, a specific operation of the PC 14 (CPU) for configuring the above-described conversion formula calculation unit 28 will be described with reference to FIG.

  As shown in the figure, when the automatic tracking is started, the PC 14 proceeds to step S1, sets the count value m for counting the frames to m = 1, and is initialized. Then, the PC 14 proceeds to step S3, and acquires a one-frame image (from the image input unit 22).

  Further, the PC 14 proceeds to step S5, and whether or not the frame image acquired in step S3 is acquired for the first time after the start of automatic tracking, that is, whether or not the step S3 is executed for the first time after the start of automatic tracking. To determine. In step S5, for example, when step S3 is executed for the first time, the PC 14 proceeds to step S7, and stores the frame image acquired in step S3 as the previous frame image. In step S9, N feature points are extracted from the previous frame image by the Harris method described above.

  After execution of step S9, the PC 14 proceeds to step S11, and compares the count value of m with the value representing the number of frames of M described above. For example, if the count value of m is smaller than the number of frames of M (m <M), that is, if the number m of frame images to be acquired does not reach M frames, the process proceeds to step S13, and the count value of m is set. Increment by one. This step S13 is executed every time one frame image is acquired. Then, the PC 14 returns to step S11 again. That is, step S11 and step S13 are repeated until the number m of frame image acquisitions reaches M frames.

  In step S11, when the frame image acquisition number m reaches M frames (m = M), the PC 14 proceeds to step S15. In step S15, it is determined whether or not the automatic tracking is finished. When the automatic tracking is finished, the series of operations shown in FIG. 9 is also finished. On the other hand, if the automatic tracking has not ended, the process returns to step S1.

  In step S5 described above, if the frame image acquired in the previous step S3 is not acquired for the first time after the start of automatic tracking, the PC 14 proceeds to step S17. In step S17, the frame image acquired in step S3 is stored as the current frame image.

  Further, the PC 14 proceeds to step S19 and estimates where the N feature points of the previous frame image extracted in step S9 described above are located on the current frame image by the KLT method. As described above, the estimated number N ′ of feature points on the current frame image is equal to or less than the number N of feature points extracted on the previous frame image (N ′ ≦ N).

  After execution of step S19, the PC 14 proceeds to step S21, and assembles the coordinate relational expression of Expression 2 described above for the combination of N ′ feature points corresponding to each other between the previous frame image and the current frame image. In step S23, an arbitrary coordinate X in the previous frame image is changed to a coordinate Y in the previous frame image by the least square method using these N ′ coordinate relational expressions (or any other appropriate regression analysis method). The coordinate conversion formula of the above-described formula 1 for conversion is obtained. The coordinate conversion formula of Formula 1 is given to the coordinate conversion unit 36 and is used for coordinate conversion processing by the coordinate conversion unit 36.

  In step S25, the PC 14 compares the number N ′ of feature points in the current frame image with the number N of feature points in the previous frame image. In this step S25, for example, when the number N ′ of feature points in the current frame image is smaller than the number N of feature points in the previous frame image, that is, the number N of feature points in the current frame image that becomes the next frame image next. If 'is less than the prescribed number N (N' <N), the process proceeds to step S27. In step S27, the shortage of feature points (= N−N ′) is additionally extracted by the Harris method, and then the process proceeds to step S29. On the other hand, if the number N ′ of feature points in the current frame image satisfies the specified number N (N ′ = N) in step S25, step S27 is skipped and the process proceeds directly to step S29.

  In step S29, the PC 14 stores the current frame image as the previous frame image again. Accordingly, the previous previous frame image is discarded. And after execution of this step S29, it progresses to step S11.

  By operating the PC 14 in this way, the conversion formula calculation unit 28 is configured in software.

  In the present embodiment, as shown in FIG. 7, the captured video is displayed on the entire screen of the display 16, but the present invention is not limited to this. For example, as shown in FIG. 10, reduced images obtained by reducing the captured video in a thumbnail manner frame by frame may be displayed side by side over a plurality of frames. Incidentally, in FIG. 10, four reduced images are displayed in order from the left side to the right side of the screen of the display 16, and a row of the four reduced images is 3 from the upper side to the lower side of the screen of the display 16. An example displayed in a row, that is, an example in which reduced images for a total of 12 frames are collectively displayed is shown. Each frame number (update order) is attached below each reduced image, and the reduced images of each frame after the 13th frame are overwritten in order from the smallest frame number to the reduced image being displayed. Is displayed. According to such a display mode, it becomes easy to recognize the movement of the moving body 100 that is difficult to recognize in the mode in which the captured image is displayed on the entire screen of the display 16, and more accurate, effective, and novel monitoring. It is expected to contribute to realization. Of course, not only the reduced images for 12 frames, but also reduced images for a plurality of frames other than this may be displayed collectively. Further, instead of displaying reduced images based on all output frame images (generated sequentially for each M frame), for example, the output frame images are taken out every P (P; an integer of 1 or more), and this P Only a reduced image based on the output frame image that is taken out individually may be displayed.

