The grayscale image display of my dataset doesn't seem right.
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Q21. The grayscale image display of my dataset doesn't seem right.
The default mapping from image voxel values to grayscale values is to compute the histogram of the displayed slice, then map the 2% point on the cumulative distribution to the lowest grayscale and the 98% point to the highest grayscale. Intermediate voxel values are mapped linearly to the intermediate grayscale levels in the colormap. This technique of clipping off the smallest and largest values works well for MRI data, which are often plagued by a few bright spots caused by arterial inflow artifacts.
You can switch to map the smallest slice value to the lowest grayscale and the largest slice value to the highest grayscale using the "Disp" control panel in the image window: just select the "Min-to-Max" switch. This is probably a good idea when you are viewing a mask image or other artificially generated data.
When you are making a montage, whichever mode you use is applied to each slice separately and the final montage is pasted together from the results. If you want to control the scaling from voxel values to grayscales so that all slices are treated equally, see the answer to Q8.
This FAQ applies to: Any version.
