JPH1075453A - Device and method for detecting motion vector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the detection error of a motion vector by calculating weighting quantity based on the difference of motion vector values between a reference block and an evaluation block and detecting the motion vector at the position where a block difference value provided by this calculation is minimized. SOLUTION: At a motion vector detector 1, encoded image data D1 are respectively successively stored in a memory 2 for current frame and a memory 3 for preceding frame at a difference operating part 1A for each frame. Namely, the current frame is stored in the memory 2 for current frame and the preceding frame is stored in the memory 3 for preceding frame respectively. In order to detect the motion vector, a designate signal S1 for designating the position of the reference block fixed in the current frame is sent out to a reference block address control circuit 5 by a block position count circuit 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Table of Contents] The present invention will be described in the following order. BACKGROUND OF THE INVENTION Problems to be Solved by the Invention (FIGS. 6 and 7) Means for Solving the Problems Embodiments of the Invention (FIGS. 1 to 5) Effects of the Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motion vector detecting device and a motion vector detecting method, for example, a digital VT for HDTV (High Definition Television).
This method is suitable for application to the case where a motion vector is detected when a moving image is highly efficiently encoded in R.

[0003]

2. Description of the Related Art Conventionally, when a moving picture is highly efficiently coded, a motion vector, that is, a moving direction and a size of an object in a temporally different picture are used. Used for inter-frame coding. As a method for obtaining a motion vector of an image, there is a block matching method (Japanese Patent Publication No. 54-12492).
No. 7).

In this block matching method, an appropriate number of pixels (M × N pixels) are respectively formed from an image of a current frame (basic image) and an image of a previous frame (reference image) which is one frame past. Form a block. Then, the block of the basic image is fixed (hereinafter, the block on the fixed side is referred to as a reference block),
When the block of the reference image is moved within the predetermined search area (hereinafter, the block on the side to be moved in this way is called an evaluation block), the sum S of the differences between the pixel values of the reference block and the pixel values of the evaluation block is obtained. _The motion vector is detected by obtaining the position of the evaluation block on the reference image side where _um (x, y) is minimized.

[0005]

In the above-described block matching method, it is general that weighting by a vector is not originally performed. However, weighting is performed on a zero vector position of a stationary portion in an image. 0 if
The entire screen moves when the vector position is within a block of a continuous pattern such as a roof tile and a block wall, or a block of a continuous image pattern with a constant brightness, such as a blue sky or a lawn, with a small difference in shading ( (Panning), a motion vector detection error may occur. However, when the weighted 0 vector position is in the still image area in the image, the motion vector is naturally 0, and detection errors hardly occur.

That is, as shown in FIGS. 6 (A) and 6 (B), the entire screen moves from right to left when performing block matching by focusing on blocks of a continuous image pattern such as a block wall. In the case of (panning) (movement only in the x direction but not in the y direction), a position different from the original motion vector position in the search area due to the presence of a block similar to the image pattern of the reference block Therefore, the sum of the differences between the pixel values of the reference block and the pixel values of the evaluation block may be minimized. In practice, as shown in FIG. 7, an evaluation block that minimizes the sum S _um (x, 0) of the difference between the pixel value of the reference block and the pixel value of the evaluation block is found at some positions in the search area. The presence of a plurality of (four) locations makes it difficult to identify which position of the evaluation block is genuine, thereby causing a problem that a motion vector detection error occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has a motion vector detecting apparatus and a motion vector detecting method capable of reducing a motion vector detection error in an image in which similar image patterns are continuous and in an image having a constant luminance. It is intended to propose a method.

[0008]

According to the present invention, there is provided a reference block formed in a predetermined size in a current frame and fixed at a predetermined position, and a reference block having the same size as a reference block in a previous frame. In the case where a motion vector is detected by moving the evaluation block consisting of in a search area within a predetermined range and performing block matching, the image data of the reference block and the image data of the evaluation block at each position moving in the search area are obtained. Is calculated, and the motion vector values of the surrounding blocks, which have already been processed for the image data before the reference block, and the motion vectors of the reference block and the evaluation block at each position moving in the search area. Weights based on the differences between the pixel values and the pixel values. Calculating a block difference value by adding the sum, so that the block difference value for detecting the motion vector from the position of the evaluation block with the smallest to the reference block. Thus, even when there are a plurality of evaluation blocks in which the total sum of the differences between the pixel values is minimized, the motion vector can always be accurately detected because the weighting amounts are added.

