JPH11146401A - Motion vector detection method and motion vector detection circuit of moving image signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of motion vector detection by reducing the erroneous detection of an initial deflection vector in the case that deflected motion is present in the entire video. SOLUTION: An initial deflection vector selection part 12 reads plural candidate vectors from motion vectors already detected before a block to be detected and selects the optimum motion vector in them as the initial deflection vector. In this case, a priority imparting part 14 detects the number of times of the selection at least over one field of the positions of the candidate vector selected as the initial deflection vector and imparts priority orders to the respective positions. Thus, in the initial deflection vector selection part 12, the candidate vector at the position corresponding to the motion of the entire video image is selected. With the initial deflection vector of the result as an origin, a true motion vector is detected in a vector computing part 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and a circuit for detecting a motion vector of a moving image signal.
In particular, the present invention relates to a motion vector detection method and a motion vector detection circuit for a moving image signal suitable for use in, for example, a television system conversion device that performs signal conversion between different television systems or a high-efficiency encoding device in image transmission. .

[0002]

2. Description of the Related Art A technique of detecting a moving area in a moving image as a motion vector and performing motion correction using the motion vector is a technique for improving inter-frame coding efficiency in high-efficiency coding at the time of image transmission. Or, it is effectively used to reduce the discontinuity of motion due to the conversion of the number of fields in the conversion of the television system. For example, as a television system conversion apparatus, JP-A-01-309597, JP-A-03-280681, and the Journal of the Institute of Television Engineers of Japan (Vol. 45, No. 12, pp. 1534 to 1543, published in 1991) ) Or in the proceedings (20-5) at the 1989 National Convention of the Institute of Television Engineers of Japan.

Conventionally, as a method of detecting a motion vector used in the above apparatus, for example, Japanese Patent Laid-Open No.
No. 2,683, JP-A-55-162684, or the pattern matching method described in JP-A-60-158786,
Each of the detection methods based on the iterative gradient method described in, for example, JP-A-62-206980 has been proposed.

In particular, the latter method of detecting a motion vector by the repetitive gradient method can detect a motion vector more compactly and more accurately than the pattern matching method. In the motion vector detection method, each field of a digitized television signal is subdivided into blocks of a predetermined size of m × n pixels including, for example, m pixels in the horizontal direction and n lines in the vertical direction. In addition, the amount of motion is estimated by an iterative gradient calculation based on a signal gradient in the screen and a physical correspondence of a signal difference value between corresponding screens.

[0005] In this case, JP-A-62-206980 discloses that
From the motion vectors already detected before the detected block as the initial value when estimating the motion amount, the optimal one among the motion vectors of a plurality of blocks near the detected block is set as the initial deviation vector. The number of gradient operations is reduced by selecting the selected operation and starting the operation from a value close to the true motion vector of the detected block.
A true motion vector is detected by the number of calculations.

[0006]

However, in the above-mentioned conventional technique, when selecting an initial deviation vector from a plurality of candidate vectors, the initial deviation vector is individually selected for each block. Therefore, even in the case where the entire image is skewed, the position of the block of the candidate vector to be selected as the initial deflecting vector may be different in each block, and there is a disadvantage that the detection accuracy is not improved by a certain degree or more. .

For example, when the screen pans, the entire screen moves in the same direction at the same speed. In this case, in each block, if the image is the same object and is a flat image, the motion vectors of the detected blocks around the detected block have the same value, and the pixel values when they are displaced are also the same. When selecting the initial displacement vector, the comparison results may have the same value. In this case, if the positions of the candidate vectors selected in each block are different even though the entire screen is moving in the same direction at the same speed, the gradient calculation using these as initial deviation vectors is performed. In some cases, an error occurred in each block in the result. Similarly, even in the case of a video with little motion, the position of the selected initial deviation vector may be different in each block.

In other words, in the above-described prior art, since the initial deviation vector is not selected in view of the motion characteristics of the entire video, the motion vector of the vertical block is erroneously detected in the video of the horizontal motion. However, there is a drawback that the accuracy of motion vector detection is not improved beyond a certain level, such as erroneous detection of a motion vector of a horizontal block in a video of a vertical motion.

