JPH11205816A - Moving vector detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent mis-detection and to improve the detection accuracy in detecting a moving vector while considering color information by selecting the final moving vector from the outputs of respective moving vector search means, based on a prediction error calculation. SOLUTION: Moving vector search parts 30-32 obtain the moving vectors on a luminance signal Y and color difference signals CB and CR. A movement compensation prediction error, when the moving vector of previous frame detection is allocated in prediction error operation parts 51-53 on the respective blocks of the luminance signal Y, and the color difference signals CB and CR of a present frame is calculated from the respective moving vectors. A moving vector memory 50 stores the moving vector of the previous frame. A moving vector selection part 33 executes different processings, in accordance with the fact that which one among the luminance signal Y and the color difference signals CB and CR is at the selection mode of the previous frame. Then, it is adjusted to the screen sizes of luminance and color difference. In this way, the vector of the luminance signal Y and the color difference signals CB and CR is selected according to a previous frame movement compensation prediction error operation result so as to use it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motion vector detecting device for dividing a moving image into blocks each having a predetermined number of horizontal pixels and a predetermined number of vertical lines, and detecting a motion vector of the moving image for each block. is there.

[0002]

2. Description of the Related Art As a technique for compressing and transmitting an image or the like, there is a technique using motion compensation prediction. In order to perform motion compensation prediction, it is necessary to detect a motion vector. This method includes a method using only the luminance signal Y and a method using the color difference signals CB and CR in addition to the luminance signal Y. There are extended ways. As the latter, for example, Japanese Patent Laid-Open No. 5-2
There is one shown in Japanese Patent Application Laid-Open No. 19529.

FIG. 5 is a block diagram showing an image compression apparatus using motion compensation prediction by a motion vector detector similar to that disclosed in Japanese Patent Application Laid-Open No. 5-219529. In FIG. 5, 1 is an input image luminance signal Y, 2 is an input image color difference signal CB, 3 is an input image color difference signal CR, 4 is a luminance signal Y,
A buffer circuit which receives a color difference signal CB and a color difference signal CR and outputs them as a sequential signal a (Y / CB / CR) in the order of, for example, a luminance signal Y, a color difference signal CB, and a color difference signal CR;
0 is a subtractor, 11 is an orthogonal transformer, 12 is a quantizer, 13
Is a variable length encoding unit that assigns codes to input signals, 14 is a multiplexing unit, 15 is a buffer circuit that temporarily stores and outputs data, 16 is encoded data, 20 is an inverse quantization unit, and 21 is orthogonally transformed data. Orthogonal transform unit for performing an inverse transform on
Is an adder, 23 is an image memory, 24 is a motion compensator for performing motion compensation prediction according to the motion vector detected by the motion vector detector 100, 30, 31, and 32 are current color signals for each input signal based on the form of color specification. A motion vector search unit that searches for a motion vector from the frame and the reference frame,
33 is a motion vector selection unit for selecting a final motion vector from the output of each motion vector search unit;
Reference numerals 1 and 42 denote flatness determination units, and 100 denotes a motion vector detector.

Next, the operation of the image compression apparatus using the motion compensated prediction according to the above configuration will be described. Input image luminance signal Y
1, input image color difference signal CB2, input image color difference signal CR3
Is input to the buffer circuit 4 and is converted into a sequential signal of, for example, a luminance signal Y, a color difference signal CB, and a color difference signal CR. The difference between the serialized image signal a and the motion-compensated predicted image signal b is calculated by the subtracter 10 and output as a motion-compensated predicted error signal c. The motion-compensated prediction error signal c is orthogonally transformed by the orthogonal transformation unit 11, quantized by the quantization unit 12, assigned with a code by the variable-length encoding unit 13, and then, by the multiplexing unit 14. And output as encoded data 16 via the buffer circuit 15.

Here, generation of the motion-compensated predicted image signal b is performed as follows. The output of the quantization unit 12 is inversely quantized by the inverse quantization unit 20, subsequently, inversely orthogonally transformed by the inverse orthogonal transformation unit 21, and further added to the motion compensated prediction image signal b by the adder 22. And stored in the image memory 23.

The motion vector detector 100 detects a motion vector using the image signal of the reference frame output from the image memory 23 and the image signal of the current frame. The detection of the motion vector by the motion vector detector 100 will be described later. In response to the motion vector data, the motion compensation unit 24 generates and outputs a motion-compensated predicted image signal b. Further, the motion compensating unit 24 calculates the motion compensated prediction image signal b
Is also encoded and output to the multiplexing unit 14.

