Kyle M. Douglass @kmdouglass.bsky.social · 15/09/2026Today I heard someone describe an off-axis hyperbolic lens surface as "violently non-aplanatic." #optics #poetry 030
Kyle M. Douglass @kmdouglass.bsky.social · 21/08/2026I've been playing with PyTorch's autograd for only one week and already I lay awake at night wondering whether my latent variables are flowing differentiably through my inference chains. #everydayproblems 030
Kyle M. Douglass @kmdouglass.bsky.social · 17/08/2026#Radiometry is a challenging topic in #optics because the physics and the mathematics are often presented together as one subject, when in reality there is a clear delineation between the two. Here I provide a primer on the basic mathematics of radiometry. kylemdouglass.com/posts/a-prim... 000
Kyle M. Douglass @kmdouglass.bsky.social · 07/08/2026I added beam scanning capabilities to our lab's vector focal field simulation library just now: github.com/LEB-EPFL/jus... You can use it to simulate beam scanning using arbitrary vector beams in the focus of a high NA microscope objective.github.comGitHub - LEB-EPFL/just-focus: Vector electromagnetic field calculations in the focus of high NA microscope objectives.Vector electromagnetic field calculations in the focus of high NA microscope objectives. - LEB-EPFL/just-focus 030
Kyle M. Douglass @kmdouglass.bsky.social · 04/08/2026I started a thread on Microforum searching for cameras similar to the Photometrics Kinetix and have shared a spreadsheet with my search results. If you know of others that fall within this category, then please do share. forum.microlist.org/t/equivalent...forum.microlist.orgEquivalent cameras to the Photometrics Kinetix?Thanks again @Hazen_Babcock . It’s a good point to look at the sensor itself. Here is the spreadsheet I compiled of similar cameras: Proton Drive The cameras I looked at were: Photometrics Kinetix... 160
Kyle M. Douglass @kmdouglass.bsky.social · 29/06/2026Last night I learned that the effective focal length of a lens can differ in the backward and forward directions if the refractive index of the media in object and image spaces differ. I think often about how little we treat this scenario in #optics education given its ubiquity in #microscopy. 130
Kyle M. Douglass @kmdouglass.bsky.social · 11/06/2026Is the infinity mark on cheap machine vision lenses always this wrong? This is the setting at which I'm able to focus on some clouds 🤔 Am I missing something? #optics #computervision 320
Reposted by Kyle M. Douglassreto @galactic-forensics.space · 10/06/2026Do you write/want to write drivers to communicate with (scientific) instruments in Rust? Check out my latest blog post on how to make this hopefully easier in the future. Comments, ideas, etc. are always welcome. blog.galactic-forensics.space/blog/07-inst... #Rustblog.galactic-forensics.spaceinstrumentRs v0.2.0 design ideasThoughts and ideas... 3163
Kyle M. Douglass @kmdouglass.bsky.social · 09/06/2026You can place a mirror at 45 deg. AOI at the focus of a lens whose back focal distance is known by using a ruler with straight edge against the lens housing and extending beyond the mirror. Under collimated input, the intersection of the reflected beam with the ruler should be the BFD. #optics 030
Kyle M. Douglass @kmdouglass.bsky.social · 02/06/2026"What we saw was this pretty striking pattern that software engineers got about 20% more feedback if they were sitting near their colleagues than if they were distant from them... It was [young workers] who had the most to learn that really saw this deficit in feedback." www.npr.org/2026/06/01/n...npr.orgRemote work -- not AI -- has sidelined recent college graduates, research findsResearch from the New York Fed finds that younger college graduates have been sidelined by remote work in recent years, as companies may be reluctant to hire those needing more training and mentoring. 000
