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September 20, 2021

'YOU HAVE NOW REACHED LEVEL 5'

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Breaking news from AAA, just in.

My heart skipped a beat when I opened the envelope.

Not.

Gimme a break.

Below, how AAA rewards me for 45 years of being a member. 

Zzzz

I can't imagine how stupendous the benefits will be in 2051 when I hit 75 years.

Why, I bet I'll have close to 1,000 YouTube subscribers by then.

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Hint.

September 20, 2021 at 04:01 PM | Permalink | Comments (1)

Keyhole Imaging

Be afraid.

Be very afraid.

From Gizmodo:

A Single Laser Fired Through a Keyhole Can Expose Everything Inside a Room

Being able to see inside a closed room was a skill once reserved for superheroes. But researchers at the Stanford Computational Imaging Lab have expanded on a technique called non-line-of-sight imaging so that just a single point of laser light entering a room can be used to see what physical objects might be inside.

Non-line-of-sight (NLOS, for short) imaging is by no means a new idea. It's a clever technique that's been refined in research labs over the years to create cameras that can remarkably see around corners and generate images of objects that otherwise aren't in the camera's field of view, or are blocked by a series of obstacles.

Previously, the technique has leveraged flat surfaces like floors or walls that are in the line of sight of both the camera and the obstructed object. A series of light pulses originating from the camera, usually from lasers, bounce off these surfaces and then bounce off the hidden object before eventually making their way back to the camera’s sensors.

Algorithms then use the information about how long it took these reflections to return to generate an image of what the camera can't see. The results aren't high resolution, but they're usually detailed enough to easily determine what the object in question is.

It's an incredibly clever technique, and one day it could be a very useful technology for devices like autonomous cars that would potentially be able to spot potential hazards hidden around corners long before they're visible to passengers in a vehicle, improving safety and obstacle avoidance.

But, the current NLOS techniques have a big limitation: They're dependent on a large reflective surface where light reflections coming off a hidden object can be measured. Trying to image what's inside a closed room from the outside is all but impossible — or at least it was until now.

The keyhole imaging technique, developed by researchers at Stanford University's Computational Imaging Lab, is so named because all that's needed to see what's inside a closed room is a tiny hole (such as a keyhole or a peephole) large enough to shine a laser beam through, creating a single dot of light on a wall inside.

As with previous experiments, the laser light bounces off a wall, an object in the room, and then off the wall again, with countless photons eventually being reflected back through the hole and to the camera which utilizes a single-photon avalanche photodetector to measure the timing of their return.

When an object hidden in the room is static, the new keyhole imaging technique simply can't calculate what it’s seeing. But the researchers have found that a moving object paired with pulses of light from a laser generate enough usable data over a long period of exposure time for an algorithm to create an image of what it's seeing.

The quality of the results is even worse than with previous NLOS techniques, but it still provides enough detail to make an educated guess on the size and shape of the hidden object. A wooden mannequin ends up looking like a ghostly angel (below),

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but when paired with a properly trained image recognition AI, determining that a human (or human-shaped object) was in the room seems very feasible.

The research could one day provide a way for police or the military to assess the risks of entering a room before actually breaking down the door and storming their way inside, using nothing but a small crack in the wall or a gap around a window or doorway. The new technique could also provide new techniques for autonomous navigation systems to spot hidden hazards long before they become a threat in situations where the previous NLOS techniques weren't practical given the environment.

September 20, 2021 at 02:01 PM | Permalink | Comments (2)

This Chair — Part 2

Zzz

I featured the chair pictured above — which I happened on while browsing reddit — in a September 10 post, remarking "I love it."

Reader xoxoxoBruce then sent me a link to this August 10, 2015 post on imgur, in which the chair's maker describes in detail with numerous pictures exactly how he made it.

After reading every word, I'm even more amazed that it exists.

A few excerpts:

This was the original design.

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The overall cutout is one lateral section where the leg would be. I eventually scratched this design and tweaked it into a second design.

The curves on the leg would eventually form the interior arch of the legs.

I nearly lost my mind at this point.

The image below

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is a little trick I learned in math class of how to make a precise curve with lines. On the Y axis, I made a series of 2mm (I think) marks and on the X axis, I made a series of 10mm marks. And then just connect the dots to get a curve. This is the basic curve of where the back and butt rests. Well, it is half the curve.

For the first line right or left of the middle of the leg, 4*(Fibonacci)mm were marked from the bottom of the innermost section of the seat down. For the second line to the right or left of the middle of the leg, 3*(Fibonacci)mm was marked. Third line to the right or left....2*(Fibonacci)mm. Fouth line... 1*(Fibonacci)mm. I know this probably doesn't make any sense. Believe me, I nearly had a stroke trying to figure it out.

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Let's talk about wood.

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I use plywood to make fine furniture... GASP.

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The main reason I chose this is that I could cut out big pieces that were consistently the same width. Also I knew the patterns of the lamina would produce neat patterns. The search began for plywood that was hardwood all the way through. This is apparently very rare. I eventually found 13-ply 3/4" ply that was 100% birch through and through. It costs about $70 a sheet. I eventually needed about 1.4 sheets for the one chair.

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For finishing, I applied 10 coats (yeah... overkill is my name) of glossy lacquer) followed by 2 coats of red wax paste. It really brought out the colors. Now I just have to make 5 more. :|

September 20, 2021 at 12:01 PM | Permalink | Comments (0)

Amazon's website when it made its debut in 1995

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September 20, 2021 at 10:01 AM | Permalink | Comments (0)

Helpful Hints from joeeze: Clean your headlamps

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First, wipe off the dirt and dust with a wet rag or paper towels.

Do every light: turn signals, the ones on your mirrors, fog lamps, brake lights: don't forget the one in your rear window.

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Then, wipe them off with this stuff and gaze in wonder at how the cloudy plastic headlamp covers are suddenly clear.

Way safer while driving at night.

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$12.16.

FunFact: Back in the day when I used to stop by friends' homes to hang out, using this stuff to clean their cars' lights was one of the many things I did both outside and inside their places to make things better, never letting on I'd done anything such that later they'd think "Huh."

September 20, 2021 at 08:01 AM | Permalink | Comments (3)

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