Question

Rgb color model in computer graphics wikipedia

Answer 1

In computer graphics, the RGB color model is an important way to represent colors. Here is a detailed introduction to it:

Basic concepts

The RGB color model is based on the three basic colors of red, green, and blue. It produces rich and wide colors through different degrees of superposition, so it is also called the three-primary color model. In the eyes of the human eye, most of the colors in nature can be mixed by red, green, and blue. The RGB model can represent more than 16 million different colors, which is very close to the colors of nature, so it is also called the natural color model.

Model principle

The principle of the RGB color model is derived from the three-stimulus theory. The theory assumes that there are three color-sensitive cone cells in the center of the human eye, which are most sensitive to red, green, and blue light. By adjusting the intensity and proportion of these three colors, a variety of different colors can be generated. For example, when the three primary colors overlap, different mixing ratios can produce various intermediate colors, and the addition of the three primary colors can produce white, so the RGB model is an additive process.

Space model

RGB color space can be represented by a cube of unit length, with the following specific features:

Coordinate axis: With red, green and blue as the coordinate axis, the eight common colors of black, blue, green, cyan, red, purple, yellow and white are located at the eight vertices of the cube. Usually black is placed at the origin of the three-dimensional rectangular coordinate system, red, green and blue are placed on the three coordinate axes respectively, and the entire cube is placed in the first quadrant.

Color representation: In the RGB color space, any color can be represented by a point in the three-dimensional space. For example, red can be represented as (1,0,0), green as (0,1,0), blue as (0,0,1), white as (1,1,1), and black as (0,0,0).

Parameter range: The value range of each parameter is usually R:0-255, G:0-255, B:0-255. The parameter value is also called the trichromatic coefficient or the primary color coefficient, which can be normalized to between 0 and 1 after dividing by 255.

Since each gray level is set to 256, the red, green and blue components can be combined to represent 256 cubed = 16777216 different colors.

Expression

The RGB color model can be expressed in various ways, using floating point numbers (between 0 and 1), percentages (0% to 100%) or integers (eight-bit numbers between 0 and 255, usually expressed in decimal and hexadecimal). For example, red is represented in different ways as follows:

Floating point: (1.0, 0.0, 0.0)

Percentage: (100%, 0%, 0%)

Eight-bit number: (255, 0, 0) or #FF0000 (hexadecimal)

Application area

The RGB color model is widely used in video, multimedia and web design. It is one of the most commonly used color models in life, and most of the CRT monitors of televisions and computers use this model. In addition, on the display, the RGB color model produces colors by hitting the red, green and blue light-emitting electrodes of the screen with an electron gun. Computers can generally display 32-bit colors, which is about one million colors. In the field of LED, the use of three-in-one dot matrix full-color technology, that is, full-color pixels composed of RGB three-color chips in one light-emitting unit, can bring a richer and more realistic color experience.

Advantages and Disadvantages

Advantages: The biggest advantage of the RGB color space is that it is intuitive and easy to understand, which conforms to the intuitive way humans perceive color.

Disadvantages: The RGB color model depends on the device, and different devices may detect and reproduce specific RGB values differently. In addition, because color substances (fluorescent agents or dyes) and their individual response levels to red, green and blue vary from manufacturer to manufacturer, even the same device may vary at different times.

Answer 2

The RGB color model is a color representation system in computer graphics based on the principle of superposition of the three primary colors of red (R), green (G), and blue (B). By adjusting the intensity of the three channels (usually in the range of 0-255 or 0.0-1.0), about 16.7 million colors can be synthesized. It is widely used in screen display, image processing, digital media and other fields.

Answer 3

The RGB color model is an additive color mixing system in computer graphics based on the principle of human vision. Its underlying mechanism can be analyzed from three dimensions:

Physical basis

The model is based on the theory of three primary colors, and simulates most of the colors that the human eye can perceive through a linear combination of three visible light bands: red (R, 620-750nm), green (G, 495-570nm), and blue (B, 450-485nm). Each channel uses an 8-bit binary number (0-255) to quantify the brightness, forming a color gamut space of about 16.77 million colors.

Mathematical representation

The color value is represented as a three-dimensional vector C=(R,G,B), where R,G,B∈[0,255]∩Z. Mixing follows the addition principle: Cmixed =αR+βG+γB (α,β,γ are weight coefficients), which conforms to the physical characteristics of light intensity superposition.

Hardware Implementation

The display uses red, green, and blue sub-pixels in the pixel array to emit light independently, and achieves color synthesis through spatial color mixing (adjacent pixel stimulation) or temporal color mixing (rapid alternating display). The GPU processes RGB data through linear algebra operations (such as matrix transformation and interpolation) in the rendering pipeline, and finally outputs it to the RGB channels of the frame buffer.

This model has become the standard for display devices due to its efficient hardware implementation and wide color gamut coverage, but it has limitations such as uneven color gamut and nonlinear response (gamma correction is required).