Image interpolation method and apparatus, and method for obtaining interpolation coefficients

An image interpolation method, wherein an image comprises multiple pixel points and the pixel points are arranged in a two-dimensional matrix composed of rows in a horizontal direction and columns in a vertical direction, the method comprising:

• obtaining pixel values of a first set of pixel points in a same row as a first pixel point, the row being in a horizontal direction;
• obtaining a first set of interpolation coefficients corresponding to the first set of pixel points;
• interpolating the first pixel point based on the pixel values of the first set of pixel points and the first set of interpolation coefficients;
• obtaining pixel values of a second set of pixel points in a same column as a second pixel point, the column being in a vertical direction;
• obtaining a second set of interpolation coefficients corresponding to the second set of pixel points;
• interpolating the second pixel point based on the pixel values of the second set of pixel points and the second set of interpolation coefficients;
• obtaining pixel values of a third set of pixel points in a same line as a third pixel point, the line being in a direction of positive 45 degrees or negative 45 degrees;
• obtaining a third set of interpolation coefficients corresponding to the third set of pixel points;
• and
• interpolating the third pixel point based on the pixel values of the third set of pixel points and the third set of interpolation coefficients,
• wherein an interpolation formula of the interpolating the second pixel point is:
• b=B1·h1b+B2·h2b+B3·h3b+ . . . +BN·hNb, wherein b indicates the pixel value of the second pixel point, B1, B2, . . . , BN indicate the pixel values of the second set of pixel points, h1b, h2b, . . . , hNb indicate the second set of interpolation coefficients, and N is a positive integer.

An image interpolation method, wherein an image comprises multiple pixel points and the pixel points are arranged in a two-dimensional matrix composed of rows in a horizontal direction and columns in a vertical direction, the method comprising:

• obtaining pixel values of a first set of pixel points in a same row as a first pixel point, the row being in a horizontal direction;
• obtaining a first set of interpolation coefficients corresponding to the first set of pixel points;
• interpolating the first pixel point based on the pixel values of the first set of pixel points and the first set of interpolation coefficients;
• obtaining pixel values of a second set of pixel points in a same column as a second pixel point the column being in a vertical direction;
• obtaining a second set of interpolation coefficients corresponding to the second set of pixel points;
• interpolating the second pixel point based on the pixel values of the second set of pixel points and the second set of interpolation coefficients;
• obtaining pixel values of a third set of pixel points in a same line as a third pixel point, the line being in a direction of positive 45 degrees or negative 45 degrees;
• obtaining a third set of interpolation coefficients corresponding to the third set of pixel points;
• and
• interpolating the third pixel point based on the pixel values of the third set of pixel points and the third set of interpolation coefficients,
• wherein an interpolation formula of the interpolating the third pixel point is one of the following:
• c=C1·h1c+C2·h2c+C3·h3c+ . . . +CI·hIc, wherein c indicates the pixel value of the third pixel point, C1, C2, . . . , CI indicate the pixel values of the third set of pixel points, h1c, h2c, . . . , hIc indicate the third set of interpolation coefficients, and I is a positive integer;
• and
• d=D1·h1d+D2·h2d+D3·h3d+ . . . +DK·hKd, wherein d indicates the pixel value of the third pixel point, D1, D2, . . . , DK indicate the pixel values of the third set of pixel points, h1d, h2d, . . . , hKd indicate the third set of interpolation coefficients, and K is a positive integer.

A method for obtaining image interpolation coefficients for a pixel point, the method comprising:

• constructing a one-dimensional Wiener-Hopf equation from any of the following:
• a set of pixel points in a same row as a first pixel point, the row being in a horizontal direction,
• a set of pixel points in a same column as the first pixel point, the column being in a vertical direction, and
• a set of pixel points in a same line as the first pixel point, the line being in a direction of positive 45 degrees or negative 45 degrees;
• and
• solving the one-dimensional Wiener-Hopf equation to obtain interpolation coefficients for the first pixel point, wherein the set of pixel points, from which the one-dimensional Wiener-Hopf equation is constructed, comprises a sub-pixel point, and the accuracy of the first pixel point is equal to or higher than the accuracy of the sub-pixel point, and
• wherein the interpolation coefficients for the first pixel point are designated for interpolating the first pixel point via the following formula:
• a=A1·h1a+A2·h2a+A3·h3a+ . . . +AM·hMa, wherein a indicates the pixel value of the first pixel point, A1, A2, . . . , AM indicate the pixel values of the first set of pixel points, h1a, h2a, . . . , hMa indicate the first set of interpolation coefficients, and M is a positive integer.

An image interpolation apparatus, comprising:

• a memory for storing instructions;
• and
• a processor coupled to the memory configured to execute the instructions to allow the apparatus to:
• obtain pixel values of a first set of pixel points in a same row as a first pixel point, the row being in a horizontal direction;
• obtain a first set of interpolation coefficients corresponding to the first set of pixel points;
• interpolate the first pixel point based on the pixel values of the first set of pixel points and the first set of interpolation coefficients;
• obtain pixel values of a second set of pixel points in a same column as a second pixel point, the column being in a vertical direction;
• obtain a second set of interpolation coefficients corresponding to the second set of pixel points;
• interpolate the second pixel point based on the pixel values of the second set of pixel points and the second set of interpolation coefficients;
• obtain pixel values of a third set of pixel points in a same line as a third pixel point, the line being in a direction of positive 45 degrees or negative 45 degrees;
• obtain a third set of interpolation coefficients corresponding to the third set of pixel points;
• and
• interpolate the third pixel point based on the pixel values of the third set of pixel points and the third set of interpolation coefficients, wherein the first set of interpolation coefficients are designated for interpolating the first pixel point via the following formula:
• a=A1·h1a+A2·h2a+A3·h3a+ . . . +AM·hMa, wherein a indicates the pixel value of the first pixel point, A1, A2, . . . , AM indicate the pixel values of the first set of pixel points, h1a, h2a, . . . , hMa indicate the first set of interpolation coefficients, and M is a positive integer.

An image interpolation apparatus, comprising:

• a memory for storing instructions;
• and
• a processor coupled to the memory configured to execute the instructions to allow the apparatus to:
• construct a one-dimensional Wiener-Hopf equation from any of the following:
• a set of pixel points in a same row as a first pixel point, the row being in a horizontal direction,
• a set of pixel points in a same column as the first pixel point, the column being in a vertical direction, and
• a set of pixel points in a same line as the first pixel point, the line being in a direction of positive 45 degrees or negative 45 degrees;
• and
• solve the one-dimensional Wiener-Hopf equation to obtain interpolation coefficients for the first pixel point, wherein the set of pixel points, from which the one-dimensional Wiener-Hopf equation is constructed, comprises a sub-pixel point, and the accuracy of the first pixel point is equal to or higher than the accuracy of the sub-pixel point, and
• wherein the interpolation coefficients for the first pixel point are designated for interpolating the first pixel point via the following formula:
• a=A1·h1a+A2·h2a+A3·h3a+ . . . +AM·hMa, wherein a indicates the pixel value of the first pixel point, A1, A2, . . . , AM indicate the pixel values of the first set of pixel points, h1a, h2a, . . . , hMa indicate the first set of interpolation coefficients, and M is a positive integer.