By multiplying the weighting amount by a coefficient proportional to the variance of the image data of the reference block, weighting can be performed in accordance with the sum of the differences between the pixel values, and thus the evaluation of the position at which the block difference value is minimized Detection of a motion vector from a block to a reference block can be facilitated to reduce detection errors.

The surrounding block is composed of an upper block adjacent to the top of the reference block and a left block adjacent to the left of the reference block, so that the motion vector of the block at the nearest position adjacent to the reference block. Since the weighting amount can be calculated based on the value, the calculation can be facilitated and the calculation time can be reduced, and thus the detection of the motion vector can be processed in real time.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1A, a block for performing block matching is formed by dividing a current frame (hereinafter referred to as a current frame) into a size of M × N pixels. . The blocks divided in the current frame are sequentially moved from the upper left to the lower right (0, 0),
(0, 1) (0, n ₀ ), (1, ₀ ), (1, 1)
(2, 0), (2, 1) (m, 0) (m,
In the case where the reference block is positioned at (n), the reference block to be fixed for obtaining the motion vector is positioned, for example, at (m ₀ , n ₀ ).

Here, since the image data of the ordinary scanning line system (non-interlace system) is input from the upper left to the lower right, the (0, 0) is also used in each block for detecting the motion vector. (0,1) ... (0, n
₀ ), (1, ₀ ), (1, 1) ... (2, 0), (2,
1) Image data is processed in the order of (m ₀ , n ₀ ) (m, n). In the present invention, the reference block (m _0, n ₀₎ the reference block (m _0, n ₀₎ among the surrounding blocks positioned around the the block adjacent the top on block of (m ₀ -1, n ₀ ), the block adjacent to the left part is positioned as the left block (m ₀ , n ₀ -1).

As shown in FIG. 1B, the search area of the previous frame is provided in a range (± x ₀ , ± y ₀ ) having an area about twice as large as the reference block. The reference block (m ₀ , n ₀ ) and the evaluation block (m ₋₁ , n ₋₁ ) are moved while moving the position of the evaluation block (m ₋₁ , n ₋₁ ) one pixel forward, backward, left and right in the search area. And block matching.

FIG. 2 shows the configuration of a motion vector detecting device 1 for performing block matching. In the motion vector detecting device 1, the encoded image data D
1 are sequentially stored in the current frame memory 2 and the previous frame memory 3 of the difference calculation unit 1A for each frame. That is, the current frame F ₀ is stored in the current frame memory 2.
However, the previous frame F _-1 is stored in the previous frame memory 3.

The block position counting circuit 4 designates the position of a fixed reference block (m ₀ , n ₀ ) in the current frame F ₀ stored in the current frame memory 2 in order to detect a motion vector. To the reference block address control circuit 5. Here, since the image data is input from the upper left to the lower right, the upper block (m ₀ , n ₀ ) adjacent to the upper part of the reference block (m ₀ , n ₀ ) around the reference block (m ₀ , n ₀ ) ₀ −1, n ₀ ) and the left block (m ₀ , n ₀ −1) adjacent to the left part have already been processed with the image data, and the detection of the motion vector value is performed in each block. Finished.

Therefore, a block position counting circuit
4 designates the designation signal S1 as a reference block address control.
Simultaneously with the reference block (m₀, N
₀Processing of image data has already been completed in blocks around
On top block (m₀-1, n₀) Motion vector value
(X m-1, y n) (Hereafter, this is the upward block motion
Vector value) and left block (m₀, N₀-1)
Motion vector value (x m₀, Y n₀-1) (hereinafter, this
This is called the left block motion vector value).
To the vector value memory 6 and the left block vector value memory 7.
Each is sent and stored.

Here, as shown in FIG.
Motion vector value (x m-1, y n) is the previous frame
F_-1From the top block to the current frame F₀Up to the block
, Which is a fixed value already calculated. Ma
The left block motion vector value (x m₀, Y n₀−
1) Also in the previous frame F_-1From the left block to the current frame F
₀Is the vector value up to the left block of
Is a fixed value.

Reference block address control circuit 5
Generates an address signal S2 for reading out the image data D2 of the reference block (m ₀ , n ₀ ) from the current frame memory 2 based on the designation signal S1, and sends it to the current frame memory 2. The current frame memory 2 reads out the image data D2 of the reference block (m ₀ , n ₀ ) based on the address signal S2 and sends it to the difference calculation circuit 8.

