More on retina and vision

They already exist. Pentax does something like that instead of anti-alias filtering in front of its sensor and also for shake reduction:

On a sunny day (Sat, 29 Oct 2022 08:02:25 +0100) it happened Martin Brown <'''newspam'''@nonad.co.uk> wrote in <tjij62$uc4$ snipped-for-privacy@gioia.aioe.org>:

I see, some review! What I like about my [very old now] Mustek video camera over my 48 Mpixels smartphone as camera, is that the Mustek has a LCD viewfinder that you can flip upwards.

But as to image quality: my Xiaomi is hard to beat at 48 M pixels. My Canons work great too, and can be scripted with chdk, see:

What are the patent application numbers? Which countries?

John

Speaking of retinas...

The good news is that it can be mostly fixed. The guy who did it is a genius with a very steady hand.

The tomography is amazing. Just a few seconds looking at some blue lights.

On a sunny day (Sat, 29 Oct 2022 07:34:47 -0700) it happened John Larkin snipped-for-privacy@highlandSNIPMEtechnology.com wrote in snipped-for-privacy@4ax.com:

Look into a laser?

Yes, looks almost better now than the right eye!

What exactly does the blue light do?

Not even a laser. One looks into a lens and sees some blue rectangles for a few seconds. LEDs, not lasers.

It does. The right eye is normal, a little puckered around the macula. The treatment is for the doc to peel away the top two layers of cells in a big patch of the retina, which relieves stress and lets the hole close. Done by hand. With tweezers. It was interesting, a half hour of wild light show.

Don't know. I should look it up, "Optical coherence tomography of macular holes." The original resolution is much better than what I posted, which was scanned from a paper report.

Amazing.

Here's a really good tomograph.

I find it very hard to believe that you can have any "pending" patents at the moment. If you really were subject to an NDA you would hardly have told us all about it, breaking your own NDA. Also, vibrating two mirrors is much more complicated than vibrating one sensor (which nowadays is unlikely to be a CCD) because the use of mirrors requires a more convoluted optical path.

John

inverting everything the "a a" character writes is a pretty good bet

??? Patent applications are public knowledge, no? At least the fact that they are filed and the meta data.

He didn't say it was a good patent.

On a sunny day (Sat, 29 Oct 2022 11:47:39 -0700) it happened John Larkin snipped-for-privacy@highlandSNIPMEtechnology.com wrote in snipped-for-privacy@4ax.com:

Thank you very much for the links Always learning! Very impressive that wikipedia link!

He is talking *COMPLETE UTTER BOLLOCKS* (TM). When does he not?

Single axis tip-tilt compensation won't get you anything like what he claims. The problem is that for anything larger than a 4" telescope the phase differences across the scope aperture cannot be compensated without *deforming* the compensation mirror in the optical path. It is cheap enough that some keen amateurs had it once, but increasingly they do it by one of the software based shift and add packages instead.

Lucky seeing is all the rage and requires very little hardware. Amateurs with 10" scopes can image planets routinely now at what would have been at the limits of the worlds major observatories a couple of decades ago. It has had interesting side effects - near continuous hires imaging of Jupiter reveals things crash into it more often than we thought!

Wavefront correction systems in astronomy have been almost routine since the 1990's on the bigger telescopes. There are no significant patents worth even looking at - it is mostly public domain or top secret!

There are companies that make the kit - spin offs of the various astronomy/electronics departments that made the earliest units.

The classic implementation is a so called rubber mirror in the light cone that can be deformed slightly up and down by piezo transducers to null out the seeing. They work very well if you have a guide star.

Increasingly the bigger telescopes create their own guide star by exciting Na-D emission in the stratosphere with a focused yellow laser. This isn't a bad summary introduction:

Astronomers - wanting the sharpest possible ground based images Military - wanting to better focus their laser death rays.

Neither bother to publish in the open patent literature although you can find plenty of interesting articles in Proc IEEE or ADS Abstracts. eg.

It's interesting to think of making a split-beam interferometer with wideband light. You get good interference over a very short range of distances, as opposed to periodic interferance over a wide range with long-coherence light.

I did see a red line sweep top to bottom when they did the scan.

I guess that a femtosecond monochromatic pulse would have the same effect, wideband optical spectrum and good distance resolution, but an incoherent red LED is a lot cheaper.

On a sunny day (Mon, 31 Oct 2022 12:29:35 -0700) it happened John Larkin <jlarkin@highland_atwork_technology.com> wrote in snipped-for-privacy@4ax.com:

A very short pulse would have many harmonics, but I do not see that as a usable spectrum, the shorter the pulse the more the harmonics are apart? And possibly outside the usable spectrum?

Yes redish noise ;-)

A short sinewave burst is wideband about the nominal sine center frequency. It's not a matter of harmonics.

Exactly.

On a sunny day (Mon, 31 Oct 2022 22:05:35 -0700) it happened John Larkin snipped-for-privacy@highlandSNIPMEtechnology.com wrote in snipped-for-privacy@4ax.com:

A pure sinewave burst that starts at zero and ends at zero with length t can be compared to an amplitude modulated signal (as in radio) and should have, apart from the main carrier, 2 sidebands -1/t and +1/t apart | | | | AM signal ?

If the sinewave pulse is distorted somehow you will get more spectral components, Also if the frequency is changing during the presence of that pulse (FM spectrum).

If the envelope of the sinewave burst is a pulse, then the AM signal will have the bandwidth of that pulse. For example, if you modulate the carrier with a Gaussian, say, the modulated signal spectrum will have a Gaussian shape centred on the carrier.

Jeroen Belleman