JP2000156819A - Method and device for detecting still image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a moving image information detecting method capable of highly accurately detecting an image subjectively felt as an image of small movement from a moving image sequence, and a device for realizing the method. SOLUTION: The device is provided with a frame memory 301 for storing images, a changed block detection means 302 for finding out a changed block from a difference between plural frames, a connection degree calculation means 303 for finding the degree of connection between the frames, an image characteristic judging means 304 for detecting a still image by a previously determined threshold based on the degree of connection between the frames, and a judged result output means 305. Thus the still image can be detected with high sensitivity and high accuracy by using the connection degree of the changing block.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting moving image information in a video signal encoding system and an apparatus for implementing the method, and more particularly to a method for subjectively perceiving a video image with little motion as a series of scenes. It is possible to detect from among the following.

[0002]

2. Description of the Related Art In recent years, devices handling digital video signals have increased, and various compression encoding methods have been defined to reduce the data amount of digital video signals handled by those devices.

[0003] One of such systems, MPEG1 or M
PEG2 is often used for video signals used in computers. In this method, image data is compressed by combining reduction of spatial redundancy within a frame by DCT (Discrete Cosine Transform) and reduction of temporal redundancy between frames by motion compensation.

In order to reduce the redundancy by the motion compensation, when encoding the current frame image, a prediction image is created from a past reference frame image, and the difference data between the two image data is obtained and encoded. Thus, the data amount is reduced.

However, when a scene change occurs between the reference frame image and the current frame image, the frame of the scene change is forcibly changed without performing motion compensation in order to measure the improvement in the image quality of the encoded data. It is necessary to switch to the internal compression method only.

[0006] Further, with the spread of devices that handle digital video signals, opportunities for editing and processing digital moving images have increased. For example, video captured by a digital video camera or the like can be imported to a personal computer and edited freely.
Can be processed. In addition, the user can access the video database on the network, capture the data, and edit and process the data similarly.

However, when editing and processing a moving image, it is necessary to know what data exists in which part in a series of moving image sequences. Therefore, many moving image editing apparatuses have a function of detecting a scene change from a moving image, dividing the moving image into scenes, and presenting a user with a scene change.

[0008] From the two requirements described above, a moving image information detecting device such as a scene change detecting device is required, and a number of moving image information detecting methods and devices have been conventionally proposed. When a specific frame is extracted from a series of moving image sequences, it is general to use a feature amount unique to the frame or a temporal change in the feature amount.

Tomomura and Abe published "Technical Report on Video Database Handling" published in the 1989 Technical Report of the Institute of Information and Communication Engineers (IEICE Technical Report, IE89-33, pp.49-5).
6, 1989), a luminance histogram is used as a frame feature value, and the sum of differences between the luminance histogram and the immediately preceding frame is calculated. When the difference is large, the scene change frame is determined.

Japanese Unexamined Patent Publication No. Hei 6-133305 relates to a moving image information detecting method in which moving image data is compressed, using a code amount of each frame as a frame feature amount, and calculating a difference value of the code amount from the immediately preceding frame. Is calculated, and when the value is equal to or greater than the detection condition, the scene change frame is set.

In Japanese Patent Application Laid-Open No. 5-37853, the area of a changing pixel is used as a frame feature amount. This moving image information detection method will be briefly described with reference to FIG. FIG. 15 is a configuration diagram of a moving image automatic dividing apparatus. The moving image automatic dividing apparatus includes a moving image input unit 2001 and a changing pixel area calculating unit 20.
02, a scene change determination unit 2003, and a scene change frame output unit 2004.

Next, this moving picture information detecting method will be briefly described. The moving image input unit 2001 sequentially sends the input frames to the changing pixel area calculation unit 2002. The changed pixel area calculation unit 2002 obtains a difference between each pixel of the currently transmitted frame and that of the immediately preceding frame, and determines a pixel whose value is equal to or larger than the first threshold value as a changed pixel. Then, the number of changed pixels is calculated for each frame and sent to the scene change determination unit 2003 as the area A (N) of the changed pixels. N is the frame number. The scene change determination unit 2003 calculates A (N) -A (N-1)>
When B and A (N + 1) −A (N) <− B, N is determined to be a scene change frame. B is a second threshold. Scene change frame output means 2004
The scene change frame number sent from the scene change determination unit 2003 is output.

[0013] Also, while a moving picture information detecting device such as a scene change detecting device is required, a video (static video) which is subjectively perceived as having little movement, such as a videophone or a video conference, is required. A moving image information detecting device for detection has also been required. When transmitting video over networks with limited transmission bandwidth, such as the Internet or ISDN, lower bit rate video compression by reducing the frame rate or reducing the amount of information in each frame such as frame resolution and frame image quality Perform However, in the former case, the image becomes awkward, such as frame-by-frame movement, and in the latter case, the image quality is remarkably deteriorated, making it difficult to view.

