What is parallax and why is this important in my inspection of conformal coated circuit boards?
Parallax is defined as a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.
How this relates to conformal coating AOI is that with a fixed camera or a standard scanner the camera is at a fixed point and the circuit board with its 3D components may have “shadows” where the camera cannot see down the side of the components. This can be seen in the two photos below.
In figure 1 some components are obscured by others since the camera is not vertically above the board. In figure 2 the image shows the components directly from above and no components are hidden by others.
Click Automated Conformal Coating Inspection System for further information on how to avoid parallax.