JP3214660B2 - Motion vector detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for obtaining a motion vector necessary for performing motion-compensated inter-picture coding of a moving picture and for converting a motion-compensated picture format.

[0002]

2. Description of the Related Art Inter-picture predictive coding of a moving image, conversion of an interlaced signal to a progressive signal, or N
In image format conversion such as conversion from TSC to PAL, there is a motion compensation (motion correction) process of moving an image block by block in accordance with the motion of the image. In this motion compensation processing, a motion vector (hereinafter, also referred to as MV) is used as an amount of moving the image, and it is necessary to obtain this. As a method of detecting a motion vector, it is general to use block matching between a reference frame and a frame on which motion compensation is performed. As a specific method, a number of temporarily set MVs (hereinafter, temporarily set MVs are
V), the motion compensation target image is moved block by block, and a matching value is obtained between the corresponding block of the reference frame and the temporary M that minimizes the matching value.
Let V be the final MV. Here, the matching value is obtained by summing the square error and the absolute value error of each pixel in the block, as described later.

In the block matching, if a block is set small in order to cope with a more complicated motion, an MV different from the actual motion of the image is often detected. Such erroneous detection occurs because the number of pixels referred to in matching decreases, and the influence of noise and aliasing components increases. As a countermeasure against this, a method in which the matching value of peripheral blocks is considered instead of independently obtaining the MV for each block has been proposed by the same inventor and applicant as the present invention.
217184). In this case, when adding the matching value of the peripheral block, the matching value of the peripheral block is nonlinearly converted, and when the peripheral block moves differently with respect to the block to be subjected to motion compensation, The addition of the matching value is prevented.

Next, the above-described conventional vector detecting device will be specifically described with reference to FIG. FIG. 3 is a diagram showing a first configuration example of a conventional vector detection device, which is a conventional example of a motion vector detection device that adds matching values of peripheral blocks. In the figure, each of the portions 100, 101 and 102 separated by a broken line is an evaluation circuit corresponding to each motion vector (temporary MV) temporarily set. The signal of the reference frame input from the image A input terminal 4 is
It is provided to a matching detector 31 of the V evaluation circuit. The signal of the frame to be subjected to motion compensation input from the image B input terminal 8 is supplied to the motion compensator 34 of each temporary MV evaluation circuit.

[0005] In the motion compensator 34, the image is spatially moved in accordance with the provisional MV predetermined for each provisional MV evaluation circuit, and is output to the matching detector 31. In the matching detector 31, the difference between the signal of the reference frame and the signal of the motion-compensated frame is calculated for each pixel, and the absolute value or the square value thereof is added for one block and output as a matching value. In the basic block matching, this matching value becomes the evaluation value of each temporary MV as it is, and the temporary MV having the smallest matching value is selected as the final MV. When the final MV is selected, the following processing is performed.

The matching value obtained in block units is delayed in block units in a delay unit 32 and a delay unit 35 including a memory. The output of the matching detector 31 is the matching value of the subsequent block, and the output of the delay unit 32 is MV. The matching value of the center block to be detected is added to the delay unit 3
The output of 5 is the matching value of the previous block. here,
Assuming that the matching detection processing has been performed sequentially in the horizontal direction of the image, the rear block is the block on the left and the previous block is the block on the right with respect to the central block.

The matching value of the subsequent block is determined by the nonlinear circuit 3.
3, the matching value of the previous block is given to the non-linear circuit 36. In the non-linear circuits 33 and 36, when the input is equal to or less than a predetermined value, the output is, for example, 0.5 of the input.
When the input is more than a predetermined value, the output has a saturation characteristic. The non-linear circuits 33 and 36 are also provided with the matching value of the central block, and the boundary from the linear to the saturation characteristic is set to a value three to four times the matching value of the central block. Outputs of nonlinear circuits 33 and 36 and delay unit 32
(The matching value of the central block) is
And the final evaluation value of each temporary MV is provided to the minimum value detector 38. In the minimum value detector 38, the evaluation values of the respective temporary MVs output from the respective temporary MV evaluation circuits 100, 101, 102 are compared, and the temporary MV that gives the minimum evaluation value is output as the final MV. In this configuration example, only the matching values of the left and right blocks are used, but more peripheral blocks may be added.

FIG. 4 is a diagram showing a second configuration example of the conventional vector detection device. In the second configuration example shown in FIG. 4, the processing contents are the same as those in FIG. However, FIG. 3 shows parallel processing for each temporary motion vector (temporary MV), whereas FIG. 4 shows a method for obtaining matching values of all temporary MVs with one matching detector.
The image memory 9 is used for the motion compensation processing for general purpose.