Next, detection of a motion vector in the motion vector detector 100 will be described. As described above, the motion vector detector disclosed in Japanese Patent Application Laid-Open No. 5-219529 detects a motion vector using the color difference signals CB and CR in addition to the luminance signal Y. First, the three motion vector search units 30, 31, and 32 determine the motion vector for each of the luminance signal Y and the color difference signals CB and CR using, for example, a block matching method. As is well known, for example, the block matching method divides the current frame into blocks (for example, 16 pixels × 16 lines in luminance, and the chrominance has a size such that the ratio of the entire screen to the block is equal to the luminance), and sums the absolute values of the differences. In this method, a block closest to the block is obtained from the reference frame by using the error evaluation criterion described above, and is used as a motion vector of the block.

The motion vector selection unit 33 selects one of the motion vectors for the luminance signal Y and the color difference signals CB and CR obtained in this manner as follows.
First, for each block of the luminance signal Y and the color difference signals CB and CR of the current frame, the flatness determination units 40, 41, and 42 compare evaluation criteria such as standard deviation and variance with predetermined thresholds, and determine whether the block is flat. Is determined. If the luminance block is not flat, a luminance motion vector is selected. When the luminance block is flat, the processing is divided depending on whether the color difference CB block is flat. If the color difference CB block is not flat, a motion vector of the color difference CB is selected. When the chrominance CB block is flat, the processing is divided depending on whether or not the chrominance CR block is flat. If the color difference CR block is not flat, a motion vector of the color difference CR is selected. If the chrominance CR block is flat, that is, if all of the luminance block, chrominance CB block, and chrominance CR block are flat, a luminance motion vector is selected. The motion vector selected in this manner is used after being enlarged or reduced according to the screen size of luminance and color difference.

Next, the operation of detecting a vector from an image will be described with reference to FIG. FIG. 6 shows an example in which stripes having the same luminance but different colors move from right to left. In FIG. 6, it is assumed that a portion with a pattern greatly differs from a white portion in value. The luminance signal Y is flat over the entire screen, but the color difference signals CB and CR have edges at the boundaries of the stripes. At the illustrated block positions, since the luminance block is flat, the motion vector detection is performed using the color difference CB block, and the motion vector can be detected.

[0010]

In the above-described conventional motion vector detection method, for example, in the case shown in FIG. 7, there is a possibility that a motion vector detection error occurs. That is, in the case of FIG. 7, the color difference is the same as in FIG. However, the difference is that there are stripes in the luminance. One cycle of the color difference stripes includes two cycles of luminance stripes. In the conventional motion vector detection method, since the luminance block is not flat at the block position shown in FIG. 7, a luminance motion vector is selected, and which of block 1 and block 2 of the reference frame (time t-1) is correct. Since it cannot be determined that the motion vector is a motion vector, there has been a problem that a motion vector detection error occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems of the prior art, and when detecting a motion vector in consideration of color information, it is possible to prevent a detection error of the motion vector and to obtain a correct motion. It is an object of the present invention to obtain a motion vector detecting device capable of detecting a vector with high accuracy.

[0012]

A motion vector detecting device according to the present invention divides an image into a plurality of blocks, and obtains a motion vector for each block. A plurality of motion vector searching means for respectively searching the input signal for a motion vector from a current frame and a reference frame; and a vector selection means for selecting any one of the motion vectors respectively output from the plurality of motion vector searching means. Means,
A motion vector storage means for storing a motion vector selected in the previous frame by the vector selection means, and respective inputs in the current frame when using the motion vector selected in the previous frame stored in the vector storage means A plurality of prediction error calculation means for respectively calculating a prediction error for the signal, wherein the vector selection unit includes a plurality of prediction error calculation values output from the plurality of prediction error calculation means. A final motion vector is selected from the output.

According to another aspect of the present invention, there is provided a motion vector detecting apparatus for dividing an image into a plurality of blocks and obtaining a motion vector for each of the blocks.
Signal selecting means for selecting one of a plurality of input signals from a current frame and a reference frame for a plurality of input signals based on a color specification form; and a current frame based on the input signal selected by the signal selecting means. Motion vector search means for searching for a motion vector from a reference frame, a motion vector storage means for storing a motion vector searched for in a previous frame by the motion vector search unit, and a previous frame stored in the motion vector storage means. A plurality of prediction error calculation means for respectively calculating a prediction error for each input signal in the current frame when the motion vector searched for in the current frame is used, and the signal selection means includes a plurality of the prediction error calculation means. Selecting one of a plurality of input signals based on a prediction error operation value output from the It is.

