Window Level in JPEG

[Muhammad Umar Hayat]

Hi, i am Muhammad Umar Hayat Mobile Application developer. I am building a mobile application in react native. I get data on Medical images in the form of JPEG. I control the brightness and contrast by hand-coded value.  
My Problem is how to calculate window leveling for JPEG images. For the brain, by default value is 80/40.

[Alvin Aloshyous]

Hi,

If you have access to the pixel data, you can control the brightness contrast using below equation:

• if (x <= c - 0.5 - (w-1) /2), then y = y_min

• else if (x > c - 0.5 + (w-1) /2), then y = y_max

• else y = ((x - (c - 0.5)) / (w-1) + 0.5) * (y_max- y_min) + y_min

where x is  the input pixel and y is the output pixel.

More details can be found on the following link:

https://dicom.nema.org/medical/dicom/current/output/html/part03.html#sect_C.11.2.1.2

BR

On Tue, Aug 30, 2022 at 5:56 PM Muhammad Umar Hayat <umarha...@gmail.com> wrote:

Hi, i am Muhammad Umar Hayat Mobile Application developer. I am building a mobile application in react native. I get data on Medical images in the form of JPEG. I control the brightness and contrast by hand-coded value.  
My Problem is how to calculate window leveling for JPEG images. For the brain, by default value is 80/40.

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