Please Note: This blog post is part of a series of five posts altogether.
The posts include: Part 1, Part 2, Part 3, Part 4 and Part 5.
The quality of an image is determined by many things: Illumination, lens and camera parameters. In the following text, we are going to take a look at how to set camera parameters for optimal image quality.
Shutter (Exposure Time)
The shutter determines the CCD‘s exposure time. It may be adjusted manually or automatically. The three first sample images show a key ring (the LED is initially off) with correct exposure time, one which is too short and another which is too long:
Switching on the LED, the image is overexposed in such a way that it only shows a big, white spot. The LED is correctly represented, if we decrease the exposure time. There is, however, a vertical line which disturbs the image. This is a typical CCD problem and is known as "smear". To avoid this, we close the diaphragm and increase the exposure time: