Method for searching for objects in video data received from a fixed camera
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H04N-007/18
G06K-009/78
G06F-017/30
출원번호
US-0632310
(2012-10-01)
등록번호
US-9092699
(2015-07-28)
우선권정보
RU-2011139659 (2011-09-30)
발명자
/ 주소
Falomkin, Igor Igorevich
Suchkov, Egor Petrovich
출원인 / 주소
Obschestvo s ogranichennoy otvetstvennostyu “ITV Group”
대리인 / 주소
Collard & Roe, P.C.
인용정보
피인용 횟수 :
0인용 특허 :
4
초록▼
The invention relates to methods for searching for objects in video data represented by a sequence of frames showing images of a scene received from a fixed video camera and is based on the display of synthetic frames to the operator, each of said synthetic frame being capable of combining objects c
The invention relates to methods for searching for objects in video data represented by a sequence of frames showing images of a scene received from a fixed video camera and is based on the display of synthetic frames to the operator, each of said synthetic frame being capable of combining objects captured in different source frames. The method comprises constructing movement trajectories of each of the objects of interest to the operator; ordering said trajectories; compiling an updatable schedule for displaying the number of objects preset by the operator and automatically choosing for said schedule the display start times of each trajectory; constructing a plan for forming synthetic frames such that the condition of permissible mutual occlusion of the objects is fulfilled; and forming synthetic frames according to said plan and displaying them to the operator. The technical result consists in speeding the search and reducing memory size requirements and computational load.
대표청구항▼
1. A method for searching for objects in video data received from a fixed video camera comprising: detecting objects of interest to the operator in a source sequence of frames received from a fixed video camera, each frame representing an image of a scene and having a timestamp specifying the moment
1. A method for searching for objects in video data received from a fixed video camera comprising: detecting objects of interest to the operator in a source sequence of frames received from a fixed video camera, each frame representing an image of a scene and having a timestamp specifying the moment in time said frame was captured;constructing a trajectory of movement for each of the detected objects such that each point of the trajectory corresponds to the position of the object in a frame and the capture moment in time of said frame, the position of the object in the frame being represented by a set of frame pixels forming the image of said object;forming a queue of movement trajectories of the detected objects;compiling a schedule for displaying the detected objects to the operator, said schedule indicating, for the trajectory of each object, a start time upon which said object will be displayed on screen;constructing a plan for forming synthetic frames in accordance with said schedule, said synthetic frames may show images of several objects simultaneously in positions that, in the general case, they had in captured frames at different moments in time;forming successive synthetic frame in accordance with said plan by inserting the images of objects in said synthetic frame that, according to said plan, are to be shown in said synthetic frame simultaneously and the background against which they are to be shown;displaying the formed synthetic frames on screen to the operator; wherein said forming a queue of movement trajectories comprises: (a) ordering all the trajectories in said queue in ascending order of the moments in time when a respective object appeared in the video camera field of view;(b) assigning a serial number to each trajectory in the obtained ordered queue of said trajectories and to the object corresponding to said trajectory; and wherein said schedule for displaying the detected objects is compiled in the order of their serial numbers as follows: (a) including initially in said schedule the first object alone, and then(b) updating said schedule by removing therefrom objects with trajectories already fully displayed to the operator and adding thereto new objects, if the number of objects included in said schedule is not larger than the value preset by the operator; and wherein said constructing said plan for forming synthetic frames comprises constructing it when said schedule for displaying the detected objects is first compiled and then each time said schedule is updated; said plan consisting of elements, each one representing a set of trajectory points of different objects to be combined in one synthetic frame. 2. The method of claim 1, wherein updating the schedule for displaying the detected objects comprises: adding to said schedule a successive object that has not so far been displayed;determining a suitable time to start displaying said added object such that the condition of permissible mutual occlusion of objects be fulfilled in all synthetic frames being formed on the basis of said schedule;compiling an updated schedule for displaying the detected objects; wherein said determining a suitable time and said compiling an updated schedule comprises: (a) checking sequentially step by step that said condition of permissible mutual occlusion of objects holds for tentative values of start time of displaying said added object, these tentative time values are being tested in an ascending order at specified discreteness within the range from display start time of an object having a preceding serial number to the display completion time of all objects included in the schedule, except for the added object;(b) compiling, at each checking step, a tentative schedule for displaying the detected objects, including said added object, wherein compiling the tentative schedule comprises setting in said tentative schedule the successive tentative time value as the start time to display said added object;(c) constructing a plan for forming synthetic frames according to said tentative schedule for all objects included in said schedule;(d) checking thereafter if the condition of permissible mutual occlusion of objects holds in all synthetic frames and, depending on the outcome, proceeding to the steps of:(e) proceeding-to checking the next tentative time