Patent US 7,733,489

The color difference and/or chromaticness difference between target objects and background objects can be enhanced. Different colors with different color attributes mean different objects. In some cases, different chromaticness, such as saturation and hue, mean different two- or three-band ratio. The light from the surface of objects is filtered by optical system integrated with two- and three-band mixing method so that only the light in the wavelength range of the pass bands can reach optical sensors for opto-electronic sensing devices. With this kind of opto-electronic sensing devices, two- and/or three-band ratio criteria widely used in remote sensing and machine vision applications can be calculated in terms of color attributes. Multi-spectral imaging system can be replaced by this kind of sensing devices. This kind of two- or three-band mixing illumination can be used to identify, classify, and detect objects for human visual application, remote sensing, and machine vision application.