Saya menulis sebuah fungsi yang memecahkan ini dalam StackOverflow Q2080835 GitHub Repository saya (Lihat CreateImageConvMtx()
).
Sebenarnya fungsi tersebut dapat mendukung bentuk konvolusi yang Anda inginkan - full
, same
dan valid
.
Kode tersebut adalah sebagai berikut:
function [ mK ] = CreateImageConvMtx( mH, numRows, numCols, convShape )
CONVOLUTION_SHAPE_FULL = 1;
CONVOLUTION_SHAPE_SAME = 2;
CONVOLUTION_SHAPE_VALID = 3;
switch(convShape)
case(CONVOLUTION_SHAPE_FULL)
% Code for the 'full' case
convShapeString = 'full';
case(CONVOLUTION_SHAPE_SAME)
% Code for the 'same' case
convShapeString = 'same';
case(CONVOLUTION_SHAPE_VALID)
% Code for the 'valid' case
convShapeString = 'valid';
end
mImpulse = zeros(numRows, numCols);
for ii = numel(mImpulse):-1:1
mImpulse(ii) = 1; %<! Create impulse image corresponding to i-th output matrix column
mTmp = sparse(conv2(mImpulse, mH, convShapeString)); %<! The impulse response
cColumn{ii} = mTmp(:);
mImpulse(ii) = 0;
end
mK = cell2mat(cColumn);
end
Saya juga membuat fungsi untuk membuat Matriks Penyaringan Gambar (Ide serupa dengan MATLAB imfilter()
):
function [ mK ] = CreateImageFilterMtx( mH, numRows, numCols, operationMode, boundaryMode )
%UNTITLED6 Summary of this function goes here
% Detailed explanation goes here
OPERATION_MODE_CONVOLUTION = 1;
OPERATION_MODE_CORRELATION = 2;
BOUNDARY_MODE_ZEROS = 1;
BOUNDARY_MODE_SYMMETRIC = 2;
BOUNDARY_MODE_REPLICATE = 3;
BOUNDARY_MODE_CIRCULAR = 4;
switch(operationMode)
case(OPERATION_MODE_CONVOLUTION)
mH = mH(end:-1:1, end:-1:1);
case(OPERATION_MODE_CORRELATION)
% mH = mH; %<! Default Code is correlation
end
switch(boundaryMode)
case(BOUNDARY_MODE_ZEROS)
mK = CreateConvMtxZeros(mH, numRows, numCols);
case(BOUNDARY_MODE_SYMMETRIC)
mK = CreateConvMtxSymmetric(mH, numRows, numCols);
case(BOUNDARY_MODE_REPLICATE)
mK = CreateConvMtxReplicate(mH, numRows, numCols);
case(BOUNDARY_MODE_CIRCULAR)
mK = CreateConvMtxCircular(mH, numRows, numCols);
end
end
function [ mK ] = CreateConvMtxZeros( mH, numRows, numCols )
%UNTITLED6 Summary of this function goes here
% Detailed explanation goes here
numElementsImage = numRows * numCols;
numRowsKernel = size(mH, 1);
numColsKernel = size(mH, 2);
numElementsKernel = numRowsKernel * numColsKernel;
vRows = reshape(repmat(1:numElementsImage, numElementsKernel, 1), numElementsImage * numElementsKernel, 1);
vCols = zeros(numElementsImage * numElementsKernel, 1);
vVals = zeros(numElementsImage * numElementsKernel, 1);
kernelRadiusV = floor(numRowsKernel / 2);
kernelRadiusH = floor(numColsKernel / 2);
pxIdx = 0;
elmntIdx = 0;
for jj = 1:numCols
for ii = 1:numRows
pxIdx = pxIdx + 1;
for ll = -kernelRadiusH:kernelRadiusH
for kk = -kernelRadiusV:kernelRadiusV
elmntIdx = elmntIdx + 1;
pxShift = (ll * numCols) + kk;
if((ii + kk <= numRows) && (ii + kk >= 1) && (jj + ll <= numCols) && (jj + ll >= 1))
vCols(elmntIdx) = pxIdx + pxShift;
vVals(elmntIdx) = mH(kk + kernelRadiusV + 1, ll + kernelRadiusH + 1);
else
vCols(elmntIdx) = pxIdx;
vVals(elmntIdx) = 0; % See the accumulation property of 'sparse()'.