[0014]

When a static image is detected from a moving image sequence, a conventional moving image information detecting method represented by Japanese Patent Application Laid-Open No. 5-37853 discloses a scene change determining section 20.
There is a problem in that it is difficult to accurately detect a static image even if the determination conditions in 03 are adjusted. When a video sequence in which a normal video, a static video, and a dynamic video are mixed is input, the conventional video information detection device peaks sensitively for a dynamic video, but normally for a static video. Although the output is slightly smaller than that of the video, there is no significant difference between them, and it is difficult to determine the static video by the threshold.

The present invention is to solve such a conventional problem, and provides a moving picture information detecting method capable of detecting a static picture from a moving picture sequence with high accuracy.
It is intended to provide an apparatus for performing the method.

[0016]

Therefore, in the static image detection method of the present invention, first, a changed block is obtained from a difference between frames, and a plurality of changed blocks existing in a frame are located near eight adjacent blocks. Change blocks that exist (connected ones) are sequentially integrated to create a change block group, the degree of connection of frames is determined from the degree of connection of the change blocks, and static image detection is performed using the degree of connection. Perform

According to this method, since the degree of connection between frames is determined based on the degree of connection between groups of changed blocks, highly accurate detection can be performed on a static image.

Further, according to the static image detection method of the present invention, when the changed blocks constituting the changed block group surround a part or many of the non-change blocks, the enclosed non-change blocks are changed. Integrate into blocks.

According to this method, the surrounding non-change block is corrected to a change block, thereby correcting the degree of connection of an erroneous change block group that occurs when a large object having a small change in gray level value moves, and correct frame connection. Degree can be detected.

Further, in the static image detection method of the present invention, a frame is divided into a plurality of regions, and from among these regions,
Static image detection is performed with the area including the largest number of changed blocks belonging to the changed block group that gives the largest connectivity as the connectivity calculation area for the next frame.

In this method, the area for calculating the connectivity of a frame is limited to a certain area from the entire frame. Therefore, the calculation load for creating the changing block group and calculating the connectivity is reduced without lowering the accuracy of the static video detection. Can be reduced.

Further, in the static image detection method of the present invention, the frame is divided into a plurality of regions, and the region where the number of changed blocks included in each region is the maximum is set as the region for calculating the connectivity of the next frame. Perform static video detection.

According to this method, the area for calculating the connectivity of a frame is limited to a certain area from the entire frame. Therefore, the calculation load for creating a changing block group and calculating the connectivity is reduced without deteriorating the accuracy of static image detection. Can be reduced.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to these embodiments at all, and can be implemented in various modes without departing from the gist thereof.

As a premise of the following embodiments, in the present invention, a video code which can be compressed into a video which is easy to view even at a low bit rate video compression by classifying the video into several types and performing different processings respectively. Was used. This video encoding device first classifies a video signal input first into a static video, a dynamic video, and other normal video.

This video encoding apparatus classifies the type of the input video signal and then performs priority on the quality of the static video, so that the smoothness of the motion of the moving image other than the static video is reduced. Without loss, it is possible to provide a clearer image than a normal low bit rate encoding device.

Note that a static image is an image that is subjectively perceived as having little movement, for example, a still image that is completely the same image for a certain period of time, an image in which the moving area is extremely small with respect to a frame, and an object that is slightly vibrated. I will refer to a video that looks like For example, a case where a leaf of a tree sways in an image of a forest is classified as a static image.

On the other hand, a dynamic image refers to a scene change image in which an image suddenly changes, or an image in which a region moving with respect to a frame is extremely large. For example, an image captured while moving the camera sideways is classified as a dynamic image.

(Embodiment 1) The static video detection method according to the first embodiment is implemented in a video signal encoding apparatus that compresses a video signal into a video signal of a low bit rate. First, an overview of the video signal encoding device according to the present embodiment will be described.

The video signal encoding apparatus receives a digital moving image and creates and outputs a compressed image of a low bit rate by a video encoding unit in an encoder unit. The input digital video is also sent to the static video detector to detect the static video, and the static video is encoded into a low bit rate compressed image by the static video encoder in the encoder. Is done. The outputs of the static video encoding unit and the video encoding unit are connected and output.

FIG. 1 is a block diagram showing the configuration of the video signal encoding device. The video signal encoding apparatus includes an input unit 102 composed of a frame memory that holds a digital image 101 to be input, and a static video detection unit 103 that detects a static video.
And a static video encoding unit 107 that compresses the video signal at a low bit rate using the detected frame number, an encoder unit 104 including a video encoding unit 108, and an encoded low bit rate compressed image 106. Output means 105 for outputting.