In FIG. 4, matching value detecting means 30
Is a means for detecting matching values for all provisional motion vectors set in advance for a block to be subjected to motion compensation and its surrounding blocks, and is constituted by a matching value detector 5 and an image memory 9. The signal of the reference frame input from the image A input terminal 4 is provided to the matching detector 5. The signal of the frame to be subjected to the motion compensation input from the image B input terminal 8 is given to the image memory 9.

In order to obtain the MV for each block in the screen, the block generator 13 generates a block number and a corresponding address on the image memory 9. The number of each block is given to the matching value memory 6 and the delay unit 14. On the other hand, in order to obtain a matching value of each temporary MV in a predetermined block, the MV generator 10 sequentially outputs a vector value corresponding to the number of the temporary MV. The number of each temporary MV is given to the matching value memory 6 and the comparator 11.
In the image memory 9, the block address and the vector value are synthesized, and a predetermined temporary M
The image signal of the V value is read and provided to the matching detector 5. That is, in the image memory 9, writing is performed once at a predetermined address, and reading is repeatedly performed by shifting the address by the number of temporary MVs.

In the matching detector 5, a matching value is obtained in the same manner as in the case of the matching detector 31 shown in FIG. 3, and stored in a predetermined block of the matching value memory 6 at an address of a predetermined temporary MV. The delay unit 14 performs processing after matching values of peripheral blocks used in the non-linear addition processing are stored in the matching value memory 6.
Block numbers are delayed. The same MV number is used for both writing and reading. From the matching value memory 6, the matching values in the central block to be subjected to MV detection and the blocks around the central block are read out for each temporary MV, and given to the matching adder 22. The matching adder 22 corresponds to a circuit including the non-linear circuits 33 and 36 and the adder 37 in FIG. 3, and obtains an evaluation value of each temporary MV. The comparator 11 compares the evaluation values of the respective temporary MVs that are sequentially input, and outputs the temporary MV having the smallest evaluation value as the final MV.

[0012]

In the conventional motion vector detecting device, in adding the block matching values of the peripheral blocks, peripheral blocks having different motions are excluded by non-linear conversion. Since it differs for each vector and is not restricted by the non-linear transformation, the influence of the matching values of the peripheral blocks having different motions cannot be eliminated stably, and an appropriate addition result of the matching values may not be obtained. Further, since the addition processing is performed on all the temporary motion vectors, the processing amount of the addition operation and the memory amount of the block matching value are large. The present invention has been made in view of the above points, and an object corresponding to claims 1 to 4 is to provide a coefficient for weighting a matching value of a peripheral block on a block basis according to a similarity between motion blocks. The object of the present invention is to provide a motion vector detecting device capable of detecting a more probable motion vector by setting. Claims 3 to
An object corresponding to claim 4 is to provide a motion vector detecting device that requires a small amount of processing by selecting temporary vectors to be added.

[0013]

According to the motion vector detecting device of the present invention, when a motion vector (MV) of a block to be subjected to motion compensation is detected, a target block and its surroundings are detected. For each block, a matching value is obtained for all preset temporary MVs, and the matching value is temporarily stored. The similarity between blocks of the MV high-order candidate selected in each block is regarded as the similarity of motion, and the matching value is set. A motion vector detecting device that sums the matching value of each peripheral block multiplied by a given weighting coefficient and the matching value of the target block, and determines the MV as an evaluation value of each temporary MV of the target block. .

In the motion vector detecting device according to the present invention, when detecting the MV of a block to be subjected to motion compensation, a predetermined value is set for the target block and its surrounding blocks. Block matching values are obtained for all temporary MVs. Then, for each block, the upper candidate of the MV finally selected is set to the temporary MV.
The matching value is held only for the upper candidate, and the matching values are summed only for the upper candidate. The total value is used as the evaluation value of each temporary MV of the target block, and the MV is calculated based on the evaluation value. This is a motion vector detecting device to be determined.

[0015]

According to the present invention, when the motion vector (MV) is obtained, the matching values of the peripheral blocks are weighted and added according to the similarity of the motion. Regardless of the matching value of MV,
Since the matching value of that block will not be added,
It does not depend on matching values of different movements in the vicinity. In addition, by limiting the provisional MV to be subjected to the addition processing by the matching result of only the target block, the processing amount of the addition processing decreases in proportion to the number of limited vectors. The MV finally selected is, when viewed from the selection of only the target block,
Even if it is not optimal, it generally ranks higher, so even if it is limited, there is almost no deterioration.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment
An embodiment will be described with reference to FIG. FIG. 1 is a diagram showing a configuration example of a first embodiment according to the motion vector detecting device of the present invention. In FIG. 1, elements having the same functions as those of the conventional example shown in FIG. 4 are denoted by the same reference numerals. The matching value detection unit 30 is a unit that detects a matching value for all the provisional motion vectors set in advance for a block to be subjected to motion compensation and its surrounding blocks,
It comprises a matching value detector 5 and an image memory 9. The weighting coefficient setting means 40 is a means for setting a weighting coefficient of each peripheral block according to the similarity between the motion of the motion compensation target block and its peripheral blocks,
It comprises an MV selector 1, a selection MV number memory 2, and a weight setting device 3.

