Browsing by Author "Raj, Kannan"

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    Investigations of three-dimensional optical transfer functions
    Raj, Kannan (Virginia Tech, 1990)
    The performance of two-dimensional image processing systems has been well documented. In this thesis we study the performance of three-dimensional imaging systems. Such a study helps in understanding the fundamental restrictions of the propagation of three-dimensional (3-D) wavefields. The knowledge of the obtainable 3-D wave structures are useful for applications such as 3-D data acquisition, material processing, radiation therapy, radiative non-invasive surgery, 3-D microscopy and robotic vision. This thesis primarily deals with some investigations of 3-D optical transfer functions (OTFs). Specific emphasis has been made on the interpretation of 3-D wavefield distributions as an extension of 2-D defocused OTFs and also the interpretations of 3-D diffraction images from convolution relations.
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    Visibility-Dependent Depth Of Focus For Incoherent Sinusoidal Sources
    Pieper, Ronald J.; Raj, Kannan; Poon, Ting-Chung (Optical Society of America, 1992-05-01)
    A visibility-dependent depth of focus is developed for incoherent sinusoidal sources. This analysis is based on a derived relationship between the visibility and the optical transfer function (OTF). The formalism developed is general for any aperture topology and arbitrary orientation of sinusoidal sources. To illustrate the application of the method the cases of an annular aperture and a Gaussian aperture are analyzed. It is found that as the level of defect of defocus increases, the maximum visibility for which a particular spatial frequency can be resolved decreases.