Doc Russ' Magic Seven Step Elixer for Image Processing
The following series of operations will handle a large fraction of the image processing requirements for cleaning up and enhancing forensic images. Within most of the steps there are a few alternative possibilities that can be selected. There are a few steps that can sometimes be performed in a different order than that shown (for instance, Step 1 may be deferred until later in the sequence) but the sequence as shown is usually a safe choice.
By following this outline and becoming familiar with the results that are produced at each step, you will develop enough experience to recognize situations in which a different procedure may be required to accomplish a useful result in less common situations. These steps use only a tiny fraction of the built-in Photoshop routines or the algorithms provided by plug-ins such as Fovea Pro or ClearID. The functions listed here are the ones that are most frequently useful, most straightforwardly applied, and most easily learned. Adding more selections to your personal toolbox will further broaden the range of images and applications that can be addressed.
Tech details: Explanations are provided for the various algorithms that are illustrated. All of the techniques shown are well documented in the scientific literature. Comprehensive references (and more detailed explanations and examples) can be found in texts such as John Russ, The Image Processing Handbook, 6th edition, CRC Press, 2010, or in other standard texts. A more detailed set of step-by-step instructions for image processing and analysis using Photoshop and various plug-ins is available in John Russ, The Image Processing Cookbook, 2009, published by Amazon.
The Seven Steps:
- Back to course listing
- Go to DrJohnRuss.com
- Step 0. Average multiple frames.
- Step 1. Adjust the colors.
- Step 2. Remove or reduce artifacts.
- Step 3. Remove or reduce noise.
- Step 4. Remove or reduce blur.
- Step 5. Maximize image contrast.
- Step 6. Enhance sharpness and detail.
- Step 7. Save results and document.
A final word: You can't learn this stuff by just reading about it. It takes practice with real images and software, and visual examination of the results produced by
the various operations, to become familiar with them and to be able to choose an appropriate sequence for a particular situation.
Just do it!
John C. Russ
Materials Science and Engineering Dept.
North Carolina State University