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image-processingscilab

scilab - Implementing log function on images

I want to apply a log function to images. But it fails showing this error: function is not defined on this type of argument.

uk=imread('image.jpg');
result=log(uk(:,:,1));
Solution

  • I think your problem is that imread returns a matrix of uint8 type. To apply log, you should convert it to double. There are at least 2 ways to do this, one built in, and one from SIVP:

    clc;
clear;
im = imread("d:\Attila\PROJECTS\Scilab\Stackoverflow\mixer_crop.jpg");
//imshow(im);
disp(typeof(im(:,:,1)),"Original type:");

//use double
M = double(im(:,:,1));
disp(typeof(M),"Modified type:");
result=log(M);
//imshow(uint8(M));

//use im2double
M2 = im2double(im);
disp(typeof(M2(:,:,1)),"Modified type 2:");
result=log(M2(:,:,1));
//imshow(im2uint8(M2));