JP2762791B2 - 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 interpolation apparatus for converting an interlaced image into a non-interlaced image.

[0002]

2. Description of the Related Art As a device for detecting a motion vector of an image, moving image information one field before according to the value of the motion vector, and interpolating a scanning line, for example, Japanese Patent Application Laid-Open No. 1-188886 discloses a device.
There is one as shown in Japanese Patent Publication No.

FIG. 3 is a schematic diagram of a conventional scanning line interpolation device. 31 is image information of 2: 1 interlaced scanning;
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 image information obtained by 2: 1 interlaced scanning is supplied to an input terminal 31, image information of a subsequent field is supplied from a field memory 32 to a field memory 33.
From the field memory 3
4 outputs the image information of the previous field. The image information of the previous field and the image information of the next field are input to a motion vector detection circuit 31, and a motion vector for one frame is detected. The detected motion vector is input to the position moving circuit 32, and the image information of the previous field is the motion vector 1
/ 2 moves.

On the other hand, the image information of the preceding field and the succeeding field are also inputted to the motion detecting circuit 35, and the motion of each pixel is detected based on the absolute value of the luminance difference between the preceding field and the following field.

The output of the position shift circuit 32 and the image information of the previous field are input to a mixing circuit 36, and a signal obtained by mixing the two 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 scanning line of the current field is interpolated only by the image information of the current field. A signal is output.

The image information of the current field and the output of the mixing circuit 36 are input to time compression circuits 37 and 38, respectively.
It is compressed by half on the time axis. Thereafter, the switching circuit 39 switches and outputs the outputs of the time compression circuits 37 and 38 every one horizontal period, and outputs the non-interlaced image information 4.
0 is obtained.

[0009]

However, in the above configuration, the current field image information is mixed with a signal obtained by moving the previous field image information by a half of the detected motion vector, thereby mixing the current field image information with the current field image information. If the detected motion vector is inaccurate to interpolate between the scanning lines, the scanning line is interpolated by incorrect image information, and the image quality deteriorates. Therefore, it is necessary to determine whether or not the motion vector has been correctly detected, and to obtain an interpolation signal based on the result.

In a general image, pixels having short distances have a high correlation with each other. Therefore, a motion vector detected in a certain block has a high correlation with a motion vector of a surrounding block. 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. Then, by comparing the detected motion vector with the motion vector of the adjacent block, it can be determined whether or not the motion vector has been correctly detected.

According to the present invention, as described above, it is determined whether or not a detected motion vector is accurate to prevent interpolation by an inaccurate motion vector, and to provide a scanning line interpolation apparatus with less image quality deterioration. 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 on a block-by-block basis from image information before and after one field; Circuit for calculating the difference between the obtained motion vector and the motion vector of the adjacent block, and outputting a sum of values according to the difference result, and a field in which image information of the previous field is moved by １ ／ of the detected motion vector A mixed interpolation signal is output by changing the mixing ratio of the inter-field interpolation signal and the intra-field interpolation signal obtained by interpolating between the scanning lines of the current field using only the image information of the current field by the sum of values according to the detected difference result. It is provided with a mixing circuit and a non-interlace signal output circuit for outputting a non-interlace signal from the interpolation 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 little image quality deterioration can be obtained.

[0014]

FIG. 1 is a block diagram of a scanning line interpolation apparatus according to an embodiment of the present invention, wherein 1 is 2: 1 interlaced image information, 2 and 3 are field memories, and 4 is a motion vector detecting circuit. Reference numeral 5 denotes a moving circuit, 6 denotes an intra-field interpolation circuit, 7 denotes a judgment circuit, 8 denotes a mixing circuit, 9 denotes a non-interlaced signal output circuit, and 10 denotes non-interlaced image information.

The operation of the scanning line interpolation device shown in FIG. 1 will be described below. The input terminal 1 is supplied with 2: 1 interlaced image information, and the field memory 2 outputs the current field image information and the field memory 3 outputs the previous field image information.