The present invention eliminates such disadvantages of the prior art, and improves the accuracy of motion vector detection by reducing erroneous detection of an initial deviation vector in each block when there is a motion in the entire video. It is an object of the present invention to provide a motion vector detection method and a motion vector detection circuit for a moving image signal which can be caused to be caused.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention divides each field of a moving image signal into a plurality of blocks of a predetermined size, and each block has at least one field. Memory means for storing at least one field of motion vectors detected for each block in a motion vector detection circuit for a moving image signal for detecting a motion vector representing the magnitude and direction of motion between signals separated from each other; Read out the motion vectors of a plurality of blocks near the detected block from among the motion vectors stored in the storage means as candidate vectors,
An initial displacement vector selecting means for selecting a motion vector having a value closest to the motion of the detected block from the candidate vectors as an initial displacement vector, and an initial displacement vector selected by the initial displacement vector selecting means as a starting point. Vector calculating means for performing a gradient calculation a plurality of times to obtain a true motion vector of the detected block, further comprising an initial displacement vector selected by the initial displacement vector selecting means, A priority assigning means for detecting whether the block is a motion vector of a block located at a position over at least one field for each position and assigning a priority to each position in descending order of the number of selections; The vector selecting means selects an initial vector from candidate vectors at a plurality of positions based on at least the priority obtained in the previous field. Position and selects the vector.

In this case, the priority assigning means sequentially counts the position of the block of the candidate vector selected for each block as the initial displacement vector by the initial displacement vector selecting means, and sequentially counts the number of selections for each position. A plurality of counting means, a comparing means for comparing the counting result by the counting means, and an output means for delaying the comparison result by the comparing means by at least one field and outputting the result. It is preferable that the position priority is supplied to the initial deviation vector selection means.

[0012] When the initial deviation vector is selected from a plurality of candidate vectors, the initial deviation vector selecting means sets the position of the block of the candidate vector with respect to the detected block as selection information of a predetermined number of bits. Including selection information generating means for supplying to the priority assigning means, the priority assigning means receives the selection information from the selection information generating means, decodes the position of the block selected from the selection information, It is advantageous to have a candidate decoder that supplies the count signal to the corresponding counting means.

Further, the initial deviation vector selection means obtains, for each pixel, a difference value between the fields of the block deviated by each candidate vector and the detected block, and determines that the sum of the absolute values of the results is minimum. The motion vector of the block is preferably selected as the initial deviation vector.

In this case, the initial displacement vector selecting means includes:
When there are a plurality of blocks in which the total of the absolute values of the inter-field difference values is the smallest, it is preferable to select a candidate vector of a block at a position with a higher priority from the priority assigning unit as the initial deviation vector.

The initial deviation vector selecting means adds a predetermined value corresponding to the priority of each position to the total of the absolute values of the inter-field difference values, compares the resultant values, and compares the resultant value with the initial deviation. A position vector may be selected. In this case, the predetermined value according to the priority order may increase as the priority order decreases.

Further, it is advantageous that the initial deviation vector selecting means reads out from the storage means the motion vectors of the detected blocks corresponding to the eight neighboring blocks adjacent to the detected block as candidate vectors. In this case, the motion vector of the detected block may include an average vector that is the average value of the motion vectors of eight blocks around the block corresponding to the detected block in the previous field. Also, the motion vector of the detected block may include an acceleration vector obtained by subtracting the average vector of the field before the previous field from twice the average vector of the previous field.

On the other hand, the motion vector detecting method according to the present invention divides each field of a moving image signal into blocks of a predetermined size, and moves each signal between signals separated by at least one field. In the motion vector detection method of a moving image signal for detecting a motion vector representing a magnitude and a direction, a motion vector of at least a plurality of blocks near a detected block is selected as a candidate vector from motion vectors of a detected block. Step 1, a second step of selecting a motion vector having a value closest to the motion of the detected block from the candidate vectors selected in the first step as an initial deviation vector, and Performing multiple gradient operations using the selected initial deviation vector as a starting point to obtain the true motion vector of the detected block And a third step, wherein when the initial deviation vector is selected in the second step, the initial deviation vector is a candidate vector selected from any position of the detected block with respect to the detected block. A fourth step of detecting at least one field for each position and assigning a priority to each position in descending order of the number of selections. The second step is performed at least in the previous field. The optimum initial deviation vector is selected from the candidate vectors at the respective positions based on the priority order.