  Furthermore, as shown in FIG. 11, a captured image when the camera 12 is in an initial state, for example, a frame image immediately before the start of automatic tracking is used as a reference image, and the current position mark 120, The locus mark 130 and the locus line 140 may be attached, and the reference image may be displayed on the display 16. In this case, the position of the moving body 100 in the frame image (that is, the current frame image) sequentially obtained from the camera 12 during automatic tracking is obtained for each M frame described above. Then, the current position coordinates of the moving body 100 on the current frame image are converted into coordinates on the reference image (that is, the frame image in the initial state), and the current position mark 120 is placed at the converted coordinate position. Attached. In addition, a locus mark 130 is added to the past converted coordinate position. Further, a locus line 140 is attached so as to connect the current position mark 120 and the locus mark 130. In addition, the entire current frame image or a portion of the current frame image including at least the moving body 100 and the rectangular frame 100 is superimposed on the reference image by so-called mosaicing processing. Accordingly, the moving body 100 and the rectangular frame 110 are also displayed on the wide-angle reference image, and it is expected that the transition of the moving body 100 can be easily recognized from another viewpoint. In this mosaicing process, the coordinates of each point of the superimposition target portion in the current frame image are converted into coordinates on the reference image, and each corresponding point in the current frame image is converted to each coordinate position on the reference image after the conversion. This is realized by superimposing.

  Further, using this mosaicing process, instead of the locus mark 130 and the locus line 140 in FIG. 11, as shown in FIG. 12, the image of the moving body 100 obtained during automatic tracking is superimposed on the reference image. May be. That is, a portion including the moving body 100 in the current frame image may be cut out for each M frame, and the cut out portion may be superimposed on the reference image. However, in this case, if the image to be superimposed has a size as shown by a one-dot chain line 150 in FIG. 13, for example, the old one of the superimposed images 150 is overwritten by the new one, and the hatched pattern in FIG. As indicated by 160, there may be a portion that disappears in the shade. In order to avoid this, it is necessary to take appropriate measures such as reducing the size of the superimposed image 150 or increasing the superposition cycle, that is, the above-described M frame.

  Of course, the reference image is not limited to the frame image in the initial state, and may be an arbitrary frame image.

  In addition, as described above, an arbitrary frame image is used as a reference image, and a part of the frame image that is being automatically tracked is not superimposed on the image, but the frame image that is being automatically tracked is appropriately pasted by mosaic processing. May be displayed. To do so, for example, as shown in FIG. 14, a plain so-called white canvas-like reference image 700 in which the same coordinate system as the frame image in the initial state is set is prepared. A portion 150 including the moving body 100 in the current frame image for each M frame is superimposed on the reference image 700. In this case, the size of the superimposed image 150 is determined so that the superimposed images 150 are continuous (overlapped) and the background of the house 200 or the like is appropriately displayed. In this case as well, as described with reference to FIG. 13, the shade 160 may be generated. Therefore, it is necessary to make the shade 160 as inconspicuous as possible. In any case, it is important to display the transition of the moving body 100 so that it can be easily recognized.

  In the present embodiment, the trajectory mark 130 and the trajectory line 140 are displayed in addition to the current position mark 120, but the present invention is not limited to this. For example, only one of the locus mark 130 and the locus line 140 may be displayed. In addition, the locus mark 130 is displayed as whitish as it is new, and is displayed as dark as the old one, but it may be reversed, or a different color such as rainbow may be added. . Of course, all the trajectory marks 130 may be displayed in the same manner. In addition, the trajectory mark 130 may be expressed by an arrow or the like so that the moving direction of the moving body 100 can be understood. The rectangular frame 110 may not be displayed.

  In addition, in the present embodiment, the feature point of the previous frame image is obtained by the Harris method, but the present invention is not limited to this. For example, the feature points may be extracted using another algorithm such as a SIFT (Scale Invariant Feature Transform) method.

  Furthermore, by extracting the feature points corresponding to each other between the previous frame image and the current frame image by estimating where the feature points of the previous frame image are located on the current frame image by the KLT method; However, it is not limited to this. For example, instead of the KLT method, the motion of the feature point of the previous frame image may be estimated using another algorithm such as a template matching method. Further, instead of estimating the movement of feature points, an appropriate algorithm for extracting feature points corresponding to each other between the previous frame image and the current frame image based on their similarity may be used. Further, not only the feature points but also feature portions having a certain range such as lines and surfaces may be extracted.