[0020] Subsequently, as shown in FIG. 3 (B), the vector control circuit 9 Bro poke in order to perform the pine quenching, all evaluation blocks before the search area of the frame F _-1 (m _-1, n _{- 1} ) to the motion vector value (x, y) from the reference block (m ₀ , n ₀ ) of the current frame F ₀
(Hereinafter referred to as a reference block motion vector value) are sequentially generated and sent to the evaluation block address control circuit 10 and the vector difference weight calculation circuits 11 and 12 as a motion vector value signal S3.

Evaluation block address control circuit 1
0 generates an address signal S4 for reading out the image data D3 of the evaluation block (m _-1 , n _-1 ) based on the input motion vector value signal S3 and sends it to the memory 3 for the previous frame. The previous frame memory 3 reads out the image data D3 of the evaluation block (m _-1 , n _-1 ) based on the address signal S4 and sends it to the difference calculation circuit 8.

The difference calculation circuit 8 receives the input image data D2 of the reference block (m ₀ , n ₀ ) and the evaluation block (m
₋₁ , n ₋₁ ) of the pixel data and the sum S _um (x, y) of the absolute values of the differences between the pixel values and the image data D 3.
As a result, the pixel value difference calculation section 1A sets the reference block (m
₀ , n ₀ ) and the evaluation block (m ₋₁ , n ₋₁ ) can be calculated. Here, the address values of all pixels within the reference block (m ₀ , n ₀ ) are (h,
v), each pixel value of the reference block (m ₀ , n ₀ ) is represented by Y (h, v), and each pixel value of the corresponding evaluation block (m ₋₁ , n ₋₁ ) is represented by Y xy (h, v), the sum S _um (x, y) of the absolute values of the differences between the pixel values is
Next formula

(Equation 1) Can be represented by

On the other hand, the upper block vector value memory 6 stores the stored upper block motion vector value (x m ₀ -1, y n ₀ ) to the vector difference weighting operation circuit 11. Similarly, the left block vector value memory 7 stores the stored left block motion vector value (x m ₀ , y n ₀ -1) is sent to the vector difference weight calculation circuit 12.

The vector difference weight calculation circuit 11 receives the input
The top block motion vector value (x m₀-1, y
n₀) Is input from the vector control circuit 9
Evaluation block (m_-1, N_-1) Or
Reference block (m₀, N₀Reference block movement up to)
Value proportional to the difference (distance) from the vector value (x, y)
With the weight value W_upAs (x, y), the following equation

(Equation 2) Is calculated.

Similarly, the vector difference weight calculation circuit 12
Is the input left block motion vector value (x m ₀ ,
y A value proportional to the difference (distance) between n ₀ -1) and the reference block motion vector value (x, y) input from the vector control circuit 9 is defined as a weight value W _left (x, y) as follows:

(Equation 3) Is calculated.

Here, the coefficient k used in the equations (2) and (3) is a value that changes according to the variance (variation) of the image data D2 read from the memory 2 for the current frame. Yes, each time the position of the reference block is changed by the coefficient operation circuit 16, the signal is newly generated, and is multiplied by the weight values W _up (x, y) and W _left (x, y) via the multiplier 17. Has been made.

That is, the coefficient operation circuit 16 outputs the image data D
2 is large, each evaluation block (m ₋₁ , n
_Since the sum S _um (x, y) of the absolute values of the differences from _-1 ) naturally increases, the weights W _up (x, y) and W _left (x, y) are increased by increasing the coefficient k. y) is made large and weighted heavily. Also,
When the variation of the image data D2 is small, the coefficient calculating circuit 16 naturally reduces the variation of the sum S _um (x, y) of the absolute values of the differences from the respective evaluation blocks (m ₋₁ , n ₋₁ ). By setting k to a small value, the weight value W
_Up (x, y) and W _left (x, y) are reduced and weighted smaller.

As described above, the coefficient calculation circuit 16 varies the value of the coefficient k in accordance with the variation of the image data D2, so that the total sum S _um ( _{E- 1} ) at each position of the evaluation block (m ₋₁ , n ₋₁ ). When the values of (x, y) are weighted, they are not largely changed (canceled) by the coefficient k. Therefore, the weight values W _up (x, y) and W
_left (x, y) is a very small value compared to the value of the sum S _um (x, y). In this case, the weight values W _up (x, y) and W _left (x, y) are obtained by changing the reference block motion vector value (x, y) to the upper block motion vector value (x m ₀ −
1, y n ₀ ) and the left block motion vector value (x m
₀ , y As the distance becomes closer to n ₀ -1), the distance becomes shorter, so that the difference becomes smaller, and naturally the weight value becomes smaller.