In this case, in the fourth step, the position of the block of the candidate vector selected for each block as the initial deviation vector in the second step is sequentially counted for each position. It is preferable to compare each of the counting results and assign a priority to each position based on the comparison result.

Further, the respective positions of the blocks of the candidate vector selected as the initial deviation vector in the second step with respect to the detected block are generated as selection information of a predetermined number of bits. Decoding the position of the selected block from the selection information generated for each block in the second step, generating a count signal for each position, and counting the number of selections for each position over at least one field This is advantageous.

Further, in the second step, an inter-field difference value between the block deviated by each candidate vector selected in the first step and the detected block is obtained for each pixel, and the absolute value of the result is obtained. It is preferable to select a motion vector of a block having the smallest sum of values as an initial deviation vector.

In this case, in the second step, when the total of the absolute values of the inter-field difference values is obtained, if there are a plurality of blocks with the minimum result, the fourth step obtains the sum from the plurality of blocks. It is preferable to select a candidate vector of a block at a position with a higher priority in the previous field as an initial deviation vector.

In the second step, after calculating the total of the absolute values of the inter-field difference values, a predetermined value corresponding to the priority of each position is added to the total value, and the resultant value is calculated. May be compared to obtain the motion vector of the block having the minimum value. In this case, the predetermined value according to the priority order may increase as the priority order decreases.

Further, the candidate vector selected in the first step is preferably a motion vector of a detected block corresponding to eight neighboring blocks adjacent to the detected block.
In this case, the motion vector of the detected block includes the surrounding 8 of the block corresponding to the detected block in the previous field.
It is advantageous to include an average vector which is the average of the motion vectors of the blocks. Also, the motion vector of the detected block may include an acceleration vector obtained by subtracting the average vector of the field before the previous field from twice the average vector of the previous field.

[0024]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a motion vector detecting circuit for a moving picture signal according to the present invention. FIG. 1 shows an embodiment of a motion vector detection circuit to which a motion vector detection method according to the present invention is applied. The motion vector detection circuit according to the present embodiment includes:
A moving image signal input for each field is divided into a plurality of blocks of m pixels × n lines (m and n are integers), and each block is separated from a corresponding block in the moving image signal one field before. This is a motion amount detection circuit for obtaining a motion vector representing the direction and magnitude of the motion of the motion vector, starting from an initial displacement vector selected from already detected motion vectors, for example, by performing two gradient method calculations. This is a vector operation circuit for obtaining a true motion vector.

In particular, in the present embodiment, the motion vectors of the detected blocks corresponding to the eight neighboring blocks adjacent to the detected block are set as candidate vectors of the initial deviation vector, and the motion vector of the block at each position is The main feature is that priorities are given to respective positions from the number of times selected as the initial deviation vector in the field, and the initial deviation vector in each block in the current field is selected based on the result. It is.

More specifically, as shown in FIG. 1, the motion vector detecting circuit according to the present embodiment includes a vector memory 10, an initial deviation vector selecting unit 12, a priority assigning unit 14, and a vector calculating unit 16. including. The initial displacement vector selection unit 12 and the vector calculation unit 16 respectively provide the current field signal B
Then, the previous field signal C is supplied via the delay circuit 18 and the field signal is divided into blocks of, for example, 8 pixels × 8 lines, and a motion vector is detected for each block.

The vector memory 10 is a storage circuit including a random access memory (RAM) for storing motion vectors for at least one field already detected for each block. A storage circuit which is connected and sequentially updates and stores the detected motion vector K at an address corresponding to the position of a divided block, for example.

The initial deviation vector selection unit 12 selects a motion vector having the value closest to the motion of the detected block from among the motion vectors of the detected blocks stored in the vector memory 10 as an initial deviation as a starting point of the gradient method operation. This is a selection circuit for selecting as the displacement vector G. In this embodiment, the motion vectors of eight blocks around the block of the previous field corresponding to the detected block are read out as candidate vectors L, and an initial displacement vector is selected from among them. .

