function [r, g, b] = rgbconv2(a, c)
    r = im2uint8(mat2gray(conv2(a(:,:,1), c)));
    g = im2uint8(mat2gray(conv2(a(:,:,2), c)));
    b = im2uint8(mat2gray(conv2(a(:,:,3), c)));
endfunction

im = jpgread("Lenna100.jpg");
emboss = [-2, -1,  0;
	  -1,  1,  1;
	  0,  1,  2 ];
sobel = [-1., -2., -1.;
	 0.,  0.,  0.;
	 1.,  2.,  1. ];
sharpen =   [ -1.0, -1.0, -1.0;
	     -1.0,  9.0, -1.0;
	     -1.0, -1.0, -1.0 ];

[r, g, b] = rgbconv2(im, emboss);
jpgwrite("LennaEmboss.jpg", r, g, b, 100);
[r, g, b] = rgbconv2(im, sobel);
jpgwrite("LennaSobel.jpg", r, g, b, 100);
[r, g, b] = rgbconv2(im, sharpen);
jpgwrite("LennaSharpen.jpg", r, g, b, 100);