JPH0815334B2 - Scan line interpolator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning line interpolating device for converting an interlaced-scanned image into a non-interlaced scan.

[0002]

2. Description of the Related Art An apparatus for detecting a motion vector of an image, moving image information one field before according to the value, and interpolating a scanning line is disclosed in, for example, Japanese Unexamined Patent Publication No. 1-10886. There is something.

FIG. 3 is a schematic diagram of a conventional scanning line interpolation device. 31 is image information of 2: 1 interlaced scanning, 32 to
34 is a field memory, 35 is a motion detection circuit, 36 is a mixing circuit, 37 and 38 are time compression circuits, 39 is a switching circuit, 40 is non-interlaced scanning image information, 41 is a motion vector detection circuit, and 42 is position movement. Circuit.

When the image information obtained by the 2: 1 interlaced scanning is supplied to the input terminal 31, the image information of the subsequent field is supplied from the field memory 32 to the field memory 33.
The image information of the current field from the field memory 3
4 outputs the image information of the previous field. The image information of the front field and the rear field is input to the motion vector detection circuit 41, and the motion vector for one frame is detected. The detected motion vector is input to the position movement circuit 42, and the image information of the previous field is 1 of the motion vector.
/ 2 is moved.

On the other hand, the image information of the front field and the rear field is also input to the motion detection circuit 35, and the motion of each pixel is detected by the absolute value of the brightness difference between the front field and the rear field.

The output of the position moving circuit 32 and the image information of the previous field are input to the mixing circuit 36, and a signal obtained by mixing the both is output. At that time, the mixing circuit 36 changes the mixing ratio according to the output of the motion detection circuit 35.

Further, the image information of the current field is also input to the mixing circuit 36, and when the motion vector cannot be detected by the motion vector detection circuit 31, the image information of the current field alone is used to interpolate between the scanning lines of the current field. The signal is output.

The image information of the current field and the output of the mixing circuit 36 are input to the time compression circuits 37 and 38, respectively.
It is compressed to 1/2 on the time axis. After that, the switching circuit 39 switches and outputs the outputs of the time compression circuits 37 and 38 for each horizontal period, and the non-interlaced scanning image information 4 is output.
0 is obtained.

[0009]

However, in the above-mentioned structure, the current field is obtained by mixing the image information of the previous field and the signal obtained by moving the image information of the previous field by 1/2 of the detected motion vector. When the detected motion vector is inaccurate due to the interpolation between the scanning lines, the scanning quality is deteriorated because the scanning lines are interpolated by the wrong image information. Therefore, it is necessary to determine whether or not the motion vector has been accurately detected, and obtain the interpolation signal based on the result.

In a general image, pixels having a short distance have a high correlation with each other, so that the motion vector detected in a certain block has a high correlation with the motion vectors of surrounding blocks. That is, when an accurate motion vector is detected, the correlation with the motion vector of the surrounding block is high, and when an incorrect motion vector is detected, the correlation with the motion vector of the surrounding block is low. Therefore, by comparing the detected motion vector with the motion vector of the adjacent block, it can be determined whether or not the motion vector is accurately detected.

As described above, according to the present invention, it is possible to determine whether or not the detected motion vector is accurate to prevent interpolation due to an inaccurate motion vector, and to provide a scanning line interpolating device with less image quality deterioration. To aim.

[0012]

In order to achieve this object, a scanning line interpolating apparatus according to the present invention comprises a motion vector detecting circuit for obtaining a motion vector between frames in block units from image information before and after one field, and detecting the motion vector. A determination circuit that determines whether or not the detected motion vector matches each motion vector of the adjacent block by comparing the difference between the motion vector of the adjacent block and the motion vector of the adjacent block with the image of the previous field. The inter-field interpolation signal obtained by moving the information by ½ of the detected motion vector and the inter-field interpolation signal obtained by interpolating between the scanning lines of the current field by the image information of the current field are adjacent to each other. A mixing circuit that outputs an interpolated signal that is mixed by changing the number that matches the block motion vector, and And a non-interlaced signal output circuit for outputting a non-interlaced signals from the signal and the image information of the current field.

[0013]

With this configuration, it is determined whether or not the detected motion vector is accurate, and it is possible to prevent incorrect image information from being interpolated by an incorrect motion vector. Therefore, a non-interlaced signal with less image quality deterioration can be obtained.

[0014]

(Embodiment 1) FIG. 1 is a block diagram of a scanning line interpolating device in one embodiment of the present invention, in which 1 is an input terminal for image information of 2: 1 interlace, 2 and 3 are the same image. A field memory for storing information, 4 is a motion vector detection circuit for detecting a motion vector between flumes in block units, 5
Is a moving circuit for halving the motion vector detected by the motion vector detecting circuit 4 to move the image information of the previous field, and 6 is the field information obtained by interpolating between the scanning lines of the current field only with the image information of the current field. An intra-field interpolating circuit for obtaining an interpolating signal, 7 a judging circuit for judging whether or not the motion vector is accurately detected by the motion vector detecting circuit 4, and 8 an interpolating signal by mixing the inter-field interpolating signal and the intra-field interpolating signal. Is a non-interlaced signal output circuit for interpolating the interpolation signal output by the mixing circuit 8 between the scanning lines of the image information of the current field. Reference numeral 10 is an output terminal for non-interlaced image information.