The calculated weight value W
_up (x, y) and W _left (x, y) are added by the adder 13, and further added to the sum S _um (x, y) of the absolute values of the differences output from the difference calculation circuit 8. And a block difference value D _iff (x, y)

(Equation 4) And a vector value detection circuit 1 as detection means
5 is sent.

In this way, the block difference values _Diff (x, y) calculated for all the evaluation blocks (m _-1 , n _-1 ) in the search area are input to the vector value detection circuit 15. . The vector value detection circuit 15 compares all the block difference values D _iff (x, y), and determines the reference block motion vector value (x, y) when the block difference value D _iff (x, y) becomes the smallest. Is output. Further, the vector value detection circuit 15 sends the detected reference block motion vector value (x, y) to the upper block vector value memory 6 and the left block vector value memory 7, and the right and lower blocks are next to the reference block ( m ₀ ,
n ₀ ) can be used as a motion vector value.

In the above arrangement, the motion vector detecting device 1 is based on the reference blocks (m ₀ , n ₀ ) and the evaluation blocks (m _-1 , n _-1 ) shown in FIGS. 6A and 6B. The case where the image moves from the right side to the left side will be described. In the motion vector detection device 1, the reference block of the difference connexion by the calculating unit 1A current frame _{F 0 (m 0, n 0} ) Evaluation of the search area of the image data D2 to the previous frame F _-1 of the block (m _-1, The sum S _um (x, y) of the absolute value of the difference between each pixel value and the image data D 3 of (n ₋₁ ) is calculated by the equation (1).

Here, the sum S _um (x, y) of all the evaluation blocks (m ₋₁ , n ₋₁ ) in the search area is calculated, and the evaluation block (m ₋₁ ) that minimizes the calculation result is obtained. ,
n _-1) is only determined the position of the sum for block images of consecutive identical pattern of bricks there are multiple S _um (x, y) is the minimum evaluation block (m _-1,
An accurate motion vector cannot be detected when a plurality of positions (n _-1 ) are detected (FIG. 7).

Therefore, the motion vector detecting device 1 uses the upper block motion vector value (x x) stored in advance by the block difference value calculator 1B. m ₀ -1, y n ₀ ) and the left block motion vector value (x m ₀ , y n ₀ -1)
(FIG. 3A), the reference block motion vector value (x,
y) and weight values W _up (x, y) and W _left (x, y) obtained by multiplying the absolute value of the difference between FIG. 3 (B) and the coefficient k by the equations (2) and (3). And the weight value W _up (x,
y) and W _left (x, y) are added to the sum S _um (x, y) of the absolute values of the differences between the pixel values according to equation (4) to obtain a block difference value _Diff (x, y). Ask.

In practice, the motion vector detecting device 1 uses the upper block motion vector value (x m ₀ -1, y n ₀ ) and the left block motion vector value (x m ₀ , y n ₀ −
1) is a fixed value, and all the reference block motion vector values (x, y) in the search area are evaluation blocks (m ₋₁ ,
n _-1 ), the weight value W is obtained only when the evaluation block (m _-1 , n _-1 ) is located at a position representing the original motion vector in the search area.
_up (x, y) and W _left (x, y) are minimized, and thus the block difference value _Diff (x, y) is minimized.

Accordingly, as shown in FIG. 4, in the motion vector detecting device 1, each evaluation block (m _-1 ,
block difference value D _iff at each location n _-1)
(X, y) are weight values W _up (x, y), W _left (x,
It is displayed as a graph having a slope corresponding to the magnitude of y). As a result, the motion vector detecting device 1 can detect the reference block motion vector value (x, y) at the position where the block difference value D _iff (x, y) is minimized by the vector value detecting circuit 15. Thus, a motion vector can be detected without error even in a block image of a continuous pattern such as a brick.

When calculating the weight values W _up (x, y) and W _left (x, y), the motion vector detecting device 1 uses the value of the coefficient k as the reference block (m ₀ , n ₀ ) pixel. By varying according to the variation, it is possible to change the inclination angle of the graph representing the block difference value _Diff (x, y) by weighting the sum S _um (x, y) without canceling by the coefficient k. The block difference value D _iff (x,
y) is the minimum reference block motion vector value (x,
y) can be easily detected, and the detection error of the motion vector can be reduced.

