Scanner Snooping Uncovers Focus Farce

January 20, 2021 by Tom Nardi 8 Comments

From his comments about the noisy image and limited controls, we’re going to go out on a limb and assume [Andrew Jeddeloh] isn’t a huge fan of using his Epson V550 for scanning film. But is it really irredeemable? That’s what he set out to determine in a recent series of posts on his blog, and from what we can tell, it’s not looking good for the old Epson.

The first post attempts to quantify the optical capabilities of the scanner by determining its modulation transfer function (MTF), point spread function (PSF), and comparing its horizontal and vertical resolution. As you might expect, the nuances of these measurements are a bit beyond the average user. The short version of his analysis is that the scanner’s slide frame does indeed seem to be holding objects at the proper “sweet spot” for this particular image sensor; meaning that contrary to the advice he’d seen online, there’s nothing to be gained by purchasing custom film or slide holders.

While investigating the optical properties of the scanner, [Andrew] became curious about the automatic focus options offered by the VueScan software he was using. The images produced appeared to be identical regardless of what option he selected, and he began to suspect the feature wasn’t actually doing anything. To confirm his theory, he wrote a shim program that would sit between the proprietary VueScan program and the V550 driver and log all of the data passing between them.

After tweaking various options and comparing the captured data streams, [Andrew] determined that enabling automatic focus in VueScan doesn’t do anything. At least, not with his scanner. He did notice a few extra bytes getting sent to the driver depending on which focus options were selected, but the response from the scanner didn’t change. He thinks the program likely has some kind of generic framework for enabling these kind of features on supported hardware, and it’s just mistakenly showing the autofocus options for a scanner that doesn’t support it.

If there’s some film you want to digitize, but you’re saddled with a scanner like the V550, you could always do it with a camera instead. You could even put together a passable film scanner with LEGO.

Why Your Scanner Has A Hole In It

December 19, 2020 by Jenny List 51 Comments

The SDR revolution has completely changed the way radio enthusiasts pursue their hobby, but there is still a space for the more traditional scanning receiver. If you are an American, have you ever noticed that it has a gap in its coverage between 800 and 900 MHz? The curious reason for this is explored by [J. B. Crawford], and it’s a tale of dusty laws relating to a long-gone technology, remaining on the books only because their removal requires significant political effort.

What we might today refer to as “1G” phones used an entirely analogue transmission scheme, with an easily-receivable FM carrier for the voice and extremely low-bandwidth bursts of serial data only for the purposes of managing the call. Listening to these calls was an illegal activity, but for those with the appropriate scanners it became a voyeuristic hobby within a hobby. It even made the world news via the pages of the gossip sheets, when (truthfully or not) it was credited for the leak of a revealing and controversial conversation involving Diana Princess of Wales.

This caused significant worry to the cellular phone companies who understandably didn’t want their product to become associated with insecurity. Thus they successfully petitioned the US Congress to include a clause restricting the capabilities of scanning receivers into another telecoms-related Act, and here we are three decades later with analogue phones a distant memory and the law still on the books. It may be ancient and unnecessary but there is neither the will nor the resources to remove it, so it seems destined to become one of those curious legal oddities that remains on the books for centuries. Whether an RTL-SDR breaks it is something we’ll leave for the lawyers, but the detail in the write-up makes it well worth a read.

Header image: krystof.k (Twitter) & nmuseum, CC BY-SA 3.0.

Raspberry Pi Makes A Practical Tricorder

August 24, 2020 by Al Williams 3 Comments

What do you get when you add a thermal camera, a software-defined radio dongle, and a battery to a Raspberry Pi? If you are [saveitforparts] you make a tricorder for sniffing radio signals and viewing heat signatures. He admits, the videos (see below) aren’t exactly a “how-to” but it will still give you some ideas for your next build.

You can sense the frustration with some Linux configuration issues, but [saveitforparts] admits he isn’t a Linux or Raspberry Pi guru. Version 1 seemed to be a bit of a prototype, but version 2 is more polished. We still aren’t sure we’d see Spock carrying a case like that, but some 3D printing could spiff that right up.