More specifically, as shown in FIG. 3, for example, as shown in FIG. 3, the initial displacement vector selecting section 12 of the present embodiment includes a candidate vector detecting section 120, a coordinate converting section 122, and a subtracting section 124.
, An absolute value accumulating unit 126, a comparing unit 128, and a priority selecting unit 13.
Contains 0. The candidate vector detector 120 stores a vector memory in accordance with the position of the detected block of the current field signal B.
This is a memory access circuit that accesses 10 and reads out a motion vector 8 candidate L of a detected block. The read motion vector L is supplied to the coordinate conversion unit 122.

The coordinate conversion unit 122 is a conversion circuit that shifts each pixel of the block of the previous field C to the current field using the motion vector for each motion vector L. The converted pixel signal is supplied to the subtraction unit 124. The subtraction unit 124 is a difference circuit that calculates a difference between each pixel value of the coordinate-transformed block and the pixel value of the block of the current field B. The result is supplied to the absolute value accumulator 126.

The absolute value accumulating section 126 is an accumulating circuit for accumulating the absolute value of the difference value for each pixel by the number of pixels of the block, and the result is supplied to the comparing section 128, respectively. The comparing section 128 is a comparing circuit for comparing the respective accumulation results from the absolute value accumulating section 126, and supplies the block having the minimum result to the priority selecting section. The result of the comparison is not always that the number of the minimum blocks is one.

If the comparison shows that there are a plurality of minimum blocks, the priority selection unit 130 determines the motion of the block with the highest priority according to the information F indicating the priority of each position from the priority assignment unit 14. This is a selection circuit for selecting a vector. In this embodiment, for example, 3-bit selection information D is generated which indicates which of the eight blocks read as candidate vectors has been selected as the initial displacement vector. A selection information generating unit 132 is included.

Returning to FIG. 1, the priority assigning unit 14 determines at least one of the eight candidate blocks from the selection information D for each block from the initial deviation vector selecting unit 12. This circuit detects over the field and assigns a priority to each position. In this embodiment, for example, as shown in FIG. 2, a candidate decoder 142, eight counters 144 to 158, and a comparison circuit 160 , And a delay circuit 162.

The candidate decoder 142 is a detection circuit that decodes the 3-bit selection information D and detects which of the eight blocks has been selected for each block.
This is a signal generation circuit that supplies the count signals DA to DH to any of the counters 144 to 158 corresponding to the selected position.

The counters 144 to 158 are provided for the candidate decoder 142.
In this embodiment, at least one of the A to H counters corresponding to the positions of the eight blocks selected as the candidate vectors is used to count the count signals DA to DH. Count for the field. The counting results of the respective counters 144 to 158 are sequentially supplied to a comparison circuit 160.

The comparison circuit 160 includes a counter 144
This is an information generating circuit for comparing the counting results from .about.158 to output information E indicating the priority of each position. In this embodiment, the information generating circuit 3 indicates the priority for each field, for example, for each position. Bit information E is output in a predetermined order.

The delay circuit 162 is an information supply circuit for delaying the priority information E from the comparison circuit 160 by one field and outputting the delayed information. In this embodiment, the priority information E detected in the previous field is used for the current field. The information is sequentially supplied to the initial deviation vector selection circuit 12 as priority information F when selecting the initial deviation vector of the detected block.

Returning to FIG. 1, the vector operation unit 16
This is an arithmetic circuit that obtains a true motion vector K by a gradient method operation with the initial deviation vector G selected by the initial deviation vector selection unit 12 as a starting point. Specifically, as shown in the figure, a first gradient method operation circuit 200 and a first addition circuit 20
2, the second gradient method operation circuit 204, and the second addition circuit 20
For example, as shown in FIG. 5, the initial deviation vector is V0, the first deviation V1 and the second deviation
V2 and a motion vector V (= V0 + V1)
+ V2). As a result, when the block at the coordinates (m1, n1) in the previous field moves to the coordinates (m1 + α0, n1 + β0) in the current field as shown in FIG. Desired.

More specifically, the first gradient operation circuit 200
The motion amount of the current field is estimated from the coordinates where the previous field signal C is displaced by the initial displacement vector V0 as a starting point.
This is an arithmetic circuit for obtaining the first motion deviation V1 according to, for example, the following equations (1) to (4).

