Grayscale image and OS version issue

Jayl · **Joined:** Wed Sep 19, 2012 9:08 am **Posts:** 10

Hi all,

I write a program to count the intensity value of each gray level(0~255) in grayscale image.
The strange thing is I got the different result when I ran it in different OS version(Win7 32bit pro and Win XP 32 bit pro),
the GTK version(2.24),program and grayscale image are the same besides OS version.

Could anyone give me a favor.

please find enclosed.
(grayscale image,count table)

thank you.
Jay.

asdfgh2091 · **Joined:** Fri Sep 04, 2009 6:53 am **Posts:** 61

I suspect gtk uses for decoding of jpeg images the functions of the os, which might have changed between the two version. Encoding of images in jpeg is lossy. And so might the decoding not be exact. http://en.wikipedia.org/wiki/Jpeg#Required_precision.

Have you tried an bmp file wich is lossless?

By the way using python2 and python-imaging with:

Code:

#!/usr/bin/env python2
# -*- coding: utf-8 -*-

import Image

histo=Image.open("tp1.JPG").convert("L").histogram()
for i in range(222,256):
    print i, histo[i]

# How long is your program?

I'll get:

Code:

Jayl · **Joined:** Wed Sep 19, 2012 9:08 am **Posts:** 10

Hi sir,

I had tried to load image in two kinds of OS and it looked like you are right.
When I turn it into bmp format,I get the identical grayscale intensity.

my program is as follows:

Code:

#define MAX_VAL 256
int itst[MAX_VAL];
//===statistics===//
for(j=0;j<height;j++){
for(i=0;i<width;i++){
p=pixels+j*rowstride + i*n_channels;                  
itst[p[0]]++;                   
}
}

//===out put===//
for(i=0;i<MAX_VAL;i++){
if(itst[i]!=0){
g_print("The count of gray level %d intensity is %d\n",i,itst[i]);
}
}

thanks for your help :P

Jay.

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Grayscale image and OS version issue

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