As described above, the motion vector detecting device 1 uses the difference calculating section 1A to calculate the difference between the pixel value at each position of the reference block (m ₀ , n ₀ ) and the evaluation block (m _-1 , n _-1 ). The sum S _um (x, y) of the absolute values of the weights W _up (x, y) is calculated by the block difference value calculation unit 1B.
y) and W _left (x, y) are calculated, and the weight value W is calculated.
_up (x, y) and W _left (x, y) are calculated as the sum S at each position of the evaluation block (m ₋₁ , n ₋₁ ).
_um (x, y) and each block difference value D
_iff (x, y) is calculated, and a reference block motion vector value (x, y) at which the block difference value D _iff (x, y) is minimized is detected by a vector value detection circuit 15 as a detecting means. Can be.

According to the above-described configuration, the motion vector detecting device 1 performs the image data D2 of the reference block (m ₀ , n ₀ ).
And evaluation block (m _-1, n _-1) sum of absolute values of differences between each pixel value of the image data D3 of the S _um (x, y), the upper block motion vector value (x m ₀ -1, y n ₀ ) and the left block motion vector value (x m ₀ , y n ₀ -1)
Weights W _up (x, y) and W _left obtained by multiplying the absolute value of the difference between the reference block motion vector value (x, y) and the coefficient k by the coefficient k.
(X, y) is added to the block difference value D _iff (x, y)
Is calculated, the block difference value D
_It is easy to detect the reference block motion vector value (x, y) that minimizes _iff (x, y), and thus, even when the image patterns of the blocks are similar, the detection error of the motion vector is reduced to achieve high quality. Image data can be transmitted.

Further, the motion vector detecting device 1 uses the reference block.
Tsuku (m₀, N₀) Is proportional to the variance of the image data D2.
The coefficient k obtained by adding the upper block motion vector value (x m₀-1,
y n₀) And the left block motion vector value (x m₀, Y
n₀-1) and the reference block motion vector value (x,
y), by multiplying the absolute value of the difference from
Sum of differences S_umWeight value W according to (x, y)_up(X,
y), W_left(X, y) can be calculated, and
Block difference value D_iffWhen (x, y) is minimized
Reference block (m₀, N₀) Easy motion vector detection
To reduce detection errors.

[0040] Furthermore, among the surrounding blocks motion vector detection device 1 located around the reference block (m _0, n _0), the reference block (m _0, n ₀₎ on adjacent the top of the block (m ₀ - 1, n ₀ ) and a left block (m ₀ , n ₀ -1) adjacent to the left portion, and a weight value W _up (x,
By calculating y) and W _left (x, y), the calculation can be facilitated and the calculation time can be reduced, and thus the motion vector can be detected in real time.

In the above embodiment, the motion vector
In the current frame F₀Reference block of
(M₀, N₀) And the upper blower adjacent to the upper and left
Tsuku (m₀-1, n₀) And left block (m₀, N₀−
1) each motion vector value (x m₀-1, y n₀)as well as
(X m₀, Y n₀-1) and the reference block motion vector
Weight value W based on the absolute value of the difference from the torque value (x, y).
_up(X, y), W_left(X, y) was calculated.
Although the case has been described, the present invention is not limited to this.
As shown in FIG.
Previous frame vector value memo to store the vector value
Motion vector 31 and the vector difference weight calculation circuit 32
The motion of the previous frame in addition to the
Vector value and reference block motion vector value (x, y)
Weight value W based on the absolute value of the difference between_for(X, y)
Calculated and the weight value W_for(X, y) is represented by a weight value W
_up(X, y), W_left(X, y) plus block difference
Value D_iff(X, y) may be obtained. This place
In this case, the same effect as in the above-described embodiment can be obtained.

In the above embodiment, the case where the area range of the search area is set to be about four times the area of the reference block (m ₀ , n ₀ ) has been described, but the present invention is not limited to this. Instead, the area range of the search area may be set freely according to the pattern of the image or the processing time.

Further, in the above embodiment, the block
Difference value D_iffReference block to find (x, y)
(M₀, N₀) Around the top and left
Tsuku (m₀-1, n₀) And left block (m₀, N₀−
1) each motion vector value (x m₀-1, y n₀)as well as
(X m₀, Y n₀-1)
However, the present invention is not limited to this.
Tsuku (m₀, N₀) Has already been processed for image data.
If the block is calculated with the motion vector value
Movement of either block or left block
Block difference value D using only torque value_iff(X, y)
Of the upper left diagonal block and the upper right diagonal block.
May be used.

