Near infrared (NIR) cameras are rapidly advancing machine vision capabilities and growing the number and types of applications in which machine vision is deployed. Once solely a possibility with CCD sensors, the emergence of high-performance CMOS sensors has made NIR cameras commercially viable for a wide range of machine vision applications.
NIR cameras can perform vision and inspection functions that other cameras simply cannot. But what are NIR cameras? What are they used for in today’s industrial setting?
Typical Near Infrared Camera Applications
NIR wavelengths are directly adjacent to the visible light spectrum, meaning they cannot be seen by cameras that operate in the visible light spectrum. NIR cameras sense light that’s invisible to the naked eye, but still valuable for machine vision applications.
NIR cameras are often deployed in low-light or no-light settings, such as traffic monitoring and other outdoor conditions where visible light intensity varies. As opposed to far infrared (FIR) or thermal vision systems where body heat is detected and a bright negative image is produced, NIR vision systems still detect photons to produce a sharp and clear image.
Real World Near Infrared Camera Application
Some NIR vision systems leverage the three native colors in the visible spectrum (R, G and B), but also detect NIR wavelengths simultaneously. These are called quadlinear multispectral cameras and they can be quite useful in the right application.
For example, fruit inspection is a common multispectral application for NIR cameras. When apples are bruised, sometimes the bruise takes time to discolor the skin of the apple, even if the interior of the apple is discolored.
A typical machine vision camera could not detect this. However, multispectral NIR cameras can detect bruising before it affects the peel of the apple. This allows factories to more effectively sort out damaged fruit before it reaches store shelves.
This solution is commercially available off the shelf and represents just one way that NIR cameras advance overall machine vision capabilities.
Infrared imaging in general has proven to be useful for machine vision, especially for inspection and non-destructive testing applications. To learn more about how different types of infrared imaging are deployed in today’s industrial settings, read the Feature Article "Nondestructive Testing Relies on X-ray, IR Imaging for Product Integrity."