pnmconvol

Convolute a PNM image. More information: https://netpbm.sourceforge.net/doc/pnmconvol.html.

• Convolve a PNM image with the specified convolution matrix:

pnmconvol -matrix=-1,3,-1 {{path/to/image.pnm}} > {{path/to/output.pnm}}

• Convolve a PNM image with the convolution matrix in the specified files, one for each layer in the input image:

pnmconvol -matrixfile {{path/to/matrix1,path/to/matrix2,...}} {{path/to/image.pnm}} > {{path/to/output.pnm}}

• Convolve a PNM image with the convolution matrix in the specified PNM file:

pnmconvol {{path/to/matrix.pnm}} {{path/to/image.pnm}} > {{path/to/output.pnm}}

• Normalize the weights in the convolution matrix such that they add up to one:

pnmconvol -matrix=-1,3,-1 -normalize {{path/to/image.pnm}} > {{path/to/output.pnm}}