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@ -16,75 +16,257 @@ function xc = bayer2rgb(xb, M, N, method) |
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gridPointsStepLengthY = (bayerPatternDimY - 1) / (M - 1); |
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gridPointsStepLengthX = (bayerPatternDimX - 1) / (N - 1); |
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% Calculates the coordinates of the grid points for both axes |
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gridPointsCoordinatesY = 1:gridPointsStepLengthY:bayerPatternDimY; |
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gridPointsCoordinatesX = 1:gridPointsStepLengthX:bayerPatternDimX; |
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gridPointsCoordinatesY = (1:gridPointsStepLengthY:bayerPatternDimY)'; |
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gridPointsCoordinatesX = (1:gridPointsStepLengthX:bayerPatternDimX)'; |
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if (strcmp(method, 'nearest')) |
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% Determines the indeces of the even rows of the original image |
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% that are closest to each ordinate of the new image grid |
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gridPointYmod2 = mod(gridPointsCoordinatesY, 2) >= 1; |
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nearestEvenRow = floor(gridPointsCoordinatesY); |
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nearestEvenRow(gridPointYmod2) = nearestEvenRow(gridPointYmod2)+1; |
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nearestEvenRow(nearestEvenRow > bayerPatternDimY) = ... |
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nearestEvenRow(nearestEvenRow > bayerPatternDimY) - 2; |
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% Determines the indeces of the odd rows of the original image that |
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% are closest to each ordinate of the new image grid |
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nearestOddRow = floor(gridPointsCoordinatesY); |
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nearestOddRow(~gridPointYmod2) = nearestOddRow(~gridPointYmod2)+1; |
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nearestOddRow(nearestOddRow > bayerPatternDimY) = ... |
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nearestOddRow(nearestOddRow > bayerPatternDimY) - 2; |
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% Determines the indeces of the even columns of the original image |
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% that are closest to each abscissa of the new image grid |
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gridPointXmod2 = mod(gridPointsCoordinatesX, 2) >= 1; |
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nearestEvenCol = floor(gridPointsCoordinatesX); |
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nearestEvenCol(gridPointXmod2) = nearestEvenCol(gridPointXmod2)+1; |
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nearestEvenCol(nearestEvenCol > bayerPatternDimX) = ... |
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nearestEvenCol(nearestEvenCol > bayerPatternDimX) - 2; |
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% Determines the indeces of the odd columns of the original image |
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% that are closest to each abscissa of the new image grid |
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nearestOddCol = floor(gridPointsCoordinatesX); |
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nearestOddCol(~gridPointXmod2) = nearestOddCol(~gridPointXmod2)+1; |
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nearestOddCol(nearestOddCol > bayerPatternDimX) = ... |
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nearestOddCol(nearestOddCol > bayerPatternDimX) - 2; |
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% Determines the indeces of the rows (even or odd) of the original |
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% image that are closest to each ordinate of the new image grid |
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totalNearestRow = round(gridPointsCoordinatesY); |
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% Determines the indeces of the columns (even or odd) of the |
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% original image that are closest to each abscissa of the new image |
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totalNearestCol = round(gridPointsCoordinatesX); |
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% Closest neighbors for red and blue can be determined by observing |
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% the Bayer pattern |
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xc.red = xb(nearestOddRow, nearestEvenCol); |
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xc.blue = xb(nearestEvenRow, nearestOddCol); |
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for currentRow = 1:M |
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% Determines the index of the even row of the original image |
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% that is closest to this ordinate (currentRow) of the new |
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% image |
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idx = mod(gridPointsCoordinatesY(currentRow), 2) >= 1; |
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nearestEvenRow = floor(gridPointsCoordinatesY(currentRow)); |
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nearestEvenRow(idx) = nearestEvenRow(idx)+1; |
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if (nearestEvenRow > bayerPatternDimY) |
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nearestEvenRow = nearestEvenRow - 2; |
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for currentCol = 1:N |
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if ((mod(totalNearestRow(currentRow), 2) == 0 && ... |
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mod(totalNearestCol(currentCol), 2)) ~= 0 || ... |
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(mod(totalNearestRow(currentRow), 2) ~= 0 && ... |
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mod(totalNearestCol(currentCol), 2) == 0)) |
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% This point of the original image doesn't contain |
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% information about the green colour |
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% Calculates the vertical displacement of the two |
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% diagonal lines that cross this point |
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b1 = totalNearestRow(currentRow) - ... |
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totalNearestCol(currentCol); |
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b2 = totalNearestRow(currentRow) + ... |
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totalNearestCol(currentCol); |
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% Calculates the ordinate of the two diagonals at the |
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% abscissa of the current point (currentCol) |
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y1 = gridPointsCoordinatesX(currentCol) + b1; |
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y2 = -gridPointsCoordinatesX(currentCol) + b2; |