Next, the operation of the entire apparatus according to the first embodiment will be described with reference to the flowchart of FIG. Step 101: First, the input means 102 loads a digital image into an internal frame memory (not shown). Step 102: The static video detection unit 103 reads a frame from the input unit 102 and outputs a frame number determined to be a static video to the encoder unit 104. Step 103: the encoder unit 104 reads the frames in order from the input unit 102, Step 104: If the frame is determined to be a static video, the static video encoding unit 107 performs encoding of the frame, Step 105: If it is not determined that the video is a static video, the video encoding unit 108 encodes the frame. Step 106: The encoder unit 104 connects the data of each frame encoded by the static video encoding unit 107 or the video encoding unit 108 in order.Step 107: If the currently processed frame is not the last frame, The static video detection unit 103 reads the next frame (Step 102) and repeats the processing. Step 108: After completing the encoding of the last frame, the encoder unit 104 sends the encoded data to the output unit 105.

Here, the process (Step 105) of the video encoding unit 108 in the encoder unit 104 is the same as that of a normal low bit rate video encoding device, and for example, H.263, MPEG1, MPEG4, etc. can be used. .

Next, the operation (Step 104) of the static video encoding unit 107 in the encoder unit 104 will be described. In a normal low bit rate video encoding device, an intra frame (I frame) in which only intra prediction encoding is performed
In general, a predicted image is created from a reference frame, and the encoded image is divided into interframes (P frames) in which inter-frame prediction is also performed.

The static video encoding unit 107 holds the reference frame and its original frame. If it is determined that the current frame to be encoded is a static video, the encoding of the current frame is performed. Instead, the P frame encoding is performed on the assumption that the original frame of the reference frame is the original frame of the current frame. Since a plurality of frames are encoded from the same source video, the image quality can be improved. Further, by adjusting the amount of information allocated to the encoding of the plurality of frames, it is possible to improve the image quality of the still image step by step during the continuous period of the static image.

Subsequently, the processing (Ste
p102) is explained in detail. FIG. 3 is a block diagram illustrating a configuration of the static video detection unit 103. Static video detector 1
03 is a frame memory 301 and a changed block detecting means 302
, A coupling degree calculating unit 303, an image characteristic determining unit 304, and a determination result output unit 305.

The operation of the static video detection unit 103 will be described with reference to the flowchart of FIG. Step 201: The static video detection unit 103 inputs the frame n.
(N is a frame number) Step 202: If n is the first frame, Step 203: Write frame n to the frame memory 301 and read frame (n + 1) (Step 201). Step 204: When n is not the first frame, the changed block detection means 302 detects a changed block of the frame (n-1) using the frame (n-1) and the frame n stored in the frame memory 301, The map information of the changed block is output to the connection degree calculation means 303. Step 205: The frame (n-1) is deleted from the frame memory 303, and a frame n is newly written in the frame memory 301. Step 206: The connection degree calculating means 303 is a changed block detecting means.
Based on the map information of the changed blocks received from 302, a changed block group is created, and the connectivity of the frames is calculated. Step 207: The image characteristic determining means 304 is the coupling degree calculating means 303
The degree of coupling calculated in step (1) is compared with a predetermined threshold value, and the result of the determination is output to the determination result output means 305. Step208: When n is not the last frame, the frame (n +
1) is read (Step 201).

Next, the changed block detection processing by the changed block detection means 302 will be described. The changed block detecting means 302 calculates a difference for each pixel between the current frame stored in the frame memory 301 and the next input frame. A pixel whose absolute value of the difference between the pixels is larger than a predetermined threshold value A is set as a changed pixel. Then, the frame is divided into blocks of a fixed size, and a block in which the number of changed pixels included in each block is larger than a predetermined threshold B is set as a changed block.

The changed block detecting means 302 detects one of the blocks belonging to the frame that is a changed block,
The map information of the changed block in which the non-changed block is set to 0 is created and output. In addition, as a method of determining a changed block, the absolute value of the difference of each pixel is added for each block, and the value is added to a predetermined threshold C.
Larger blocks can also be changed blocks.

Next, the coupling degree calculation processing by the coupling degree calculation means 303 will be described. The coupling degree calculation unit 303 obtains map information of the changed block from the changed block detection unit 302. FIG. 5 shows map information of the changed block. The black blocks are change blocks. The coupling degree calculation means 303
The target block is shifted in order from the upper left block to the lower right block. If the block of interest is a changed block, it is checked whether blocks adjacent to the block 8 adjacent to the block of interest are changed blocks.

As a result of the above integration, three changed block groups (a), (b) and (c) are obtained from the map information of the changed blocks in FIG. Subsequently, the connection degree calculating unit 303 checks the number of changed blocks included in the changed block group, and sets the number as the connection degree of the changed block group. Then, the maximum degree of connection among the changed blocks included in the frame is set as the degree of connection of the frame.

As described above, in the static image detection according to the present embodiment, whether or not the image is a static image is determined by calculating the degree of connection between frames. FIG. 6 shows the output result of the conventional image information detecting method based on the changing pixel area and the detecting method of the present embodiment.

