The principle of Hadamard transform imaging is analyzed, and the specific features of Hadamard transform imaging are discussed with emphasis placed on the basic performance and the channel capacity of the signal chain. An analyzing method for the minimum signal amount that can be detected in the non- ideal situation where there are disturbances in the sensing system and photon noise in the signal is discussed. The results of analysis show that the quantity of system signal in a chain is only about half the total of all signals and the capacity of the signal chain is not fully utilized when the S- matrix is used to carry out the code measurement, so the minimum amount of detectable signals is rather large. The method of Hadamard transform imaging with maximum signal capacity and the analyzing method for the minimum detectable signals are discussed. Based on the transmission and diffraction theory of near-field optics and the principle of Hadamard transform with maximum capacity, an imaging method with nano-resolution is proposed.
"Imaging method with nanoresolution", Proc. SPIE 4231, Advanced Optical Manufacturing and Testing Technology 2000, (6 October 2000); doi: 10.1117/12.402833; https://doi.org/10.1117/12.402833