As reflectance varies quickly while illumination does not, this method normalizes brightness and enhances contrast.
Alan Oppenheim's introduction of the complex cepstrum reduced the complexity of using this method, which is a generalization of cepstral analysis, aka quefrency analysis. This method applies to nonlinear 3 systems that obey a principle of superposition under an operation other than addition because such systems can be transformed to a summed system that can be linearly filtered. Thus, this method is notably used to remove (*) multiplicative noise. In image processing, this method specifically refers to 6 applying a high-pass filter to the Fourier transform of the sum of the natural log of the illumination and natural log of the reflectance. As reflectance varies quickly while illumination does not, this method normalizes brightness and enhances contrast. For 10 points, identify this "filtering" technique named for the fact that it9 uses a structure-preserving map.
Alan Oppenheim's introduction of the complex cepstrum reduced the complexity of using this method, which is a generalization of cepstral analysis, aka quefrency analysis.
homomorphic filtering [in place of "filtering": "convolution", "processing"; do not accept: "homomorphism"] 