Kyle M. Douglass @kmdouglass.bsky.social · 18/05/2026Using a wavefront sensor and bisection to place the focal plane of a microscope tube lens in the back focal plane of an objective lens. I used beam diameter as the readout because the radius of curvature did not change significantly over the range of lens positions that I tested. #microscopy 110
Kyle M. Douglass @kmdouglass.bsky.social · 10/05/2026I'm still trying to work out whether this is truly useful, but you can use a coverslip to pick off the beam from an alignment laser that is back reflected from a mirror at the end of a setup (not shown). Deviations of the beam upon insertion of a lens indicate its misalignment. #optics 190
Kyle M. Douglass @kmdouglass.bsky.social · 08/05/2026I added a galvo and scan lens example to my Cherry ray tracer to help one of our PhD students understand scan systems. Click and drag on the theta rotational offset value for the first mirror surface to see what happens to the ray fan in real time. #optics #microscopy kmdouglass.github.io/cherry 050
Reposted by Kyle M. DouglassEugene Katrukha 🇺🇦 @ekatrukha.bsky.social · 30/04/2026After 9 years, I am finally finishing the story about normalized cross-correlation (and reviving my blog). The new blog post about deep technical details on the most used image registration technique. I know y'all have been waiting. katpyxa.info/feedbacks/?p...katpyxa.infoCalculating normalized cross-correlation (part 3) – //><=~!=// 22310
Kyle M. Douglass @kmdouglass.bsky.social · 22/04/2026"[I]n any science less complete than physics, the more general mind still has its uses, though everyday the chances grow less." C. P. Snow, lamenting the loss of synthesis within a science as it matures. 000
Kyle M. Douglass @kmdouglass.bsky.social · 10/04/2026When a single line of code you wrote without thought three years ago leads to three weeks of nightly debugging after the kid goes down. Ray-Surface Intersections with the Newton-Raphson Algorithm kylemdouglass.com/posts/ray-su...kylemdouglass.comRay-Surface Intersections with the Newton-Raphson AlgorithmI take a deep dive into computing ray-surface intersections using the Newton-Raphson algorithm. 030
Kyle M. Douglass @kmdouglass.bsky.social · 26/03/2026An apologia for theoretical biology. From "Energy Flow in Biology" by Harold J. Morowitz. 170
Kyle M. Douglass @kmdouglass.bsky.social · 19/03/2026"Optimal lens design and use in laser-scanning microscopy" doi.org/10.1364/BOE.... #optics #journalclub 000
Kyle M. Douglass @kmdouglass.bsky.social · 18/03/2026I implemented folds into the Cherry Ray Tracer today. Rather than freely placing components in space, I took inspiration from video games and used a RUF coordinate system to build up the system surface by surface. kmdouglass.github.io/cherry kylemdouglass.com/posts/3d-seq... #optics 041
Kyle M. Douglass @kmdouglass.bsky.social · 17/03/2026Does anyone have any tips for putting a galvo in the center of a 4f system in the scan/descan arm of a laser point scanning fluorescence microscope? I normally align everything to the objective, but here I wonder whether the galvo should be the primary datum to align to. 000
Kyle M. Douglass @kmdouglass.bsky.social · 13/03/2026I can never remember the electrostatic conventions for the mitochondrial membrane potential, so I wrote them down: kylemdouglass.com/posts/electr... 041
Kyle M. Douglass @kmdouglass.bsky.social · 12/03/2026I finally managed to rewrite the Cherry Ray Tracer GUI using egui, an immediate mode GUI for Rust with WASM support. In addition, I figured out threading in WebAssembly via SharedArrayBuffers, so this thing is now lightning fast. kmdouglass.github.io/cherry #optics #wasm #raytracing 2122
Kyle M. Douglass @kmdouglass.bsky.social · 26/01/2026Last week I learned that I can use the internal counter on a NI-DAQ board as a triggerable pulse sequence that serves as the clock for an analog output waveform. Pretty cool! #microscopy kylemdouglass.com/posts/trigge...kylemdouglass.comTriggering Analog Voltage Outputs using a NI-DAQ CounterI explore routing signals from counters on a NI-DAQ device for custom triggering and waveform generation. 030
