bookofjoe

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),

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.

This Chair — Part 2

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.

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

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.

Let's talk about wood.

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

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.

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. :|

Amazon's website when it made its debut in 1995

Helpful Hints from joeeze: Clean your headlamps

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.

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.

$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."

Find the 12 differences

Why does it cost so much to build things in America?

The title of this post is the headine of a Vox story.

Very long answer — and article — short: no one really knows.

But all the experts think they know.

You can own — and drive — a 'Mad Max' vehicle

From Ben Evans:

The vehicles from the last Max Max film are for sale.

Yes, really.

They work.

Probably not road legal, except in Texas.

I thought Charlize Theron's performance as Furiosa in the most recent of the series (2015), "Mad Max: Fury Road" was deserving of an Academy Award, though she wasn't even nominated.

If you buy one of these epic vehicles and park it on your street, I doubt you'll ever have to worry about cars parking too close and boxing you in such that it's hard for you to get out.

Same deal in supermarket and shopping center parking lots: I'd be surprised if anyone ever parked next to you.

heh 

Nikon Small World Microscopy Contest 2021

[Synthetic sapphire that became contaminated during production.]

From Ars Technica:

Microscopy is essential to many areas of science.

[Detailed photo of quartz.]

We use it to look at everything from the small devices we fabricate to the tiny structures inside cells.

[Fairburn agate]

Microscopy wouldn't function without input from many other areas of science: chemistry helps with stains, dyes, and sample preparation; physics determines what's possible with different forms of optics; fields like biology and geology tell us where to look.

[Meteorite cross-section.]

Combined, these tools give us a nearly infinite suite of options for looking at the world of the small.

[Crystal of common table salt.]

When things come together just so, a microscope can do far more than just advance science; it can also create works of art.

[Cross-section of sedimentary rock.]

Each year, when Nikon releases the results of its annual microscopy competition, we struggle for new superlatives to describe the images.

Marvel Sound Effects Machine

From the website:

This bright red collectible plays eight signature Marvel soundbites so you can relive the good old Avenger days, including:

• Hulk's "HULK SMASH!"
• Iron Man's suit launch
• Captain America's Shield Toss
• Spider Man's web shooters
• Falcon's wing darts
• Groot's "I am Groot"
• Hawkeye's arrow shot
• Thor's Hammer Blow

Guaranteed to provide hours of entertainment for Marvel super-fans and a must-have for any memorabilia collection.

Features and Details:

• Requires 2 AAA batteries (included!)

• Dimensions: 3"W x 2"H x 0.8"D

$19.

2021 Fall Foliage Prediction Map

 

Use the slider under the map.

 

 

[via Kottke]

'Orinoco Flow' (Sail Away) — Enya

Harpy Eagle

From Wikipedia:

The harpy eagle (Harpia harpyja) is a neotropical species of eagle.

It is also called the American harpy eagle or Brazilian harpy eagle to distinguish it from the Papuan eagle, which is sometimes known as the New Guinea harpy eagle or Papuan harpy eagle.

It is the largest and most powerful raptor found throughout its range, and among the largest extant species of eagles in the world.

Harpy eagles may measure up to 3'6" in length and have a wingspan of up to 7'4".

They usually inhabit tropical lowland rainforests in the upper (emergent) canopy layer.

Destruction of its natural habitat has caused it to vanish from many parts of its former range, and it is nearly extirpated from much of Central America.

In Brazil, the harpy eagle is also known as royal-hawk (in Portuguese: gavião-real).

The genus Harpia, together with Harpyopsis and Morphnus, form the subfamily Harpiinae.

'Bitchin': The Sound and Fury of Rick James'

Wow.

The only thing I knew about Rick James before watching this great film was his song "Super Freak."

The movie gripped me from the get-go.

What an amazing, tragic life.

Japanese work from home mini-office

[The Hanare Zen is a 36-inch-wide and 71-inch-long home office that aims to help workers in Japan as the Covid-19 pandemic keeps them out of the office.]

I like it.

From the Guardian:

Japanese design is renowned for its minimalism, and for keeping things simple and uncluttered.

So it's no surprise that a leading housebuilder is trying to tackle the lack of space for pandemic-era working from home by marketing a tiny home-office building that can be constructed adjacent to houses in just two days, fine weather permitting.

The so-called Hanare Zen is a 91cm-wide and 1.8 metre-long building equipped with power sockets, a counter-type desk, and very little else.

KI Star Real Estate, a popular housebuilder, began taking orders for the Hanare Zen on September 6, hoping to find a market among those struggling to work in cramped homes.

Hanare means separate or detached in Japanese, while Zen is written in both the Chinese character for Zen Buddhism and the alphabet.

"We had already created the Hanare building as a kind of storage space, and with the situation in the pandemic, the idea came about to develop the Hanare Zen as a work space," said Chisa Uchiyama, a spokesperson for KI Star Real Estate. "The use of 'Zen' in the name represents the minimalist concept of stripping down the size and features to only what is necessary.

"It is designed for people who have difficulty in finding a comfortable space to work in their home and don't want to get in the way of their family," added Uchiyama.

[A single chair fits snugly inside the tiny office.]

The Hanare Zen costs 547,800 yen ($4,992) and is available in Tokyo and the surrounding prefectures.

Order here.

minus: A finite social network where you get 100 posts — FOR LIFE

That's different.

From the website:

Minus is a finite social network where you get 100 posts — for life.

While you can reply to a post as often as you like, every time you add to the feed, it subtracts from your lifetime total.

When you reach 0 posts left, that's it.

No exceptions.

The feed is reverse chronological, not algorithmic.

Post timestamps are vague.

Nothing is monetized.

There are no likes or follows or noisy notifications.

The site's only visible metric counts down, showing how many posts each user has remaining.

How disorienting will it be to interact on a platform that doesn't try to induce endless engagement from your every waking second?

What will you say — or make — when freed from infinite demand?

Just like life, Minus has limits.

Try it out today and see what online interaction feels like on a social network designed for less.

Free, the way we like it.