Value range of grayscale image not being correct?

Hi, I used following script to convert a cmyk image into rgb and then convert it into grayscale, but after this I got a array with all values being either 35 or 37, not 0 or 1.

I think that grayscale image should generate array with values being either 0 or 1, right?

How can get final array with values in the range [0,1]?

clear all, close all clc I_cmyk=imread('jetflow.tiff'); C=makecform('cmyk2srgb'); I_rgb=applycform(I_cmyk,C); I_gray=rgb2gray(I_rgb);

Plus: after I use imread function to load the tiff image, it generated a 1280x800x4 uint8 array, which should be cmyk format, so I used the following 3 lines of commands.

Thank you.

Answer 1

[Image Analyst]

They're probably in the range 0-255. If it's a uint8 image, they they almost certainly are in that range.

[zy]

Thank you for your help. If so, when should the values of the grayscale image be within the range of [0,1]?

Thanks.

[Image Analyst]

When you want to deal with an image in that range, which I never do. It's just confusing to me so I don't. I always use the original range, even when it gets converted to double.