Black and white camera
From today's point of view, black and white cameras seem to be a leftover of the early days of the photo and television technology. This is true for consumer cameras. Here we only find color cameras providing a black and white mode for "artistic purposes".
In contrast to this, the majority of industrial USB cameras, FireWire cameras and GigE cameras "only" provides black and white images. In the context of machine vision, they are also called "monochrome images". Manufacturers, such as The Imaging Source, offer industrial cameras for applications beyond industrial purposes. Thus, they provide black and white cameras and color cameras.
Black and white cameras measure light intensities
But why do black and white cameras dominate machine vision systems? Is this field really behind its times?
Not at all! The majority of industrial applications is based on the automated analysis of differences in light intensity. Black and white cameras are much better at doing this than color ones. This is due to the nature of CCD sensors and CMOS sensors: they are color-blind. The reason for this, and how colors can be captured at all, is explained in the article Color cameras - What is the origin of the colors?.
Therefore, one of the golden rules of machine vision applications is: Only use a color camera, if the application really requires a distinction between colors. In contrast, use a black and white camera, if it is only about the distinction between light intensities.
