What is the difference between true color, false color and pseudo-color?

True Color Image: True color refers to an image in which each pixel is composed of three primary color components—Red (R), Green (G), and Blue (B)—with each component directly controlling the intensity of the corresponding primary color on the display device. A true color image is essentially the image we see in everyday life, where the R, G, and B components correspond to the visible light bands, generating the image through these three channels.

False Color Image: False color, also known as color composite, is a technique used in image enhancement. It involves using different wavelength bands' black-and-white (spectral) images of the same region or scene, which are processed through various filter systems to accurately overlap and generate a color image of the region or scene. A false color image also has three channels, but the three channels do not represent the R, G, and B bands. Instead, they are composed of different spectral bands, creating a color composite image. From a technical perspective, false color is similar to true color, as both use RGB channels for display.

Pseudo-Color Image: A pseudo-color image is a single-band image, similar to a grayscale image, but the pixel values are represented in color rather than in grayscale. Each grayscale value corresponds to a color in the color space. Pseudo-color display uses a color table or a color lookup table (CLUT), where the intensity values of actual R, G, and B components are retrieved based on the index. If a color in the image does not exist in the color table, the closest matching color is used. The color values derived from this table are not the actual colors of the image itself. In simple terms, a pseudo-color image can be viewed as an indexed image, where the color values are obtained through the index. This technique is widely used in medical imaging, industrial applications, scientific research, data visualization, and infrared imaging, to enhance image details and contrast. Take Quanhom's ITZ1212 as an example, there are many modes such as white hot, black hot, red hot, iron red, rainbow, etc.