An analysis and experimental results are presented of a new color camera technique using a single camera tube. To avoid the difficult registration problem of conventional color cameras, the color information is encoded as the amplitude of two diffraction grating patterns. This is accomplished by imaging the colored scene onto a pair of colored diffraction gratings. The recovery of the color information is done by band-pass filtering of each channel followed by envelope detection. The three color signals are derived using linear combinations of the two decoded carriers along with the average signal which represents a weighted sum of all three colors.
The performance of the camera is determined by resolution, beats, crosstalk, and noise considerations. Many of these considerations are aided by proper design of the grating filter from the viewpoint of the two-dimensional spatial frequency spectrum of the encoded image. These considerations lead to the conclusion that the optimum configuration uses two gratings which are equal in periodicity and are at different angles. The final system uses a vertical red-absorbing grating and a 45° blue-absorbing grating, each having the same periodicity.