Kyle M. Douglass @kmdouglass.bsky.social · 13/01/2026I finally got around to writing the discussion section of our lab's basic training course on live cell #microscopy. I explain the tradeoffs involved in designing an imaging experiment and the art of thinking of the experiment as an optimization problem. leb-epfl.github.io/basic_traini...leb-epfl.github.ioIntroduction - Microscopy Basic Training 1144
Kyle M. Douglass @kmdouglass.bsky.social · 13/01/2026I had the happy realization the other day that conservation of radiance / étendue is purely geometrical. Radiance is just proportional to the size of the set of all lines through two area elements, and the product of area and solid angle is an invariant over this set. #optics #radiometry 010
Kyle M. Douglass @kmdouglass.bsky.social · 22/11/2025A holiday demonstration of the different penetration depths of red and blue light into tissue. #optics 03210
Kyle M. Douglass @kmdouglass.bsky.social · 18/11/2025When X-rays are incident upon a crystal, some of their energy is reflected from the lattice planes. Certain angles of incidence will lead to the observation of diffraction peaks due to constructive interference between the reflected wavefronts. #optics #microscopy youtu.be/FZ4gilAe7x0youtu.beThe Bragg ConditionYouTube video by Kyle Douglass 041
Kyle M. Douglass @kmdouglass.bsky.social · 20/10/2025The construction of the support of the 3D aperture (a.k.a. the optical transfer function or OTF) using the Ewald sphere in a brightfield microscope under partially coherent illumination. #optics #microscopy 020
Kyle M. Douglass @kmdouglass.bsky.social · 14/10/2025How to use the Ewald Sphere to determine the support of the 3D aperture of a brightfield microscope under coherent illumination. #optics #microscopy 031
Kyle M. Douglass @kmdouglass.bsky.social · 09/10/2025Object models for image formation theory in brightfield microscopes. kylemdouglass.com/posts/image-...kylemdouglass.comImage Formation in Brightfield Microscopy: Part 1 - Object ModelsI describe how objects are treated in image formation models for brightfield microscopy. 030
Kyle M. Douglass @kmdouglass.bsky.social · 03/10/2025I spent the morning playing with GeoGebra for the first time and, along the way, published an app about aligning a laser beam to an axis in space defined by two irises using two rotating mirrors. There's a learning curve, but it's not too bad. #optics www.geogebra.org/m/tfrykp7ygeogebra.orgAlignment with Two MirrorsAligning a laser beam to an axis in space using two mirrors. 010
Kyle M. Douglass @kmdouglass.bsky.social · 25/09/2025Check out my dope new fixed focal length lens. 090
Kyle M. Douglass @kmdouglass.bsky.social · 23/09/2025It's kind of nuts that most of the cost of kinematic #optics mounts usually covers the alignment phase of a setup, after which the mount serves the same role as an unmovable piece of stock metal. 130
Kyle M. Douglass @kmdouglass.bsky.social · 14/09/2025Trying to get a sense of how much current I can pass through salt water and happened to observe electrolysis by accident. 020
Kyle M. Douglass @kmdouglass.bsky.social · 05/09/2025Do any of you fellow #optics nerds know whether First Contact solution will remove residue from alcohols left behind on glass? 000
Kyle M. Douglass @kmdouglass.bsky.social · 12/08/2025The more I learn about floating point arithmetic, the more I am impressed that scientists can get anything done at all on a computer. 010
Kyle M. Douglass @kmdouglass.bsky.social · 07/08/2025Pro-tip: you can use the hole in a Thorlabs FC/PC fiber mount to self-center a domed LED when gluing it to a cage plate blank. #optics 140
Kyle M. Douglass @kmdouglass.bsky.social · 06/08/2025This week I wrote a small Python library for computing vector EM fields in the focal region of high NA objectives. github.com/LEB-EPFL/jus... I'd be pleased if would try it out and leave any feedback or bugs in the issue tracker. :)github.comGitHub - LEB-EPFL/just-focus: Vector electromagnetic field calculations in the focus of high NA microscope objectives.Vector electromagnetic field calculations in the focus of high NA microscope objectives. - LEB-EPFL/just-focus 030