  In the present embodiment, the coordinates after conversion by the coordinate conversion unit 36 are stored again in the previous position storage unit 38, and all the previous positions including the converted coordinates stored in the previous position storage unit 38 are coordinate converted. Although the maximum number Q of trajectory marks 130 is displayed as a result of being subjected to the conversion at the time of the next conversion by the unit 36, the present invention is not limited to this. For example, the following configuration may be employed. That is, the conversion formula calculation unit 28 has a storage area for one frame for storing the current frame image and a storage area for the Q frame for storing the previous frame image for the past Q frames. And Then, in the storage area for the total [Q + 1] frames, a frame image is stored for each M frames by the above-described FIFO method, and among the frame images for the [Q + 1] frames, The coordinate conversion equation shown in Equation 1 is obtained between the previous frame image and the coordinate conversion equation 36. In addition, the position coordinates of the moving body 100 in each previous frame image, that is, the position coordinates of the moving body 100 detected by the moving body detection unit 30 when each previous frame image is the current frame image, It is stored in the previous position storage unit 38 via the position storage unit 34 and is then taken into the coordinate conversion unit 36. The coordinate conversion unit 36 converts the position coordinates of the moving body 100 in each previous frame image into the coordinates in the current frame image using the corresponding coordinate conversion expression of Expression 1. Each post-conversion coordinate is provided to the output image generation unit 24 via the post-conversion position storage unit 40. The output image generation unit 24 attaches a trajectory mark 130 to each post-conversion coordinate position given from the coordinate conversion unit 36 on the current frame image input from the image input unit 22. As a result, a maximum of Q trajectory marks 130 are displayed. In this case as well, a current position mark 120 is attached to the current position of the mobile object 100, and a locus line 140 is attached so as to connect each locus mark 130 in time series with the current position mark 120 as the head. So that

  In other words, the update cycle of the current position mark 120, the trajectory mark 130, and the like can be arbitrarily set. For example, the smaller the number of frames M, the narrower the distance between the current position mark 120 and each trajectory mark 130. On the other hand, the larger the number M of frames, the wider the interval. The number M of frames is appropriately set according to various conditions such as the movement of the moving body 100 and the shooting conditions by the camera 12 together with the display number Q of the trajectory marks 130 described above.

  In addition, the coordinate conversion expression of the above-described expression 1 (and expression 2) is a projective conversion expression, but is not limited thereto. For example, other conversion formulas such as a coordinate conversion formula based on the known R.Y.Tsai method may be employed.

  In the present embodiment, feature points corresponding to each other between the previous frame image and the current frame image are extracted, and the coordinate conversion formula of Formula 1 is obtained from the positional relationship between the feature points. Not limited to this. For example, parameters including the pan angle / tilt angle / zoom magnification may be acquired from the camera 12, the movement of the camera 12 may be recognized from these parameters, and the coordinate relational expression of Expression 1 may be obtained. Further, by using an external detection means such as a gyro sensor, the movement of the camera 12 may be recognized, and the equation 1 may be obtained.

  Furthermore, it is desirable that the installation position of the camera 12 be unchanged, but the present invention can also be applied in a variable environment such as in-vehicle use.

  In the present embodiment, the camera control device and the moving body trajectory display device are realized by the PC 14, but the present invention is not limited to this. For example, instead of the PC 14, a dedicated camera control device and a moving body trajectory display device may be configured. Further, when the camera 12 is a combination camera with a built-in CPU, the function as the camera control device and the moving object locus display device may be mounted on the combination camera itself.

10 surveillance system 12 camera 14 PC
DESCRIPTION OF SYMBOLS 16 Display 24 Output image generation part 26 Image output part 28 Conversion formula calculating part 30 Moving body detection part 34 Current position memory | storage part 36 Coordinate transformation part 38 Previous position memory | storage part

Claims (4)

A moving body trajectory display device that displays a trajectory of a moving body on a video composed of a plurality of frame images sequentially obtained by photographing means having a variable photographing area,
Position detecting means for detecting the position of the moving body in each of the plurality of frame images;
Position conversion means for converting the detection position by the position detection means into a position in the latest frame image;
Output image generation means for generating an output image by superimposing the symbol of the moving object on the position after the conversion by the position conversion means of the latest frame image;
A moving body trajectory display device comprising: A specifying unit that specifies a portion including the moving body in each of the plurality of frame images based on a detection position by the position detection unit;
The output image generating means superimposes the image of the portion specified by the specifying means as the symbol;
The moving body locus | trajectory display apparatus of Claim 1. The output image generation means changes the display mode of the symbol corresponding to each of the plurality of frame images according to the time series order of the plurality of frame images.
The moving body locus | trajectory display apparatus of Claim 1 or 2. A moving object trajectory display program for displaying a trajectory of a moving object on a video composed of a plurality of frame images obtained sequentially by a photographing means whose imaging area is variable,
A position detection procedure for detecting the position of the moving body in each of the plurality of frame images;
A position conversion procedure for converting the position detected by the position detection procedure into a position in the latest frame image;
An output image generation procedure for generating an output image by superimposing the symbol of the moving body on a position after conversion by the position conversion procedure of the latest frame image;
A moving object trajectory display program that causes a computer to execute.

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