Recording HDR Video With A Raspberry Pi

The Raspberry Pi line of single-board computers can be hooked up with a wide range of compatible cameras. There are a number of first party options, but you don’t have to stick with those—there are other sensors out there with interesting capabilities, too. [Collimated Beard] has been exploring the use of the IMX585 camera sensor, exploiting its abilities to capture HDR content on the Raspberry Pi.

The IMX585 sensor from Sony is a neat part, capable of shooting at up to 3840 x 2160 resolution (4K) in high-dynamic range if so desired. Camera boards with this sensor that suit the Raspberry Pi aren’t that easy to find, but there are designs out there that you can look up if you really want one. There are also some tricks you’ll have to do to get this part working on the platform. As [Collimated Beard] explains, in the HDR modes, a lot of the standard white balance and image control algorithms don’t work, and image preview can be unusable at times due to the vagaries of the IMX585’s data format. You’ll also need to jump some hurdles with the Video4Linux2 tools to enable the full functionality of these modes.

Do all that, recompile the kernel with some tweaks and the right drivers, though, and you’ll finally be able to capture in 16-bit HDR modes. Oh, and don’t forget—you’ll need to find a way deal with the weird RAW video files this setup generates. It’s a lot of work, but that’s the price of entry to work with this sensor right now. If it helps convince you, the sample shots shared by [Collimated Beard] are pretty good.

If you’re looking to record some really juicy, colorful imagery with the Raspberry Pi, this is a difficult but viable way to go. We’ve seen some other hardcore Raspberry Pi camera hacks of late, too.

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Seeing The World Through Animal Eyes

If you think about it, you can’t be sure that what you see for the color red, for example, is what anyone else in the world actually sees. All you can be sure of is that we’ve all been trained to identify whatever we do see as red just like everyone else. Now, think about animal vision. Most people know that dogs don’t see as many colors as we do. On the other hand, the birds and the bees can see into ultraviolet. What would the world look like with extra colors? That’s the question researchers want to answer with this system for duplicating different animals’ views of the world.

Of course, this would be easy if you were thinking about dogs or cats. They can’t see the difference between red and green, making them effectively colorblind by human standards. Researchers are using modified commercial cameras and sophisticated video processing to produce images that sense blue, green, red, and UV light. Then they modify the image based on knowledge of different animal photoreceptors.

We were somewhat surprised that the system didn’t pick up IR. As we know snakes, for example, can sense IR. You’d think more sophisticated animals would have better color vision, but that seems to be untrue. The mantis shrimp, for example, has 12-16 types of photoreceptors. Even male and female humans have different vision systems that make them see colors differently.

Maybe you need a photospectrometer. You wonder if animals dream in color, too.

Experiment With The Pi Camera The Modular Way

The various Raspberry Pi camera modules have become the default digital camera hacker’s tool, and have appeared in a huge number of designs over the past decade. They’re versatile and affordable, and while the software can sometimes be a little slow, they’re also of decent enough quality for the investment. Making a Pi camera can be annoying though, because different screens, lenses, and modules have their own mounting requirements. [Jacob David C Cunningham] has a solution here, with a modular Raspberry Pi camera, as an experimentation platform for different screens and lenses.

It takes the form of a central unit that holds the Pi and its support components, and front and rear modules for the screens or displays. Examples are given using the HQ and non-HQ modules, as well as with round or rectangular displays.

When designing a camera for 3D printing it’s a very difficult task, to replicate or exceed the industrial design of commercial cameras. Few succeed, and we’d include ourselves among that number. But this one comes close; it looks like a camera we’d like to use. We like it.

The Tragic Demise Of The Technirama Prism-Based Anamorphic Lens

A commercial Delrama prism-based anamorphic lens for large cameras. (Source: Mathieu Stern, YouTube)
A commercial Delrama prism-based anamorphic lens for large cameras. (Source: Mathieu Stern, YouTube)

Although to the average person a camera lens is just that bit of glass you stick on the front of the camera to make stuff appear in focus, there’s a whole wide world out there of lens designs and modifications with enough variety to make your head spin. Some of these designs make a big impact, while others fade away again, sometimes at the whims of film makers and photographers. Prism-based anamorphic lenses are an oddity that recently [Mathieu Stern] got his hands on. (Video, embedded below.)

