Window and Level Contrast Enhancement

An interactive contrast enhancement tool normaly available in image processing software is called Window and Level. It is a expansion of the contrast of the pixels within a given window range. Two parameters define the range: the middle point Level, and the width of the range Window. Another name for this operation is Intensity of Interest (IOI).

A graphic visualization of this process is shown below.

Example 1

A practical application of this tool is given below. The original image is a CT Image with pixel values ranging from 1024 to 1862. The histogram plotted ranges from 1000 to 1862.

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Original image

Applying the Window and Level technique with parameters Window=100 and Level=1100 yields

Window and Level contrast enhanced

• Building a visual program (workspace) in cantata
• Execute the visual program window-level.wk

Example 2

Depicted below is the original image and the result after applying the Window and Level technique with parameters Window=38 and Level=74.

Original image

Window and Level contrast enhanced