Method and apparatus for deinterlacing

A deinterlacing method for converting an interlaced image into a progressive image, said method comprising:

• performing a filtering process to pixels of at least one of three fields, a deinterlacing target field to be subjected to a deinterlacing process and forward and backward fields of the deinterlacing target field within the interlaced image so as to generate an interpolation pixel for the deinterlacing target field;
• measuring a quantity of motion of the deinterlacing target field;
• and
• changing a filter coefficient of a filter used in the filtering process based on the quantity of the motion measured in said measuring of the quantity of motion,
• wherein in said changing of the characteristics of the filtering, the characteristics of the filtering are changed so that gain of components from the forward and backward fields of the deinterlacing target field is reduced to zero when the quantity of the motion measured in said measuring of the quantity of motion is increased.

A deinterlacing apparatus for converting an interlaced image into a progressive image, said apparatus comprising:

• a frame memory for storing the interlaced image;
• a filter unit for receiving, from said frame memory, a deinterlacing target field to be subjected to a deinterlacing process and one or both of forward and backward fields of the deinterlacing target field within the interlaced image, and performing a filtering process to pixels of at least one of the received fields so as to generate an interpolation pixel for the interlacing target field;
• a difference operation unit for receiving, from said frame memory, the deinterlacing target field or a frame including the deinterlacing target field, and a field or frame which is adjacent to the deinterlacing target field or frame including the deinterlacing target field within the interlaced image and operating a difference therebetween so as to measure a quantity of motion of the deinterlacing target field;
• a filter coefficient setting unit for changing filter characteristics of said filter unit based on the quantity of the motion measured by said difference operation unit;
• and
• a double-speed converter for composing the interlaced image and the interpolation pixel generated by said filter unit, and generating the progressive image.

A deinterlacing method for performing a decoding process to a code sequence, field by field or frame by frame, which code sequence is obtained by coding an interlaced image composed of plural fields using motion compensation, and converting a decoded image of the interlaced image, which is obtained by the decoding process, into a progressive image, said method comprising:

• decoding the interlaced image so as to obtain the decoded image and to obtain a motion vector at the motion compensation which indicates a prescribed reference field for a target field;
• converting a motion vector for each of the fields, having a size corresponding to a time interval between the target field and the prescribed reference field, into a motion vector of a size corresponding to a time interval of a fixed unit;
• obtaining pixels from reference fields which are forward and backward fields of a deinterlacing target field to be subjected to a deinterlacing process based on the motion vectors converted in said converting of the motion vector, and generating a first interpolation pixel for the deinterlacing target field;
• generating a second interpolation pixel by using pixels in the deinterlacing target field;
• deciding a weighting factor which indicates a weighting ratio between the first interpolation pixel and the second interpolation pixel;
• and
• obtaining a weighted mean of the first interpolation pixel and the second interpolation pixel by using the weighting factor decided in said deciding of the weighting factor so as to generate a third interpolation pixel, and interpolating the decoded image by using the third interpolation pixel so as to generate the progressive image.

A deinterlacing method for performing a decoding process to a code sequence, field by field or frame by frame, which code sequence is obtained by coding an interlaced image composed of plural fields using motion compensation, and converting an decoded image of the interlaced image, which is obtained by the decoding process, into a progressive image, said method comprising:

• decoding the interlaced image so as to obtain the decoded image and to obtain a motion vector at the motion compensation which indicates a prescribed reference field for a target field;
• a converting a motion vector for each of the fields having a size corresponding to a time interval between the target field and the prescribed reference field into a motion vector of a size corresponding to a time interval of a fixed unit;
• judging an effectiveness of the motion vectors converted in said converting of the motion vector;
• obtaining pixels from reference fields which are forward and backward fields of a deinterlacing target field to be subjected to a deinterlacing process based on the motion vectors converted in said converting of the motion vector and a result of the judgment in said judging of the effectiveness of the motion vectors, and generating a first interpolation pixel for the deinterlacing target field;
• generating a second interpolation pixel by using pixels in the deinterlacing target field;
• deciding a weighting factor which indicates a weighting ratio between the first interpolation pixel and the second interpolation pixel;
• and
• obtaining a weighted mean of the first interpolation pixel and the second interpolation pixel by using the weighting factor so as to generate a third interpolation pixel, and interpolating the decoded image by using the third interpolation pixel so as to generate the progressive image.

A deinterlacing method for generating an interpolation pixel for an interlaced image which is composed of plural fields, using pixels in each of the fields, and converting the interlaced image into a progressive image, said method comprising:

• detecting a direction indicated by a line passing through a position to be interpolated where the interpolation pixel is generated and connecting peripheral pixels of the position to be interpolated, as a direction of an edge;
• obtaining a strongness of a correlation between pixels existing in the direction of the edge, as a reliability of the edge;
• and
• generating the interpolation pixel by using the pixels existing in the direction of the edge when the reliability of the edge is equal to or larger than a predetermined value, and generating the interpolation pixel by using pixels existing in upper and lower directions of the position to be interpolated when the reliability of the edge is smaller than the predetermined value.

A deinterlacing apparatus for performing a decoding process to a code sequence obtained by coding an interlaced image which is composed of plural fields using motion compensation, field by field or frame by frame, and converting a decoded image of the interlaced image, which is obtained by the decoding process, into a progressive image, said apparatus comprising:

• a decoder for decoding the interlaced image so as to obtain the decoded image and to obtain a motion vector at the motion compensation which indicates a prescribed reference field for a target field;
• an image memory for storing the decoded image;
• a parameter memory for storing the motion vector;
• a motion vector converter for converting a motion vector for each of the fields, having a size corresponding to a time interval between the target field and the prescribed reference field, which is read from said parameter memory, into a motion vector of a size corresponding to a time interval of a fixed unit;
• an inter-field interpolation pixel generator for obtaining pixels from reference fields which are forward and backward fields of a deinterlacing target field to be subjected to a deinterlacing process based on the motion vectors converted by said motion vector converter, and generating a first interpolation pixel for the deinterlacing target field;
• an intra-field interpolation pixel generator for generating a second interpolation pixel by using pixels in the deinterlacing target field;
• a weighting factor decision unit for deciding a weighting factor which indicates a weighting ratio between the first interpolation pixel and the second interpolation pixel;
• and
• a progressive image generator for obtaining a weighted mean of the first interpolation pixel and the second interpolation pixel by using the weighting factor so as to generate a third interpolation pixel, and interpolating the decoded image read from said image memory by using the third interpolation pixel so as to generate the progressive image.

A deinterlacing apparatus for performing a decoding process to a code sequence obtained by coding an interlaced image which is composed of plural fields using motion compensation, field by field of frame by frame, and converting a decoded image of the interlaced image, which is obtained by the decoding process, into a progressive image, said apparatus comprising:

• a decoder for decoding the interlaced image so as to obtain the decoded image and to obtain a motion vector at the motion compensation which indicates a prescribed reference field for a target field;
• an image memory for storing the decoded image;
• a parameter memory for storing the motion vector;
• a motion vector converter for converting a motion vector for each of the fields, having a size corresponding to a time interval between the target field and the prescribed reference field, which is read from said parameter memory, into a motion vector of a size corresponding to a time interval of a fixed unit;
• a motion vector judgment unit for judging an effectiveness of the motion vectors converted by said motion vector converter;
• an inter-field interpolation pixel generator for obtaining pixels from reference fields which are forward and backward fields of a deinterlacing target field to be subjected to a deinterlacing process based on the motion vectors converted by said motion vector converter and a result of the judgment by said motion vector judgment unit, and generating a first interpolation pixel for the deinterlacing target field;
• an intra-field interpolation pixel generator for reading pixels in the deinterlacing target field so as to generate a second interpolation pixel;
• a weighting factor decision unit for deciding a weighting factor which indicates a weighting ratio between the first interpolation pixel and the second interpolation pixel;
• and
• a progressive image generator for obtaining a weighted mean of the first interpolation pixel and the second interpolation pixel by using the weighting factor so as to generate a third interpolation pixel, and interpolating the decoded image read from said image memory by using the third interpolation pixel so as to generate the progressive image.