imshow not working when going from unit8 to double

I converted an image from uint8 to double but when I use imshow on the matrix type double, it shows a white box. Why does that happen ?

Answer 1

[Stephen23]

Most likely because you did not scale the image when you converted the type.

• uint8 images are treated as having values from 0 to 255.
• floating point images are treated as having values from 0 to 1.

So if you convert to double you will need to divide by 255:

Im_double = double(Im_uint8) / 255

or just use im2double, which does this conversion:

Im_double = im2double(Im_uint8)

[raheem mian]

Oh I see. Thanks so much.

Answer 2

[Steven Lord]

How did you convert the image from uint8 to double? See this page in the Image Processing Toolbox documentation and this one in the MATLAB documentation for more information as to why that matters.