The motion vector determining means 50 is a means for determining a motion vector of a block to be subjected to motion compensation using the similarity of motion between blocks, and comprises a weighting adder 7 and a comparator 11. I have. The main difference between the first embodiment shown in FIG. 1 and the conventional example shown in FIG. 4 is that the matching adder 22 becomes the weighting adder 7 and has weighting coefficient setting means 40. In FIG. 1, the operations of the matching detecting means 30, the MV generator 10, the block generator 13, the delay unit 14, the matching value memory 6, and the comparator 11 are the same as those of the conventional example shown in FIG.

The signal of the reference frame input from the image A input terminal 4 is supplied to the matching detector 5 and the image B input terminal 8
The input frame signal to be subjected to motion compensation is supplied to the image memory 9. The matching value of each temporary motion vector (temporary MV) obtained by the matching detector 5 is sequentially supplied to the matching value memory 6 and the MV selector 1.
In the MV selector 1, the matching values of the respective temporary MVs are sequentially compared within the block, and ten values are selected in ascending order of the matching values, and the numbers of the corresponding temporary MVs are selected in the selection M.
Output as V number. The selection MV number is the selection MV
It is stored in the number memory 2 for each block. That is, ten temporary MV numbers are stored for each block.

The selected MV number is read from the selected MV number memory 2 in accordance with the block number delayed by the delay unit 14 in the same manner as the matching value memory 6, and is given to the weight setting unit 3. The weight setting unit 3 compares the MVs of the central block and its peripheral blocks to be subjected to the MV detection with the MVs of the central block and the MVs of the peripheral blocks. Is counted as the motion similarity. If n out of 10 are the same, the weight coefficient for the peripheral block is n × 0.1. As described above, the weighting factor is determined by the degree of adaptation of the MV, and is 1.0 when all the selected MVs are the same, 0.5 when all 5 MVs are the same, and 0 when all the MVs are different. The weight coefficient of each peripheral block obtained in this way is given to the weight adder 7. As described above, the weight coefficient is common to each motion provisional vector, and is set for each block.

FIG. 6 is a diagram showing the weighting factors of the peripheral blocks in the first embodiment. As shown in FIG. 9A, when the motion is uniform and the peripheral block is similar to the upper candidate MV, a high weight coefficient is obtained for all the peripheral blocks. On the other hand, as shown in FIG. 6B, when there is a different motion in the periphery, the peripheral block including the different motion (upper right in the diagram) also has a higher candidate of the motion vector, and thus has a lower weighting coefficient. . Note that the weighting coefficient of the peripheral block having the same motion remains high. FIG. 5 is a diagram showing an example of the internal configuration of the weight adder 7. As shown in the drawing, multipliers 51 and 53 multiply the matching results of the peripheral blocks (in the example, the rear block and the front block) given from the matching value memory 6 of FIG. And the matching result of the center block are added by the adder 52. This addition result is given to the comparator 11 of FIG. 1 as an evaluation value of each temporary MV.

In the comparator 11, a temporary MV having the smallest evaluation value is selected as in the conventional example, and its MV number is set to the final MV.
Is output from the MV output terminal 12. Note that the overall gain of the weight adder 7 also changes with the change of the weight coefficient, but the weight coefficient is given for each block.
Since each temporary MV in the block is common, there is no inconvenience in selecting the MV, and processing such as gain normalization is not required in this embodiment.

Next, a second embodiment of the motion vector detecting device according to the present invention will be described with reference to FIG. FIG.
It is a figure showing the example of composition of the 2nd example concerning the motion vector detecting device of the present invention. In FIG. 2, elements having the same functions as those of the conventional example shown in FIG. 4 are denoted by the same reference numerals. FIG.
2 is different from the conventional example shown in FIG. 4 in that the MV selector 1 is provided. In the figure, a signal of a reference frame input from an image A input terminal 4 is applied to a matching detector 5, and a signal of a frame subjected to motion compensation input from an image B input terminal 8 is applied to an image memory 9. The operations of the matching detector 5 and the image memory 9 are the same as those of the conventional example of FIG.
Are given to the matching value memory 6 and the MV selector 1.