[0040]

[Equation 1] Vx = GNSGN ΔX · DFD / Σ | ΔX | ··· (1) Vy = ΣSGN ΔY · DFD / Σ | ΔY | ··· (2) ΔX = (A _{n + 1, m-} A _{n-1, m} ) / 2 ・ ・ ・ ・ (3) ΔY = (A _{n, m + 1} -A _{n, m-1} ) / 2 ・ ・ ・ ・ (4) where Vx is the motion vector V X, Vy is the y direction component of the motion vector V, _{An, m} is n pixels, the signal value of the coordinates of the m line, ΔX is the gradient of the image in the x direction, ΔY is the gradient of the image in the y direction, DFD Indicates an inter-field difference value. SGNΔX and SGNΔY indicate directions of gradients represented by +, −, and 0, respectively.

The first adding circuit 202 calculates the initial displacement vector
This is an arithmetic circuit for adding V0 and the first motion deviation V1 obtained by the first gradient method arithmetic circuit 200, and the result (V0 + V1)
To the second gradient operation circuit 206 and the second addition circuit 208
Respectively.

The second gradient method operation circuit 206 uses the same operation formulas (1) to (4) as the first gradient method operation circuit 200 based on the motion vector from the first adder circuit 202 to generate a second gradient method operation circuit 206. Deviation
This is an arithmetic circuit for calculating V2. The result is supplied to a second adding circuit 208.

The second adder circuit 208 includes the first adder circuit 20
4 and the second gradient method operation circuit 206
And outputs the output as the detected true motion vector K,
In addition, they are sequentially supplied to the vector memory 10.

The method of detecting a motion vector of a moving image signal according to the present embodiment in the above configuration will be described together with the operation of the motion vector detection circuit. In the operation state, the current field signal B and the input via the delay circuit 18 are input. The initial deviation vector selection unit 12
And the vector calculation unit 16. Initial deviation vector selection unit 12 receiving field signals B and C firstly
The candidate vector detection unit 120 sequentially reads the motion vectors of eight blocks around the block corresponding to the detected block from the vector memory 10.

Next, the read candidate vectors are supplied to the respective coordinate converters 122, and the preceding field signal C
Is shifted by the motion vector, and the result is supplied to the subtraction unit 124. As a result, each subtraction unit 124 obtains a difference for each pixel between the previous field signal C and the current field signal B subjected to coordinate conversion, and supplies the result to the absolute value accumulation unit 126. As a result, the respective absolute value accumulators 126 accumulate the absolute values of the differences between the respective pixels by the number of pixels of the block, and output the results to the comparators 128, respectively.

Next, the comparing section 128 having received the accumulation results of the respective candidate vectors compares them, detects the block having the minimum result, and supplies the comparison result to the priority selecting section 130. I do. In this case, assuming that only one block has been detected, the priority selection unit 130 selects the motion vector of the block with the smallest accumulation result, and uses the motion vector of the block as the initial displacement vector G in the vector calculation unit 16. Supply. At this time, selection information D indicating the position of the selected block is generated and supplied to the priority assignment unit 14.

Thus, in the priority assigning section 14, the position is decoded by the candidate decoder 142 which has received the selection information D, and the count signals DA to DH are supplied to the corresponding counters 144 to 158. As a result, one of the counters 144 to 158 at the position of the selected block updates the count value.

On the other hand, the vector operation unit 16 having received the initial deviation vector G deviates the target block of the previous field C by the initial deviation vector G, and sets the target block of the current field B as a starting point. , The first displacement is calculated by the first gradient method calculation unit 200, and the result is supplied to the first addition circuit 202. Next, a first adder circuit
At 202, the operation result of the first gradient operation unit 200 and the initial displacement vector are added, and the result is added to the second gradient operation unit.
204 and a second adder circuit 206. As a result, the second gradient calculator 204 further deviates the target block of the previous field C based on the addition result from the first adder circuit 202, and performs the second shift from this and the target block of the current field B. Calculate the deviation. The result is further supplied to the second adding circuit 206 and added to the operation result of the first adding circuit 202.

As a result, the true motion vector of one detected block in the current field B is detected and output, and is supplied to a predetermined address of the vector memory 10 and updated.

In the same manner, from among the motion vectors for at least one field detected before each detected block in each detected block, 8 of the motion vectors in the vicinity of the detected block are similarly obtained.
The motion vector of the block corresponding to the block is read from the vector memory 10, and the motion vector having the value closest to the motion of the detected block is selected as the initial displacement vector. A true motion vector is detected by the calculation.