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% Initializes temporary coordinates of the point which |
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% will be selected as the closest one |
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fixedNearestRow = totalNearestRow(currentRow); |
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fixedNearestCol = totalNearestCol(currentCol); |
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% Checks the relative position between the point and |
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% the two diagonals |
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if (gridPointsCoordinatesY(currentRow) >= y1 && ... |
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gridPointsCoordinatesY(currentRow) >= y2) |
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fixedNearestRow = totalNearestRow(currentRow) - 1; |
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elseif (gridPointsCoordinatesY(currentRow) < y1 && ... |
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gridPointsCoordinatesY(currentRow) < y2) |
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fixedNearestRow = totalNearestRow(currentRow) + 1; |
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elseif (gridPointsCoordinatesY(currentRow) >= y1 && ... |
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gridPointsCoordinatesY(currentRow) < y2) |
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fixedNearestCol = totalNearestCol(currentCol) - 1; |
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elseif (gridPointsCoordinatesY(currentRow) < y1 && ... |
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gridPointsCoordinatesY(currentRow) >= y2) |
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fixedNearestCol = totalNearestCol(currentCol) + 1; |
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end |
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% Determines the index of the odd row of the original image |
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% that is closest to this ordinate (currentRow) of the new |
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% image |
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idx = mod(gridPointsCoordinatesY(currentRow), 2) < 1; |
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nearestOddRow = floor(gridPointsCoordinatesY(currentRow)); |
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nearestOddRow(idx) = nearestOddRow(idx)+1; |
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if (nearestOddRow > bayerPatternDimY) |
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nearestOddRow = nearestOddRow - 2; |
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if (fixedNearestRow < 1) |
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% Fix for the marginal first row case |
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xc.green(currentRow, currentCol) = ... |
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xb(1, fixedNearestCol - 1); |
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else |
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xc.green(currentRow, currentCol) = ... |
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xb(fixedNearestRow, fixedNearestCol); |
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end |
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else |
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xc.green(currentRow, currentCol) = ... |
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xb(totalNearestRow(currentRow), ... |
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totalNearestCol(currentCol)); |
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end |
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end |
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end |
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elseif (strcmp(method, 'linear')) |
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% Calculates helper variables |
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flooredCoordinatesY = floor(gridPointsCoordinatesY); |
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flooredCoordinatesX = floor(gridPointsCoordinatesX); |
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% Calculates the ordinate of the upper couple of nearest points |
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% that will be used in the interpolation for the blue colour |
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upperBlueY = flooredCoordinatesY; |
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upperBlueY(mod(upperBlueY, 2) ~= 0) = ... |
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upperBlueY(mod(upperBlueY, 2) ~= 0) - 1; |
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upperBlueY = upperBlueY + 2; |
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% Calculates the ordinate of the upper couple of nearest points |
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% that will be used in the interpolation for the red colour |
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upperRedY = flooredCoordinatesY; |
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upperRedY(mod(upperRedY, 2) == 0) = ... |
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upperRedY(mod(upperRedY, 2) == 0) - 1; |
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upperRedY = upperRedY + 2; |
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% Calculates the abscissa of the left couple of nearest points that |
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% will be used in the interpolation for the blue colour |
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leftBlueX = flooredCoordinatesX; |
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leftBlueX(mod(leftBlueX, 2) == 0) = ... |
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leftBlueX(mod(leftBlueX, 2) == 0) - 1; |
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leftBlueX = leftBlueX + 2; |
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% Calculates the abscissa of the left couple of nearest points that |
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% will be used in the interpolation for the red colour |
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leftRedX = flooredCoordinatesX; |
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leftRedX(mod(leftRedX, 2) ~= 0) = ... |
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leftRedX(mod(leftRedX, 2) ~= 0) - 1; |
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leftRedX = leftRedX + 2; |
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% Determines the indeces of the rows (even or odd) of the original |
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% image that are closest to each ordinate of the new image grid |
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centerPointRow = round(gridPointsCoordinatesY); |
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% Determines the indeces of the columns (even or odd) of the |
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% original image that are closest to each abscissa of the new image |
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centerPointCol = round(gridPointsCoordinatesX); |
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% Adds a padding to the original image, replicating the last two |
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% rows and columns of each egde |
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xbPadded = [xb(:, end - 1) xb(:, end - 2) xb xb(:, end - 2) ... |