end
end
end
end
end
mK = sparse(vRows, vCols, vVals, numElementsImage, numElementsImage);
end
function [ mK ] = CreateConvMtxSymmetric( mH, numRows, numCols )
%UNTITLED6 Summary of this function goes here
% Detailed explanation goes here
numElementsImage = numRows * numCols;
numRowsKernel = size(mH, 1);
numColsKernel = size(mH, 2);
numElementsKernel = numRowsKernel * numColsKernel;
vRows = reshape(repmat(1:numElementsImage, numElementsKernel, 1), numElementsImage * numElementsKernel, 1);
vCols = zeros(numElementsImage * numElementsKernel, 1);
vVals = zeros(numElementsImage * numElementsKernel, 1);
kernelRadiusV = floor(numRowsKernel / 2);
kernelRadiusH = floor(numColsKernel / 2);
pxIdx = 0;
elmntIdx = 0;
for jj = 1:numCols
for ii = 1:numRows
pxIdx = pxIdx + 1;
for ll = -kernelRadiusH:kernelRadiusH
for kk = -kernelRadiusV:kernelRadiusV
elmntIdx = elmntIdx + 1;
pxShift = (ll * numCols) + kk;
if(ii + kk > numRows)
pxShift = pxShift - (2 * (ii + kk - numRows) - 1);
end
if(ii + kk < 1)
pxShift = pxShift + (2 * (1 -(ii + kk)) - 1);
end
if(jj + ll > numCols)
pxShift = pxShift - ((2 * (jj + ll - numCols) - 1) * numCols);
end
if(jj + ll < 1)
pxShift = pxShift + ((2 * (1 - (jj + ll)) - 1) * numCols);
end
vCols(elmntIdx) = pxIdx + pxShift;
vVals(elmntIdx) = mH(kk + kernelRadiusV + 1, ll + kernelRadiusH + 1);
end
end
end
end
mK = sparse(vRows, vCols, vVals, numElementsImage, numElementsImage);
end
function [ mK ] = CreateConvMtxReplicate( mH, numRows, numCols )
%UNTITLED6 Summary of this function goes here
% Detailed explanation goes here
numElementsImage = numRows * numCols;
numRowsKernel = size(mH, 1);
numColsKernel = size(mH, 2);
numElementsKernel = numRowsKernel * numColsKernel;
vRows = reshape(repmat(1:numElementsImage, numElementsKernel, 1), numElementsImage * numElementsKernel, 1);
vCols = zeros(numElementsImage * numElementsKernel, 1);
vVals = zeros(numElementsImage * numElementsKernel, 1);
kernelRadiusV = floor(numRowsKernel / 2);
kernelRadiusH = floor(numColsKernel / 2);
pxIdx = 0;
elmntIdx = 0;
for jj = 1:numCols
for ii = 1:numRows
pxIdx = pxIdx + 1;
for ll = -kernelRadiusH:kernelRadiusH
for kk = -kernelRadiusV:kernelRadiusV
elmntIdx = elmntIdx + 1;
pxShift = (ll * numCols) + kk;
if(ii + kk > numRows)
pxShift = pxShift - (ii + kk - numRows);
end
if(ii + kk < 1)
pxShift = pxShift + (1 -(ii + kk));
end
if(jj + ll > numCols)
pxShift = pxShift - ((jj + ll - numCols) * numCols);
end
if(jj + ll < 1)
pxShift = pxShift + ((1 - (jj + ll)) * numCols);
end
vCols(elmntIdx) = pxIdx + pxShift;
vVals(elmntIdx) = mH(kk + kernelRadiusV + 1, ll + kernelRadiusH + 1);
end
end
end
end
mK = sparse(vRows, vCols, vVals, numElementsImage, numElementsImage);
end
function [ mK ] = CreateConvMtxCircular( mH, numRows, numCols )
%UNTITLED6 Summary of this function goes here
% Detailed explanation goes here
numElementsImage = numRows * numCols;
numRowsKernel = size(mH, 1);
numColsKernel = size(mH, 2);
numElementsKernel = numRowsKernel * numColsKernel;
vRows = reshape(repmat(1:numElementsImage, numElementsKernel, 1), numElementsImage * numElementsKernel, 1);
vCols = zeros(numElementsImage * numElementsKernel, 1);
vVals = zeros(numElementsImage * numElementsKernel, 1);
kernelRadiusV = floor(numRowsKernel / 2);
kernelRadiusH = floor(numColsKernel / 2);
pxIdx = 0;
elmntIdx = 0;
for jj = 1:numCols
for ii = 1:numRows
pxIdx = pxIdx + 1;
for ll = -kernelRadiusH:kernelRadiusH
for kk = -kernelRadiusV:kernelRadiusV
elmntIdx = elmntIdx + 1;
pxShift = (ll * numCols) + kk;
if(ii + kk > numRows)
pxShift = pxShift - numRows;
end
if(ii + kk < 1)
pxShift = pxShift + numRows;
end
if(jj + ll > numCols)
pxShift = pxShift - (numCols * numCols);
end
if(jj + ll < 1)
pxShift = pxShift + (numCols * numCols);
end
vCols(elmntIdx) = pxIdx + pxShift;
vVals(elmntIdx) = mH(kk + kernelRadiusV + 1, ll + kernelRadiusH + 1);
end
end
end
end
mK = sparse(vRows, vCols, vVals, numElementsImage, numElementsImage);
end
Kode divalidasi terhadap MATLAB imfilter()
.
Kode lengkap tersedia di Repositori GitHub StackOverflow Q2080835 saya .