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Digital Image Processing: A Remote Sensing Perspective FW 5560 Lecture 5. Additional Display Alternatives. The RGB color coordinate system is the most widely used display system for scientific visualization. However, alternatives exist- such as the IHS system. R G B Color Coordinate System.
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Digital Image Processing: A Remote Sensing Perspective FW 5560 Lecture 5 Additional Display Alternatives The RGB color coordinate system is the most widely used display system for scientific visualization. However, alternatives exist- such as the IHS system.
Artists tend to describe scenes not in terms of red, green, and blue, but as hue, saturation, and intensity (HSI). We do not see things as quantities of primary colors mixed in certain proportions. We see the brilliant orange of a sunset or the dark, muted greens of a forest. We see things as colors, or hues, that either have a washed-out look or have deep, rich tones. This means having low or high saturation, respectively. A bright afternoon sun gives everything a high-intensity look, while dusk provides dark images of low intensity.
HSI space – Gray levels are located on diagonal of color cube joining black and white vertices – Saturation is distance from this diagonal – Hue is angle around this diagonal
Intensity, Hue, Saturation (IHS) Color Coordinate System The vertical axis represents intensity (I) which varies from black (0) to white (255) and is not associated with any color.
The circumference of represents hue (H), which is the dominant wavelength of color. Hue values begin with 0 at the midpoint of red tones and increase counterclockwise around the circumference of the sphere to conclude with 255 adjacent to 0.
If cone is viewed from above, it becomes a circle. Different colors, or hues, are arranged around this circle - the familiar color wheel used by artists. Hues are determined by their angular location on this wheel.
Saturation (S) represents purity of the color and ranges from 0 at the center of the sphere to 255 at the circumference. A saturation of 0 represents a completely impure color in which all wavelengths are equally represented and which the eye will perceive as a shade of gray that ranges from white to black depending on intensity.
Merging Different Types of Remotely Sensed Data for Effective Visual Display Intensity-Hue-Saturation (IHS) Substitution: IHS values can be derived from the RGB values through the transformation equations:
