The following color transform options are available in ENVI to transform an RGB image into another color space:

• RGB to HSV: Transforms an RGB image into the HSV color space. The input RGB values must be byte data in the range 0 to 255. You must have either an input file with at least three bands or a color display open to use this function. The stretch that is applied in the color display is applied to the input data. The hues produced are in the range of 0 to 360 degrees (where red is 0 degrees, green is 120 degrees, and blue is 240 degrees) and saturation and value in the range 0 to 1 (floating-point).
• RGB to HLS: Transforms an RGB image into the HLS color space. The Hues produced are in the range of 0 to 360, where 0 = red, 120 = green, and 240 = blue; and lightness and saturation are in the range 0 to 1 (floating-point). You must have either an input file with at least three bands or a color display open to use this function. The input RGB values must be byte data in the range 0 to 255.
• USGS Munsell RGB to HSV: Transforms an RGB image into the USGS Munsell HSV color space. The input RGB values must be byte data in the range 0 to 255. You must have either an input file with at least three bands or a color display open to use this function.

1. From the Toolbox, select one of the following:

   • Transform > Color Transforms > RGB to HSV Color Transform

   • Transform > Color Transforms > RGB to HLS

   • Transform > Color Transforms > RGB to HSV (USGS Munsell) Color Transform

     The Input Bands dialog appears.

2. Select the bands to transform from the Available Bands List. The names of the bands appear in the R, G, and B fields.
3. To spatially subset your data, click Spatial Subset.
4. Click OK. The Parameters dialog appears.
5. Select output to File or Memory.
6. Click OK. ENVI adds the resulting output to the Layer Manager.