The operation of the scanning line interpolation device of FIG. 1 will be described below. Image information of 2: 1 interlace is supplied to the input terminal 1, image information of the current field is output from the field memory 2, and image information of the previous field is output from the field memory 3.

The image information of the front field and the image information of the rear field supplied to the input terminal 1 are input to the motion vector detection circuit 4, and the motion vector between frames is detected in block units. The detected motion vector is input to the movement circuit 5 and the determination circuit 7.

The motion vector between fields is obtained by halving the motion vector between frames.
Therefore, in order to obtain the inter-field interpolated signal, the movement circuit 5 halves the motion vector detected by the motion vector detection circuit 4 to move the image information of the previous field and inputs it to the mixing circuit 8.

However, since inter-field interpolation with an inaccurate motion vector deteriorates the image quality, it is necessary to judge whether or not the motion vector is accurately detected. In general, pixels having a short distance have a high correlation with each other, and thus a motion vector detected in a certain block has a high correlation with a motion vector of a surrounding block. That is, when the accurate motion vector is detected, the correlation with the motion vector of the surrounding blocks is high, and when the incorrect motion vector is detected, the correlation with the motion vector of the surrounding blocks is low. Therefore, the determination circuit 7, adjacent the detected motion vector in the block indicated by hatching as shown in Figure 2 the block B ₁
.. to B ₈ are compared with each other to determine whether the motion vectors match each other and control the mixing circuit 8. However, if the difference between the detected motion vector and the motion vector of the adjacent block is smaller than the threshold, it is determined that they match, and if the difference is greater than the threshold, it is determined that they do not match.

Further, the intra-field interpolation circuit 6 interpolates between the scanning lines of the current field using only the image information of the current field to obtain an intra-field interpolation signal.

If the resolution suddenly changes at the boundary between the inter-field interpolated area and the intra-field interpolated area, an unnatural image is formed. In order to eliminate such image quality deterioration, the mixing circuit 8 mixes the inter-field interpolation signal and the intra-field interpolation signal and outputs the interpolation signal. That is, the greater the number of detected motion vectors and the motion vectors of adjacent blocks that match, the greater the ratio of mixing interfield interpolation signals, and the smaller the number of matching interfield interpolation signals. The interpolation signal thus obtained by the mixing circuit 8 is input to the non-interlaced signal output circuit 9.

The non-interlaced signal output circuit 9 interpolates the interpolation signal output from the mixing circuit 8 between the scanning lines of the image information of the current field. In this way, non-interlaced image information with little image quality deterioration can be obtained from the non-interlaced signal output circuit 9.

[0022]

As described above, according to the present invention, the detected motion vector is compared with the motion vector of the adjacent block,
Determine if the motion vector was correctly detected.
Based on this determination result, interpolation of wrong image information is prevented, and a scanning line interpolation device with little image quality deterioration is realized.

[Brief description of drawings]

FIG. 1 is a block connection diagram of a scanning line interpolation device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a determination circuit that is a main part of the device.

FIG. 3 is a block connection diagram of a conventional scanning line interpolation device.

[Explanation of symbols]

 1 2: 1 interlaced image information input terminal 2 field memory 3 field memory 4 motion vector detection circuit 5 moving circuit 6 intrafield interpolation circuit 7 determination circuit 8 mixing circuit 9 non-interlaced signal output circuit 31 2: 1 interlace Signals 32-34 Field memory 35 Motion detection circuit 36 Mixing circuit 37, 38 Time compression circuit 39 Switching circuit 40 Non-interlaced signal 41 Motion vector detection circuit 42 Position movement circuit

Claims (1)

[Claims] 1. A motion vector detection circuit for obtaining a motion vector between frames in block units from image information before and after one field, and comparing a difference between the detected motion vector and a motion vector of an adjacent block with a threshold value. A determination circuit for determining whether or not the detected motion vector matches the motion vector of each adjacent block, and an inter-field interpolated signal obtained by moving the image information of the previous field by ½ of the detected motion vector and the current signal. Mixing that interpolates between the scanning lines of the field only with the image information of the current field and changes the mixing ratio of the interpolated signal in the field according to the number of the detected motion vector and the motion vector of the adjacent block to output the interpolated signal mixed Circuit,
A scanning line interpolation device comprising a non-interlaced signal output circuit for outputting a non-interlaced signal from an interpolated signal and image information of a current field.