(A), (b), (c), and (d) of FIG. 6 show changed pixels in the frame. FIGS. 6A and 6B are graphs showing the output of the conventional image information detection method based on the changed pixel area with respect to the changed pixel area of the frame, and the output of the detection method of the present embodiment. In FIG. 6A, the output is the area of the changed pixel in the frame, so that the output is almost the same in frames (a), (b), and (c). On the other hand, in the frame (d), the output is prominent because the area of the changed pixel is large. In FIG. 6B, the frames (b), (c), and (d) have a certain degree of coupling, but the coupling of the frame (a) is extremely small. 6 (A) and 6 (B), when trying to detect image information with a predetermined threshold value, and FIG. 6 (B), the sensitivity to static images is good, Can be accurately detected from a series of image sequences.

As described above, in the static image detection according to the present embodiment, since the degree of connection between frames is obtained and the image information is determined using the obtained value, the sensitivity is high with respect to the static image and the accuracy is high. Can be detected.

(Embodiment 2) The static image detecting method according to the second embodiment is implemented in a video signal encoding apparatus for compressing a video signal into a video signal of a low bit rate. The video signal encoding device is exactly the same as the configuration in FIG. 1 of the first embodiment, but differs in the internal configuration and operation of the static video detection unit 103.

The processing of the static image detecting section of this embodiment will be described in detail. FIG. 8 is a block diagram illustrating a configuration of the static video detection unit. The static video detector is a frame memory
801, change block detection means 802, and coupling degree calculation means 80
4, image characteristic determination means 805, and determination result output means 806
And change block compensation means 803.

The operation of the static video detector will be described with reference to the flowchart of FIG. Step 301: The static image detecting unit inputs the frame n. n
Is the frame number. Step 302: If n is the first frame, Step 303: Write frame n to frame memory 801 and read frame (n + 1) (Step 301). Step 304: When n is not the first frame, the changed block detection means 802 detects the changed block of the frame (n-1) using the frame (n-1) and the frame n stored in the frame memory 801. The map information of the changed block is output to the changed block compensation means 803. Step 305: The frame (n-1) is deleted from the frame memory 801 and a frame n is newly written in the frame memory 801. Step 306: The changed block compensation means 803 compensates for the changed block based on the map information of the changed block received from the changed block detection means 802 and rewrites the map information. Step 307: The coupling degree calculating means 804 is a changed block compensation means
Based on the map information of the changed block updated in 803,
Create a changing block group and calculate the degree of connection of the frame. Step 308: The image characteristic determining means 805 is the coupling degree calculating means 804
Then, the degree of coupling calculated in is compared with a predetermined threshold value, and the determination result is output to the determination result output means 806. Step 309: If n is not the last frame, frame (n +
1) is read (Step 301).

Next, a description will be given of a process of supplementing a changed block in the changed block supplementing means 803. FIG.
The map information of the changed block inputted from the changed block detecting means 802 and the map information after the changed block is supplemented by the changed block supplementing means 803 are shown. The changed block compensation means 803 detects, from the map information of the changed blocks, a group of non-changed blocks completely surrounding the four neighborhoods of the changed block in the upper, lower, left, and right directions, and sets those non-changed blocks as changed blocks. Rewrite information. FIG.
At 0 (A), the changed block groups (a) and (d) each have two and one non-changed block completely surrounded by the changed blocks. Therefore, the changed block compensation unit 803 compensates for the changed block and updates the map information as shown in FIG. The coupling degree calculating means 804 calculates the coupling degree of the frames based on the updated map information.

Here, consider a changing pixel between frames. When a large object with little shading changes in a frame, a change pixel between frames occurs only around the boundary of the object. In such a situation, in the part where the shading change is small at the center of the object, the changed pixel does not appear even though the object is moving, so it is necessary to supplement the changed pixel in order to perform highly accurate image information detection. .

In the static image detection method according to the present embodiment, since the changed blocks are used for detecting the degree of continuity, the degree of continuity of the group of changed blocks is corrected by compensating for the changed blocks as described above. , An accurate frame coupling degree can be detected.

Note that as a criterion for supplementing the changed block,
Although the case where the sides forming the outer periphery of the non-change block group are completely surrounded (the case where all the horizontal and vertical directions are surrounded) has been described, the present invention is not limited to this. For example, there are various modes of “surrounding” such as enclosing 80% or more, encircling 60% or more in the horizontal and vertical directions and obliquely (see FIG. 7).

As a more specific method, for example, the following method can be considered. The distance to the farthest block is determined for each block in the changing block group. A block that generates the distance A with the longest distance is defined as a block on both ends. Both end blocks are connected by a straight line, and a non-change block existing on the straight line is changed into a change block. Thereafter, the distance between both end blocks is obtained in the direction of the supplemented block, and the distance is set as the distance B.

(Distance A) / (Distance A + Distance B)> n (where 0 <n <1) is used as a reference for “change block compensation”. When the above expression is not satisfied, the changed block changed earlier is returned to the non-changed block. When the above expression is satisfied, a newly completely enclosed non-change block is compensated.

