Grey Level Histogram of IMAGE

Can any one tell me how to calculate the grey level histogram of image without using direct function in matlab imhist?

Answer 1

[Image Analyst]

Loop over every pixel. For each pixel, get the gray level. The gray level is an index to your "counts" array. Increment that element by one. Details are left up to you.

[Algorithms Analyst]

As my code is I=imread('lena.bmp'); A=rgb2gray(I); B=double(A); [M N]=size(B); for i=o:M for j=0:N

now how to get the gray level further?

[Algorithms Analyst]

I=imread('lena.bmp'); A=rgb2gray(I); B=double(A); [M N]=size(B); for i=o:M for j=0:N

[Image Analyst]

The gray level is the array's value. No need for B. I should be called rgbImage to be more clear and help distinguish I from l and 1, which are hard to tell apart in most fonts. Use grayImage instead of A - again because it's a much more clear and descriptive variable name.

grayImage = rgb2gray(I);
for column = 1 : N
  for row = 1 : M
     grayLevel = grayImage(row, column);

See if you can take it from there...

[Algorithms Analyst]

Tyhank you very much for your help...