value, if said condition does not hold; or otherwise,(f) accepting the current tentative time value as the time to start displaying the added object and accepting the compiled tentative schedule as said updated schedule for displaying the detected objects, if said condition is held. 3. The method of claim 2, wherein constructing the plan for forming synthetic frames for all objects included on the schedule for displaying the detected objects comprises: translating the source trajectory of each object along the time axis such that the translated trajectory would begins at the display start time indicated in the schedule and storing the translation value, being equal to the difference between the moment in time corresponding to said object's source trajectory first point and the display start time of said object;adding a fictitious point to the translated trajectory of each object, wherein said fictitious point corresponds to a fictitious moment in time identical for all objects that is smaller than the display start time for any object in said schedule;setting the collection of fictitious points of all translated trajectories, corresponding to said fictitious moment in time, as the initial fictitious element of said plan being constructed;constructing consecutively elements of said plan, wherein each of said elements has a set of points of translated trajectories of different objects to be shown in one synthetic frame, said set containing not more than one point of each translated trajectory, wherein constructing each next element of said plan comprises the sequence of the following operations:(a) adding a fictitious point of the trajectory of the added object to the last formed element of said plan, if the need for updating the schedule for displaying the detected objects arose before the completion of constructing said plan;(b) selecting, in each translated trajectory, a point that, on the time axis, is next-but-one to the right of said trajectory's point included in the preceding element of the plan;(c) finding a point having the minimum moment in time among said selected points of all trajectories; and(d) selecting a point for each translated trajectory that is nearest in time to the left of said minimum moment in time and setting the set of said selected points as the next element of the plan. 4. The method of claim 2, wherein checking the condition of permissible mutual occlusion of objects comprises: (a) checking each element of said plan for forming synthetic frames, provided said element contains the successive added object, for the presence of pixels in the image of said object having identical within-frame coordinates with pixels of other objects contained in said element of the plan;(b) putting on record the fact of impermissible intersection of the added object with other objects in said element of the plan, if the number of said pixels common for the added object and at least one of other objects exceeds the threshold preset by the operator;(c) counting the number (A) of the elements of said plan for each object contained in said tentative schedule, except for the added object, for which said object intersects impermissibly with the added object;(d) counting the number (B) of the elements of said plan for each object in which said object occurs;(e) checking the conditions: Ai/Bi<αi, (11)Ai/Bc<αc, (12)where: i is the object serial number, except for the object added to the current schedule to be updated;c is the serial number of the object added to said current schedule;Ai is the number of elements of said plan for which the i-th object intersects impermissibly with the added object;Bi is the number of elements of said plan in which the i-th object occurs;Bc is the number of elements of said plan in which the added object occurs; andαi and αc are constants that may be chosen depending on the importance of the object to the operator; in a particular case, αi=αc=const for all i; and(f) generating a message that the condition of permissible mutual occlusion of objects is fulfilled, if conditions (11) and (12) are satisfied simultaneously. 5. The method of claim 3, wherein forming the successive synthetic frame corresponding to any element of the plan for forming synthetic frames comprises: (a) finding, in the source sequence, frames that correspond to points of the translated trajectories of objects, these points are contained in the element of said plan, said element corresponding to the synthetic frame being formed, finding said frames is performed by the capture times of said frames, said time being calculated as a sum of the translation value corresponding to the translated trajectory of said object and the moment in time corresponding of said point of said trajectory;(b) choosing from said frames a frame that corresponds to the object with the least serial number and accepting said frame as a reference frame on the basis of which a synthetic frame is to be constructed;(c) forming an intermediate frame on the basis of the reference frame, wherein the intermediate frame contains objects of the reference frame to be displayed and the background against which they are to be displayed; and(d) composing said successive synthetic frame by inserting, in the obtained intermediate frame, the images of other objects the trajectory points of which were included in the plan element corresponding to the synthetic frame being formed. 6. The method of claim 5, wherein composing the synthetic frame background comprises replacing reference frame fragments occupied by any objects except those that are to be shown in the synthetic frame being formed with object-free fragments from other frames of the source sequence, said other frames corresponding to the trajectory points of objects shown in said plan element corresponding to the synthetic frame being formed. 7. The method of claim 1, further comprising displaying to the operator on the screen each successive formed synthetic frame with a delay equal to the minimum nonzero difference between the capture moments in time of any object represented into the preceding and successive synthetic frames.
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이 특허에 인용된 특허 (4)
Brown Russell R. (1034 Missouri Ave. Deer Lodge MT 59722), Automatic security monitor reporter.
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