clc
clear all

%greyscale picture, 512*512, 0-255 for every pixel
pic = imread('lena512.bmp');

%show original picture
figure(1)
imshow(pic)
title('original')

%quantization, 8-level for 0-255, 32 length for each level
%grey scale picture, unit8 for every pixel, need to transform unit8 to double
%15, 47, 79, 111, 143, 175, 207, 239 represent 8 level
temp=fix(double(pic)/32);
quan_pic=uint8(temp*32+15);

figure(2)
imshow(quan_pic)
title('quantized')


pic = imread('baylorbear.jpg');

figure(3)
imshow(pic)
title('original')

temp=fix(double(pic)/64);
quan_pic=uint8(temp*64+31);

figure(4)
imshow(quan_pic)
title('quantized')