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| -rw-r--r-- | macros/filter2.sci | 93 |
1 files changed, 65 insertions, 28 deletions
diff --git a/macros/filter2.sci b/macros/filter2.sci index b8b48e4..f565e14 100644 --- a/macros/filter2.sci +++ b/macros/filter2.sci @@ -1,33 +1,70 @@ -function Y = filter2 (B, X, SHAPE) -//Apply the 2-D FIR filter B to X. -//Calling Sequence -//Y = filter2(B, X) -//Y = filter2(B, X, SHAPE) -//Parameters -//B, X: Matrix -// SHAPE: -// 'full': pad X with zeros on all sides before filtering. -// 'same': unpadded X (default) -// 'valid': trim X after filtering so edge effects are no included. -//Description -//This function applies the 2-D FIR filter B to X. If the argument SHAPE is specified, return an array of the desired shape. -//Examples +function y = filter2 (b, x, shape) +//Apply the 2-D FIR filter b to x. +//Calling Sequence: +//y = filter2(b, x) +//y = filter2(b, x, shape) +//Parameters: +//b, x: vectors +//If the optional argument 'shape' is specified, return a vector of the desired shape. +//Possible values are: +// "full"- pad x with zeros on all sides before filtering. +// "same"- unpadded x (default) +// "valid"- trim x after filtering so edge effects are no included. +//Examples: //filter2([1,3], [4,5]) -//ans = -// 19. 5. -funcprot(0); -lhs = argn(1) -rhs = argn(2) -if (rhs < 2 | rhs > 3) -error("Wrong number of input arguments.") -end +//ans = +//[19, 5] -select(rhs) - - case 2 then - Y=callOctave("filter2",B,X) - case 3 then - Y = callOctave("filter2",B,X,SHAPE) + funcprot(0); + rhs = argn(2); + + if (rhs < 2 | rhs > 3) then + error("filter2: wrong number of input arguments"); + end + if (rhs < 3) then + shape = "same"; + end + [nr, nc] = size(b); + A = x; + B = b(nr:-1:1, nc:-1:1); + fullConv = convol2d(A, B); + sizeA = size(A); + sizeB = size(B); + sizeFull = size(fullConv); + + select(shape) + case "full" + y = fullConv; + case "same" + startRow = floor(sizeB(1) / 2) + 1; + startCol = floor(sizeB(2) / 2) + 1; + endRow = startRow + sizeA(1) - 1; + endCol = startCol + sizeA(2) - 1; + y = fullConv(startRow:endRow, startCol:endCol); + case "valid" + startRow = sizeB(1); + startCol = sizeB(2); + endRow = sizeFull(1) - sizeB(1) + 1; + endCol = sizeFull(2) - sizeB(2) + 1; + if endRow >= startRow & endCol >= startCol then + y = fullConv(startRow:endRow, startCol:endCol); + else + y = []; + end + else + error("Invalid shape parameter."); end endfunction + +//input validation: +//assert_checkerror("filter2()", "filter2: wrong number of input arguments"); +//assert_checkerror("filter2(1, 2, 3, 4)", "Wrong number of input arguments."); + +//tests: +//assert_checkequal(filter2([1, 2; 3, 5], [1, 3; 5, 7]), [57, 24; 19, 7]); +//assert_checkequal(filter2(1, 5), filter2(1, 5, "same")); +//assert_checkequal(filter2([1, 2], [4; 5; 6], "full"), [8, 4; 10, 5; 12, 6]); +//assert_checkequal(filter2([3; 1], [5; 4], "valid"), 19); +//x=1; +//assert_checkequal(filter2([3 x*2; 3*x+1 9^x], [5 7; 4 8], "valid"), 117); |