Of course, a real tricorder is a McGuffin that does whatever the plot calls for. This one is a bit more practical, but it can monitor thermal and RF energy and could accommodate more sensors. This is a great example of a project that would have been very hard to do in the past but is much easier today. The availability of cheap computers and ready-made modules along with associated software open up many possibilities.

If you want to do your own Tricorder hacking you could take over a commercial model. Then again, there’s an official replica on its way that seems like it might have some similar features.

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Russell Kirsch: Pixel Pioneer And The Father Of Digital Imaging

August 20, 2020 by Kristina Panos 28 Comments

It’s true what they say — you never know what you can do until you try. Russell Kirsch, who developed the first digital image scanner and subsequently invented the pixel, was a firm believer in this axiom. And if Russell had never tried to get a picture of his three-month-old son into a computer back in 1957, you might be reading Hackaday in print right now. Russell’s work laid the foundation for the algorithms and storage methods that make digital imaging what it is today.

Russell reads SEAC’s last printout. Image via TechSpot

Russell A. Kirsch was born June 20, 1929 in New York City, the son of Russian and Hungarian immigrants. He got quite an education, beginning at Bronx High School of Science. Then he earned a bachelor’s of Electrical Engineering at NYU, a Master of Science from Harvard, and attended American University and MIT.

In 1951, Russell went to work for the National Bureau of Standards, now known as the National Institutes of Science and Technology (NIST). He spent nearly 50 years at NIST, and started out by working with one of the first programmable computers in America known as SEAC (Standards Eastern Automatic Computer). This room-sized computer built in 1950 was developed as an interim solution for the Census Bureau to do research (PDF).

Standards Eastern Automatic Computer (SEAC) was the first programmable computer in the United States. Credit: NIST via Wikimedia

Like the other computers of its time, SEAC spoke the language of punch cards, mercury memory, and wire storage. Russell Kirsch and his team were tasked with finding a way to feed pictorial data into the machine without any prior processing. Since the computer was supposed to be temporary, its use wasn’t as tightly controlled as other computers. Although it ran 24/7 and got plenty of use, SEAC was more accessible than other computers, which allowed time for bleeding edge experimentation. NIST ended up keeping SEAC around for the next thirteen years, until 1963.

The Original Pixel Pusher

This photo of Russell’s son Walden is the first digitized image. Public Domain via Wikimedia

The term ‘pixel’ is a shortened portmanteau of picture element. Technically speaking, pixels are the unit of length for digital imaging. Pixels are building blocks for anything that can be displayed on a computer screen, so they’re kind of the first addressable blinkenlights.

In 1957, Russell brought in a picture of his son Walden, which would become the first digital image (PDF). He mounted the photo on a rotating drum scanner that had a motor on one end and a strobing disk on the other. The drum was coupled to a photo-multiplier vacuum tube that spun around on a lead screw. Photo-multipliers are used to detect very low levels of light.

As the drum slowly rotated, a photo-multiplier moved back and forth, scanning the image through a square viewing hole in the wall of a box. The tube digitized the picture by transmitting ones and zeros to SEAC that described what it saw through the square viewing hole — 1 for white, and 0 for black. The digital image of Walden is 76 x 76 pixels, which was the maximum allowed by SEAC.

Variable-Shaped Pixels

If Russell Kirsch had any regrets, it is that he designed pixels to be square. Ten years ago at the age of 81, he started working on a variable-shaped pixels with the hope of improving the future of digital imaging. He wrote a LISP program to explore the idea, and simulated triangular and rectangular pixels using a 6×6 array of square pixels for each.

Alternative pixel geometries. Image via Cloudseed Films

In in the video below, Russell discusses the idea and proves that variable pixels make a better image with more information than square pixels do, and with significantly fewer pixels overall. It takes some finagling, as pixel pairs of triangles and rectangles must be carefully chosen, rotated, and mixed together to best represent the image, but the image quality is definitely worth the effort. Following that is a video of Russell discussing SEAC’s hardware.