Further, in the above motion vector detecting apparatus, the plurality of input signals based on the color specification form are a luminance signal Y, a color difference signal CB, and a color difference signal CR.

According to another aspect of the present invention, there is provided a motion vector detecting apparatus for dividing an image into a plurality of blocks and obtaining a motion vector for each of the blocks.
Y / CB / CR weighting means for performing a predetermined weighting operation on the input luminance signal Y, color difference signal CB, and color difference signal CR to obtain a Y / CB / CR weighting signal, and Y / CB / CR weighting of the previous frame A motion detection Y / CB / CR weighting signal storage means for storing a signal;
Motion vector searching means for searching for a motion vector from the current frame and the reference frame for each of the Y and CB / CR weighting signals, and determining whether the luminance signal Y and the Y / CB / CR weighting signal are flat for each block. Flatness determining means for determining whether or not the motion vector is detected, a motion vector storing means for storing a motion vector detected in the previous frame,
And Y / C from the Y / CB / CR weighting means.
A B / CR weighting signal, a motion vector detected in the previous frame stored in the motion vector storage means, and a Y / CB / CR weighting signal stored in the motion detection Y / CB / CR weighting signal storage means. Prediction error calculation means for calculating a prediction error in the current frame based on the prediction error calculation value in the current frame output from the prediction error calculation means when the motion vector detected in the previous frame is used, and the flatness determination Motion vector selecting means for selecting a final motion vector from the output of the motion vector searching means based on the output of the means.

A motion vector detecting apparatus according to still another aspect of the present invention is a motion vector detecting apparatus which divides an image into a plurality of blocks and obtains a motion vector for each of the blocks. , Y / CB / CR by performing a predetermined weighting operation on the color difference signal CR
Y / CB / CR weight calculation means for obtaining a weight signal, Y / CB / CR weight signal storage means for motion detection for storing the Y / CB / CR weight signal of the previous frame,
Flatness determining means for determining whether or not the luminance signal Y and the Y / CB / CR weighting signal are flat for each block; motion vector storing means for storing a motion vector detected in the previous frame; Y and the Y / CB /
A Y / CB / CR weighting signal from the CR weighting means, a motion vector detected in the previous frame stored in the motion vector storage means, and the Y / C for motion detection
Y / CB / B / CR stored in the B / CR weight signal storage means
Prediction error calculating means for calculating a prediction error in the current frame based on the CR weighting signal, and prediction output from the prediction error calculating means for calculating a prediction error in the current frame when a motion vector detected in the previous frame is used A signal selecting means for selecting one of the luminance signal Y and an output of the Y / CB / CR weighting calculating means based on an error calculation value and an output of the flatness determining means; and an input signal selected by the signal selecting means. And a motion vector searching means for searching for a motion vector from the current frame and the reference frame based on the current frame and the reference frame.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a configuration diagram of an image compression device using a motion vector detection device according to Embodiment 1 of the present invention. 1, the basic configuration is the same as the conventional example shown in FIG. 5, and only the configuration of the motion vector detector 100 is different. Hereinafter, only the motion vector detector 100 will be described, and the same portions as those in FIG. 4 will be denoted by the same reference numerals and description thereof will be omitted. As a new code, 50 is a motion vector detected in the previous frame, that is, a motion vector memory storing the motion vector selected by the vector selection unit 33, and 51, 52, and 53 are motion vectors detected in the previous frame. Is a prediction error calculation unit that calculates a prediction error in the current frame, and the motion vector selection unit 33 selects one of the motion vectors output from the motion vector search units 30, 31, and 32, respectively. At this time, the final motion vectors output from the respective motion vector search units 30, 31, 32 are selected based on the prediction error operation values output from the prediction error operation units 51, 52, 53.

Next, the operation will be described. First, the three motion vector search units 30, 31, and 32 determine a motion vector for each of the luminance signal Y and the color difference signals CB and CR. The motion vector selection unit 33 selects one from the motion vectors for the luminance signal Y and the color difference signals CB and CR obtained by the motion vector search units 30, 31, and 32 as follows. First, a motion compensation prediction error (hereinafter, referred to as the following) when the motion vector detected in the previous frame by the prediction error calculation units 51, 52, and 53 is applied to each block of the luminance signal Y and the color difference signals CB and CR of the current frame. (Referred to as a previous frame motion compensation prediction error). The motion vector of the previous frame is stored in the motion vector memory 50.

