DarkSucker

The paper describes a split Alvarez (Lohmann) lens [1,2] with a phase modulator between them. I didn't do the math, but it looks like the phase modulator is optically equivalent to a mechanical shift of the Alvarez lenses over regions of the field of view. Alvarez lenses have higher aberrations, and are relatively bulky, compared to normal lenses. AR was referenced in the paper, but this lens will be hard to make compact, and have great image quality, over large fields of view.

1. https://www.laserfocusworld.com/optics/article/16555776/alva... 2. https://pdfs.semanticscholar.org/55af/9b325ba16fa471e55b2e49...

Each pixel of such a scanner would need to somehow scan the spectral content. For example, imagine an array of fibers each transporting light from image plane pixel coupled to a spectrometer (bulky, expensive). Slit (a.k.a. push broom) scanners take each pixel of its slit and disperses the light perpendicular to the slit onto a 2D sensor array (more compact, 1D mechanical scan required). I recall seeing spectral (color) filters made from dispersive materials sandwiched between rotating polarizers to filter (scan) the light entering camera (expensive, compact).

Sounds great, but I often find myself wondering "where's the catch?". There's not enough info in the abstract judge for myself whether the idea has legs. I'm sure it'll get more press if there's something to it.

As I read the article. The tsunami wave (water) displaces air at the surface and creates a sound wave, and gravity waves, that travels to the upper atmosphere. These waves then interact with electrons in the upper atmosphere.

Thanks. I wasn't thinking of enums. To the extent one designs a trait to use an enum type (or the enum to satisfy the trait), one wins. But it seems impossible to avoid code to handle all future {type, op} combinations. The nice thing I've seen with Rust is the ability to add to what's been done before without breaking what already works. I'm thinking of "orphan rules" here.

The article's `expression problem matrix` section states that the goal is make it `easy to add ops` and `easy to add types`. My learning of Rust so far indicates Rust satisfies both: traits satisfies the `ops` problem for all traits you want to support the op, and Rust's implementations (impl) solves the problem of adding types. Of course, for each new {op,type} combination, one must write the code, but Rust allows you to do that with its trait and generic systems. Am I missing something important?

I think the alternative is shown in figure 2. SiN (silicon nitride) is different from optical fiber. Both versions shown in figure 2 lack detail, especially in the small boxes labeled GC, Mirror, and PD. Depending on the details, one might put micro optical assemblies between or in those boxes in the figure. In any case, SiN waveguides are small, so you can pack many lanes in a small space.

Can anyone speak to the image processing used? In particular, how is depth inferred from a single 2D image? It seems to me one would need both depth and angle over the field of view to back out the lens focal length. The EXIF format doesn't seem to contain meta data helpful to the focal length calculation.

That link made my day! Thank you. From what I read, their builds perform better than the originals, and they even make landscape versions. Woo hoo! RPN rules in my book. I picked up an HP 32 before they were gone forever, but I've been afraid to use it. It's great to know about SwissMicros; they'll get my business soon.

Thanks! I'm sick and couldn't bring myself to do the wavelength calculation. Your comment helped my thoughts. I think people working on microwave equipment (frequency counters, ...) work in Hz.That's probably why they used the term.

Neither the article nor official link gave much optical design detail. Here's my guess. A (substantially) radially symmetric system comprising a wide-angle positive-short-focal-length first lens followed closely by a negative-short-focal-length whose diameter is small (thus covering a small range of angles, in the center field of view, from the first lens). A single central sensor behind the negative element is for telephoto images, while a collection of sensors distributed radially around the first lens and off axis capture wide angle images.

Imagine a low-index ball lens in contact with a thin high-index negative lens. That's the idea. I'm sure the real design uses multiple surfaces/elements for each lens, and I'm sure it's hyper-optimized. I'm interested to learn how close my guess is to reality.

Apologies for the complex wording to describe geometry.

The new design design uses on axis mirrors to image the photomask onto the wafer, and on axis mirror systems are far easier to design and fabricate compared to zig zag (off axis) systems. I've never designed an EUV system, and I guess that Shintake's team had to solve some materials or optical coating technology issues that allowed them to consider the simpler on axis design. Having worked on zig zag and on axis designs in the IR and VIS range, I can say that Shintake's design will be much (orders of magnitude?) easier to align and assemble.

