Joint transform correlator: Aberrations in the joint spectrum and their influence on the correlation peak
An approximate but simplified method to evaluate the influence of aberrations in the optical system of the first step of a joint transform correlator on the correlation signals is given. In the optical system of the second step the effects of its aberrations can be easily calculated with classical a...
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| Autores principales: | , , |
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| Publicado: |
1997
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09639659_v6_n2_p173_Comastri http://hdl.handle.net/20.500.12110/paper_09639659_v6_n2_p173_Comastri |
| Aporte de: |
| Sumario: | An approximate but simplified method to evaluate the influence of aberrations in the optical system of the first step of a joint transform correlator on the correlation signals is given. In the optical system of the second step the effects of its aberrations can be easily calculated with classical aberration theory so that this problem is left aside from the present analysis and this system is considered free from aberrations. The correlation signals are estimated assigning to every spatial frequency which synthesizes the scene (or the target) the wavefront aberration which corresponds to a convenient spatial frequency chosen as that which yields the maximum difference between the wavefront aberrations in the scene and target. Therefore, an upper limit of the attenuation of the correlation peak is obtained and tolerance criteria can be established. The criteria of Rayleigh and of Marechal are extended for the correlator and a numerical method to compute the aberrated correlation signal is developed. As an example, numerical results for the correlation in the presence of each primary aberration when the target and scene are rectangular apertures are shown. © 1997 IOP Publishing Ltd. |
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