HSV
A color model that represents colors using hue, saturation, and value axes. It aligns with human color perception and is widely used in color pickers and image adjustment tools.
HSV (Hue, Saturation, Value) is a color model that describes colors using three perceptually intuitive attributes. Proposed by Alvy Ray Smith in 1978, it reinterprets the RGB cube as a hexcone model. HSV is used in color pickers and in computer vision for color-based segmentation.
- Hue (H): Represents the type of color as an angle from 0 to 360 degrees on the color wheel. Red sits at 0 degrees, green at 120, and blue at 240. Complementary colors are 180 degrees apart
- Saturation (S): Measures color purity from 0% (achromatic gray) to 100% (fully vivid). Reducing saturation desaturates the color toward neutral gray
- Value (V): Indicates brightness from 0% (black) to 100% (maximum brightness). At V=0% the color is always black regardless of hue or saturation
A closely related model is HSL (Hue, Saturation, Lightness). In HSL, pure colors appear at L=50%, and L=100% always yields white. CSS natively supports HSL through the hsl() function.
OpenCV provides cv2.cvtColor(img, cv2.COLOR_BGR2HSV) for conversion to HSV. One technique involves thresholding specific hue ranges to create masks for object detection, such as isolating red signs or green vegetation.