The process of selecting the motion vector selecting section 33 is different depending on whether the selection mode of the previous frame is the luminance signal Y or the color difference signals CB or CR. For example, when the selection mode of the previous frame is the luminance signal Y, that is, when the motion vector of the luminance signal Y has been selected in the previous frame, first, the prediction error calculation unit 53 performs the previous frame motion compensation prediction of the color difference signal CR. The error calculation result is compared with a preset threshold value, and the processing is divided depending on the result.
If the calculation result is larger than the preset threshold, the motion vector of the color difference signal CR by the motion vector search unit 32 is selected. If the calculation result is equal to or less than the preset threshold value, the prediction error calculation unit 52 compares the previous frame motion compensation prediction error calculation result of the chrominance signal CB with the preset threshold value, and the processing is divided depending on the result. .
If the calculation result is larger than the preset threshold, the motion vector of the color difference signal CB is selected by the motion vector search unit 31. If the calculation result is equal to or less than the preset threshold, the luminance signal Y
Are selected.

If the selection mode of the previous frame is the color difference signal CR, that is, the color difference signal CR
Is selected, first, the result of the previous frame motion compensation prediction error calculation of the luminance signal Y by the prediction error calculation unit 51 is compared with a preset threshold value.
Processing is divided depending on the result. If the calculation result is larger than a preset threshold, the motion vector search unit 30
, A motion vector of the luminance signal Y is selected. If the calculation result is equal to or less than the preset threshold value, the prediction error calculation unit 52 compares the previous frame motion compensation prediction error calculation result of the chrominance signal CB with the preset threshold value, and the processing is divided depending on the result. . If the calculation result is larger than the preset threshold, the motion vector of the color difference signal CB is selected by the motion vector search unit 31. If the calculation result is equal to or less than the preset threshold, the motion vector of the color difference signal CR is selected by the motion vector search unit 32.

Further, when the selection mode of the previous frame is the color difference signal CB, that is, the color difference signal C
When the B motion vector is selected, first, the result of the previous frame motion compensation prediction error calculation of the luminance signal Y by the prediction error calculation unit 51 is compared with a preset threshold value, and the processing is divided depending on the result. . If the calculation result is larger than the preset threshold, the motion vector of the luminance signal Y is selected by the motion vector search unit 30.
If the calculation result is equal to or less than the preset threshold value, the prediction error calculation unit 53 compares the previous frame motion compensation prediction error calculation result of the color difference signal CR with a preset threshold value, and the processing is divided according to the result. . If the calculation result is larger than the preset threshold, the motion vector of the color difference signal CR by the motion vector search unit 32 is selected.
If the calculation result is equal to or smaller than the preset threshold, the motion vector of the color difference signal CB is selected by the motion vector search unit 31.

The motion vector selected by the motion vector selecting section 33 is used after being enlarged or reduced according to the screen size of luminance and color difference. The motion vector memory 50 stores the selected motion vector and the selection mode.

As described above, according to the first embodiment, based on the previous frame motion compensation prediction error calculation result,
Since the vectors of the luminance signal Y and the color difference signals CB and CR are selected and used, for example, even if the luminance block is not flat as shown in FIG. Are selected.

Embodiment 2 FIG. FIG. 2 is a configuration diagram showing an image compression device using a motion vector detection device according to Embodiment 2 of the present invention. The basic configuration is the same as that of FIG. Are different. Hereinafter, only the motion vector detector 100 will be described, and the same parts as those in FIG. 1 will be denoted by the same reference numerals and description thereof will be omitted. As a new code, reference numeral 60 denotes a signal selection unit for selecting one of the luminance signal Y and the color difference signals CB and CR from the current frame and the reference frame for each input signal based on the color specification. The selection unit 60 includes prediction error calculation units 51, 5
Signal selection is performed based on the prediction error calculation values output from 2, 53. Reference numeral 34 denotes a motion vector search unit that searches for a motion vector from the current frame and the reference frame based on the input signal selected by the signal selection unit 60.

Next, the operation will be described focusing on the parts different from the first embodiment. The motion vector search unit 34, the prediction error calculation units 51, 52, 53 and the motion vector memory 50 are the same as those in FIG. In Embodiment 1 described above, one is selected from the output results of the three motion vector search units. In Embodiment 2, however, only one motion vector search unit is provided. Is selected by the signal selection unit 60 as follows.

