Image sensor format: Difference between revisions

Revision as of 17:43, 19 April 2024

Revision as of 18:42, 19 June 2024

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===Dynamic range===

Dynamic range is the ratio of the largest and smallest recordable signal, the smallest being typically defined by the 'noise floor'. In the image sensor literature, the noise floor is taken as the readout noise, so <math> DR = Q_\text{max} / \sigma_\text{readout}</math><ref>{{cite journal|last=Kavusi|first=Sam|author2=El Gamal, Abbas|editor3-first=Ricardo J|editor3-last=Motta|editor2-first=Nitin|editor2-last=Sampat|editor1-first=Morley M|editor1-last=Blouke|title=Quantitative Study of High Dynamic Range Image Sensor Architectures|journal=Proc. Of SPIE-IS&T Electronic Imaging|series=Sensors and Camera Systems for Scientific, Industrial, and Digital Photography Applications V|year=2004|volume=5301|pages=264–275|doi=10.1117/12.544517|bibcode=2004SPIE.5301..264K|s2cid=14550103|url=http://www-isl.stanford.edu/groups/elgamal/abbas_publications/C099.pdf|access-date=17 December 2011}}</ref> (note, the read noise <math>\sigma_{readout}</math> is the same quantity as <math>N_r</math> referred to in the SNR calculation<ref name="noise" />).

== Sensor size and diffraction ==

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== Sensor size and shading effects ==

Semiconductor image sensors can suffer from shading effects at large apertures and at the periphery of the image field, due to the geometry of the light cone projected from the exit pupil of the lens to a point, or pixel, on the sensor surface. The effects are discussed in detail by Catrysse and Wandell.<ref name=Catrysse>{{cite journal|last=Catrysse |first=Peter B. |author2=Wandell, Brian A. |title=Roadmap for CMOS image sensors: Moore meets Planck and Sommerfeld |journal=Proceedings of the International Society for Optical Engineering |volume=5678 |issue=1 |pages=1 |doi=10.1117/12.592483 |year=2005 |url=http://www.imageval.com/public/Papers/EI%205678-01%20Peter%20Catrysse.pdf |access-date=29 January 2012 |url-status=dead |archive-url=https://web.archive.org/web/20150113004959/http://www.imageval.com/public/Papers/EI%205678-01%20Peter%20Catrysse.pdf |archive-date=13 January 2015 |series=Digital Photography |bibcode=2005SPIE.5678....1C |citeseerx=10.1.1.80.1320 |s2cid=7068027 }}</ref>

In the context of this discussion the most important result from the above is that to ensure a full transfer of light energy between two coupled optical systems such as the lens' exit pupil to a pixel's photoreceptor the [[Etendue|geometrical extent]] (also known as etendue or light throughput) of the objective lens / pixel system must be smaller than or equal to the geometrical extent of the microlens / photoreceptor system. The geometrical extent of the objective lens / pixel system is given by

<math display="block"> G_\mathrm{objective} \simeq \frac{w_\mathrm{pixel}}{2{(f/\#)}_\mathrm{objective}}\,, </math>