Operator RGB2HSI

The operator RGB2HSI converts the color space from RGB (Red, Green, Blue) to HSL (Hue Saturation Luminance).

[Warning] Warning

The operator implements the RGB to HSL (Hue Saturation Luminance) color space conversion and not RGB to HSI (Hue Saturation Intensity).

Operator Features and Restrictions

  • Empty Images (i.e., images with no pixels) are fully supported.

  • Not empty Images with empty lines are fully supported.

  • Images with varying line lengths are fully supported.

I/O Properties

Property Value
Operator Type O
Input Link I, image data input
Output Link O, image data input

Supported Link Format

Link Parameter Input Link I Output Link O
Bit Width [24, 48]1 as I
Arithmetic unsigned as I
Parallelism any as I
Kernel Columns 1 as I
Kernel Rows 1 as I
Color Format VAF_COLOR as I
Color Flavor FL_RGB FL_HSI
Max. Img Width any2 as I
Max. Img Height any as I


The Bit Width must be divisible by three without remainder.


VALT_IMAGE2D and VALT_LINE1D: The Maximal Image Width must be divisible by the parallelism without remainder (not important for VALT_PIXEL0D and VALT_SIGNAL).


Type static parameter
Default 255
Range [1; (1 << (BitWidth(I) / 3)) - 1]

This parameter defines the maximum value for the hue. 9bit at 360 degrees corresponds to a result in degrees.

[Warning] Range Violation leads to DRC error

If the value of HueAmplitude is not in range, the parameter state is set to error and the parameter is reported by the DRC.

Examples of Use

The use of operator RGB2HSI is shown in the following examples:

  • 'HSL Color Classification'

    Examples - Color Classification is very simple on HSL images. The applet converts the RGB image into an HSL image and performs a color classification. The hue is filtered using a lookup table. Moreover, the saturation and lightness is thresholded using custom threshold values.