The process of selecting the signal selecting section 60 differs depending on whether the selection mode of the previous frame is the luminance signal Y or the color difference signals CB or CR. If the selection mode of the previous frame is the luminance signal Y, that is, if the luminance signal Y has been selected as an input to the motion vector search unit 34 in the previous frame, first, the prediction error calculation unit 53 calculates the color difference signal CR. The calculation result of the motion compensation prediction error of the previous frame is compared with a preset threshold value, and the processing is divided depending on the result. If the calculation result is larger than a preset threshold, the color difference signal CR is selected as an input to the motion vector search unit 34. If the calculation result is equal to or smaller than the preset threshold value, the color difference signal C
The result of the previous frame motion compensation prediction error calculation for B is compared with a preset threshold value, and processing is divided depending on the result. If the calculation result is larger than the preset threshold, the color difference signal CB is input to the motion vector search unit 34.
Is selected. If the calculation result is equal to or smaller than the preset threshold, the luminance signal Y is selected as an input to the motion vector search unit 34.

When the selection mode of the previous frame is the chrominance signal CR, that is, when the chrominance signal CR is selected as the input to the motion vector search unit 34 in the previous frame, first, the luminance by the prediction error calculation unit 51 The result of the previous frame motion compensation prediction error calculation of the signal Y is compared with a preset threshold value, and processing is divided depending on the result. If the calculation result is larger than a preset threshold, the luminance signal Y is selected as an input to the motion vector search unit 34. If the calculation result is equal to or smaller than the preset threshold value, the prediction error calculation unit 52 compares the previous frame motion compensation prediction error calculation result of the chrominance signal CB with the preset threshold value, and the processing is divided depending on the result. . If the calculation result is larger than a preset threshold, the color difference signal CB is selected as an input to the motion vector search unit 34. When the calculation result is equal to or smaller than the preset threshold, the color difference signal CR is selected as an input to the motion vector search unit 34.

If the selection mode of the previous frame is the chrominance signal CB, that is, if the chrominance signal CB has been selected as an input to the motion vector search unit 34 in the previous frame, first, the prediction error calculation unit 51 The result of the motion compensation prediction error calculation for the previous frame of Y is compared with a preset threshold value, and the processing is divided depending on the result. If the calculation result is larger than a preset threshold, the luminance signal Y is selected as an input to the motion vector search unit 34. If the calculation result is equal to or smaller than the preset threshold value, the prediction error calculation unit 53 compares the previous frame motion compensation prediction error calculation result of the color difference signal CR with a preset threshold value, and the processing is divided according to the result. . If the calculation result is larger than a preset threshold, the color difference signal CR is selected as an input to the motion vector search unit 34. If the calculation result is equal to or smaller than the preset threshold, the color difference signal CB is selected as an input to the motion vector search unit 34.

The motion vector selected in this way is
It is enlarged and reduced according to the screen size of luminance and color difference. The motion vector memory 50 stores the selected motion vector and the selection mode.

As described above, according to this embodiment, the same effects as those of the first embodiment can be obtained, and an even simpler apparatus can be obtained.

Further, in the first and second embodiments, three signals of the luminance signal Y and the color difference signals CB and CR are used as the input signals.
The processing may be simplified by using only two of the three signals.

Embodiment 3 FIG. FIG. 3 is a configuration diagram of an image compression device using a motion vector detection device according to Embodiment 3 of the present invention. 3, the basic configuration is the same as that of FIG. 1, but only the configuration of the motion vector detector 100 is different. Hereinafter, only the motion vector detector 100 will be described, and the same portions as those in FIGS. 2 and 7 will be denoted by the same reference numerals and description thereof will be omitted. As new codes, 70 and 71 are used for performing predetermined operations on the luminance signal Y and the color difference signals CB and CR.
/ CB / CR weighting operation unit, 72 is the Y /
A signal from the CB / CR weighting operation unit 71 (hereinafter, Y /
This is a motion compensation frame memory for storing CB / CR weighting signals).

Next, the operation will be described focusing on the parts different from the first embodiment. Motion vector search units 30, 3
1. The prediction error calculation units 51 and 52 and the motion vector memory 50 are the same as those in FIG. First, the Y / CB / CR weighting calculation units 70 and 71
Performs an operation represented by, for example, the following equation on the luminance signal Y and the color difference signals CB and CR to generate a Y / CB / CR weighted signal. I = αY + βCb + γCr, where Y: luminance signal Cb: color difference (CB) signal Cr: color difference (CR) signal α, β, γ: constant (where α + β + γ ≦ 1.0)

In the first embodiment, the vector search unit 33 determines the final motion vector by using the prediction error calculation units 51, 52, 5
3, the motion vector search units 30, 31, 32
In the third embodiment, the motion vector selection unit 33 selects the final motion vector according to the outputs of the prediction error calculation units 51 and 52 and the flatness determination units 40 and 41. The selection is made as follows from the motion vector of the / CB / CR weight signal.

