i need to brighten or darken an 8 bit image by taking an input , a number between 0 (means no change ) and 100 (means intensity of all pixels is 255 ) , can anyone help ??

the aim is to perform brightness correction or contrast improvement using suggested algorithm !

Answer 1

[Image Analyst]

It's simple algebra:

image1 = imread('cameraman.tif');
minValue = double(min(image1(:)))
maxValue = double(max(image1(:)))
slope = (255 - minValue)/100
v = 100;  % Whatever you want in the range 0-100.
amountToAdd = slope * v
image2 = uint8(image1 + amountToAdd);
imshow(image2);
newMinValue = double(min(image2(:)))
newMaxValue = double(max(image2(:)))

[Amir]

its not effective at all . whether i enter 10 or 90 ,there is no visible difference. any other way ??

[Image Analyst]

I made a small edit. Try it now.