(Embodiment 3) The static image detection method according to the third embodiment is implemented in a video signal encoding apparatus for compressing a video signal into a video signal of a low bit rate. The video signal encoding device is exactly the same as the configuration in FIG. 1 of the first embodiment, but differs in the internal configuration and operation of the static video detection unit 103.

The processing of the static image detecting unit according to this embodiment will be described in detail. FIG. 11 is a block diagram illustrating a configuration of the static video detection unit. The static video detection unit includes a frame memory 1101, a changed block detection unit 1102, a coupling degree calculation unit 1103, an image characteristic determination unit 1105, a determination result output unit 1106, an area information processing unit and 1104. I have.

The operation of the static video detector will be described with reference to the flowchart of FIG. Step 401: The static image detecting unit inputs the frame n. n
Is the frame number. Step 402: If n is the first frame, Step 403: Write frame n to the frame memory and read frame (n + 1) (Step 401). Step 404: When n is not the first frame, the changed block detecting means 1102 detects a changed block of the frame (n-1) using the frame (n-1) and the frame n stored in the frame memory 1101, The map information of the changed block is output to the connection degree calculating unit 1103. Step 405: The frame (n-1) is deleted from the frame memory 1101, and the frame n is newly written in the frame memory 1101. Step406: When frame (n-1) is the first frame,
(Specifically, at the time of the second frame, since there is always a designated area, the designated area is designated first, otherwise the entire frame is designated.) Step 407: Coupling degree calculating means 1103 Based on the map information of the changed blocks received from the changed block detection means 1102, create a changed block group, calculate the degree of connection of the frame, the connection degree and changed block group information to the area information processing means 1104 Output. Step 408: When the frame (n-1) is not the first frame, the connection degree calculating unit 1103 obtains the connection degree of the changed block group in the area specified by the area information processing unit 1104, and obtains the maximum connection degree in the area. Step 409: When the maximum degree of coupling in the specified area is equal to or greater than a predetermined threshold, the area information processing unit 1104 uses the degree of coupling as the degree of coupling of the frame. Output to the image characteristic determination means 1105. If it is not equal to or larger than the threshold value, the area information processing means 1104 returns the connection degree calculation target area to the entire frame, and requests the connection degree calculation means 1103 to calculate the connection degree again (Step 407). Step 410: The image characteristic determining means 1105 is the area information processing means 1.
The degree of connection of the frames output from 104 is compared with a predetermined threshold value, and the determination result is output to determination result output means 1106. Step 411: When n is not the last frame, the frame (n +
1) is read (Step 401).

Next, the operations (Steps 406 to 409) relating to the connection degree calculating means 1103 and the area information processing means 1104 will be described in detail with reference to FIG.

The area information processing means 1104 divides the frame into several equal sizes as shown in FIG. 13A, and distinguishes each area by the area ID. FIG.
In this example, the frame is divided into nine frames, and the region IDs 1 to 9 are assigned. Also, it is determined that the area ID 0 indicates the entire frame. Then, the area information processing means 1104 notifies the connection degree calculating means 1103 of the area ID for obtaining the connection degree of the changed block group, and the connection degree calculation means 1103 obtains the connection degree from the area.

When the map information of the changed block of the first frame of the moving image sequence is input to the connection degree calculating means 1103 (Step 406), the area information processing means 1104 outputs the area ID 0
Is specified. Therefore, the connection degree calculating unit 1103 detects the changed block group from the entire frame as in the first embodiment, and determines the connection degree of the largest changed block group as the area information processing unit.
Output to 1104. At the same time, the connection degree calculating means 1103 also outputs information on the changed block group in order to determine the search area for the subsequent frames (Step 40).
7).

The area information processing means 1104 determines an area in which to search for the connectivity of the next frame from the received information on the changed block group. FIG. 13A shows information on a changed block group received from the connection degree calculation unit 1103. In the frame, there are three groups of changed blocks, (a), (b) and (c).
At this time, the area information processing means 1104 focuses on the changed block group (a) having the largest degree of connection, and selects an area including the largest number of changed blocks constituting (a). However, (a)
If there are a plurality of areas that include the largest number of changed blocks, the smaller area ID is given priority. The area ID of the determined area for calculating the degree of connection is notified to the degree-of-connection calculating means 1103 in this manner.

FIG. 13 (B) shows a coupling degree calculation target area determined from the changed block group information of FIG. 13 (A). FIG.
The area ID 2 in the shaded area in (B) is selected by the area information processing means 1104. Upon receiving the map information of the changed block in the next frame, the coupling degree calculating unit 1103 detects a changed block group in the area specified by the area information processing unit 1104. Then, the detection of the changed block group detected at that time is continued even outside the area. As a result, it is possible to detect, from the frame, a changed block group in which a changed block belonging to the changed block group is present in the area designated first. The maximum coupling degree among the detected changed block groups is sent to the area information processing means 1104 (Step 408).