First, the luminance signals Y, Y / CB of the current frame
For each block of the / CR weighting signal, the flatness determination units 40 and 41 compare evaluation criteria such as standard deviation and variance with a preset threshold value to determine whether or not the block is flat.
The selection mode of the previous frame is the luminance signal Y, Y / CB / CR
The processing differs as follows depending on which of the weighting signals it is.

When the selection mode of the previous frame is the luminance signal Y, that is, when the luminance signal Y is selected as the input to the motion vector search unit in the previous frame, the motion vector The result of the previous frame motion compensation prediction error calculation of the Y / CB / CR weighted signal by the calculation unit 52 is compared with a preset threshold value, and the processing is divided depending on the result. If the calculation result is larger than the preset threshold, the motion vector of the Y / CB / CR weighted signal by the motion vector search unit 31 is selected. If the calculation result is equal to or less than a preset threshold, the luminance block and Y
The processing is divided depending on whether the / CB / CR weighted signal block is flat or not. Brightness block is flat and Y / CB
If the / CR weighted signal block is not flat, the motion vector of the Y / CB / CR weighted signal by the motion vector search unit 31 is selected. Otherwise, the motion vector of the luminance signal Y by the motion vector search unit 30 is selected.

The selection mode of the previous frame is Y / CB / CR
If the signal is a weighted signal, that is, Y /
If the motion vector of the CB / CR weighting signal has been selected, first, the luminance signal Y
The result of the previous frame motion compensation prediction error calculation is compared with a preset threshold value, and processing is divided depending on the result. If the calculation result is larger than a preset threshold, the motion vector of the luminance signal Y is selected by the motion vector search unit 30. If the calculation result is equal to or smaller than the preset threshold value, the processing is divided depending on whether or not the Y / CB / CR weighted signal block is flat by the flatness determination unit 41. If the Y / CB / CR weighted signal block is flat, the luminance signal Y
Are selected. Otherwise, the motion vector of the Y / CB / CR weighting signal by the motion vector search unit 31 is selected.

The motion vector selected in this way is
It is enlarged and reduced according to the screen size of luminance and color difference. The motion vector memory 50 stores the selected motion vector and the selection mode.

As described above, according to this embodiment, the same effects as those of the first embodiment can be obtained, and an even simpler apparatus can be obtained.

In the third embodiment, the luminance signals Y and Y
Although the selection is made from two signals of the / CB / CR weighting signal, a plurality of Y / CB / CR weighting signals having different calculation contents may be prepared, and the selection may be made from N signals (N> 2).

Embodiment 4 FIG. FIG. 4 is a configuration diagram of an image compression device using a motion vector detection device according to Embodiment 4 of the present invention. In FIG. 4, the basic configuration is the same as in FIGS. 2 and 3, except for the configuration of the motion vector detector 100. Hereinafter, only the motion vector detector 100 will be described, and the same portions as those in FIGS. 2 and 3 will be denoted by the same reference numerals and description thereof will be omitted.

Next, the operation will be described focusing on the parts different from the second embodiment. The motion vector search unit 34, the prediction error calculation units 51 and 52, and the motion vector memory 50 are the same as those in FIG. First, the Y / CB / CR weighting calculation units 70 and 71 perform the calculation represented by, for example, the expression shown in the third embodiment on the luminance signal Y, the color difference signals CB and CR, and perform Y / CB / CR.
Generate a weighting signal.

In the second embodiment, the motion vector search unit 3
The signal selection unit 60 inputs the input to 4 into the prediction error calculation units 51 and 5.
2, 53, the luminance signal Y and the color difference signals CB, C
However, in the third embodiment, the signal selection unit 60 inputs the input to the motion vector search unit 34 according to the outputs of the prediction error calculation units 51 and 52 and the flatness determination units 40 and 41. One of the CB / CR weighting signals is selected as follows.

First, the luminance signals Y, Y / CB of the current frame
For each block of the / CR weighting signal, the flatness determination units 40 and 41 compare evaluation criteria such as standard deviation and variance with a preset threshold to determine whether or not the block is flat. The processing differs as follows depending on whether the selection mode of the previous frame is the luminance signal Y or the Y / CB / CR weighting signal.

