30 April 2012 Composed filter for attenuating bi-frequential noise on LCD-generated ronchigrams
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This work aims to design a filter to attenuate high- and medium- frequency noise in optical test images without changing the edges and original characteristics of the test image, generated by traditional filters (spatial or frequential). The noise produced by the LCD pixels (used as a diffraction grating in the Ronchi test) was analyzed. The diffraction is modulated by the spherical wavefront of the mirror under test, generating at least two frequency band noise levels. To reduce this bi-frequential noise, we propose to use an array of filters with the following structure: a low-pass frequential filter LPFF, a band- pass frequential filter BPFF and a circular mask spatial filter CMSF; thus obtaining the composed filter CF=LPFF-(BPFF)(CMSF). Various sizes of filters were used to compare their signal-to-noise ratio against simple filters (low-pass and band-stop).
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Miguel Mora-González, Miguel Mora-González, Roger Chiu-Zarate, Roger Chiu-Zarate, Jesús Muñoz-Maciel, Jesús Muñoz-Maciel, Julio C. Martinez-Romo, Julio C. Martinez-Romo, Javier Salinas-Luna, Javier Salinas-Luna, Juan Campos Colma, Juan Campos Colma, Francisco J. Luna-Rosas, Francisco J. Luna-Rosas, } "Composed filter for attenuating bi-frequential noise on LCD-generated ronchigrams", Proc. SPIE 8436, Optics, Photonics, and Digital Technologies for Multimedia Applications II, 84360K (30 April 2012); doi: 10.1117/12.922141; https://doi.org/10.1117/12.922141


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