JPS62206980A - Initial deviation system in moving presumption of dynamic image - Google Patents

Abstract

PURPOSE:To detect an moving quantity with a high accuracy by obtaining the moving quantity of three types of an average deviation, an acceleration deviation and an adjoining position, selecting one deviation which comes to be optimum out of them, and using it as an initial deviation. CONSTITUTION:An adjoining deviation BN21 is obtained by reading a left block BL, a just overhead block BU and a right upper block BR of a presuming block B0 from a presumed value memory circuit 17 and a directly below block BD from a presumed value memory circuit 16 with a reading control circuit 20. An average deviation BM22 is obtained by calculating the average value of an moving quantity VX,Y of a block Bn from the presumed value memory circuit 16 through a local smoothing circuit 18. An acceleration deviation BA23, on one hand, is added by the material to invert the output of the local smoothing circuit 18 and an adder 24, on the other hand, added by the output of the adder 24 and an adder 25 and an acceleration deviation BA is obtained. Respective deviations of the candidate of the obtained initial deviation are sent to an inter-frame difference arithmetic circuit 10, compared with the inter- frame difference value of field memories 12 and 14, and the deviation, which comes to be the nearest value, is selected as an initial deviation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a method for estimating the amount of motion in moving images such as television screens.

(Prior Art) As one of the coding methods for moving image signals, active research and development is being conducted on a high-efficiency interframe coding method using motion compensation technology and a standard frame number conversion method. In order to perform this motion compensation, a technique for estimating the amount of motion in a video signal with high precision is required. There is a method of estimating the amount of motion by grouping a number of pixels into blocks.The latter method of estimating the amount of motion in blocks is generally widely adopted, so this method will be used in the following explanation. I will explain in detail.

Note that the former method performed in pixel units can be performed in almost the same way by simply replacing the latter block units with pixel units.

When estimating the amount of motion of a moving image signal in units of blocks, one frame is divided into blocks each consisting of a total of 64 pixels, for example, 8 pixels in the horizontal direction and 8 lines in the vertical direction. Next, we will introduce a method for estimating the amount of each block in the current frame (Japanese Unexamined Patent Publication No. 5
5-162683-5).

(2) A method of estimating the amount of motion based on the physical correspondence between the intra-frame signal gradient and the inter-frame signal difference value (Japanese Patent Application Laid-Open No.
-158786).

etc. are known.

Figure 3 is a block diagram of a conventional method for estimating the amount of motion using the similarity of signal patterns within blocks. A G motion displacement section 5 in which the block read from the feed memory 4, whose contents are signals 2 degrees ahead of the field memory in units of blocks, is input to the motion displacement section 5.
is used to detect the degree of coincidence (similarity) between both frame signals; the current frame signal is directly input to the comparator 6, while the previous frame signal is input to the variable delay circuit 7 within the range ( A delay amount is given according to the estimation range), and its output is input to the comparator 6. The comparator 6 compares the degree of similarity between the two frame signals, and reads out the delay amount of the variable delay circuit 7 when the two frame signals are most similar. In this way, pattern similarity has conventionally been determined for each block between consecutive frames.

(Problem to be Solved by the Invention) However, when trying to estimate the amount of motion of a certain block over a wide range from block B at the same position in the previous frame, the variable delay circuit It becomes enormous in size. Therefore, conventional techniques have had the disadvantage that the estimation range is limited due to hardware limitations, making it impossible to accurately estimate the amount of motion.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is possible to estimate the amount of motion with high accuracy without being limited to the estimation range of the amount of motion. The purpose is to provide a method.

(Means for Solving the Problem) The feature of the present invention is that three types of motion amount estimation values, average deviation, acceleration deviation, and adjacent deviation, are calculated based on the properties of the moving image signal prior to actual estimation. By using the calculated value considered to be optimal as the initial deviation in estimation, the range of estimation of the amount of motion that is actually required can be reduced, and the amount of motion can be calculated using equal constraints. The reason is that the estimation range is no longer limited.

(Principle of the Invention) The terms and characteristics of (1) average deviation, (2) acceleration deviation, and (2) adjacent deviation, which are candidates for initial deviation in the present invention, will be explained.

In the following, it is assumed that an actual television signal is not simply a repetition of frames, but that one frame consists of two fields, an odd field and an even field.

FIG. 4 is a diagram for explaining the structure of one frame used in the present invention. Normally, when one screen (one frame) is sent, it is divided into two fields (solid line and broken line) by interlaced scanning. Therefore, the interframes F are odd fields (broken lines) or even fields (real R).

(2) Average deviation (BM) FIG. 5 is an explanatory diagram of the average deviation used in the present invention. In the figure, the average deviation is calculated from several blocks centered at the same position in the previous field memory, centering on the block B O (BM) for which the motion amount V is to be estimated in the current field FQ. (The figure shows an example of nine blocks B1 to B9.) The average value of these motion amount estimation results is taken.

Therefore, if this average deviation is used, for example, when a flat portion of the image is moving in parallel, the error in the amount of motion in the previous field F1 is smoothed out and the estimation accuracy is improved.

