JPH06292167A - Motion decision device - Google Patents

Abstract

PURPOSE:To improve the accuracy of motion decision for a high definition still picture by suppressing a component in a digital moving image signal unrequired for the motion decision. CONSTITUTION:An inter-field differential value is detected by a delay line 2 and a subtractor 3, and an inter-line differential value by a delay line 9 and a subtractor 10. The presence/absence of motion can be decided by finding the absolute value of each differential value at absolute value circuits 4, 11, and finding the sum of the differential values of absolute value by an adder 12 and a sum circuit 13. Thereby, it is possible to select and sample only a high frequency component in a perpendicular direction equivalent to the motion of the digital moving image signal and to reduce the probability of erroneous motion decision for a still picture with a striped pattern, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in the case of compressing, encoding and recording or transmitting a digital image signal whose coordinates have been transformed into a frequency domain using orthogonal transformation, and is used for determining the movement of the image signal. It relates to the device.

[0002]

2. Description of the Related Art FIG. 4 shows a motion determining apparatus used in a conventional digital VTR or the like. In FIG. 4, an input terminal 1 is provided with a digital moving image signal in units of orthogonal transform blocks composed of vertical and horizontal 8 × 8 pixels. Is entered. This digital moving image signal is applied to the delay line 2 and the subtractor 3 with a constant delay amount, and the output of the delay line 2 is applied to the subtractor 3.

The subtractor 3 calculates and outputs a difference value between the current digital moving image signal and the digital moving image signal at the same position one field before. The output of the subtractor 3 is added to the absolute value circuit 4, and the absolute value circuit 4 outputs the absolute value of the difference value. The output of this absolute value is added to the adder 5, and the output of this adder 5 is added to the delay line 6 having a constant delay amount. The output of the delay line 6 is added to the adder 5.

With the delay amount of the delay line 6 as one sample time, the adder 5 outputs the sum of the absolute value outputs (absolute value of interfield difference). The output of the delay line 6 is applied to the motion determination circuit 7, and the presence or absence of motion is determined by comparing the sum of the absolute values of the difference values with a predetermined threshold value, and a motion determination signal is output from the output terminal 8.

As described above, the motion determining apparatus in the conventional digital VTR or the like utilizes the property that the motion of an image becomes a vertical high frequency component in terms of spatial frequency, and utilizes the orthogonal transform block unit (8 × 8 pixels etc.). Block), the motion of the image in the block (8 × 8 pixels or the like) is determined by the sum of absolute values of the inter-field difference values obtained for the digital moving image signal input.

[0006]

In the above-mentioned conventional example, the presence or absence of the motion of the image in the block is determined by the sum of the absolute values of the inter-field difference values (the absolute values of the differences between all two pixels in the vertical direction) taken in block units. Since it is a method of judging, when the original image has a high-definition (diagonal stripes etc.) pattern, the sum of the absolute values of the difference values inevitably becomes large regardless of the presence or absence of motion, and it is erroneously determined to be motion There was a drawback that there were things to do.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and an object thereof is to obtain a motion judging device which does not erroneously judge a high-definition still image as a moving image.

[0008]

According to the present invention, first detecting means for detecting a difference value between fields of an image signal, second detecting means for detecting a difference value between lines of the image signal, and The image based on the sum of the difference values between the inter-field difference values and the line-to-line difference values detected by the first and second detecting means, or based on the sum of the inter-field difference values and the sum of the line-to-line difference values. A motion determination processing unit that determines the motion of the signal is provided.

[0009]

The components unnecessary for motion determination are suppressed from the digital moving image signal, and only the high frequency component in the vertical direction corresponding to the motion is selectively extracted to reduce the probability of motion erroneous determination for a still image having a pattern such as a horizontal stripe pattern. .

[0010]

1 is a block diagram showing a first embodiment of the present invention.

In FIG. 1, a digital moving image signal is inputted to an input terminal 1 in a unit of orthogonal transformation, and a delay line 2 having a delay amount corresponding to one field scanning period and a delay corresponding to one horizontal line scanning period. It is added to the delay line 9 having a quantity and the subtractors 3 and 10. The subtractor 3 outputs the difference between the current digital moving image signal and the digital moving image signal one field before, that is, the inter-field difference value. The output of the subtractor 3 is added to the absolute value circuit 4, and the absolute value circuit 4 outputs the absolute value of the inter-field difference value.