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xb(:, end - 1)]; |
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xbPadded = [xbPadded(1, :); xbPadded(2, :); xbPadded; ... |
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xbPadded(end - 2, :); xbPadded(end - 1, :)]; |
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for currentRow = 1:M |
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lowerInterpPointBlue = ... |
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((leftBlueX + 2 - gridPointsCoordinatesX) / 2)' .* ... |
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xbPadded(upperBlueY(currentRow) + 2, leftBlueX) + ... |
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((gridPointsCoordinatesX - leftBlueX) / 2)' .* ... |
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xbPadded(upperBlueY(currentRow) + 2, leftBlueX + 2); |
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upperInterpPointBlue = ... |
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((leftBlueX + 2 - gridPointsCoordinatesX) / 2)' .* ... |
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xbPadded(upperBlueY(currentRow), leftBlueX) + ... |
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((gridPointsCoordinatesX - leftBlueX) / 2)' .* ... |
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xbPadded(upperBlueY(currentRow), leftBlueX + 2); |
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xc.blue(currentRow, :) = ... |
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((upperBlueY(currentRow) - ... |
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gridPointsCoordinatesY(currentRow)) / 2) * ... |
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lowerInterpPointBlue + ... |
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((gridPointsCoordinatesY(currentRow) - ... |
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upperBlueY(currentRow) + 2) / 2) * ... |
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upperInterpPointBlue; |
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lowerInterpPointRed = ... |
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((leftRedX + 2 - gridPointsCoordinatesX) / 2)' .* ... |
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xbPadded(upperRedY(currentRow) + 2, leftRedX) + ... |
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((gridPointsCoordinatesX - leftRedX) / 2)' .* ... |
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xbPadded(upperRedY(currentRow) + 2, leftRedX + 2); |
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upperInterpPointRed = ... |
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((leftRedX + 2 - gridPointsCoordinatesX) / 2)' .* ... |
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xbPadded(upperRedY(currentRow), leftRedX) + ... |
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((gridPointsCoordinatesX - leftRedX) / 2)' .* ... |
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xbPadded(upperRedY(currentRow), leftRedX + 2); |
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% Determines the index of the row (even or odd) of the original |
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% image that is closest to this ordinate (currentRow) of the |
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% new image |
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totalNearestRow = round(gridPointsCoordinatesY(currentRow)); |
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xc.red(currentRow, :) = ... |
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((upperRedY(currentRow) - gridPointsCoordinatesY(currentRow)) / 2) * ... |
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lowerInterpPointRed + ... |
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((gridPointsCoordinatesY(currentRow) - upperRedY(currentRow) + 2) / 2) * ... |
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upperInterpPointRed; |
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for currentCol = 1:N |
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% Determines the index of the even column of the original |
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% image that is closest to this abscissa (currentCol) of |
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% the new image |
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idx = mod(gridPointsCoordinatesX(currentCol), 2) >= 1; |
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nearestEvenCol = floor(gridPointsCoordinatesX(currentCol)); |
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nearestEvenCol(idx) = nearestEvenCol(idx)+1; |
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if (nearestEvenCol > bayerPatternDimX) |
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nearestEvenCol = nearestEvenCol - 2; |
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end |
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if ((mod(centerPointRow(currentRow), 2) == 0 && ... |
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mod(centerPointCol(currentCol), 2)) == 0 || ... |
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(mod(centerPointRow(currentRow), 2) ~= 0 && ... |
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mod(centerPointCol(currentCol), 2) ~= 0)) |
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% This point of the original image DOES contain |
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% information about the green colour |
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% Calculates the vertical displacement of the two |
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% diagonal lines that cross this point |
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b1 = centerPointRow(currentRow) - ... |
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centerPointCol(currentCol); |
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b2 = centerPointRow(currentRow) + ... |
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centerPointCol(currentCol); |
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% Calculates the ordinate of the two diagonals at the |
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% abscissa of the current point (currentCol) |
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y1 = gridPointsCoordinatesX(currentCol) + b1; |
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y2 = -gridPointsCoordinatesX(currentCol) + b2; |
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% Initializes temporary coordinates of the point which |
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% will be selected as the center |
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fixedCenterPointRow = centerPointRow(currentRow); |
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fixedCenterPointCol = centerPointCol(currentCol); |
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% Determines the index of the even column of the original |
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% image that is closest to this abscissa (currentCol) of |
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% the new image |
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idx = mod(gridPointsCoordinatesX(currentCol), 2) < 1; |
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nearestOddCol = floor(gridPointsCoordinatesX(currentCol)); |
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nearestOddCol(idx) = nearestOddCol(idx)+1; |
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if (nearestOddCol > bayerPatternDimX) |
