# After dividing a 512*512 image into non overlapping two pixel blocks, why can't i perform operations on the pixel values? If i multiply a pixel value (163) with 5, it shows 255 everytime..what could be done to perform operations on the pixel values?

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Kiruba S on 28 Jan 2019
Commented: Kiruba S on 10 Feb 2019
After dividing a 512*512 image into non overlapping two pixel blocks, why can't i perform operations on the pixel values?
If i multiply a pixel value (163) with 5, it shows 255 everytime..what could be done to perform operations on the pixel values?

Munish Raj on 7 Feb 2019
It is my understanding that you are not able to perform a multiplication operation (pixel*5) on individual pixels of your blocks. When you multiply your pixel by 5, it shows 255 every time.
This might be because the pixel values in MATLAB vary from 0 – 255 (0 being the minimum and 255 being the maximum).
When you try to modify a pixel to anything above 255, MATLAB will automatically keep the pixel at 255.
If your application requires you to scale a particular pixel by 5 times as compares to the other pixels,
you could scale all pixels down by a factor of 5 and then multiply the required pixel by 5.
I=I/5; %scale down all pixels by 5
%
%
%
%all the pixels will be dim, except the pixels you multiply by 5.
Munish Raj

#### 1 Comment

Kiruba S on 10 Feb 2019
Thank you sir