However, when the initial displacement vector is selected, the number of blocks in which the sum of the absolute values of the differences between the signal values obtained by displacing the previous field signal by the candidate vectors and the current field signal value is not necessarily one is not necessarily one. May not always be the case. For example, if the pixel value of the detected block and its surrounding eight blocks are objects having similar values, and the screen has been panned and has similar motion vectors, the respective accumulation results will be similar values. Become. In this case, the comparison unit 128 of the initial deviation vector selection unit 12 regards the plurality of blocks as the minimum and sequentially supplies the results to the priority selection unit 130.

On the other hand, the priority selection section 130 receives the information F indicating the priority order of the eight blocks in the previous field in the priority assignment section.
The priority selector 130 selects a block having a higher priority from the plurality of blocks which are the smallest from the comparator 128 and supplies the selected block as the initial deviation vector G to the vector calculator 16. I do. As a result, a motion block according to the characteristics of the entire screen is selected, and the motion vector is selected as the initial deviation vector.

Hereinafter, similarly, the priority order F of the eight blocks in the previous field is supplied to the initial displacement vector selecting unit 12 from the priority assigning unit 14, so that the initial displacement vector selecting unit
When the initial deviation vector is selected in step 12, when the absolute value accumulation of the difference values of the blocks between the previous field and the current field deviated by the candidate vector is plural, and the smallest block appears, The motion vector of the block with the higher priority in the field is selected as the initial displacement vector.

Thereafter, in each field, an initial displacement vector G corresponding to the motion characteristics of the entire video is selected from the motion vectors stored in the vector memory 10 for each block in the same manner as described above. A true motion vector is detected starting from the initial displacement vector.

As described above, according to the motion vector detecting circuit and the motion vector detecting method of the present embodiment, which of the eight neighboring blocks with respect to the detected block has been selected in each field, which candidate vector has been selected more frequently. Since counting is performed and priority is given to each position according to the number of selections, when the initial displacement vector is selected by the initial displacement vector selecting unit 12, candidate vectors of a plurality of blocks are selected. When it becomes optimal, a more optimal candidate vector corresponding to the feature of the video can be selected as an initial deviation vector from at least the priorities of the previous fields. As a result, it is possible to unify the selection of the initial deviation vector at a location that was different in each block. Therefore, erroneous detection can be reduced, and the accuracy of detecting a motion vector can be improved.

In the above embodiment, an interlaced image signal using a field signal has been described as an example. However, the present invention may be applied to a non-interlaced image signal. In this case, the field signal at the beginning of the favorite may be read as a frame signal.

In the above embodiment, the initial deviation vector selection unit 12 compares the accumulation results of the absolute values of the inter-field differences, and considers the priority order F when the results are plural and minimum. However, in the present invention, a predetermined value that increases in advance according to the priority order F, for example, increases as the priority order decreases, is added to the accumulation result in advance. The results may be compared. In this case, for example, as shown in FIG. 6, the initial deviation vector selecting unit includes an adding unit 138 for adding a predetermined value corresponding to the priority order F to the output of each absolute value accumulating unit 126; It is preferable to provide an addition value setting unit 140 for setting a value. In this case, the selection unit 130 may be omitted and the comparison unit 128 may be provided with a selection information generation unit 132.

Further, in the above embodiment, the priority assigning section 14
Although the counters 144 to 158 count the number of times of selection for one field, the present invention is not limited to this, and the counter may count over several fields. In this case, the number of selections counted by the comparator 160 is compared for each field, and the result is compared with the delay circuit.
162 may be sequentially output for each field.

Further, in the above embodiment, eight peripheral blocks of the block corresponding to the detected block are selected as candidate vectors. In the present invention, for example, eight peripheral blocks of the target block in the previous field are selected. An acceleration vector obtained by subtracting the average vector of the previous field from the average vector including the average vector of the previous field or a value twice as large as the average vector of the previous field may include another candidate vector such as a candidate vector. In this case, when these are selected as the initial deviation vectors, a counter for counting the number of selections may be further provided in the priority assignment unit 14.

