Ayush Bhandari - Computational Imaging

Computational Imaging

Ayush Bhandari
Achuta Kadambi
Ramesh Raskar

The MIT Press
Cambridge, Massachusetts
London, England

2022 Massachusetts Institute of Technology

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Library of Congress Cataloging-in-Publication Data

Names: Bhandari, Ayush, author. | Kadambi, Achuta, author. | Raskar, Ramesh, author.

Title: Computational imaging / Ayush Bhandari, Imperial College, London, Achuta Kadambi, University of California, Los Angeles, Ramesh Raskar, Massachusetts Institute of Technology.

Description: Cambridge, Massachusetts: The MIT Press, [2022] | Includes bibliographical references and index.

Identifiers: LCCN 2021037259 | ISBN 9780262046473 (hardcover)

Subjects: LCSH: Image processingDigital techniquesMathematics. | Imaging systems.

Classification: LCC TA1637.5.B53 2022 | DDC 006.6dc23
LC record available at https:// lccn .loc .gov /2021037259

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Motion deblurring: a comparison of traditional approach with computational imaging approach. Longer exposure period results in motion blurring because the object moves during the exposure. One can use a hardware-based solution that entails a short exposure period, with the disadvantage that the resulting image is noisy. Alternatively, one can use a computational approach that entails deconvolution and is inexact. The computational imaging alternative is based on coded exposure imaging. By coding the cameras shutter pattern, the resulting image can be recovered using an algorithm that results in superior performance.

Example of a room-sized pinhole camera.

Roadmap and organization of the book.

The ideal point source: a point source with radiant flux and the irradiance/exitance for an imaginary sphere.

The steradian and the solid angle of a cone-shaped beam.

The area illuminated by a parallel beam as a function of the incident angle.

The pinhole camera. (a) The camera obscura, a darkened room with only a hole in a wall, is an example of the pinhole camera principle; (b) a diagram represents the pinhole camera principle.

The pinspeck camera: this imaging device is based on the opposite functioning principle of the pinhole camera, casting shadows that form a negative image.

The pinhole camera diffraction: when the pinhole size is comparable to the wavelength of the incoming light, a distant object is imaged as a circular disk with rings around it.

The refraction principle: a ray of light is bent at the boundary of two materials with an angle given by Snells law.

The diagram of a thin lens: a point in the scene (black dot) is in focus if the light it reflects toward the lens converges on the sensor plane. When the camera refocuses on a different point, the sensor plane moves relative to the lens.

Lens-based camera obscura: the first cameras required a manual adjustment of the exposure time. Reprinted from (Raskar and Tumblin, 2011).