It seems to me this data could be used to correlate a species/genus to a location if one knows where the samples came from. If one also knows the date of the geological strata the samples came from, then one also has a date correlation. A particular animal at a site at some time seems like information a researcher can use.

Can someone provide/link-to a principle of operation? I looked at references (https://www.dragonflytelescope.org/publications.html) but they point to publications that look to be behind pay walls.

In particular, I don't see how N co-aligned cameras is any different than N images taken in sequence with one camera (averaging over noise), other than a reduction in time required to take N images with one camera.

It's a consequence of the relationship between absorption and index of refraction in glasses, which follow the Karmers-Kronig relationship [0]. As the wavelength approaches atomic resonance, the index increases or decreases depending on which side of the absorption peak the wavelength is.

0. https://en.wikipedia.org/wiki/Kramers%E2%80%93Kronig_relatio...

I wasn't aware that Canon used flourite elements. You learn something new every day. Nice. Their telephoto lenses also use holographic elements, and I attended a talk (1990 ish) where one of their lens designers spoke about a clever scheme using diffraction order pairs (n and n + 1) to compensate each other. This allowed them to use diffractive dispersion in addition to glass (and now I know flourite) for color correction without introducing stray light (ghosts) due to unwanted diffraction orders, which are nearly impossible to get rid of. These lenses are works of art.

Industry, please give us good search tools like those for researching articles: ("fog" near "coastline") AND ("lighthouse"). Or that offer regular expressions so I can search with precision.

I got used to good search tools in grad school, and then came Google. And ever since I've not gotten better than a result salad. Sometimes a tasty salad, but still a salad.

And, to be complete, firms like Nerac offer good search tools, but you need to work with someone who performs the search for you (last I used them).

Notebooks are still a great way to preserve the little details of "what the hell was I thinking?"

Here here. WWIT (what was I thinking) is so valuable. I'm spending much more time now writing notes that provide context in addition to a bare description of what I did. I hate it when I look at old notes, have a million questions, and curse myself for not writing more.

Also, thank you for making the point about the US patent system. I recall somewhere around 1990, where people silently didn't bother to issue notebooks for me to record ideas (i.e. inventions) in favor of electronic disclosure forms.

While neither animated nor as large as animatedknots, the Notable Knot Index

https://notableknotindex.webs.com/

contains a short list of knots along with insightful comments on their use. Some, like the Slipped Buntline Hitch, show alternative forms to alleviate deficiencies (jamming in this case) or for different use cases. One of my favorites is the Versatacle, which provides a pulley like mechanical advantage. It's been my go-to tensioning knot since learning about it. Animated Knots is great for understanding the form of knots like the Zepplin Bend, and I use both sites when learning a new knot or brushing up on an old one.

I did my own experiment on starting to read the article, and, as the author describes, I got the ball color, but not the persons hair color. On thinking about my experience, I likened my mental image to my normal visual image with a fixed gaze (no eye motion), where the vast majority of color and detail is in the foveal field of view (a few degrees). Outside that region, detail and color drop off rapidly. The ball is what I'm looking at, and the person (and their hair color) is outside the foveal region and vague/less detailed.

BRIAR's how it works page depicts Wi-Fi and Tor also, so range isn't necessarily an issue.

Not being familiar with cosine distance, I found an NIST link: https://www.itl.nist.gov/div898/software/dataplot/refman2/au....

It seems like the main difference between convolution and cosine distance is the normalization. For example, if I associate vector A with the windowed data set and B with the cosine difference "kernel", then cosine difference will have a larger magnitude than a convolution for small A.

Cool idea. I plan to give it a whirl some day.

I'm not the type to get bitchy with customer service reps. I've managed teams that do that job, and I know how scripted their support has to be.

"has to be" burns. It could be different. Why is a script essential? These support scripts drive me crazy. I would probably melt down in the OP's case.

Answers like "they allow less skilled first line workers" don't count because one could hire skillful people to solve problems on first contact.

Nice. Almost what I want: simplicity, images (for plots), and no adds or tracking. However, I want to author pages on optics, and I want to use MathJax (https://www.mathjax.org/) for equations. Please let me know how I might use MathJax with Mataroa if I've misunderstood. Or, please suggest something similar that supports MathJax. Rolling my own static site (as many NH postings describe) is enticing but beyond my ability. I am not a Web programmer, and Mataroa's simplicity is perfect for me.