Further, in the above-described embodiment, a case has been described in which the present invention is applied to a VTR for HDTV. However, the present invention is not limited to this, and in the field of digital image communication, a moving image is encoded with a high efficiency code Alternatively, the present invention may be applied to various devices that transmit data in a coded form.

[0045]

As described above, according to the present invention, a reference block formed at a predetermined size in the current frame and fixed at a predetermined position, and an evaluation block having the same size as the reference block in the previous frame are provided. When detecting a motion vector by performing block matching by moving within a search area within a predetermined range, the difference between the pixel value of the image data of the reference block and the image data of the evaluation block at each position moving within the search area is calculated. The sum is calculated and weighted by the difference between the motion vector value of the surrounding block where the image data has been processed before the reference block and the motion vector value of the reference block and the evaluation block at each position moving in the search area. And calculate the block difference value by adding the weighting amount to the sum of the pixel value differences. Block difference value so as to detect the motion vector from the evaluation block position with the smallest to the reference block. Thus, even when there are a plurality of evaluation blocks in which the total sum of the differences between the pixel values is minimized, the motion vector can always be accurately detected by adding the weighting amounts.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a case where block matching according to an embodiment of the present invention is performed.

FIG. 2 is a block diagram showing a configuration of a motion vector detecting device according to an embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining each motion vector value according to the embodiment of the present invention.

FIG. 4 is a table showing a graph based on a block difference value to which a weight value is added according to the embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a motion vector detecting device according to another embodiment.

FIG. 6 is a schematic diagram for explaining block matching on an image.

7 is a graph showing the minimum value of S _um when block matching a having conducted an image of a continuous pattern.

[Explanation of symbols]

1 ... Motion vector detection device, 2 ... Memory for current frame, 3 ... Memory for previous frame, 4 ... Block position count circuit, 5 ... Reference block address control circuit, 6 ... Top block vector value memory , 7 ...
... left block vector value memory, 8 ... difference operation circuit,
9 ... vector control circuit, 10 ... evaluation block address control circuit, 11, 12, 32 ... vector difference weight calculation circuit, 13, 14 ... adder, 15
... Vector value detection circuit, 16... Coefficient operation circuit, 17
... Multiplier, 31 ... Previous frame vector value memory.

Claims (6)

[Claims] 1. A reference block formed at a predetermined size in a current frame and fixed at a predetermined position, and an evaluation block having the same size as the reference block in a previous frame are moved within a search area within a predetermined range. A motion vector detecting device that detects a motion vector by performing block matching by using a block matching method, wherein a sum of pixel value differences between the image data of the reference block and the image data of the evaluation block at each position moving in the search area is calculated. Difference calculating means for calculating each of the motion vectors, the motion vector values of surrounding blocks in which image data has already been processed before the reference block, and the motion vectors of the reference block and the evaluation block at each position moving in the search area. Weight calculating means for calculating the weighting amount by the difference from the value, Adding means for calculating the block difference value by adding the weighting amount to the sum of the pixel value differences; and detecting the motion vector from the evaluation block to the reference block at the position where the block difference value is minimum. Means for detecting a motion vector. 2. The motion vector detecting device according to claim 1, further comprising a coefficient operation circuit for multiplying the weighting amount by a coefficient proportional to a variance value of the image data of the reference block. 3. The motion vector detection according to claim 1, wherein said peripheral block comprises an upper block adjacent to an upper portion of said reference block and a left block adjacent to a left portion of said reference block. apparatus. 4. A reference block formed at a predetermined size in a current frame and fixed at a predetermined position, and an evaluation block having the same size as the reference block in a previous frame are moved within a search area within a predetermined range. A motion vector detecting method for detecting a motion vector by performing block matching by using a block matching method, wherein a sum of pixel value differences between the image data of the reference block and the image data of the evaluation block at each position moving in the search area is calculated. A first step to be calculated respectively; a motion vector value of a peripheral block in which image data has already been processed before the reference block; and a reference block and the evaluation block at each position moving in the search area. Calculate the amount of weighting based on the difference from the motion vector value, and calculate the weight A second step of calculating the block difference value by adding the blur amount to the sum of the pixel value differences, and detecting a motion vector from the evaluation block to the reference block at the position where the block difference value is minimum. A motion vector detecting method, comprising the third step of: 5. The motion vector detecting method according to claim 4, wherein the second step multiplies the weighting amount by a coefficient proportional to a variance of the image data of the reference block. 6. In the second step, the peripheral block includes an upper block adjacent to an upper portion of the reference block and a left block adjacent to a left portion of the reference block. 4. The motion vector detection method according to 1.