The operation of the MV selector 1 is the same as that of the MV selector 1 shown in FIG.
In the same manner as described above, the top 10 candidates of the final MV among the temporary MVs are selected, and the MV numbers are output as the selected MV numbers.
The selected MV number is delayed by the delay unit 21 by the same amount as that of the delay unit 14, and when the matching values of the peripheral blocks are all set in the matching value memory 6, it is given to the matching value memory 6 as a read address and compared. It is also provided to the vessel 11. The matching value given to the matching value memory 6 is recorded for all temporary MVs, but is read only for the selected MV of the central block.

The basic operations of the matching adder 22 and the comparator 11 are the same as those in the conventional example shown in FIG. 4, but in the conventional example, all the temporary MVs are performed. This is performed only for the ten selected temporary MVs. The processing amount is proportional to the number of temporary MVs. If the number of temporary MVs is about 1000 (horizontal / vertical ± 15 pixels), the processing amount is 1/100. Further, the writing to the matching value memory 6 is also M
If only the temporary MV selected in the V selector selection 1 is used, the capacity of the matching value memory can be significantly reduced.
However, since the selected block MV number is different between the peripheral block and the central block, it is searched for a matching value of the same MV in the surroundings. And other processes are required.

[0025]

According to the present invention, when obtaining a motion vector (MV), matching values of peripheral blocks are weighted and added according to the similarity of motion. Accordingly, when the motion of the peripheral block is different, the matching value of the block is not added, and the motion is not influenced by the different peripheral motion, and more reliable MV detection can be performed even for a complicated motion. According to the second aspect of the present invention, the inter-block similarity of motion can be easily obtained by obtaining the degree of matching between blocks for the upper candidate MV selected based on only the matching value of each block. According to the third aspect of the present invention, the processing amount of the addition processing can be reduced by limiting the provisional MV to be subjected to the addition processing to the upper candidate MV of the target block.
Further, according to the present invention, the number of matching values temporarily recorded in the memory is similarly limited, so that the capacity of the memory can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a first embodiment according to a motion vector detection device of the present invention.

FIG. 2 is a diagram showing a configuration example of a second embodiment according to the motion vector detection device of the present invention.

FIG. 3 is a diagram illustrating a first configuration example of a conventional vector detection device.

FIG. 4 is a diagram showing a second configuration example in the conventional vector detection device.

FIG. 5 is a diagram illustrating an example of an internal configuration of a weight adder;

FIG. 6 is a diagram illustrating a state of weighting coefficients of peripheral blocks in the first embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 MV selector 2 Selection MV number memory 3 Weight setting device 6 Matching value memory 7 Weight adder 10 MV generator 11 Comparator 13 Block generator 14, 21 Delay unit 22 Matching adder 30 Matching value detecting means (5, 9) 37, 52 Adder 40 Weighting coefficient setting means (1, 2, 3) 50 Motion vector determining means (7, 11) 51, 53 Multiplier

Claims (4)

(57) [Claims] An apparatus for detecting a motion vector of a block to be subjected to motion compensation, comprising: a matching value detecting means for obtaining matching values for all preset temporary motion vectors for a target block and its surrounding blocks; A matching value memory for temporarily storing the matching value, weighting coefficient setting means for setting a weighting coefficient for each peripheral block according to the similarity of the motion between the target block and the peripheral block, and the weighting coefficient multiplied. A weighted adder that sums the matching value of each peripheral block and the matching value of the target block to obtain an evaluation value of the temporary motion vector of the target block, and compares the evaluation values of the temporary motion vectors with each other, A motion vector detecting device, comprising: a comparator for determining a motion vector. 2. An apparatus for detecting a motion vector of a block to be subjected to motion compensation, comprising: a matching value detecting means for obtaining matching values for all preset temporary motion vectors for a target block and its surrounding blocks; Comparing an upper candidate of the selected motion vector with an MV selector for selecting the upper candidate of the motion vector from the temporary motion vector of each block based only on the matching value in each block;
A weight setting device that calculates the similarity as a motion similarity between blocks; and a motion vector determination unit that determines a motion vector of a target block using the motion similarity between the blocks. Motion vector detection device. 3. An apparatus for detecting a motion vector of a block to be subjected to motion compensation, comprising: a matching value detecting means for obtaining matching values for all preset temporary motion vectors for a target block and its surrounding blocks; An MV selector for selecting a higher candidate of the motion vector from the provisional motion vector of the target block based only on the matching value of the target block; a matching value memory for temporarily storing the matching value; A matching value adder that adds a matching value between a target block and a peripheral block to obtain a temporary motion vector evaluation value of the target block; and a comparison that determines a motion vector of the target block by comparing the evaluation values of the temporary motion vectors with each other. And a motion vector detecting device. 4. The motion vector detecting device according to claim 3, wherein the matching value memory records a matching value limited to a candidate of a higher order of the motion vector.