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10 Chapter 1 ■ Practical Aspects of a Vision System

else
fprintf( stderr, “Error reading image\n“ );
return 0;
}

Figure 1.2 shows a screen shot of this program.

Figure 1.2: The three image windows created by the thresholding program.

1.3 Image Capture

The processing of still photos or scientific images can be done quite effectively
using scanned image or data from digital cameras. The availability of digital
image data has increased many-fold over the past decade, and it is no longer
unusual to find a digital camera, a scanner, and a video camera in a typical
household or small college laboratory. Other kinds of data and other devices
can be quite valuable sources of images for a vision system, key among
these the webcam. These are digital cameras, almost always USB powered,
having image sizes of 640x480 or larger. They acquire color images at video
rates, making such cameras ideal for certain vision applications: surveillance,