The area information processing means 1104 stores the specified area ID
Is received from the degree-of-coupling calculating means 1103, a comparison is made with a predetermined threshold value D. If the degree of connection of the area IDs is equal to or greater than the threshold value D, the degree of connection is output to the image characteristic determination unit 1105, the same area ID is instructed to the degree of connection calculation unit 1103, and the processing is repeated. Also the area
When the coupling degree of the ID is equal to or smaller than the threshold value D, the area information processing means 1104 instructs the coupling degree calculating means 1103 to set the area ID to 0 and to calculate the coupling degree again for the frame ( Step409).

As described above, the area information processing unit 1104 limits the area for which the connection degree is calculated by the connection degree calculation unit 1103, so that it is possible to reduce the inoperability of the connection degree calculation. Also, by comparing the degree of connection of the area with the threshold value D, the degree of connection of the final frame is determined.
The sensitivity of static image detection is not reduced. (The static video detection method of the present embodiment can detect a static video faster with the same accuracy than the static video detection method of the first embodiment.) As a modification of the method according to the embodiment, the area information processing unit 1104 receives the coupling degree of the designated area ID from the coupling degree calculating unit 1103,
Comparison with D is performed. At this time, when the coupling degree of the region ID is equal to or less than the threshold value D, the region information processing unit 1104 specifies another region ID and specifies again for the frame. Coupling degree calculating means 11 to recalculate the coupling degree of the area
03 may be instructed.

Consider a case where the area information processing means 1104 receives information on a changed block group as shown in FIG. The area information processing means 1104 first determines the area in which to search for the connectivity of the next frame from the received information on the changed blocks, and first focuses on the changed blocks (a) having the largest connectivity. , (A) is selected. Then, the area information processing means 1104 focuses on the changed block group (b) having the second largest coupling degree, and similarly selects the area 3 including the largest number of changed blocks constituting (b). Similarly, the area information processing unit 1104 pays attention to the changed block group (c) and
Select Thus, the area information processing means 1104
Determines the connection degree calculation target region from the changed block group having a high connection degree in the frame, and stores the selected region IDs in order.

Then, the area information processing means 1104 sends the coupling degree of the designated area from the coupling degree calculating means 1103 to the coupling degree calculating means 1103 from the first selected area ID. Make a comparison. If the received coupling degree is equal to or less than the threshold value D, the area ID next selected from the stored area IDs is sent to the coupling degree calculating means 1103, and the coupling degree of the area is calculated again. Area information processing means 1104, as long as the degree of coupling of the area is equal to or less than the threshold D,
Such processing is repeated. However, the area information processing means
If the area ID stored inside 1104 runs out,
The area ID 0 is transmitted.

As described above, the area information processing unit 1104 places the order of the connection degree calculation target area and holds it inside, so that when the connection degree of a certain area is equal to or smaller than the threshold value D, the connection degree is immediately determined. Since the calculation target area does not need to be extended to the entire frame, it is possible to further reduce the inoperability of the connection degree calculation.

(Embodiment 4) The static video detection method according to the fourth embodiment is implemented in a video signal encoding device for compressing a video signal into a video signal of a low bit rate. The video signal encoding device is exactly the same as the configuration in FIG. 1 of the first embodiment, but differs in the internal configuration and operation of the static video detection unit 103.

The processing of the static image detecting section according to the present embodiment will be described in detail. The static image detection unit is exactly the same as the configuration of FIG. 11 of the third embodiment, and the operation is the same as that of the flowchart of FIG.
Are different from each other in the process of determining the connection degree calculation target region.

The process of determining the area to be calculated for the degree of connection in the area information processing means will be described in detail with reference to FIG. The area information processing means corresponds to FIG. 13 of the third embodiment.
As in (A), the frame is divided into several equal sizes, and each region is distinguished by region ID. Also in FIG. 14, the frame is divided into nine frames as in FIG.
An example in which region IDs from 9 to 9 are assigned is used. Also,
The area ID 0 is determined to indicate the entire frame.

When the map information of the changed block of the first frame of the moving image sequence is input to the coupling degree calculating means, the area information processing means specifies the area ID0. Therefore, the connection degree calculating means detects the changed block group from the entire frame as in the first embodiment, and outputs the maximum connection degree of the changed block group to the area information processing means. At the same time, the degree-of-association calculating means also outputs map information of the changed block in order to determine a search area for a subsequent frame.

The area information processing means determines an area to be searched for the coupling degree of the next frame from the received map information of the changed block. FIG. 14A shows map information of a changed block received from the coupling degree calculating means. At this time,
The area information processing means detects the number of changed blocks included in each area, and selects an area having the largest number of changed blocks. However, if there are a plurality of areas including the largest number of changed blocks, the one with the smaller area ID is prioritized.