Kyle M. Douglass @kmdouglass.bsky.social · 30/07/2025> So Lemkin's attempts to communicate with the AI model... were fundamentally misguides. Maybe the real, lasting value in LLMs is that they have brought fundamental questions about cognition from scientific specialty to the working lives of everyday people. arstechnica.com/information-...arstechnica.comTwo major AI coding tools wiped out user data after making cascading mistakes“I have failed you completely and catastrophically,” wrote Gemini. 110
Kyle M. Douglass @kmdouglass.bsky.social · 08/07/2025I've resorted to printing out code and checking it by hand just to validate AI slop. #thefutureisnow 010
Kyle M. Douglass @kmdouglass.bsky.social · 07/07/2025Can anyone recommend a service where I upload 3D models of simple machine parts and they mail me the CNC'ed results? Something like Osh Park that does small batches but for machine parts? I feel like I saw something about this recently but can't remember which platform I saw it on. 454
Kyle M. Douglass @kmdouglass.bsky.social · 07/07/2025Here's a short post about converting the surface sag of a class of common optical surfaces into the normal form of a quadric. The trick is to use a method from high school #math that doesn't get as much attention as, say, the quadratic equation or the FOIL method. kylemdouglass.com/posts/comple...kylemdouglass.comCompleting the Square and the Normal Form of QuadricsI explain how to convert the expression for the sag of an optical surface into the normal form of a quadric equation. 010
Kyle M. Douglass @kmdouglass.bsky.social · 04/07/2025You know you're f***ed when the Wikipedia article on the problem you're working on only exists in one language and it isn't English. de.m.wikipedia.org/wiki/Umrissk...de.m.wikipedia.orgUmrisskonstruktion – Wikipedia 020
Kyle M. Douglass @kmdouglass.bsky.social · 25/06/2025I'm brushing up on my computational #geometry skills and found this great resource for surface representations: "Representing Smooth Surfaces" by Ken Takusagawa Fun fact: surface sag in #optics is just an explicit surface representation. groups.csail.mit.edu/graphics/cla...groups.csail.mit.eduRepresenting Smooth Surfaces 000
Kyle M. Douglass @kmdouglass.bsky.social · 23/06/2025I realized recently that I have always taken for granted the fact that camera read noise is Gaussian, but I never questioned why this is. The answer, I think, is due to the central limit theorem. #optics #imaging kylemdouglass.com/posts/why-is...kylemdouglass.comWhy is Camera Read Noise Gaussian Distributed?I investigate why camera read noise may be modeled as a Gaussian random variable. 051
Reposted by Kyle M. DouglassSPIE @spie.org · 17/06/2025This month's Henry Poincare Webinar Series on Optical Polarization and Related Phenomena will be led by Aristide Dogariu! 💡 Join us on 24 June for this presentation on light polarization and the statistical properties of the electric field vector.⚡ Register here: spie-org.zoom.us/web... 031
Kyle M. Douglass @kmdouglass.bsky.social · 05/06/2025I did a deep dive into the mathematics for 3D optical system design software, focusing on ways that we can make layouts more intuitive. I hope you find it as interesting as I did in writing it. #optics kylemdouglass.com/posts/3d-seq...kylemdouglass.com3D Sequential Optical System LayoutsI describe the geometry involved for laying out sequential optical systems in 3D. 031
Kyle M. Douglass @kmdouglass.bsky.social · 30/05/2025Sometimes you come across a site and you just have to instantly bookmark it. Mathjax examples for easy copying and pasting: easy-copy-mathjax.nakaken88.com/en/matrix/easy-copy-mathjax.nakaken88.comMatrix | Easy Copy Mathjax 010
Kyle M. Douglass @kmdouglass.bsky.social · 26/05/2025One piece of advice I have for people living in Switzerland is to always stay grounded. 020