In the center of the picture is a colored drawing of a man wearing a kimono, climbing out of a window. To the left and right the sides of two other pictures are just visible.

The Challenges Of Digitizing Paper Films

In the 1930s, as an alternative to celluloid, some Japanese companies printed films on paper (kami firumu), often in color and with synchronized 78 rpm record soundtracks. Unfortunately, between the small number produced, varying paper quality, and the destruction of World War II, few of these still survive. To keep more of these from being lost forever, a team at Bucknell University has been working on a digitization project, overcoming several technical challenges in the process.

The biggest challenge was the varying physical layout of the film. These films were printed in short strips, then glued together by hand, creating minor irregularities every few feet; the width of the film varied enough to throw off most film scanners; even the indexing holes were in inconsistent places, sometimes at the top or bottom of the fame, and above or below the frame border. The team’s solution was the Kyōrinrin scanner, named for a Japanese guardian spirit of lost papers. It uses two spools to run the lightly-tensioned film in front of a Blackmagic cinematic camera, taking a video of the continuously-moving film. To avoid damaging the film, the scanner contacts it in as few places as possible.

After taking the video, the team used a program they had written to recognize and extract still images of the individual frames, then aligned the frames and combined them into a watchable film. The team’s presented the digitized films at a number of locations, but if you’d like to see a quick sample, several of them are available on YouTube (one of which is embedded below).

This piece’s tipster pointed out some similarities to another recent article on another form of paper-based image encoding. If you don’t need to work with paper, we’ve also seen ways to scan film more accurately.

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Video Clips With Emacs

Sometimes it seems like there’s nothing Emacs can’t do. Which, of course, is why some people love it, and some people hate it. Apparently, [mbork] loves it and devised a scheme to show a video (with a little help), accept cut-in and out marks, and then use ffmpeg to output the video clip, ready for posting, emailing, or whatever.

This was made easier by work already done to allow Emacs to create subtitles (subed). Of course, Emacs by itself can’t play videos, but it can take control of mpv, which can. Interestingly, subed doesn’t insist on mpv since it won’t work on Windows, but without it, your editing experience won’t be as pleasant.

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Stephen Hawes operating his LumenPnP

The LumenPnP Pasting Utility: Never Buy Solder Stencils Again?

Over on his YouTube channel the vivacious [Stephen Hawes] tells us that we never need to buy solder stencils again!

A big claim! And he is quick to admit that his printed solder paste isn’t presently quite as precise as solder stencils, but he is reporting good success with his technique so far.

[Stephen] found that he could print PCBs with his fiber laser, populate his boards with his LumenPnP, and reflow with his oven, but… what about paste? [Stephen] tried making stencils, and in his words: “it sucked!” So he asked himself: what if he didn’t need a stencil? He built a Gerber processing, G-code generating, machine-vision implemented… website. The LumenPnP Pasting Utility: https://paste.opulo.io/

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Front panel of Sony Blu-ray player

Blu-ray Won, But At What Cost?

Over on their substack [ObsoleteSony] has a new article: The Last Disc: How Blu-ray Won the War but Lost the Future.

In this article the author takes us through the history of Blu-ray media and how under Sony’s stewardship it successfully defeated the competing format of the time, HD DVD. Sony started behind the eight ball but through some deft maneuvering managed to come out on top. Perhaps the most significant contributing factor was the inclusion of Blu-ray drives in the PlayStation 3.

The person leading the Blu-ray initiative for Sony was Masanobu Yamamoto, whose legacy was the compact disc. What was needed was a personal media format which could deliver for high-definition 1080p video. As the DVD format did not have the storage capacity required, new formats needed to be developed. The enabling technology for both Blu-ray and HD DVD media was the blue laser as it allowed for more compact encoding.

Sony’s Blu-ray format became the dominating format for high-definition personal media…just as physical media died.

Thanks to [Stephen Walters] for writing in about this one.

Dummy Plug Gets Smarter With Raspberry Pi

[Doug Brown] had a problem. He uses a dummy HDMI plug to fool a computer into thinking it has a monitor for when you want to run the computer headless. The dummy plug is a cheap device that fools the computer into thinking it has a monitor and, as such, has to send the Extended Display ID (EDID) to the computer. However, that means the plug pretends to be some kind of monitor. But what if you want it to pretend to be a different monitor?

The EDID is sent via I2C and, as you might expect, you can use the bus to reprogram the EEPROM on the dummy plug. [Doug] points out that you can easily get into trouble if you do this with, for example, a real monitor or if you pick the wrong I2C bus. So be careful.

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A man is looking at a volumetric display while using one finger to interact with it. Two roughly-spherical blue shapes are visible in the display, and he is moving his index finger toward one of them.

Elastic Bands Enable Touchable Volumetric Display

Amazing as volumetric displays are, they have one major drawback: interacting with them is complicated. A 3D mouse is nice, but unless you’ve done a lot of CAD work, it’s a bit unintuitive. Researchers from the Public University of Navarra, however, have developed a touchable volumetric display, bringing touchscreen-like interactions to the third dimension (preprint paper).

At the core, this is a swept-volume volumetric display: a light-diffusing screen oscillates along one axis, while from below a projector displays cross-sections of the scene in synchrony with the position of the screen. These researchers replaced the normal screen with six strips of elastic material. The finger of someone touching the display deforms one or more of the strips, allowing the touch to be detected, while also not damaging the display.

The actual hardware is surprisingly hacker-friendly: for the screen material, the researchers settled on elastic bands intended for clothing, and two modified subwoofers drove the screen’s oscillation. Indeed, some aspects of the design actually cite this Hackaday article. While the citation misattributes the design, we’re glad to see a hacker inspiring professional research.) The most exotic component is a very high-speed projector (on the order of 3,000 fps), but the previously-cited project deals with this by hacking a DLP projector, as does another project (also cited in this paper as source 24) which we’ve covered.

While interacting with the display does introduce some optical distortions, we think the video below speaks for itself. If you’re interested in other volumetric displays, check out this project, which displays images with a levitating styrofoam bead.

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A Cheap Yellow Display Makes A Video Walkie Talkie

The ESP32 series of microprocessors with their cheap high-power cores and built-in wireless networking have brought us a wide variety of impressive projects over the years. We’re not sure we’ve quite seen the like of [Jonathan R]’s video walkie talkie before though, a pair of units which as you might guess, deliver two-way video and audio communications.

The trick involves not one but two ESP32s: an ESP32-S3 based camera module, and a more traditional Tensilica ESP32 in a screen module. It’s an opportunity for an interesting comparison, as one device uses the Cheap Yellow Display board, and the other uses an Elecrow equivalent. The audio uses ESP-NOW, while the video uses WiFi, and since the on-board audio amplifiers aren’t great, there’s a small amp module.

The video below has a comprehensive run-down including the rationale behind the design choices, as well as a demonstration. There’s a small lag, but nothing too unacceptable for what is after all an extremely cheap device. Perhaps after all this time, the video phone has finally arrived!

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