The area ID of the determined area for calculating the degree of connection is notified to the degree of connection calculation means. FIG.
(B) shows the connection degree calculation target area determined from the map information of the changed block in FIG. 14 (A). The area ID 8 in the shaded area in FIG. 14B is selected by the area information processing means. Upon receiving the map information of the changed block in the next frame, the coupling degree calculating means detects a changed block group in the area specified by the area information processing means. Then, the detection of the changed block group detected at that time is continued even outside the area. As a result, it is possible to detect, from the frame, a changed block group in which a changed block belonging to the changed block group is present in the area designated first. The maximum coupling degree among the detected changed block groups is sent to the area information processing means.

As described above, the connection degree calculation target area in the area information processing means of the present embodiment is determined based on the number of changed blocks included in the area. The fact that the number of changed blocks included in the region is large means that the density of the changed blocks in the region is high. Likely to exist.

As described above, by the area information processing means limiting the area for which the degree of coupling is calculated by the degree of coupling calculation means, it is possible to reduce the inability to perform the calculation for the degree of coupling. In addition, since the final degree of connection of frames is determined by comparing the degree of connection of the area with the threshold value D, the accuracy of dynamic image detection is affected, but the sensitivity of static image detection is reduced. Not even. The static image detection method according to the present embodiment is different from the static image detection method according to the first embodiment in that
Static images can be detected at high speed with the same accuracy.

As a modification of the method of the fourth embodiment, when the area information processing means receives the degree of connection of the designated area ID from the degree of connection calculation means, it compares the degree of connection with the threshold value D. At that time, when the coupling degree of the area ID is equal to or less than the threshold value D, the area information processing means specifies another area ID,
The connection degree calculating means may be instructed to recalculate the connection degree of the specified region for the frame.

Consider a case in which the area information processing means receives map information of a changed block as shown in FIG. The area information processing means detects the number of changed blocks included in each area when determining the area to search for the connectivity of the next frame from the received map information of the changed blocks, and determines the number of changed blocks included in each area. The area IDs are stored in order from the largest area. That is, the order is such as region 8, region 2, region 5,...

Then, the stored area ID is sent from the head of the area ID to the coupling degree calculating means, and when the coupling degree of the designated area is received from the coupling degree calculating means, comparison with the threshold value D is performed. If the received coupling degree is equal to or smaller than the threshold value D, the next area ID is transmitted from the stored area ID to the coupling degree calculating means, and the coupling degree of the area is calculated again. Area information processing means, as long as the degree of connection of the area is equal to or less than the threshold value D,
Such processing is repeated. However, if the area ID stored in the area information processing means is exhausted, the area
Send ID0.

As described above, the region information processing means places the connection degree calculation target regions in order and holds them inside, so that when the connection degree of a certain region is equal to or smaller than the threshold value D,
Since the connection degree calculation target area does not need to be immediately extended to the entire frame, it is possible to further reduce the inoperability of the connection degree calculation.

In the present invention, the term “degree of connection between frames” is described, but this does not mean “the degree of connection between frames” but “the degree of contact between changed blocks (number of frames) in the frame. ) ".

[0080]

As is apparent from the above description, in the static image detection method of the present invention, since the degree of connection of frames is determined based on the degree of connection of changed blocks, a plurality of small objects having no noise or meaning move randomly. It is possible to perform highly accurate detection for a static video such as

Further, in the static video detection method in which non-change blocks mainly surrounding four sides are integrated into the change blocks forming the change blocks, the degree of coupling of the change blocks is corrected and accurate. The degree of frame connection can be detected.

Further, the frame is divided into a plurality of regions, and from those regions, the region containing the largest number of changed blocks belonging to the changed block group giving the highest degree of connection is calculated as the connection degree of the next frame. In the static video detection method with the target area, when the degree of connection of the areas is smaller than the threshold value, the connection degree calculation target area is returned to the entire frame and recalculated, so that the accuracy of the static image detection is not reduced. ,
In addition, by limiting the coupling degree calculation target area, it is possible to reduce the calculation load required for static video detection.

In the static video detection method, a frame is divided into a plurality of regions, and the region in which the number of changed blocks included in each region is the maximum is set as the region for calculating the connectivity of the next frame. When the coupling degree is smaller than the threshold value, the coupling degree calculation target area is returned to the entire frame and recalculated, so that the accuracy of the static video detection is not reduced.
In addition, by limiting the coupling degree calculation target area, it is possible to reduce the calculation load required for static video detection.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a low bit rate video encoding device according to a first embodiment.

FIG. 2 is a flowchart showing the operation of the entire low bit rate moving image encoding apparatus according to the first embodiment;

FIG. 3 is a block diagram illustrating a configuration of a static video detection unit according to the first embodiment.

FIG. 4 is a flowchart illustrating an operation of a static image detection unit according to the first embodiment.

FIG. 5 is a diagram showing an example of changed block map information which is an output of a changed block detection unit according to the first embodiment.

FIG. 6 is an explanatory diagram illustrating a difference between an output result of a conventional image information detection method and an output result of the detection method according to the first embodiment.

FIG. 7 is a diagram illustrating an example of a changed block compensation target pattern according to the second embodiment;

FIG. 8 is a block diagram illustrating a configuration of a static image detection unit according to the second embodiment.