When the selection mode of the previous frame is the luminance signal Y, that is, when the luminance signal Y is selected as the input to the motion vector search unit 34 in the previous frame, the signal selection unit 60 Y /
The result of the previous frame motion compensation prediction error calculation of the CB / CR weighted signal is compared with a preset threshold value, and processing is divided depending on the result. If the calculation result is larger than a preset threshold, a Y / CB / CR weighting signal is selected as an input to the motion vector search unit 34. If the calculation result is equal to or smaller than the preset threshold, the luminance blocks and Y / CB / C
The process is divided depending on whether the R-weighted signal block is flat or not. If the luminance block is flat and the Y / CB / CR weighted signal block is not flat, the Y / CB / CR weighted signal is selected as an input to the motion vector search unit 34. Otherwise, the luminance signal Y is selected as an input to the motion vector search unit 34.

The selection mode of the previous frame is Y / CB / CR
If the signal is a weighted signal, that is, if the Y / CB / CR weighted signal has been selected as an input to the motion vector search unit in the previous frame, the prediction error calculation unit 5
The result of the previous frame motion compensation prediction error calculation of the luminance signal Y by 1 is compared with a preset threshold value, and the processing is divided depending on the result. If the calculation result is larger than a preset threshold, the luminance signal Y is selected as an input to the motion vector search unit 34. If the calculation result is equal to or less than the preset threshold, the processing is divided depending on whether the Y / CB / CR weighted signal block is flat or not. Y / CB / C
When the R-weighted signal block is flat, the luminance signal Y is selected as an input to the motion vector search unit 34. Otherwise, the Y / CB / CR weighting signal is selected as an input to the motion vector search unit 34.

The motion vector selected in this way is
It is enlarged and reduced according to the screen size of luminance and color difference. The motion vector memory 50 stores the selected motion vector and the selection mode.

As described above, according to this embodiment, the same effects as those of the second embodiment can be obtained, and an even simpler device can be obtained.

In the fourth embodiment, the luminance signals Y and Y /
Although the selection was made from two signals of the CB / CR weighting signal,
A plurality of Y / CB / CR weighting signals having different calculation contents may be prepared and selected from N signals (N> 2).

In all of the above embodiments, the three signals of the luminance signal Y and the color difference signals CB and CR are used.
Other color system signals such as G and B signals and Y, I and Q signals may be used.

Further, in all the above-described embodiments, the motion vector detection based on the frame has been described. However, it is apparent that the detection can be performed based on the field.

In all the above-described embodiments, the processing performed by the motion vector search units 30, 31, and 32 may be any processing for obtaining a motion vector for each rectangular block.

[0053]

As described above, according to the present invention, since the luminance signal Y and the color difference signals CB and CR are selected and used based on the result of the motion compensation prediction error calculation of the previous frame, the luminance block Even if it is not flat, if it is preferable to select the color difference signal vector, the color difference signal vector is selected.When detecting the motion vector in consideration of the color information, the motion vector detection error Prevent
A correct motion vector can be accurately detected.
Further, since the conventional motion vector detecting means itself can be used as it is, changes in the apparatus scale and configuration are relatively small.

Further, assuming that the number of motion vector search units is one, the output of the prediction error calculation unit and the motion vector selected in the previous frame are searched by any one of the luminance signal Y and the color difference signals CB and CR. Based on the information as to whether the input signal is a motion vector search unit, a luminance signal Y, a color difference signal CB,
Since the selection is made from the CR, the change of the apparatus scale and the configuration can be made relatively small and downsized.

Further, since the motion vector is selected based on the determination as to whether or not each block of the luminance signal and the Y / CB / CR weighting signal is flat, the selected motion vector has the luminance and the chrominance. It is suitable to be used after being enlarged or reduced in accordance with the screen size, and it is possible to prevent a detection error of a motion vector and accurately detect a correct motion vector.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a motion vector detection device according to Embodiment 1 of the present invention.

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

FIG. 3 is a configuration diagram of a motion vector detection device according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a motion vector detection device according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram showing a conventional motion vector detection device.

FIG. 6 is an explanatory diagram of motion vector determination of a conventional motion vector detection device.

FIG. 7 is an explanatory diagram of a motion vector determination of the motion vector detection device of the present invention.

