How to convert sparse matrix into image?

I have a sparse matrix which contains aa = (1,1) 72 (1,2) 101 (1,3) 108

Now I want to convert this into image ...?

Answer 1

[Meet]

Hi Bavani,

Assuming you already have the sparse matrix, to convert it to an image, you first need to convert the sparse matrix to a full matrix using the "full" function. This function will return a full matrix where the empty cell entries from the sparse matrix are filled with zeros.

If the values in the sparse matrix are in the range [0, 255] and the datatype of the matrix is "double", you need to convert it to "uint8", as "uint8" supports values in the range [0, 255]. You can then pass this "uint8" matrix to the "imshow" function to display the image.

Example code to generate an image from sparse matrix:

row = [1, 1, 1];
col = [1, 2, 3];
val = [72, 101, 108];

sparseMatrix = sparse(row, col, val);
fullMatrix = full(sparseMatrix);
output_matrix = uint8(fullMatrix);
imshow(output_matrix);

For more information, you can refer to the following documentation links:

sparse: https://www.mathworks.com/help/matlab/ref/sparse.html

full: https://www.mathworks.com/help/matlab/ref/full.html

imshow: https://www.mathworks.com/help/matlab/ref/imshow.html