[0060]

As described above, according to the motion vector detecting circuit and the motion vector detecting method for a moving image signal of the present invention,
When an initial deviation vector is selected from the already detected motion vectors and the motion vector is detected using the initial deviation vector, the number of selections of each position of the candidate vector over at least one field is detected, and each position is selected. Since the priorities are assigned and the initial deviation vector is selected based on the priority up to the previous field, the initial deviation vector according to the feature of the video can be selected. As a result, the initial deviation vector that has been selected in each block can be selected from the candidate vectors at positions corresponding to the characteristics of the video, and erroneous detection of the initial deviation vector can be reduced. Therefore, there is an excellent effect that the accuracy of detecting a motion vector can be improved according to the characteristics of the video.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a motion vector detection circuit according to the present invention.

FIG. 2 is a block diagram illustrating a configuration example of a priority assigning unit of the motion vector detection circuit according to the embodiment of FIG. 1;

FIG. 3 is a block diagram showing a configuration example of an initial displacement vector selection unit of the motion vector detection circuit according to the embodiment of FIG. 1;

FIG. 4 is a diagram illustrating a relationship between respective target blocks of a current field signal and a previous field signal according to the embodiment of FIG. 1;

FIG. 5 is a diagram illustrating the principle of motion vector detection according to the embodiment of FIG. 1;

FIG. 6 is a block diagram showing another configuration example of the initial displacement vector selection unit of the motion vector detection circuit according to the embodiment of FIG. 1;

[Explanation of symbols]

 10 Vector memory 12 Initial deviation vector selection unit 14 Priority assignment unit 16 Vector calculation unit 142 Candidate decoder 144 to 158 Counter 160 Comparison circuit 162 Delay circuit

Claims (20)

