HSV
lastmod 2023-02-02created 2014-10-2721 edits
The HSV (HSB) color space is one way of representing colors, and a way of arranging colors according to that method. It specifies a particular color using coordinates of Hue, Saturation, and Brightness (Value). It is sometimes called HSB. Similar ones include HSL (Lightness) and HSI (Intensity).
Components
Hue
Hue (色相) is one of the three main attributes of color, along with brightness and saturation. In the HSV color space, Hue forms the coordinates that specify a color, together with Saturation and Brightness (Value).
Hues are distinguished by color names such as yellow and red, and are often expressed together with words describing brightness and saturation, such as bright yellow or dark red. Distinct color names can also be named differently depending on the hue reference; for example, brown can be described as dark orange, and pink as light red.
In the HSV color space, the hue value H means the relative angle of placement on a color wheel that arranges the visible light spectrum in a ring, with red, the longest wavelength, at 0°. So H ranges from 0° to 360°, and 360° and 0° refer to the same hue, red.
Saturation
Saturation (apparently called Colorfulness in English) - the more vivid a color, the higher its saturation is said to be, and the closer it is to an achromatic color such as gray, white, or black, the lower its saturation.
A highly saturated color is often described as 'deep', and conversely a color with low saturation is often described as 'pale'. For example, deep yellow or pale yellow.
In the HSV color space, the saturation value S represents the degree of intensity, with the most intense state of a given hue as 100%. A saturation value of 0% represents an achromatic color of the same brightness.
Value
Brightness (Value; 明度) is one of the three main attributes of color, along with hue and saturation.
Low brightness is often described as 'dark', and high brightness as 'bright'. For example, 'dark gray' and 'light gray'. In the HSV color space, Value forms the coordinates that specify a color, together with Hue and Saturation.
In the HSV color space, the brightness value V or B (B is the more common notation) represents the degree of brightness, with white as 100% and black as 0%.
HSI color model
HSI Color Model
Hsi_color_system.png
Caveats when using OpenCV
When converting to HSV, the color ranges are as follows:
- hue range is [0,179]
- saturation range is [0,255]
- value range is [0,255]
See cv2.cvtColor for details.
See also
Favorite site
- Wikipedia (en) HSL and HSV
- Wikipedia (en) HSL and HSV # Lightness (how the Lightness component is represented in HSI, HSV, and HSL)