The imaging system and light source project images perpendicular to the top surface of the measured board (real-time camera imaging), sense the images, and transmit them to the computer measurement software. The software measurement tools then analyze the standard tolerance values of the image's "line width/line spacing/line width upper/lower margin/circle/connector line width, etc." to determine the measured values on the board. Measure the upper and lower width of the circuit patterns on the inner and outer layers of printed circuit boards after development and etching (before applying green oil), including the distance between lines, hole diameter, center-to-center distance, and distance from holes to edge lines. It can also be extended for applications such as measuring IC wafer line width and spacing, film width measurement, and LCD circuit board measurement in microscopic distance measurement scenarios.