On the other hand, the output of the delay line 9 is the subtractor 1
Added to 0. The subtractor 10 outputs the difference between the current digital moving image signal and the digital moving image signal one line before, that is, the interline difference value. The output of the subtractor 10 is added to the absolute value circuit 11, and the absolute value circuit 11 outputs the absolute value of the above-mentioned line difference value.

The outputs of the absolute value circuits 4 and 11 are applied to a subtractor 12, which outputs the difference value between the absolute value of the inter-field difference value and the absolute value of the line difference value. The output of the subtractor 12 is added to the summing circuit 13, and the summing circuit 13 sequentially adds and outputs the difference value between the absolute value of the inter-field difference value and the absolute value of the line difference value. The output of the summing circuit 13 is applied to the motion judging circuit 7, and the motion judging circuit 7 compares the sum of the difference values between the absolute value of the inter-field difference value and the absolute value of the line difference value with a threshold value. As a result, the presence / absence of motion of the moving image signal existing in the area divided in block units is determined, and a motion determination signal is output from the output terminal 8.

As shown in FIG. 2, the total sum F _x of the absolute values of the inter-field difference values has a large value in proportion to the vertical frequency component contained in the image signal. On the other hand, the total sum L _x of the absolute values of the inter-line difference values becomes a small value when the vertical frequency component included in the image signal is deviated to the low frequency or the high frequency. Therefore, the output level of the summing circuit 13 in FIG. 1 has a positive correlation with the high-frequency component in the vertical direction of the image signal, and the movement of the image (the inter-field image signal Change) can be detected.

FIG. 3 is a block diagram showing a second embodiment of the present invention, in which parts substantially the same as those in FIG.

In FIG. 3, the output of the subtracter 3 is added to the absolute value sum circuit 14, and the absolute value sum circuit 14 outputs the sum of the absolute values of the inter-field difference values. On the other hand, subtracter 1
The output of 0 is added to the absolute value sum circuit 15, and the absolute value sum circuit 15 outputs the sum total of the absolute values of the line difference values.

The outputs of the absolute value sum circuits 14 and 15 are applied to a selection switch 16. The selection switch 16 is controlled by a control signal input from an external control microcomputer (CPU) (not shown) via the control signal input terminal 17, and the sum of absolute values of the interfield difference values or the interline One of the sums of the absolute values of the difference values is selected and output.

The output of the selection switch 16 is the motion judging circuit 7
The motion determination circuit 7 is synchronized with the selection switch 16 by the control signal and is independently input from the sum of absolute values of inter-field difference values and the sum of absolute values of inter-line difference values. , The definition of the pattern of the digital moving image signal input from the input terminal 1 and the presence or absence of movement are determined. Further, with respect to the input digital moving image signal, a weighting coefficient having a spatial frequency as a parameter is determined, and the motion determination signal md and the weighting coefficient w are determined.
and d are output from the output terminal 8.

[0019]

According to the present invention, the image signal is based on the sum of the difference values between the inter-field difference values and the line difference values, or based on the sum of the inter-field difference values and the sum of the line difference values. By performing the motion determination of, it becomes possible to select and detect only the high frequency component in the vertical direction corresponding to the motion included in the image signal, and the motion detection can be performed only by the inter-field difference value as in the conventional method. Compared with the case of performing, the probability of motion erroneous determination with respect to a still image with horizontal stripes or diagonal stripes or an image with little motion is reduced, and the accuracy of motion determination is improved. Further, for example, as in the second embodiment, by independently providing the circuit for obtaining the inter-field difference value and the inter-line difference value, the weighting coefficient for controlling the code amount in the compression and encoding of the digital moving image signal. Selection accuracy (meaning that deterioration is not noticeable visually) is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a graph showing a process of spatial frequency discrimination.

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

FIG. 4 is a block diagram showing a conventional motion determination device.

[Explanation of symbols]

 2, 9 Delay line 3, 10, 12 Subtractor 4, 11 Absolute value circuit 7 Motion determination circuit 13 Summing circuit 14, 15 Absolute value summing circuit

Claims (1)

[Claims] 1. A first detecting means for detecting an inter-field difference value of an image signal, a second detecting means for detecting an inter-line difference value of the image signal, and the first and second detecting means. Motion determination processing for performing motion determination of the image signal based on the sum of the difference values between the detected interfield difference value and the line difference value or based on the sum of the interfield difference values and the sum of the line difference values And a motion determining device including means.