JPS62230180A - Motion vector detecting system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a motion vector detection method for moving image signals, and particularly to a motion vector detection method used during image processing such as high efficiency band compression and format conversion. be.

(Summary of Disclosure) When performing motion vector detection in a band compression device, a format conversion device, etc., adjacent motion vector detection areas (
By providing an overlapping area between pixels (range in which pixels used for vector detection are distributed) within the screen, it is possible to stably detect motion vectors in small areas.

[Conventional technology]

FIG. 6 is a diagram showing a general motion vector detection block, and FIG. 7 is a diagram showing the relationship between a motion vector detection block and a motion vector detection area in a conventional motion vector detection method.

In conventional technology, when a screen is divided into multiple blocks as shown in FIG. 6 and motion vectors are detected in each block, the motion vector detection areas of adjacent blocks are shown with diagonal lines in FIG. 7(A). Either they were in contact with each other as shown in FIG. 7(B), or they were separated from each other as shown by diagonal lines in FIG. That is, in Figure 7, the horizontal size of a certain block is ℃.

If the vertical size is h, the horizontal size of the motion vector detection area is H, and the vertical size is H, then LSI, H≦h
Met.

The block diagram shown in FIG. 8 shows an example of a method conversion device that performs motion compensation type frame number conversion, as an example of a device according to the prior art. Here, 10 is a linear interpolator, 11
1 is an output image selection unit, 12 to 15 are motion compensation interpolation units, and 1
Reference numeral 6 represents a motion vector detection section, 17 represents an optimum motion vector determination section, and 18 and 19 represent changeover switches.

FIG. 9 is a diagram showing a motion vector detection block in a 'JjJ correction type system conversion device according to the prior art.

Next, the general operation of FIG. 8 will be explained with reference to FIG.

The linear interpolation unit 10 obtains a linear interpolation output 20 by weighted averaging of two consecutive frame signals. Furthermore, the motion vector detection unit 16 divides the screen into four as shown in FIG. 9 using a so-called pattern matching method, and calculates the motion vector v in each block.

V2. V3. Detect V4. Motion compensation interpolation unit 12~
15, the motion vectors Vl, V2. V3. V
4 to perform position interpolation, and the motion compensation type interpolation output 21~
Get 24. , the optimal motion vector determination unit 17 uses the so-called minimum frame difference method to obtain motion compensation interpolation outputs 21 to 21.
24, which gives the best motion correction result, and switches the first switch 18 to output the motion correction output 25.
get. Similarly, the output image selection unit 11 outputs the linear interpolation output 2.
0 and the motion correction output 25, which gives an appropriate interpolation result, and switches the second switch 19 to obtain the converted output 2B.

[Problem that the invention seeks to solve]

However, in the conventional method conversion device that performs motion compensation type frame number conversion, when a moving object with a small area crosses the boundary of motion vector detection blocks, the correct motion vector is not detected in any block, and the motion compensation type This caused erroneous correction in the interpolators 12 to 15, resulting in significant deterioration in the image quality of the converted output 2B.

In addition, in the conventional technology, as shown by diagonal lines in Fig. 1θ,
When a small-area motion area crosses the boundary of a motion vector detection block, the motion area belonging to the motion vector detection area of each block decreases, so the number of pixels (representative points) used for motion vector detection also decreases, and the image The probability of accurate motion vector detection is reduced due to disturbances caused by noise contained in the signal.

On the other hand, increasing the spatial density of representative points in order to compensate for the decrease in the motion area results in an increase in the hardware scale.

[Purpose of the invention]

Therefore, an object of the present invention is to provide a motion vector detection method that enables stable motion vector detection without increasing the scale of hardware.

[Means for solving the problem] In the present invention,
In each block obtained by dividing the screen into multiple areas, a
In the motion vector detection method that detects the motion vector,
By expanding the area for motion vector detection to other block areas, the above objective is achieved.

(Example〕 Next, the present invention will be explained in detail based on examples.

FIG. 1 is a diagram showing the basic concept of the present invention. In this figure, the motion vector detection area is set larger than the block size (L>1.) i>h, as shown by diagonal lines.
).

FIG. 2 is a diagram showing a state in which a small-area moving region moves from position A toward position and crosses the boundary of a vector detection block. In this figure, a motion vector is detected by block (i, j) during the period from position A to position C, and by block (i, j+1) during the period from position B to position C. Therefore, motion vectors can always be detected in one or more blocks, and stable motion vectors can be obtained.

FIG. 3 is a block diagram showing one embodiment of the present invention.

In this figure, 1 is a frame memory, 2 is a representative point setting section, 3 is a block position determination section, 4 is a subtraction section, 5 is an absolute value detection section,
Reference numeral 6 indicates a frame difference addition section, and 7 indicates a minimum value detection section.

Here, the representative point setting unit 2 arranges representative points at a uniform density within the motion vector detection area indicated by diagonal lines in FIG. In addition, a finite number of possible vectors called sample vectors are set.

Then, the subtraction unit 4 calculates, for each representative point, the frame difference between the representative point and the pixel of the current frame at a point where the position of the representative point is offset by the sample vector.

Next, the output of the subtraction section 4 is subjected to absolute value conversion via the absolute value detection section 5, and then the frame difference signal calculated at each representative point is added in the frame difference addition section 6 for each sample vector.

The minimum value detection unit 7 finds a sample vector that gives the minimum value of the frame difference addition value, and outputs it as a motion vector of this block.

The block position determination unit 3 determines whether the motion vector detection block is in contact with the edge of the effective screen. Then, the motion vector detection area is changed so that the motion vector detection area does not extend outside the effective screen and cause malfunction.

FIG. 4 is a diagram showing the relationship between the effective screen and the motion vector detection and output area. Reference numeral 8 shown in the figure is a motion vector detection area deleted by the block position determination unit 3. 9 is the remaining detection area.

On the other hand, as shown in Fig. 5, if the size of the effective screen is larger than the outer circumference of the motion vector detection block, the motion vector detection area is not changed and the movement from outside the motion vector detection block to the inside of the block is The motion vector of the motion region into which the object enters can be detected prior to the entry.

(Effects of the Invention) When a small-area moving region moves across the boundary of a motion vector detection block, conventional motion vector detection methods have problems with detection stability, but the motion vector detection method according to the present invention By implementing this, stable motion vector detection becomes possible without expanding the hardware configuration.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the basic concept of the present invention, and FIG. 2 is a diagram showing the motion vector detection method of the present invention when a small-area moving region moves across the boundary of a motion vector detection block. , FIG. 3 is a block diagram showing an embodiment of the present invention, FIGS. 4 and 5 are diagrams showing the operation of the block position determining section in the motion vector detection method of the present invention, and FIG. 6 is a block diagram showing a general motion. A diagram showing a vector detection block, FIGS. 7(A) and 7(B) are diagrams showing the relationship between a motion vector detection block and a motion vector detection area in a conventional motion vector detection method, and FIG. 8 is a diagram showing a method conversion according to the conventional technology. A block diagram showing an example of the configuration of the device. FIG. 9 is a diagram showing a motion vector detection block in a system conversion device according to the prior art. FIG. FIG. 2 is a diagram illustrating a conventional motion vector detection method. 1...Frame memory 1. 2... Representative point setting section, 3... Block position determination section, 4... Subtraction section, 5... Absolute value detection section, 6... Frame difference addition section, 7... Minimum value detection Department. Figure 1 Figure 2 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1) In a motion vector detection method that detects a motion vector in each block obtained by dividing a screen into a plurality of regions, the region for motion vector detection is extended to other block regions. A motion vector detection method featuring: