Interpolation device, process and recording medium on which interpolation processing program is recorded

Claim 2

An interpolation device for performing interpolation of an image in which grid points that output a predetermined color and empty grid points that do not output the predetermined color are oriented in a checkered pattern to obtain an interpolation amount that becomes a pixel output of the empty grid point, comprising: a first similarity calculator that calculates a first vertical direction similarity indicative of a similarity of two grid points adjacent to an empty grid point in a vertical direction and a first horizontal direction similarity indicative of a similarity of two grid points adjacent to the empty grid point in a horizontal direction; a second similarity calculator that calculates a second vertical direction similarity indicative of a similarity of at least one of the grid points adjacent to the empty grid point in the horizontal direction and a second horizontal direction similarity indicative of a similarity of at least one of the grid points adjacent to the empty grid point in the vertical direction; a similarity calculator that calculates a similarity in a vertical direction of the empty grid point based on the first vertical direction similarity and the second vertical direction similarity and calculates a similarity in a horizontal direction of the empty grid point based on the first horizontal direction similarity and the second horizontal direction similarity; and an interpolation calculator that calculates an interpolation amount of the empty grid points by one of: selecting at least one pixel output of grid points positioned in a direction where the similarity determined by the similarity calculator is strong, and by weighted addition of at least one pixel output of the grid points positioned at the vertical direction and at least one pixel output of the grid points positioned at the horizontal direction, according to the similarity determined by the similarity calculator.

Claim 3

The interpolation device of claim 1 , wherein when the coordinates of the empty grid point are (i, j), the first similarity calculator calculates the first vertical direction similarity Ct(i, j) and the first horizontal direction similarity Cy(i, j) as follows: Ct ( i, j )=| G ( i, j −1)− G ( i, j +1)| Cy ( i, j )=| G ( i −1 , j )− G ( i +1 , j )|, wherein G(x, y) is the pixel output of a grid point that is positioned at the coordinates (x, y).

Claim 4

The interpolation device of claim 2 , wherein, the second similarity calculator calculates the second vertical direction similarity Ctn(i, j) based on at least one of Ct(i−1, j−1), Ct(i+1, j−1), Ct(i+1, j+1) and Ct(i−1, j+1), and calculates the second horizontal direction similarity Cyn(i, j) based on at least one of Cy(i−1, j−1), Cy(i+1, j−1), Cy(i+1, j+1) and Cy(i−1, j+1).

Claim 5

The interpolation device of claim 3 , wherein the second similarity calculator designates a sum of two of the values among Ct(i−1, j−1), Ct(i+1, j−1), Ct(i+1, j+1) and Ct(i−1, j+1) as the second vertical direction similarity Ctn(i, j), and designates a sum of two of the values among Cy(i−1, j−1), Cy(i+1, j−1), Cy(i+1, j+1) and Cy(i−1, j+1) as the second horizontal direction similarity Cyn(i, j).

Claim 6

The interpolation device of claim 3 , wherein the second similarity calculator designates a weighted addition of two of the values among Ct(i−1, j−1), Ct(i+1, j−1), Ct(i+1, j+1) and Ct(i−1, j+1) as the second vertical direction similarity Ctn(i, j), and designates a weighted addition of two of the values among Cy(i−1, j−1), Cy(i+1, j−1), Cy(i+1, j+1) and Cy(i−1, j+1) as the second horizontal direction similarity Cyn(i, j).

Claim 7

The interpolation device of claim 3 , wherein the second similarity calculator designates a minimum value among Ct(i−1, j−1), Ct(i+1, j−1), Ct(i+1, j+1), and Ct(i−1, j+1) as the second vertical direction similarity Ctn(i, j), and designates a minimum value among Cy(i−1, j−1), Cy(i+1, j−1), Cy(i+1, j+1) and Cy(i−1, j+1) as the second horizontal direction similarity Cyn(i, j).

Claim 8

The interpolation device of claim 3 , wherein the second similarity calculator calculates the second vertical direction similarity Ctn(i, j) based on two values taken in order from the smallest value among Ct(i−1, j−1), Ct(i+1, j−1), Ct(i+1, j+1) and Ct(i−1, j+1), and calculates the second horizontal direction similarity Cyn(i, j) based on two values taken in order from the smallest value among Cy(i−1, j−1), Cy(i+1, j−1), Cy(i+1, j+1) and Cy(i−1, j+1).

Claim 9

The interpolation device of claim 3 , wherein the second similarity calculator takes all possible groups of three values among Ct(i−1, j−1), Ct(i+1, j−1), Ct(i+1, j+1) and Ct(i−1, j+1), calculates a sum of the three values of each group, and designates a minimum value thereof as the second vertical direction similarity Ctn(i, j), and takes all possible groups of three values among Cy(i−1, j−1), Cy(i+1, j−1), Cy(i+1, j+1) and Cy(i−1, j+1), calculates a sum of each group, and designates a minimum value thereof as the second horizontal direction similarity Cyn(i, j).

Claim 10

The interpolation device of claim 3 , wherein the second similarity calculator takes all possible groups of three values among Ct(i−1, j−1), Ct(i+1, j−1), Ct(i+1, j+1) and Ct(i−1, j+1), calculates a weighted sum of three values of each group, and designates a minimum value thereof as the second vertical direction similarity Ctn(i, j), and takes all the possible groups of three values among Cy(i−1, j−1), Cy(i+1, j−1), Cy(i+1, j+1) and Cy(i−1, j+1), calculates a weighted sum of each group, and designates a minimum value thereof as the second horizontal direction similarity Cyn(i, j).

Claim 11

The interpolation device of claim 1 , wherein, when the coordinates of the empty grid point are (i, j), the first vertical direction similarity is Ct(i, j), the second vertical direction similarity is Ctn(i, j), the first horizontal direction similarity is Cy(i, j) and the second horizontal direction similarity is Cyn(i, j), the similarity calculator determines the similarity Ctsum(i, j) in the vertical direction of the empty grid points and the similarity Cysum(i, j) in the horizontal direction of the empty grid points as follows: Ct sum( i, j )= Ct ( i, j )+ Ctn ( i, j )× h Cy sum( i, j )= Cy ( i, j )+ Cyn ( i, j )× h wherein h is a predetermined constant.

Claim 12

The interpolation device of claim 1 , wherein the interpolation amount calculator designates an average value of the pixel output of two grid points adjacent in the direction of strong similarity as the interpolation amount of the empty grid point when either one of the vertical direction similarities and the horizontal direction similarities of the grid points determined by the similarity calculator is determined to be strong, and calculates the interpolation amount of the empty grid point by a method other than calculating the average value when both the similarities are substantially equal.

Claim 13

The interpolation device of claim 11 , wherein the interpolation amount calculator calculates the interpolation amount of the empty grid point based on a weighting factor corresponding to each similarity when the similarities in the vertical and horizontal directions of the empty grid point determined by the similarity calculator are substantially equal.

Claim 14

The interpolation device of claim 12 , wherein when the coordinates of the empty grid point are (i, j), the similarity in the vertical direction of the empty grid point is Ctsum(i, j), and the similarity in the horizontal direction of the empty grid point is Cysum(i, j), the interpolation amount calculator calculates the interpolation amount G′(i, j) of the empty grid point as follows: G ′( i, j )={( G ( i, j −1)+ G ( i, j +1))×(1 +f ( x ))+( G ( i −1 , j )+ G ( i +1 , j )×(1 −f ( x ))}/4 x =( Cy sum( i, j )− Ct sum( i, j ))/{( Cy sum( i, j )+ Ct sum( i, j ))× T 1 + T 0 } when −1≦x≦1, f(x)=x when x>1, f(x)=1 when x<−1, f(x)=−1, wherein T 1 and T 0 are predetermined constants, both of which are not 0, and G(x, y) is the pixel output of a grid point positioned at the coordinates (x, y).

Claim 15

The interpolation device of claim 11 , wherein the interpolation amount calculator calculates the interpolation amount of the empty grid point by calculating the median of the pixel outputs of four grid points adjacent to the empty grid point when the similarities in the vertical and horizontal directions of the empty grid point determined by the similarity calculator are substantially equal.

Claim 16

A recording medium in which is recorded a computer readable interpolation program for use by a computer in performing interpolation of an image in which grid points that output a predetermined color and empty grid points that do not output the predetermined color are oriented in a checkered configuration to obtain an interpolation amount that becomes a pixel output of the empty grid points, the program comprising: a first similarity calculation procedure for calculating a first vertical direction similarity indicative of a similarity of two grid points adjacent to an empty grid point in a vertical direction and a first horizontal direction similarity indicative of a similarity of two grid points adjacent to the empty grid point in a horizontal direction; a second similarity calculation procedure for calculating a second vertical direction similarity indicative of a similarity of at least one of the grid points adjacent to the empty grid point in the horizontal direction and a second horizontal direction similarity indicative of a similarity of at least one of the grid points adjacent to the empty grid point in the vertical direction; a similarity calculation procedure for calculating a similarity in a vertical direction of the empty grid point based on the first vertical direction similarity and the second vertical direction similarity and for calculating a similarity in a horizontal direction of the empty grid point based on the first horizontal direction similarity and the second horizontal direction similarity; and an interpolation calculation procedure for calculating an interpolation amount of the empty grid points by one of: selecting at least one pixel output of grid points positioned in a direction where the similarity determined by the similarity calculation procedure is strong, and by weighted addition of at least one pixel output of the grid points positioned at the vertical direction and at least one pixel output of the grid points positioned at the horizontal direction, according to the similarity determined by the similarity calculation procedure.

Claim 17

A recording medium in which is recorded a computer readable interpolation program for use by a computer in performing interpolation of an image in which grid points that output a predetermined color and empty grid points that do not output the predetermined color are oriented in a checkered configuration to obtain an interpolation amount that becomes a pixel output of the empty grid points, the program comprising: a first similarity calculation procedure for calculating a first vertical direction similarity indicative of a similarity of two grid points adjacent to an empty grid point in a vertical direction and a first horizontal direction similarity indicative of a similarity of two grid points adjacent to the empty grid point in a horizontal direction; a second similarity calculation procedure for calculating a second vertical direction similarity indicative of a similarity of at least one of the grid points adjacent to the empty grid point in the horizontal direction and a second horizontal direction similarity indicative of a similarity of at least one of the grid points adjacent to the empty grid point in the vertical direction; a similarity calculation procedure for calculating a similarity in a vertical direction of the empty grid point based on the first vertical direction similarity and the second vertical direction similarity and for calculating a similarity in a horizontal direction of the empty grid point based on the first horizontal direction similarity and the second horizontal direction similarity; and an interpolation calculation procedure for calculating an interpolation amount of the empty grid points by one of: selecting at least one pixel output of grid points positioned in a direction where the similarity determined by the similarity calculation procedure is strong, and by weighted addition of at least one pixel output of the grid points positioned at the vertical direction and at least one pixel output of the grid points positioned at the horizontal direction, according to the similarity determined by the similarity calculation procedure.

Claim 18

The recording medium of claim 15 , wherein when the coordinates of the empty grid point are (i, j), the first similarity calculation procedure calculates the first vertical direction similarity Ct(i, j) and the first horizontal direction similarity Cy(i, j) as follows: Ct ( i, j )=| G ( i, j −1)− G ( i, j +1)| Cy ( i, j )=| G ( i −1 , j )− G ( i +1 , j )|, wherein G(x, y) is the pixel output of a grid point that is positioned at the coordinates (x, y).

Claim 19

The recording medium of claim 16 , wherein, the second similarity calculation procedure calculates the second vertical direction similarity Ctn(i, j) based on at least one of Ct(i−1, j−1), Ct(i+1, j−1), Ct(i+1, j+1) and Ct(i−1, j+1), and calculates the second horizontal direction similarity Cyn(i, j) based on at least one of Cy(i−1, j−1), Cy(i+1, j−1), Cy(i+1, j+1) and Cy(i 1, j+1).

Claim 20

The recording medium of claim 17 , wherein the second similarity calculation procedure designates a sum of two of the values among Ct(i−1, j−1), Ct(i+1, j−1), Ct(i+1, j+1) and Ct(i−1, j+1) as the second vertical direction similarity Ctn(i, j), and designates a sum of two of the values among Cy(i−1, j−1), Cy(i+1, j−1), Cy(i+1, j+1) and Cy(i−1, j+1) as the second horizontal direction similarity Cyn(i, j).

Claim 21

The recording medium of claim 17 , wherein the second similarity calculation procedure designates a weighted addition of two of the values among Ct(i−1, j−1), Ct(i+1, j−1), Ct(i+1, j+1) and Ct(i−1, j+1) as the second vertical direction similarity Ctn(i, j), and designates a weighted addition of two of the values among Cy(i−1, j−1), Cy(i+1, j−1), Cy(i+1, j+1) and Cy(i−1, j+1) as the second horizontal direction similarity Cyn(i, j).

Claim 22

The recording medium of claim 15 , wherein, when the coordinates of the empty grid point are (i, j), the first vertical direction similarity is Ct(i, j), the second vertical direction similarity is Ctn(i, j), the first horizontal direction similarity is Cy(i, j) and the second horizontal direction similarity is Cyn(i, j), the similarity calculation procedure determines the similarity Ctsum(i, j) in the vertical direction of the empty grid points and the similarity Cysum(i, j) in the horizontal direction of the empty grid points as follows: Ct sum( i, j )= Ct ( i, j )+ Ctn ( i, j )× h Cy sum( i, j )= Cy ( i, j )+ Cyn ( i, j )× h wherein h is a predetermined constant.

Claim 23

The recording medium of claim 15 , wherein the interpolation amount calculation procedure designates an average value of the pixel output of two grid points adjacent in the direction of strong similarity as the interpolation amount of the empty grid point when either one of the vertical direction similarities and the horizontal direction similarities of the grid points determined by the similarity calculation procedure is determined to be strong, and calculates the interpolation amount of the empty grid point by a method other than calculating the average value when both the similarities are substantially equal.

Claim 24

The recording medium of claim 21 , wherein the interpolation amount calculation procedure calculates the interpolation amount of the empty grid point based on a weighting factor corresponding to each similarity when the similarities in the vertical and horizontal directions of the empty grid point determined by the similarity detection procedure are substantially equal.

Claim 25

The recording medium of claim 22 , wherein when the coordinates of the empty grid point are (i, j), the similarity in the vertical direction of the empty grid point is Ctsum(i, j), and the similarity in the horizontal direction of the empty grid point is Cysum(i, j), the interpolation amount calculation procedure calculates the interpolation amount G′(i, j) of the empty grid point as follows: G ′( i, j )={( G ( i, j −1)+ G ( i, j +1))×(1 +f ( x ))+( G ( i −1 , j )+ G ( i +1 , j )×(1 −f ( x ))}/4 x =( Cy sum( i, j )− Ct sum( i, j ))/{( Cy sum( i, j )+ Ct sum( i, j ))× T 1 + T 0 } when −1≦x≦1, f(x)=x when x>1, f(x)=1 when x<−1, f(x)=−1, wherein T 1 and T 0 are predetermined constants, both of which are not 0, and G(x, y) is the pixel output of a grid point positioned at the coordinates (x, y).

Claim 26

The recording medium of claim 21 , wherein the interpolation amount calculation procedure calculates the interpolation amount of the empty grid point by calculating the median of the pixel outputs of four grid points adjacent to the empty grid point when the similarities in the vertical and horizontal directions of the empty grid point determined by the similarity calculation procedure are substantially equal.