[Explanation of symbols]

1 input image luminance signal Y, 2 input image color difference signals CB,
3 input image color difference signal CR, 4 buffer circuit, 10
Subtractor, 30, 31, 32, 34 motion vector search unit, 33 motion vector selection unit, 40, 41 flatness determination unit, 50 motion vector memory, 51, 52, 53 prediction error calculation unit, 60 signal selection unit, 70, 71 Y / C
B / CR weight calculation unit, 72 image memory for motion detection, 100 motion vector detector.

Claims (5)

[Claims] 1. A motion vector detecting device that divides an image into a plurality of blocks and obtains a motion vector for each block, wherein a motion vector is obtained from a current frame and a reference frame for a plurality of input signals based on a color specification form. A plurality of motion vector searching means for searching each; a vector selecting means for selecting any one of the motion vectors respectively output from the plurality of motion vector searching means; a motion selected in a previous frame by the vector selecting means A motion vector storage means for storing a vector, and a plurality of motion vector storage means for calculating a prediction error for each input signal in the current frame when using the motion vector selected in the previous frame stored in the vector storage means. A prediction error calculation unit, wherein the vector selection unit includes a plurality of prediction error calculation units. The motion vector detection device and selects a final motion vector from the output of each of the motion vector search means based on the prediction error values outputted from stage. 2. A motion vector detecting apparatus which divides an image into a plurality of blocks and obtains a motion vector for each block, wherein a plurality of input signals based on a color specification form are input from a current frame and a reference frame. Signal selection means for selecting any one of the signals; motion vector search means for searching for a motion vector from a current frame and a reference frame based on the input signal selected by the signal selection means; Motion vector storage means for storing a motion vector searched for in the frame, and prediction for each input signal in the current frame when the motion vector searched for in the previous frame stored by the motion vector storage means is used A plurality of prediction error calculation means for calculating the respective errors, the signal selection means, Motion vector detecting apparatus characterized by selecting one from a plurality of input signals based on the prediction error calculation value outputted from the number of the prediction error calculating unit. 3. The motion vector detecting device according to claim 1, wherein the plurality of input signals based on the color specification form are a luminance signal Y, a color difference signal CB, and a color difference signal CR. Detection device. 4. A motion vector detecting device for dividing an image into a plurality of blocks and obtaining a motion vector for each of the blocks, performs a predetermined weighting operation on the input luminance signal Y, color difference signal CB, and color difference signal CR. Y / CB / CR weighting calculating means for obtaining a Y / CB / CR weighting signal; Y / CB / CR weighting signal storage means for storing a Y / CB / CR weighting signal of the previous frame; Motion vector searching means for searching for a motion vector from the current frame and the reference frame for each of the Y / CB / CR weighting signals; and determining whether the luminance signal Y and the Y / CB / CR weighting signal are flat for each block. Flatness determining means for determining whether a motion vector is detected in a previous frame, a motion vector storing means for storing a motion vector detected in a previous frame, A Y / CB / CR weighting signal from the Y / CB / CR weighting calculation means, a motion vector detected in a previous frame stored in the motion vector storage means, and a Y / CB / CR weighting signal for motion detection. Prediction error calculation means for calculating a prediction error in the current frame based on the Y / CB / CR weighting signal stored in the means; and a prediction error calculation means using a motion vector detected in the previous frame. Motion vector selecting means for selecting a final motion vector from the output of the motion vector searching means based on the prediction error operation value in the current frame and the output of the flatness determining means. Detection device. 5. A motion vector detecting device which divides an image into a plurality of blocks and obtains a motion vector for each block, performs a predetermined weighting operation on the input luminance signal Y, color difference signal CB, and color difference signal CR. Y / CB / CR weighting calculating means for obtaining a Y / CB / CR weighting signal; Y / CB / CR weighting signal storage means for storing a Y / CB / CR weighting signal of the previous frame; Flatness determining means for determining whether or not the Y / CB / CR weighting signal is flat for each block; motion vector storing means for storing a motion vector detected in the previous frame; A Y / CB / CR weighting signal from the Y / CB / CR weighting means and a motion detected in the previous frame stored in the motion vector storage means; Prediction error calculating means for calculating a prediction error in the current frame based on the vector and the Y / CB / CR weighting signal stored in the Y / CB / CR weighting signal storage means for motion detection; The luminance signal Y and the Y / CB / CR weighting operation are calculated based on the prediction error operation value output from the prediction error operation means for calculating the prediction error in the current frame when a motion vector is used and the output of the flatness determination means. A signal selecting unit for selecting one from the output of the unit; and a motion vector searching unit for searching for a motion vector from a current frame and a reference frame based on the input signal selected by the signal selecting unit. Vector detection device.