• Dr. T. Kiran Kumar
• Dr. S. Radhika

The field of image quality analysis is concerned with the development of quantitative merit functions, which can be used to evaluate the quality of the image. The basis of modern image quality analysis is the perception of the image-forming process as a two-stage Fourier transformation. Both the object and the image are perceived as two dimensional distributions of light of varying brightness. When a lens forms an image of an object, the object distribution of light is, in effect, transformed from the linear domain into an object spectrum in the spatial frequency domain, passed through a spatial frequency band-pass filter, and transformed into the linear domain to become the image distribution of light. Viewed in this framework, the lens system is a low-pass spatial frequency filter. Its effects on the image quality can, therefore, be specified in terms of a spatial frequency band-pass curve. The subject of image formation and analysis took qualitative turn with the applications of communication theory to optics. This resulted in a mathematical tool of Fourier analysis being used in the field of image science. Currently, image formation is described in terms of the impulse response of the imaging systems or in terms of the system transfer functions Key words: Filters, Annular, Pupil & Defocus etc.

Defocus, Frequency, Defocus and Annular etc.

"GAUSSIAN AMPLITUDE FILTER IN THE FOURTH-ZONE OF THE APERTURE", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.11, Issue 3, page no.d303-d306, March-2024, Available :http://www.jetir.org/papers/JETIR2403335.pdf

"GAUSSIAN AMPLITUDE FILTER IN THE FOURTH-ZONE OF THE APERTURE", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.11, Issue 3, page no. ppd303-d306, March-2024, Available at : http://www.jetir.org/papers/JETIR2403335.pdf