Recently developed high-power infrared (IR) LEDs are enabling new machine-vision applications, particularly in surveillance (CCTV, biometric access control, automatic number plate recognition, night vision) but also in 3D cameras, 3DTV, automotive-vision systems and factory automation.
Thanks to these products, machine vision technology is quickly becoming a mainstream engineering discipline, with applications in many end markets. IR LEDs aren’t only for remote controls and opto-couplers, any more.
All machine vision applications use CMOS or CCD cameras to detect light reflected from an object. Relying solely on variable ambient light isn’t good enough, however; a better signal to noise ratio requires irradiating the object with many watts of light that is totally invisible to the human eye. That is now possible, particularly with the invention of the 940 nm wavelength LED.
But, it’s not simple: Choosing the right IR illumination for an application requires an understanding of the several parameters, among them object size, distance from the camera and desired resolution. Infrared LEDs Maintain The Night Watch is a good introduction to the brave new world of machine vision. Get a handle on it.