(2) Acceleration deviation (BA) FIGS. 6 and 7 are explanatory diagrams of acceleration deviation used in the present invention.

Figure 6 is a schematic diagram for determining acceleration deviation.
In the same way as when calculating the average deviation of the figure, the current field FQ
Nine blocks 811 to B19 in the previous field F1, centered on the estimated block BO (BA), and nine blocks 82 in the field F2 one frame before.
Multiplier 4-1 calculates (-1) the average estimated value (average deviation) of the amount of motion of blocks B21 to B29 with respect to 1 to B29.
An adder 4-3 calculates the acceleration deviation of block BQ by multiplying the average estimated value of the motion amount of blocks B1+ to B19 by 2 using a multiplier 4-2. It is.

That is, the average estimated value in the immediately preceding field F1 is
The amount of change (acceleration) in the motion amount estimated value between consecutive fields (F1 and F2) is added.

This acceleration deviation has the characteristic of improving the estimation accuracy for the moving edge portion G (hatched area) as shown in FIG. For example, if the edge part G moves through the stationary background M as shown in the same figure (,) at a speed V to about 1/3 of the stationary background M as shown in the same figure (b), then , the average deviation is V/3, whereas the acceleration deviation is 2V/3 (OX(-1) ten pieces x 2)
In other words, it is possible to obtain an estimated value that is closer to the true value.

(2) Adjacent deviation (BN) FIG. 8 is an explanatory diagram of the adjacent deviation used in the present invention, and shows block B for which an estimated value is to be obtained in the current field FO. (
BN) and for which the estimated value has already been obtained, the left block BL, the block directly above BU or the upper right block BR1, and the block B in the previous field F1. Among the four blocks BD adjacent to block B1 located at a position corresponding to , and for which estimated values have already been obtained, one block BD that is closest to the true movement is selected. Furthermore, these 4
Other selections of the A'crameter blocks may be used.

This adjacent deviation is effective when a new part appears or disappears from a moving background, and has the characteristic that it can improve the estimation accuracy in scene checking in particular.

In the present invention, the above-mentioned three types of deviations (as a crameter, there are four adjacent deviations on top, bottom, left and right, and 1 of the average deviation)
The most suitable deviation is selected from among the six deviations in total (one for acceleration deviation and one for acceleration deviation), and is used as the initial deviation. The selection of this initial deviation is based on the current field F. Estimated block B. 6 blocks B where the above 6 motion amounts were read out from each field! il a B
A*BU I B Dr BL The similarity of the signal patterns between L and BR is checked using, for example, the square sum or absolute sum of the inter-frame difference values, and the one that is most similar is selected. For example, when using the absolute sum Pn of inter-frame difference values, the current field F. Block B inside. If the signal of the block Bn at the position shifted by the motion estimation value corresponding to Ax, y, n (1 to 6) is B(n)x, y, then this absolute sum Pn
is obtained for each of the six blocks, and the amount of movement of the block whose absolute sum Pn is the smallest is adopted as the initial deviation.

Figure 9 shows the experimental results for determining the actual usage rate of each deviation used as the initial deviation described in the present invention, and the vertical axis shows the average deviation, acceleration deviation, and adjacent deviation, respectively. The horizontal axis shows the actual television field number.

As is clear from the figure, the adjacent deviation (BN) is 40 to 6.
0% is used most frequently, followed by acceleration deviation (B
A) is 30-40 inches, mean deviation (BM) is 10-15%
The order is as follows. Therefore, when performing actual television transmission, it is better to use the optimal deviation as needed than to estimate the amount of motion using only one type of deviation. In addition to being executable, the estimation accuracy can be greatly improved as a result. (Structure of the Invention) The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and is a block diagram showing a method of estimating the amount of motion using the similarity of signal patterns within blocks.

The image input signal l is input to field memos IJ 2 , 3 , 4 and 5 which sequentially store four fields (two frames). Among these, the motion amount to be estimated at the current time is the image signal 6D input δ to the field memories 3 and 5, and the motion amount Vx, y is input by the motion estimation circuit 9.
is estimated. On the other hand, the contents of the field memories 12 and 14 determine the initial deviation amount at the next point in time, and are input to the interframe difference calculation circuit 10.
An inter-frame difference value is calculated. Next, the motion amount υ estimated by the motion estimation circuit 9 and y are stored for two fields in the estimated value storage circuits 16 and 17, and then
Local smoothing circuits 18 are used to obtain three types of deviations.
．． 19 and the read control circuit 20.

First, the adjacent deviation (BN) 21 is the estimated block B described above.
. The block B just above the left block BLN and the block B right above the right block BR are obtained by reading out the block BD just below the estimated value storage circuit 17 from the estimated value storage circuit 16 and the block BD just below it by the readout control circuit 20.

Next, the mean deviation (BM) 22 is passed from the estimated value storage circuit 16 through the local smoothing circuit 18 shown in FIG.
It is obtained by calculating the average value of the motion amounts vx and y (9 blocks in FIG. 5).

Finally, the acceleration deviation (BA) 23 is stored in the estimated value storage circuit 17.
One of the outputs passed through the local smoothing circuit 19 for calculating the average value of the previous field from the above-mentioned local smoothing circuit 1
8 is inverted and added by adder 24,
The other is added to the output of the adder 24 and the adder 25, and the output of the adder 25 becomes the desired acceleration deviation (BA).

In addition, in FIG. 6, multipliers 4-1 and 4-2 were used, but here, adders 24 and 4-2, which are easy to perform arithmetic processing, are used.
It was composed of 25 parts.

Each deviation of the initial deviation candidates obtained in this way is sent to the above-mentioned interframe difference calculation circuit 10, and compared with the interframe difference values of the field memories 12 and 14 that have already been obtained, the deviation is the closest. The deviation that becomes the value is selected as the initial deviation and stored in the initial deviation memory 11. next,
The contents of the field memories 12 and 14 are transferred to the field memories 13 and 15, and when estimating the amount of motion of the corresponding block, the initial deviation stored in the initial deviation memory 11 is used as an initial value.

FIG. 2 is a specific circuit configuration diagram showing how the initial deviation amount obtained by the present invention is used in the motion amount estimation circuit 9. In particular, the absolute sum Pn of the inter-frame difference values is
This figure shows the configuration when using .

Among the blocks stored in the field memories 13 and 15, each pixel in the block in which the motion amount estimation calculation is to be performed is sequentially read out by the read address control circuit 26. These are estimated blocks B of the estimated motion amount position in the current field in the field memory 13. absolute values tAx, yl of the signals Ax, y, and the signal B(n) of the block shifted by the amount of movement of the given initial deviation.
Absolute value of x, y I B”) x, y l (however, n =
1.2, .''-6), and further, the adder 27 obtains the difference between these (in the figure, x and yl are inverted and added). This result is summed up for the pixels of the block and then held in the adder 28. A similar procedure is performed for all detected motion amounts, and among the results, the one with the minimum absolute value sum of the inter-frame differences is selected by the inter-frame difference sum minimum value determination circuit 30. The adder 31 adds this output and the already calculated initial deviation amount to obtain the estimated value vX,y of the actual motion amount.

Note that when reading the signal of one frame before from the read address control circuit, the adder 32 adds the address of the control circuit 32 and the initial deviation so that the address can be shifted by the initial deviation candidate.

(Effects of the Invention) As explained above, the present invention obtains three types of motion amounts: average deviation, acceleration deviation, and adjacent deviation, selects one of them as the optimum deviation, and selects the optimum deviation as the initial deviation. By using this method, it is possible to detect the amount of motion with high precision without being limited to the estimation range of the amount of motion, and it can also be applied to high-efficiency encoding of video signals and frame number conversion. Ashi, the effect is extremely dog.

[Brief explanation of drawings]

Figure 1 shows an embodiment of the present invention, a block diagram for estimating the amount of motion, Figure 2 is a block diagram of the motion amount estimation circuit of the present invention, and Figure 3 is a conventional block diagram for estimating the amount of motion of a moving image. , Fig. 4 is a schematic diagram for explaining one frame according to the present invention, Fig. 5 is an explanatory diagram for calculating the average deviation according to the present invention, and Figs. 6 and 7 are diagrams for explaining the acceleration deviation according to the present invention. FIG. 8 is an explanatory diagram for determining the adjacent deviation according to the present invention. FIG. 9 is a diagram showing the usage ratio of the average deviation, acceleration deviation, and adjacent deviation according to the present invention. 9...Motion amount estimation circuit, 10...Inter-frame difference calculation circuit, 11...Initial deviation memory, 12, 13゜14
t, 15...Field memory. Patent Applicant International Telegraph and Telephone Co., Ltd. Patent Application Agent Patent Attorney Megumi Yamamoto Is the vomit the same as the conventional one? + Measuring device Fig. 3 Explanatory diagram of present invention 1 terro 1 Frame A Fig. 4 Condolence Fig. 5 Acceleration preparation 0 Reading diagram Fig. 6 Power rJ Figure 7 Figure 8

Claims (1)

[Claims] One field of an input moving image signal is divided into a plurality of blocks, and pattern similarity between an estimated block whose motion amount is to be estimated and the block whose motion amount has already been calculated is determined. In a video motion estimation method that uses the motion amount of the most similar block,
An average deviation that is the average value of estimated motion amounts of a plurality of blocks in the previous second field, and between the second field and a third field that is one field before the second field. an acceleration deviation that is a change in the estimated amount of motion; and a block that is close to the estimated block and for which the amount of motion has already been determined, or a block that is located at a position corresponding to the estimated block in the second field. Among the blocks that have been calculated, the estimated value of the motion of the block that is closest to the true motion is calculated as the adjacent deviation, and among the average deviation, acceleration deviation, and adjacent deviation, the block whose pattern is most similar to the amount of motion of the estimated block is calculated. An initial deviation method for estimating a motion amount of a moving image, characterized in that the deviation is used as an initial deviation.