Routines (alphabetical) > Routines: P > PSEUDO

# PSEUDO

The PSEUDO procedure creates a pseudo-color table based on the LHB (Lightness, Hue, and Brightness) system and loads it.

The pseudo-color mapping used is generated by first translating from the LHB coordinate system to the LAB coordinate system, finding N colors spread out along a helix that spans this LAB space (supposedly a near maximal entropy mapping for the eye, given a particular N) and remapping back into the RGB (Red, Green, and Blue) colorspace. The result is loaded as the current colortable.

This routine is written in the IDL language. Its source code can be found in the file `pseudo.pro` in the `lib` subdirectory of the IDL distribution.

## Syntax

PSEUDO, Litlo, Lithi, Satlo, Sathi, Hue, Loops [, Colr]

## Arguments

### Litlo

Starting lightness, from 0 to 100%.

### Lithi

Ending lightness, from 0 to 100%.

### Satlo

Starting saturation, from 0 to 100%.

### Sathi

Ending saturation, from 0 to 100%.

### Hue

Starting hue, in degrees, from 0 to 360.

### Loops

The number of loops of hue to make in the color helix. This value can range from 0 to around 3 to 5 and need not be an integer.

### Colr

An optional (256,3) integer array in which the new R, G, and B values are returned. Red = Colr[*,0], green = Colr[*,1], blue = Colr[*,2].

## Keywords

None.

## Version History

Original | Introduced

## See Also

COLOR_QUAN, COLOR_QUAN