The image information of the previous field and the image information of the subsequent field supplied to the input terminal 1 are inputted to a motion vector detecting circuit 4, and a 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 inter-field motion vector is obtained by halving the inter-frame motion vector.
Therefore, in order to obtain the inter-field interpolation signal, the moving circuit 5 moves the image information of the previous field by halving the motion vector detected by the motion vector detecting circuit 4, and inputs the image information of the previous field to the mixing circuit 8.

However, if the inter-field interpolation is performed using an incorrect motion vector, the image quality deteriorates. Therefore, it is necessary to determine whether the motion vector has been correctly detected. In general, pixels close to each other have a high correlation with each other, so that a motion vector detected in a certain block has a high correlation with a motion vector of a surrounding block. 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. Accordingly, the determination circuit 7 calculates a difference between the motion vector V ₀ detected in the hatched block as shown in FIG. 2 and the motion vectors V _{1 to} V ₈ of the adjacent blocks B _{1 to} B ₈ , and calculates the difference from the difference value. The value S ₁ according to the difference result based on Table _1.
ＳS ₈ are calculated, the sum X of the values S ₁ 〜S ₈ according to the difference result is calculated, and the mixing circuit 8 is controlled by the value of X. That is, when the sum X of the values according to the difference between the detected motion vector and the motion vector of the adjacent block is large (close to 40), the detected motion vector and the motion vector of the adjacent block match. It is determined that they match, and if they are smaller, it is determined that they do not match.

[0019]

[Table 1]

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.

An abrupt change in resolution at the boundary between the inter-field interpolated area and the intra-field interpolated area results in an unnatural image. In order to eliminate such image quality deterioration, the mixing circuit 8 mixes the inter-field interpolation signal f _A and the intra-field interpolation signal f _B to output an interpolation signal Y. That is,
As shown in equation (1), the sum X of the values S _{1 to} S ₈ corresponding to the difference between the detected motion vector V ₀ and the motion vectors V _{1 to} V ₈ of the adjacent blocks B _{1 to} B ₈ is increase the rate of mixing inter-field interpolation signal f _a larger, increasing the proportion of mixing small enough field interpolation signal f _B.

Y = (X / 40) · f _A + {(1-X) / 40} · f _B- (1) The interpolation signal Y thus obtained by the mixing circuit 8 is a non-interlace signal output. Input to the circuit 9.

The non-interlace signal output circuit 9 interpolates the interpolation signal output by 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.

[0024]

As described above, according to the present invention, the detected motion vector is compared with the motion vector of the adjacent block, and
It is determined whether the motion vector has been correctly detected.
According to this determination result, interpolation of incorrect image information is prevented, and a scanning line interpolating device with less image quality deterioration is realized.

[Brief description of the drawings]

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

FIG. 2 is a conceptual diagram of a determination circuit which is a main part of the scanning line interpolation device.

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

[Explanation of symbols]

 1 2: 1 interlace signal 2, 3 field memory 4 motion vector detection circuit 5 moving circuit 6 intra-field interpolation circuit 7 judgment circuit 8 mixing circuit 9 non-interlace signal output circuit 31 2: 1 interlace signal 32-34 field memory 35 motion detection circuit 36 mixing circuit 37, 38 time compression circuit 39 switching circuit 40 non-interlace signal 41 motion vector detection circuit 42 position moving circuit

Claims (1)

(57) [Claims] 1. A motion vector detecting circuit for obtaining a motion vector between frames on a block-by-block basis from image information before and after one field, and a difference between the detected motion vector and a motion vector of an adjacent block is calculated. A decision circuit for outputting the sum of the calculated values, an inter-field interpolation signal obtained by moving the image information of the previous field by の of the detected motion vector, and a scan line of the current field by only the current field image information. A mixing circuit that changes the mixing ratio of the intra-field interpolation signal according to the sum of values according to the detected difference and outputs a mixed interpolation signal, and outputs a non-interlaced signal from the interpolation signal and image information of the current field. A scanning line interpolation device comprising a non-interlace signal output circuit.