Image fusion using IHS color transforms - Tutorial

Perform an image fusion of a low-resolution RGB-image and a high-resolution panchromatic image. This process is a typical application for imagery of satellite sensors with low-resolution multispectral bands and a higher resolution panchromatic band like QuickBird, IKONOS, OrbView3, SPOT, Landsat 7, or IRS-1C.



  1. Download and unzip input data: (compressed, ~5.1MB).
  2. Download and install the package IHS Color Transforms.
  1. Open pan.tif:
    File > Open... pan.tif
  2. Open rgb.tif:
    File > Open... rgb.tif
  3. Select rgb.tif and scale it to the size of the panchromatic image:
    Image > Scale...
    X Scale: 4
    Y Scale: 4
    Fill with Background Color
    Create New Window
  4. Select rgb.tif and transform it from RGB to HSI:
    Plugins > IHSColorTransforms > IHS_from_RGB
  5. Split HSI-channels:
    Image > Color > RGB Split
  6. Close the intensity channel ( rgb-1.tif (red) ):
    File > Close
  7. Merge HSI-channels using the panchromatic image as intensity channel:
    Image > Color > RGB Merge...
      Red: pan.tif
    Green: rgb-1.tif (green)
     Blue: rgb-1.tif (blue)
  8. Perform the back-transformation from HSI to RGB:
    Plugins > IHSColorTransforms > IHS_to_RGB