Calculating three-dimensional position from two-dimensional projections are literal textbook examples in geometry, but those examples are the “assume a spherical cow” type of simplifications. Applicable only in an ideal world where the projections are made with mathematically perfect cameras at precisely known locations with infinite resolution. Making things work in the real world is a lot harder. But not only have [Jingtong Li, Jesse Murray et al.] worked through the math of tracking a drone’s 3D flight from 2D video, they’ve released their MultiViewUnsynch software on GitHub so we can all play with it.
Instead of laboratory grade optical instruments, the cameras used in these experiments are available at our local consumer electronics store. A table in their paper Reconstruction of 3D Flight Trajectories from Ad-Hoc Camera Networks (arXiv:2003.04784) listed several Huawei cell phone cameras, a few Sony digital cameras, and a GoPro 3. Video cameras don’t need to be placed in any particular arrangement, because positions are calculated from their video footage. Correlating overlapping footage from dissimilar cameras is a challenge all in itself, since these cameras record at varying framerates ranging from 25 to 59.94 frames per second. Furthermore, these cameras all have rolling shutters, which adds an extra variable as scanlines in a frame are taken at slightly different times. This is not an easy problem.
There is a lot of interest in tracking drone flights, especially those flying where they are not welcome. And not everyone have the budget for high-end equipment or the permission to emit electromagnetic signals. MultiViewUnsynch is not quite there yet, as it tracks a single target and video files were processed afterwards. The eventual goal is to evolve this capability to track multiple targets on live video, and hopefully help reduce frustrating public embarrassments.
In the matter of technological advancement, we are as a species, mostly insatiable. The latest toy, the fastest silicon, the largest storage, the list goes on. Take digital cameras as an example, what was your first one? Mine was a Casio QV200 in about 1997, I still have it somewhere though I can’t immediately lay my hands on it, and it could hold a what was for its time a whopping 64 VGA-resolution pictures in its 4Mb of onboard memory.
It’s a shock to realise that nearly a quarter century has passed since then, and its fixed-focus 640×480 camera module with a UV-sensitive CMOS sensor that gave everything a slight blue tint would not even grace the cheapest of feature phones in 2020. Every aspect of a digital camera has improved beyond measure since the first models in the 1980s and early 1990s that started to resemble what we’d know today as a standalone digital camera, they have near-limitless storage, excellent lenses, huge and faithfully-reproducing sensors, and broadcast-quality video capability.
But how playful have camera manufacturers been with the form factor? We see reporters in sci-fi movies toting cameras that look nothing like their film-based ancestors. What do our real-life digital cameras have on offer as far as creative body design goes?
Randomly buying some hackable gadgets just because they are cheap and seem potentially interesting for future projects is something that most of us can relate to. It also happened to [fruchti] when he bought five thermal printer modules without any specific purpose for them in mind. It was not until several years later that he put them to good use for his inverse thermal camera project.
The name perfectly summarizes the device’s function which is to convert images to heat instead of the other way around. To put it in a less cryptic manner, [fruchti] built a selfie camera that instantly prints out pictures on thermochromic paper. The project would have been easy to implement on a Raspberry Pi but instead, he chose a more minimalist approach by using an STM32 microcontroller. This involved some challenges because the MCU didn’t have enough RAM to store an entire frame and the camera module came without a FIFO buffer. To capture and store the image data [fruchti] applied a line-by-line dithering algorithm which is described in detail in his accompanying blog post while the corresponding code is available on GitHub. Even though the case was improvised from scrap PCB materials the finished device still looks great. In particular, the fuse holders that are being used to hold the paper roll make it almost steampunk.
The quality of a photograph is a subjective measure depending upon a multitude of factors of which the calibre of the camera is only one. Yet a high quality camera remains an object of desire for many photographers as it says something about you and not just about the photos you take. [Neutral Gray] didn’t have a Leica handheld camera, but did have a Sony. What’s a hacker to do, save up to buy the more expensive brand? Instead he chose to remodel the Sony into a very passable imitation.
This is a Chinese language page but well worth reading. We can’t get a Google Translate link to work, but in Chrome browser, right clicking and selecting “translate” works. If you have a workaround for mobile and other browsers please leave a comment below.
The Sony A7R is hardly a cheap camera in the first place, well into the four-figure range, so it’s a brave person who embarks on its conversion to match the Leica’s flat-top aesthetic. The Sony was first completely dismantled and it was found that the electronic viewfinder could be removed without compromising the camera. In a bold move, its alloy housing was ground away, and replaced with a polished plate bearing a fake Leica branding.
Extensive remodelling of the hand grip with a custom carbon fibre part followed, with significantly intricate work to achieve an exceptionally high quality result. Careful choice of paint finish results in a camera that a non-expert would have difficulty knowing was anything but a genuine Leica, given that it is fitted with a retro-styled lens system.
We’re not so sure we’d like to brace Leica’s lawyers on this side of the world, but we can’t help admiring this camera. If you’re after a digital Leica though, you can of course have a go at the real thing.
The photographic hire company Lensrentals had a $2k Sony FE 135mm f1.8 GM camera lens returned with a problem: it was having issues focusing. So, they decided to do the obvious thing and take it apart. It’s a fascinating insight into some of the engineering that goes into a high-end camera lens.
That is perhaps a rather scary thing to do, because this is a very new lens that doesn’t even have a service manual yet. That’s akin to rechipping a Ferrari when you’ve never even opened the hood before.
One of the interesting things inside is the presence of a number of shims that adjust the placement between the groups of lens elements. It seems that however good their manufacturing tolerances are, sometimes you just have to put a shim or two in there to align things.
Technology vanishes. It either succeeds and becomes ubiquitous or fails. For example, there was a time when networking and multimedia were computer buzzwords. Now they are just how computers work. On the other hand, when was the last time you thought about using a CueCat barcode reader to scan an advertisement? Then there are the things that have their time and vanish, like pagers. It is hard to decide which category digital cameras fall into. They are being absorbed into our phones and disappearing as a separate category for most consumers. But have you ever wondered about the first digital camera? The story isn’t what you would probably guess.
The first digital camera I ever had was a Sony that took a floppy disk. Surely that was the first, right? Turns out, no. There were some very early attempts that didn’t really have the technology to make them work. The Jet Propulsion Laboratory was using analog electronic imaging as early as 1961 (they had been developing film on the moon but certainly need a better way). A TI engineer even patented the basic outline of an electronic camera in 1972, but it wasn’t strictly digital. None of these bore any practical fruit, especially relative to digital technology. It would take Eastman Kodak to create a portable digital camera, even though they were not the first to commercialize the technology.
Large format photography gives a special quality to the images it produces, due to the differences in depth of field and resolution between it and its more modern handheld equivalents. Projecting an image the size of a dinner plate rather than a postage stamp has a few drawbacks though when it comes to digital photography, sensor manufacturersdo not manufacture consumer products at that size.
[Zev Hoover] has created a large format digital camera, and is using it not only for still images but for video. And it’s an interesting device, for the way he’s translated a huge large-format image into a relatively small sensor in a modern SLR. He’s projecting the image from the large-format lens and bellows onto a screen made from an artist’s palette, a conveniently available piece of bright white plastic, and capturing that image with his SLR mounted beneath the large-format lens assembly. This would normally cause a perspective distortion, but to correct that he’s mounted his SLR lens at an offset.
He does point out that since less light reaches the camera there is also a change in the ISO setting on the camera, but once that has been taken into account it performs satisfactorily. The result is a camera that allows something rather unusual, for Victorian-style large-format images to come to life as video. He demonstrates it in the video below, complete with friends in suitably old-fashioned looking steampunk attire.