Hypercentric optics: A camera lens that can see behind objects @AppliedScience

Applied Science | Hypercentric optics: A camera lens that can see behind objects @AppliedScience | Uploaded 4 years ago | Updated 20 hours ago
Telecentric and hypercentric optics are very different from our eyes or normal camera lenses. They have "negative" perspective or no perspective, respectively, leading to very unusual images. In this video I show how to use a common fresnel lens in the creation of your own telecentric optical system.

Fresnel lens, 300mm dia. 200mm FL is sold out... amazon.com/gp/product/B071ZQL9YZ

$5 projection lens on eBay: ebay.com/itm/Delta-108-Projection-Lens-from-U-S-Precision-Lens-inc/264605738684

Good practical discussion of telecentric optics: https://www.lockhaven.edu/~dsimanek/scenario/labman3/telecen.htm
https://www.mii.cz/art?id=626&lang=409&style=4

Idea to use macro tubes for telecentric conversion of normal lenses came from here: http://www.4photos.de/camera-diy/Telecentric-Lens.html

In-depth info on telecentric lenses: schneiderkreuznach.com/application/files/9715/0781/8897/optical-measurement.pdf

Commercial hypercentric and telecentric lens maker: lw4u.com

Paper on making telecentric lenses with fresnel front elements: https://sci-hub.tw/10.1117/12.455256

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$Etching silicon wafers to make colorful Rugate optical filters (porous silicon) Passing an electrical current through a silicon wafer in a special acid etchant will create a porous layer with a variable index of refraction. I describe how this process works, and how the Fourier transform relates filter design to electrical etch waveform and resulting spectral response. Notes: 1. The Rugate filters look especially good in polarized light because the reflection from the silicon wafer is reduced, but the reflection from the filter remains strong. I noticed this while holding the wafer in front of my computer monitor. Later, when showing it to friends, the color intensity was poor. Their monitor must have been horizontally polarized, so holding the wafer low, and tilting it upward didnt work! Some monitors are horizontally polarized, and some are vertical. 2. The magnet used to hold down the PTFE cup to the wafer may have a very slight impact on the etch process. The dramatic shift in filter performance at the periphery is due to O-ring restricting the conductive etchant to a sharp edge, creating an electrical field concentration. Outstanding visual Fourier series tutorial: http://www.jezzamon.com/fourier/index.html LR-1 spectrometer: http://www.aseq-instruments.com/LR1.html p-type wafers on eBay. (You have to hunt around and check the photos for info on the label attached to the box of wafers. Be sure to get wafers less than 0.01 ohm-cm) eg https://www.ebay.com/itm/25-silicon-wafer-P-type-150mm-100-sumco/263441166009 n-type wafers are photosensitive during the etch process. Online graphing calculator page from this video: https://www.desmos.com/calculator/hiju8zdqfz Original Desmos page that I used: https://www.desmos.com/calculator/qpnz9celzf Code for Keithley 2450 control and processing.org waveform generation: https://github.com/benkrasnow/Porous_Silicon_Optics Fourier transform to understand optical coatings: http://www.willeyoptical.com/pdfs/92_180.pdf Porous silicon refs: https://www.rp-photonics.com/rugate_filters.html https://www.intechopen.com/books/porosity-process-technologies-and-applications/porous-silicon https://sci-hub.se/https://doi.org/10.1016/j.mee.2011.03.143 https://sci-hub.se/https://doi.org/10.1080/10408436.2010.495446 https://sci-hub.se/https://doi.org/10.1007/978-3-319-71381-6_2 https://sci-hub.se/https://doi.org/10.1364/AO.44.005415 https://sci-hub.se/10.1364/OE.16.015531 https://sci-hub.se/https://doi.org/10.1002/adma.19940061214 https://sci-hub.se/https://doi.org/10.1063/1.2906337 Silicon wafer identification flats: https://www.tf.uni-kiel.de/matwis/amat/elmat_en/kap_5/illustr/i5_2_4.html Applied Science on Patreon: https://www.patreon.com/AppliedScience$

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Underwater laser cutting and silver sintering to make ceramic circuit boards

A refrigerator that works by stretching rubber bands

Decapping ICs (removing epoxy packaging from chips to expose the dies)