NASA Image Mississippi River (1/13/83 MS Bands 3,2,1)

It is the intent of these tutorials and activities to teach basic image processing skills by exploring our environment through remote sensing. Once you know the basics you can use the procedures to develop a better understanding of our world or universe.

Image processing is the use of computers to analyze images. Although the image may look like a black & white or color photograph, the colors as well as other wavelengths of information are represented by digital numbers (DN). These numbers make up the digital image. Digital images are produced by sensors which convert the information (color, temperature, etc.) into a number. It is that number which represents that particular hue, saturation and RGB component (Red, Green, Blue) of the color. Once the image has been assigned a number, it is displayed on the monitor as a pixel value (Pixel is short for Picture Element). This pixel is the dot of color which gives the image its structure.

Remote sensing is the ability to analyze and quantify phenomena from a distance. The type of sensor being used will directly affect the spatial resolution of the image, The greater the resolution the better one is able to quantify the phenomena. Although you normally don't think about it, you have remote sensors through your ability to see, hear, and smell objects which are not in direct contact with your body.

We will use NIH Image (Macintosh freeware ) from the National Institute of Health and a PC version from Scion Corporation. The software will allow you to analyze digital images based upon differences in the numbers. Some of the techniques you will learn are measuring, counting, density slicing, particle analysis, animation, and analyzing Digital Elevation Maps (DEM).

Landsat images taken at different wavelengths can give us a better understanding of geological and biological processes. The images can be converted to "false color" even though they have been recorded in black and white. These images can then be converted for analysis in NIH Image.

To give you an idea into analyzing a simple remote imaging activity, try this NASA remote sensing activity. The techniques you learn here will allow you to do simple imaging analysis throughout this workshop.

To prepare yourself for this workshop, download the software NIH Image (from the NIH Image homepage or the Scion Corp.) Place these software programs in an image processing folder. This is the folder in which you will store all of your image work. Only you can organize the work for yourself in the best manner possible.