# Using the PixelMap Tool to Map 16-bit Images to 8-bit Images

VisionPro supports the acquisition and processing of 16-bit greyscale images, but some VisionPro vision tools support only 8-bit greyscale images. While each pixel in a 16-bit greyscale image can have one of 65,536 possible pixel values, each pixel in an 8-bit greyscale image can have one of only 256 possible values.

A simple linear mapping of the pixel values from a 16-bit image to an 8-bit image means that each pixel value in the 8-bit output image corresponds to 256 pixel values in the 16-bit input image. Pixel values 0-255 in the input image are assigned a pixel value of 0 in the output image, pixel values 256-511 are assigned to 1, and so on. This mapping results in the loss of a great deal of information from the input image.

The PixelMap tool lets you control the process of mapping a 16-bit image to an 8-bit image, so you can preserve the meaningful information in the input image while reducing its overall depth. The Pixel Map Tool is capable of automatically remapping the pixels, based on the histogram data of the input image. Although there are multiple methods to generating the mapping formula, it is recommended that you use the intelligent feature first.