FIG. 9 is a flowchart illustrating an operation of a static image detection unit according to the second embodiment.

FIG. 10 is a diagram illustrating an example of supplementing map information of a changed block by a changed block compensation unit according to the second embodiment.

FIG. 11 is a block diagram illustrating a configuration of a static image detection unit according to the third embodiment.

FIG. 12 is a flowchart illustrating an operation of a static image detection unit according to the third embodiment.

FIG. 13 is a diagram illustrating an example of detection of a connection degree calculation target region by the region information processing unit according to the third embodiment.

FIG. 14 is a diagram illustrating an example of detection of a connection degree calculation target region by a region information processing unit according to the fourth embodiment;

FIG. 15 is a block diagram showing the configuration of a conventional moving image automatic cutting division device.

[Explanation of symbols]

 101 Digital image 102 Input unit 103 Static video detection unit 104 Encoder unit 105 Output unit 106 Low bit rate compressed image 107 Static video encoding unit 108 Video encoding unit 301, 801, 1101 Frame memory 302, 802, 1102 Changing block Detecting means 303, 804, 1103 Coupling degree calculating means 304, 805, 1105 Image characteristic judging means 305, 806, 1106 Judgment result output means 803 Change block compensation means 1104 Area information processing means 2001 Image input means 2004 Change pixel area calculating section 2003 Scene change judgment unit 2004 Scene change frame output means

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazunori Yamada 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Term (reference) 5B050 BA11 EA04 EA10 EA24 GA08 5C023 BA04 CA01 DA04 5C059 KK39 NN24 NN28 PP05 PP06 RC17 UA33 5L096 GA06 GA15 HA02

Claims (12)

[Claims] 1. A changing block is obtained by a difference between frames, a connecting degree of frames is obtained by a connecting degree indicating the number of connected changed blocks, and a static image is detected by using the connecting degree of the frames. A static image detection method characterized by the above-mentioned. 2. A changing block group is created by integrating, from among a plurality of changing blocks existing in a frame, changing blocks existing in the vicinity of eight adjacent blocks, and changing the number of the changing blocks included in the changing block group. 2. The connection degree of a block group, and a maximum connection degree of a changed block group in the frame is set as a connection degree of the frame.
The static image detection method according to the above. 3. In a changed block group, when a changed block constituting the changed block group surrounds a part or the whole of the neighborhood of 8 adjacent to the non-change block, the enclosed non-change block is changed to the changed block. 3. The static image detecting method according to claim 1, wherein the static image is integrated into a block group. 4. The method according to claim 1, wherein the frame is divided into a plurality of regions, and a region in which the number of changed blocks belonging to a changed block group giving the maximum degree of connection is the largest is a region for calculating the degree of connection of the next frame. The static image detection method according to claim 1 or 2, wherein 5. When the connectivity of the changed block group having the largest connectivity in the connectivity calculation area is less than or equal to a predetermined threshold, the connectivity calculation area is returned to the entire frame. The static image detection method according to claim 4, wherein: 6. A frame is divided into a plurality of regions, and the region in which the number of changed blocks belonging to the changed block group is the largest is sequentially determined from the changed block group in the frame in order from the one having the highest degree of connection. When the connectivity of the changed block group within the connectivity calculation target area is equal to or less than a predetermined threshold, the connectivity calculation target area is placed in the next order. 5. The static image detecting method according to claim 4, wherein the area has the following. 7. The method according to claim 1, wherein the frame is divided into a plurality of regions, and a region in which the number of changed blocks included in the region is maximum is set as a connection degree calculation target region of the next frame. 3. The static image detection method according to 2. 8. A frame is divided into a plurality of regions, and a region where the number of changed blocks included in the region is large is numbered in a region for calculating the degree of connection of the next frame, and the region in the region for calculating the degree of connection is determined. The connection degree calculation target area having the following order is set as the connection degree calculation target area when the connection degree of the changed block group is equal to or less than a predetermined threshold value. Static image detection method. 9. A changed block detecting means for obtaining a changed block based on a difference between frames, a connection degree calculating means for obtaining a connection degree of frames based on a connection degree indicating the number of connected changed blocks, and a connection of the frames. A static image detection device for detecting a static image using the degree. 10. A change that integrates an enclosed non-change block into the change block group when the change block constituting the change block group surrounds a part or the whole of the neighborhood 8 of the non-change block. The static image detection device according to claim 9, further comprising a block compensation unit. 11. A region information processing device that divides a frame into a plurality of regions, and sets a region having the largest number of changed blocks belonging to a changed block group that provides the maximum connectivity as a connectivity calculation target region of the next frame. The static image detecting device according to claim 9, further comprising a unit. 12. A frame is divided into a plurality of areas, the number of changed blocks included in the area is detected, and area information in which the number of changed blocks is the largest is set as a connection degree calculation target area of the next frame. The static image detecting device according to claim 9, further comprising a processing unit.