A color map, in the context of image processing, refers to a set of predefined colors that are assigned to specific pixel values in a monochrome raster image. This gives the image a consistent appearance each time it is viewed as each pixel value will always be displayed as a specific color.
Why is Color Mapping Important?
Color mapping has two primary purposes:
- Calibrating the colors of images captured by different cameras for further processing, using sample images
- Matching the colors of two images for visual compatibility
How Does Color Mapping Work?
Color mapping is a function that maps or transforms the colors of a source image to the colors of a destination image. This transformation can be achieved using various algorithms, often referred to as mapping functions. Some of the common terms used to describe this process include color transfer, brightness transfer function (BTF), photometric camera calibration or radiometric camera calibration.
Technical Details of Color Maps
Color maps can support a wide range of bit depths, except floating point data. Additionally, they can contain positive and negative values, and may also have missing color values. When an image is displayed with a color map that contains missing values, the corresponding pixels are not displayed.
Final Thoughts
Color mapping is a vital tool for image processing as it ensures images have a consistent appearance when viewed in different programs or by different people. By assigning specific colors to pixel values, the image can be calibrated or matched to other images for further processing or visual compatibility.
FAQs
What is a monochrome raster?
In the context of image processing, a monochrome raster refers to an image where each pixel has a single value representing its brightness or intensity. These values are usually displayed using a grayscale color map.
Can color maps contain negative values?
Yes, color maps can contain negative values and are not restricted to positive values only.
What happens when a color map contains missing values?
When an image is displayed with a color map that contains missing values, the corresponding pixels are not displayed.
