Example 1: Studying the rocks on Venus
This example uses false colour image processing to bring out hidden features. It is an example of image enhancement.
Courtesy of USGS Science for a changing world
No one has been able to set foot on Venus to sample the rocks and ages of the craters. To our untrained eye a black and white satellite image taken by a Russian Satellite many years ago shows little in the way of detail. The featureless surface of Venus gives little indication that the rocks and craters are of several ages.
Follow these steps to enhance the satellite image of Venus.
Open the image-processing program. If you installed IrfanView program open it.
Click on the image of Venus to open a larger version and save it to your computer.
Open the saved the image of Venus from within the image-processing program.
The image is made up of little squares called pixels, the more pixels, the more detailed the image. Three numbers corresponding to the three primary colours represent each pixel. Currently there are two common methods of describing the colours; namely Hex and RGB codes.
From within the image-processing program find the palette.
Within Irfan's menu select Image > Palette > Edit palette.
Double click on the 'grey square' or on the square that is seven in from the left. When you double click you will open another palette with colours.
Select and double click on a bright colour from the choices provided (I chose yellow)
To complete the process click O.K., then click O.K. again.
Repeat the process to further enhance the satellite image of Venus.
Your first colour changes to enhance the image would look something look like this.
Repeat the steps and change more colours. Note with each successive colour change more detail appears. Until all the hidden details are revealed.
A geologist can then interpret this information. From the final image it would appear that here are three distinct rock types or ages each of which appears to be offset by a crack or fault not quite at right angles to the contacts (boundaries) of the rock groups. This is common on earth with rocks that are under some tension.