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nearestOddCol = nearestOddCol - 2; |
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% Checks the relative position between the point and |
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% the two diagonals |
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if (gridPointsCoordinatesY(currentRow) >= y1 && ... |
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gridPointsCoordinatesY(currentRow) >= y2) |
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fixedCenterPointRow = centerPointRow(currentRow) - 1; |
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elseif (gridPointsCoordinatesY(currentRow) < y1 && ... |
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gridPointsCoordinatesY(currentRow) < y2) |
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fixedCenterPointRow = centerPointRow(currentRow) + 1; |
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elseif (gridPointsCoordinatesY(currentRow) >= y1 && ... |
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gridPointsCoordinatesY(currentRow) < y2) |
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fixedCenterPointCol = centerPointCol(currentCol) - 1; |
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elseif (gridPointsCoordinatesY(currentRow) < y1 && ... |
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gridPointsCoordinatesY(currentRow) >= y2) |
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fixedCenterPointCol = centerPointCol(currentCol) + 1; |
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end |
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% Determines the index of the column (even or odd) of the |
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% original image that is closest to this abscissa |
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% (currentCol) of the new image |
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totalNearestCol = round(gridPointsCoordinatesX(currentCol)); |
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if (mod(totalNearestRow, 2) == 0 && mod(totalNearestCol, 2) ~= 0) |
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totalNearestCol = totalNearestCol + 1; |
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elseif (mod(totalNearestRow, 2) ~= 0 && mod(totalNearestCol, 2) == 0) |
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totalNearestCol = totalNearestCol - 1; |
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if (fixedCenterPointRow < 1) |
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% Fix for the marginal first row case |
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fixedCenterPointRow = 1; |
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fixedCenterPointCol = fixedCenterPointCol - 1; |
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end |
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% Closest neighbors per colour can be determined by |
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% observing the Bayer pattern |
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xc.red(currentRow, currentCol) = xb(nearestOddRow, nearestEvenCol); |
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xc.blue(currentRow, currentCol) = xb(nearestEvenRow, nearestOddCol); |
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xc.green(currentRow, currentCol) = xb(totalNearestRow, totalNearestCol); |
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xc.green(currentRow, currentCol) = ... |
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tiltedInterp(gridPointsCoordinatesX(currentCol), ... |
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gridPointsCoordinatesY(currentRow), ... |
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fixedCenterPointCol, fixedCenterPointRow, xbPadded); |
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else |
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xc.green(currentRow, currentCol) = ... |
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tiltedInterp(gridPointsCoordinatesX(currentCol), ... |
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gridPointsCoordinatesY(currentRow), ... |
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centerPointCol(currentCol), ... |
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centerPointRow(currentRow), xbPadded); |
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end |
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end |
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end |
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elseif (strcmp(method, 'linear')) |
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end |
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% Combines colours to a single image array and shows the result |
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@ -92,3 +274,52 @@ function xc = bayer2rgb(xb, M, N, method) |
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figure(); |
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imshow(rgbImage); |
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end |
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function value = tiltedInterp(xw, yw, xc, yc, xbPadded) |
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% Calculates the vertical displacement of the main diagonal that |
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% crosses this point |
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bw = yw - xw; |
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% Calculates the abscissas of the points of intersection |
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x1 = (yc + xc - 1 - bw) / 2; |
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%x2 = (yc + xc + 1 - bw) / 2; |
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% Calculates perpendicular distance of point w to the line connecting |
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% the lower point and the left point |
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dist = sqrt((x1 - xw) ^ 2 + (x1 + bw - yw) ^ 2); |
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% Calculates the lengths of the upper parts of the lines connecting the |
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% points |
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h1 = sqrt(((xc - 1 - xw) ^ 2 + (yc - yw) ^ 2) - dist ^ 2); |
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lowerLeftInterpPoint = ... |
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((sqrt(2) - h1) / sqrt(2)) * ... |
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xbPadded(yc + 2, xc - 1 + 2) + ... |
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(h1 / sqrt(2)) * ... |
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xbPadded(yc + 1 + 2, xc + 2); |
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upperRightInterpPoint = ... |
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((sqrt(2) - h1) / sqrt(2)) * ... |
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xbPadded(yc - 1 + 2, xc + 2) + ... |
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(h1 / sqrt(2)) * ... |
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xbPadded(yc + 2, xc + 1 + 2); |
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value = ... |
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(sqrt(2) - dist) / sqrt(2) * lowerLeftInterpPoint + ... |
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dist / sqrt(2) * upperRightInterpPoint; |
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end |
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