Image Editing

This is a huge topic. There are people whose major computer activity is tinkering with computer image files for artistic reasons. For our purposes we need to edit the images that we capture so that

• they convey the information that we want
• the image file is the smallest that will convey that information
• the image is enhanced if it needs it

This section will discuss Image Editing Programs, Cropping, Re-sizing and Compression of image files.

Image Editing Programs

These vary in sophistication and price. Microsoft Image Composer is bundled with a number of Microsoft programs and you may already have it. Lview is shareware and can be downloaded and evaluated for free. Adobe Photo Deluxe comes bundled with scanning devices. Adobe Photoshop and Macromedia Fireworks are top of the line (expensive) image editing programs.

Lview http://www.lview.com/index1024.htm

Adobe Photo Deluxe http://www.adobe.com/products/photodeluxe/main.html

Microsoft Image Composer (no longer available)
Adobe Photoshop http://www.adobe.com/products/photoshop/main.html

Macromedia Fireworks http://www.macromedia.com/software/fireworks/

In this image of a child with Rickets secondary to Phenytoin the emphasis should be on the widened epiphysis. Much of the rest of the image can be cropped out.

Cropping

This involves removing from the image all the parts that don't actually convey information you want to send. In most Xrays there are large black areas that convey nothing and can be cropped out without losing useful information. Usually the program allows you to draw a rectangle around the area you want to keep (left). The rest is discarded and the image is improved (right).

Click to enlarge...

Click to enlarge...

Resizing

All Image Editing programs allow you to alter the size of the complete image. Usually this is necessary because the image as scanned may be up to 2000 pixels wide (to preserve detail). If you send this size of image the recipients won't be able to see the whole image on the screen which makes it difficult to evaluate it. Anything more than 800 X 600 may not fit on the screen and since the working space of most programs is smaller it's a good idea to send images that are maximum 600 X 400 pixels.

Compressing

The size of an image file depends on the way in which the information in the image is stored. The most profligate way to do this is to store separate information for each pixel. This results in big files. Most image editing programs allow you to compress files into JPEG or GIF format which saves space to an order of magnitude.