[Claims] 1. A motion representing a magnitude and a direction of a motion between signals separated from each other by at least one field or more for each block in each field of a video signal. In a motion vector detection circuit for a moving image signal for detecting a vector, the circuit detects at least one motion vector detected for each block.
Storage means for accumulating data for the fields; reading out, as candidate vectors, the motion vectors of a plurality of blocks near the detected block from among the motion vectors stored in the storage means; Initial displacement vector selecting means for selecting a motion vector having a value closest to the initial displacement vector as an initial displacement vector, and performing gradient calculation a plurality of times with the initial displacement vector selected by the initial displacement vector selecting means as a starting point. Vector operation means for obtaining a true motion vector of the detection block, further comprising a block in which the initial deviation vector selected by the initial deviation vector selection means is located with respect to the detected block. Is detected over at least one field for each position. A priority assigning unit for assigning a priority in descending order of the number of selections, wherein the initial deviation vector selecting unit is configured to select an initial deviation from among candidate vectors at a plurality of positions based on at least the priority obtained in the previous field. A motion vector detecting circuit for a moving image signal, wherein a motion vector signal is selected. 2. The circuit according to claim 1, wherein the priority assigning unit assigns a position of a block of a candidate vector selected for each block as an initial offset vector by the initial offset vector selecting unit. A plurality of counting means for sequentially counting the number of times of selection for each position; a comparing means for comparing the counting result of the counting means; and an output means for delaying the comparison result by the comparing means by at least one field and outputting the result. Wherein the output from the output means is supplied to the initial deviation vector selection means as a priority of each position. 3. The circuit according to claim 2, wherein said initial displacement vector selecting means, when selecting an initial displacement vector from a plurality of candidate vectors, selects a block of the candidate vector with respect to a detected block. A selection information generation unit that supplies a position to the priority assignment unit as selection information of a predetermined number of bits, wherein the priority assignment unit receives the selection information from the selection information generation unit and selects from the selection information A motion vector detection circuit comprising: a candidate decoder that decodes the position of the block that has been obtained and supplies a count signal to the counting unit corresponding to the position. 4. The circuit according to claim 1, wherein the initial deviation vector selecting means obtains, for each pixel, an inter-field difference value between the block deviated by each candidate vector and the detected block. A motion vector detecting circuit, wherein a motion vector of a block in which the sum of absolute values of the result is the minimum is selected as an initial deviation vector. 5. The circuit according to claim 4, wherein said initial deviation vector selecting means, when there are a plurality of blocks in which the total sum of the absolute values of the inter-field difference values is the smallest, receives a signal from said priority assigning means. A motion vector detecting circuit, wherein a candidate vector of a block at a position with a higher priority is selected as an initial deviation vector. 6. The circuit according to claim 4, wherein said initial deviation vector selecting means adds a predetermined value according to the priority of each position to the total of the absolute values of the inter-field difference values, A motion vector detection circuit, which compares the resulting values and selects an initial displacement vector. 7. The motion vector detecting circuit according to claim 6, wherein the predetermined value according to the priority order increases as the priority order decreases. 8. The circuit according to claim 1, wherein the initial deviation vector selection unit reads out, from the storage unit, a motion vector of a detected block corresponding to eight neighboring blocks adjacent to the detected block as a candidate vector. A motion vector detection circuit, characterized in that: 9. The circuit according to claim 8, wherein the motion vector of the detected block includes an average vector which is an average value of motion vectors of eight blocks around a block corresponding to the detected block in the previous field. A motion vector detection circuit, characterized in that: 10. The circuit according to claim 8, wherein the motion vector of the detected block includes an acceleration vector obtained by subtracting the average vector of the field before the previous field from twice the average vector of the previous field. Motion vector detection circuit. 11. Each field of a moving image signal is divided into blocks of a predetermined size, and a motion vector representing the magnitude and direction of the motion is separated between signals separated by at least one field for each block. A method for detecting a motion vector of a moving image signal to be detected, the method comprising: selecting a motion vector of at least a plurality of blocks near a detected block from among motion vectors of a detected block as a candidate vector; A second step of selecting a motion vector having a value closest to the motion of the detected block from the candidate vectors selected in the first step as an initial deviation vector; A third step of performing a gradient operation a plurality of times with the deviation vector as a starting point to obtain a true motion vector of the detected block, Further, the method includes, when selecting an initial displacement vector in the second step, determining from which position of the detected block with respect to the detected block the initial displacement vector is a candidate vector selected from each position. At least 1 per position
A fourth step of detecting over the field and assigning a priority to each position in descending order of the number of times of selection, wherein the second step is based on at least the priority obtained in the previous field. A method for detecting a motion vector of a moving image signal, wherein an optimal initial deviation vector is selected from position candidate vectors. 12. The method according to claim 11, wherein the fourth step includes the steps of: selecting a position of a block of a candidate vector selected for each block as an initial deviation vector in the second step; A motion vector detection method characterized by sequentially counting the number of times of selection every time, comparing the count results, and assigning a priority to each position based on the result. 13. The method according to claim 12, wherein each position of the block of the candidate vector selected as the initial displacement vector in the second step with respect to the detected block is a predetermined number of bits of selection information. The fourth step decodes the position of the selected block from the selection information generated for each block in the second step, generates a count signal for each position, and A motion vector detection method characterized in that the number of selections for each position is counted over at least one field. 14. The method according to claim 11, wherein the second step includes a step of determining an inter-field difference between a block displaced by each candidate vector selected in the first step and a detected block. Is obtained for each pixel, and a motion vector of a block in which the sum of absolute values of the result is minimum is selected as an initial deviation vector. 15. The method according to claim 14, wherein the second step includes, when calculating a total of absolute values of the inter-field difference values, when there are a plurality of blocks having the minimum result. A motion vector detecting method, wherein a candidate vector of a block at a position with a higher priority in the previous field obtained in the fourth step is selected as an initial displacement vector from among the candidate vectors. 16. The method according to claim 14, wherein in the second step, after calculating a total of the absolute values of the inter-field difference values, a predetermined value corresponding to the priority of each position is added to the total value. And calculating the motion vector of the block having the minimum value by comparing the resultant values. 17. The motion vector detecting method according to claim 16, wherein the predetermined value according to the priority order increases as the priority order decreases. 18. The method according to claim 11, wherein the candidate vector selected in the first step is a motion vector of a detected block corresponding to eight surrounding blocks adjacent to the detected block. Characteristic motion vector detection method. 19. The method according to claim 18, wherein the motion vector of the detected block is an average vector that is an average value of motion vectors of eight blocks around a block corresponding to the detected block in the previous field. A motion vector detection method comprising: 20. The method according to claim 18, wherein the motion vector of the detected block includes an acceleration vector obtained by subtracting the average vector of the field before the previous field from twice the average vector of the previous field. Characteristic motion vector detection method.