Russell retired from NIST in 2001 and moved to Portland, Oregon. As of 2012, he could be found in the occasional coffeehouse, discussing technology with anyone he could engage. Unfortunately, Russell developed Alzheimer’s and died from complications on August 11, 2020. He was 91 years old.

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Scanning Analog Film For The Last Time

June 19, 2020 by Lewin Day 44 Comments

Film cameras are capable of great resolution, and for a long time were superior in this regard to their digital successors. However, it’s now possible to store digital copies of analog images in superior detail, so [Jan] built a rig to scan their photos for the last time.

The general idea is to take a high enough resolution scan of film negatives or slides, such that there is no need to rescan the images when technology moves forward. To achieve this, [Jan] decided to employ a DSLR to photograph the materials in question. To do this quickly and accurately, with minimal fuss, special lens hoods were 3D printed to hold slides in perfect register in front of the lens. With a flash to provide even light, the results are excellent. Film negatives proved harder, requiring a carefully designed transport mechanism to avoid damaging the fragile materials. With some perseverance, the final tool worked well.

It’s a tidy way of digitally archiving analog photos, and with the resolution of modern cameras, one needn’t worry about lost resolution. We’ve seen mechanised builds for handling other formats too, such as this 8mm scanner. Video after the break.

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Divvy Out The Crypto With This Physical Bitcoin Faucet

March 9, 2020 by Tom Nardi 3 Comments

For those unfamiliar with the term, a “Bitcoin Faucet” is usually used as an incentive in software that wants your attention. Complete a captcha or look at and advertisement and you get one millionth of a BTC, that sort of thing. You’re never going to get rich off of one of them, but most people aren’t going to turn down free money either. The latest project from [TJ Bruno] follows that same concept and brings it into the physical world. But you still aren’t going to get rich off of it.

The hardware used for this corporeal Bitcoin Faucet is pretty simple. All you need is a Raspberry Pi, a camera module, and a 2.8″ touch LCD. Naturally you could use a larger screen if you wanted, but then it wouldn’t fit inside of the very slick 3D printed stand that [TJ] developed. We might consider upgrading to a slightly speedier Pi though, in the demonstration video it looks like the Zero is struggling pretty hard to handle the GUI.

Using the Faucet is straightforward enough. You tap the screen and place a QR code representing your Bitcoin wallet on the device’s tray, where it’s scanned by the camera. In a few seconds the Faucet shows a QR code on its own screen that will point your phone’s browser to the transaction details so you can verify your digital coinage is on the way.

You might be wondering why you’d want to have a device that sits there waiting to pay out fractions of a BTC to anyone who’s willing to flash their wallet at it. We’re not entirely sure, though it might make for an interesting way to raise awareness about cryptocurrency. In this particular case though, [TJ] says he was just looking for a project that would give him an excuse to hone his Python skills. Nothing wrong with that around these parts.

Watching the growth of cryptocurrency from our unique vantage point, we can see how the hacker’s interest in Bitcoin as changed over the years. Where we once saw people excited about building custom mining rigs, we now see counters that tick down as the last coins are put into circulation. Looking at projects like this, it seems hackers are happy enough to just give the things away in an interesting way.

3D Print Your 3D Scanner

February 19, 2020 by Al Williams 15 Comments

[QLRO] wanted a 3D scanner, but didn’t like any of the existing designs. Some were too complex. Some were simple but required you to do things by hand. That led to him designing his own that he calls AAScan. You can see the thing operating in the video below.

In general, you can move the camera around the object or you can move the object around while the camera stays fixed. This design chooses the latter. You’ll need a stepper motor with a driver board and an Arduino to make the turntable rotate. You also need a computer running Python and Meshroom. The phone also has to run Python and [QLRO] used QPython on an Android device.

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