Infrared lens machine vision detection encounters object reflections in use

In the machine vision image detection of the infrared lens machine, the glare from the surface of the object (such as metal, aluminum clamp surface, reflective film, packaging bag, smooth surface, etc.) will affect the feature extraction of the measured object. Infrared lens machines usually choose a suitable visual light source and polarizer to solve the problem of object reflection. 1. Light source selection for reflective object detection Use low-angle lighting: most of the reflections on the surface of the object under test do not enter the camera; Use diffuse reflection shadowless light source: compensate the angle change of the surface of the object to obtain a more uniform image; Backlighting is used: surface reflection does not enter the lens, only the contour information of the object is retained; Adopting coaxial light illumination: Make the reflected light of the object surface and the CCD camera on the same axis, effectively eliminating image ghosting, which is very suitable for the detection of mirror-smooth surfaces. 2. The use of polarizer The polarizer can selectively let light oscillating in a certain direction pass through, which can reduce or eliminate interference such as stray light and glare, thereby eliminating or reducing light spots. The polarizing lens is mounted on a rotatable bracket, one end can be freely rotated to adjust the angle, and the other end is connected with the lens. By rotating to an appropriate angle, part of the reflection or glare on the surface of the object can be effectively resolved. For metal surfaces or other surfaces with multiple reflection angles, we usually need to add polarizers in front of the lens and the visual light source. It is worth noting that the effect of the polarizer does not eliminate all reflections. Its function is to eliminate the light in certain vibration directions, while retaining the light in a certain direction, which reduces the reflection.