Brightness / contrast







The brightness and contrast values can be changed by assigning the brightness/contrast tool to a mouse button.
To help you set good brightness/contrast values, switch on the histogram. In the menu, go to 'Display', 'Histogram'. See the image below.




Click the right mouse button (with the correct tool selected) and move the mouse left or right to decrease or increase the range of image pixels displayed. The range is indicated by 'W:2000', see bottom right in the image. This tells you a range (W = width) of 2000 intensities are displayed.
Move to mouse up or down to move the position of the selected range. The position is indicated by 'C:1490', see bottom right in the image. This tells you the center position (C = Centre) of the range.

Play a little bit with it to get an idea of the possibilities. See the 2 images below with different brightness/contrast settings, displaying difference parts of the image.






Reset the brightness/contrast values to default by clicking the reset-button in the toolbar or via the menu 'Tools', 'Reset brightness/contrast'. See image below.
In case of stack- or scene-display (multiple images), you can set the brightness/contrast value for a single image by pressing and holding the CTRL-key which changing the values. The changes to the brightness/contrast value of a single image can be reset, but then ALL values of all images are set to the default value.




The DICOM viewer has an automatic brightness/contrast tool called 'Stretch'. This tool tries optimize the brightness/contrast for the image or multiframe runs. Click the Stretch-button on or off in the toolbar or via the menu 'Tools', 'Stretch'. See image below, with an image of bad contrast on the left and on the right the same image after automatic stretching.
This feature is un-set when a 4D stack is displayed and a new image is loaded.