During the 1950s and 1960s there was a bit of a competition between anamorphic formats, which use special lenses that ‘squeeze’ a larger image so that widescreen movies could be recorded on standard 35 mm film. By using the same lens for recording and playback, the result was a mostly distortion-free image. Here the Technirama format by Technicolor who teamed up with Dutch company De Oude Delft (‘Old Delft’) to produce the prism-based Delrama lenses that fit on existing lenses for cameras and projectors.

The last gasp of the Delrama anamorphic lenses. (Credit: Mathieu Stern, YouTube)a
The last gasp of the Delrama anamorphic lenses. (Credit: Mathieu Stern, YouTube)a

Despite having a clearly superior, distortion-free image than the cylindrical lenses of the competition, Technirama got pushed out of the commercial market, leaving De Oude Delft to try and interest the consumer market for Delrama with 8 and 16 mm adapters. These latter are the ones that [Mathieu] got his hands on and tried out with a DSLR camera.

Troublesome with these Delrama adapters is that their silver mirrors tend to degrade over time, and they also turned out to be rather fragile, which are both things that made consumers sour on them. Another challenge was the fixed four meter focus that’s great when you’re using it with a projector, but terrible for up-close shots. All of these issues resulted in Delrama fading from the market by the 1970s until all that remains are these remnants of a format that once was used to film some of the biggest Hollywood movies.

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Instant Photography For The Maker

Instant photography is a miracle of the analog age, chemical photographs that develop in your hands moments after the shutter has been pressed. You can buy instant cameras and film from Fuji and the successor company to Polaroid, the originator of the technology, but they’re expensive. Fortunately [BoxArt] is here for those seeking a cheaper alternative, with an instant camera featuring a Raspberry Pi and a printer (Lithuanian language, Google Translate link).

It’s a fairly straightforward arrangement, with the Pi Zero and camera driving a receipt printer. There’s a nicely engineered 3D printed case, and the guts of a power bank to provide the volts for the thing. There are a set of status lights on top, and that’s it. Press the button, get a not-very-good grayscale image on curly paper.

You can of course buy off-the-shelf grayscale printing cameras from your favorite import site for much less than the cost of this camera, but we think this would probably take better pictures. Meanwhile if the original instant photography interests you, we’ve got you covered.

Pan-Tilt Head For Camera Motion Control

Historically, moving and pointing a camera while filming was the job of a highly-skilled individual. However, there are machines that can do that, enabling all kinds of fancy movement that is difficult or impossible for a human to recreate. A great example is this pan-tilt build from [immofoto3d.]

The build uses a hefty cradle to mount DSLR-size cameras or similar. It’s controlled in the tilt axis by a chunky NEMA 17 stepper motor hooked up to a belt drive for smooth, accurate movement. Similarly, another stepper motor handles the pan axis, with an option for upgrade if you have a heavier camera rig that needs more torque to spin easily. Named Gantry Bot, it’s an open-source design with source files available, so you can make any necessary tweaks on your own. You will have to bring your own control mechanism, though—telling the stepper motors what to do and how fast to do it is up to you.

It’s a heavy-duty build, this one, and you’ll really want a decent metal-capable CNC to get it done, along with a 3D printer for all the plastic pieces. With that said, we’ve featured some other similar builds that might be more accessible if you don’t have a hardcore machine shop in the basement. If you’ve got your own impressive motion rig in the works, be sure to notify the tipsline!

Random Number Generator Uses Camera Noise

Random numbers are very important to us in this computer age, being used for all sorts of security and cryptographic tasks. [Theory to Thing] recently built a device to generate random numbers using nothing more complicated than simple camera noise.

The heart of the build is an ESP32 microcontroller, which [Theory to Thing] first paired with a temperature sensor as a source of randomness. However, it was quickly obvious that a thermocouple in a cup of tea wasn’t going to produce nice, jittery, noisy data that would make for good random numbers. Then, inspiration struck, when looking at vision from a camera with the lens cap on. Particularly at higher temperatures, speckles of noise were visible in the blackness—thermal noise, which was just what the doctor ordered.

Thus, the ESP32 was hooked up to an OV3660 camera, which was then covered up with a piece of black electrical tape. By looking at the least significant bits of the pixels in the image, it was possible to pick up noise when the camera should have been reporting all black pixels. [Theory to Thing] then had the ESP32 collate the noisy data and report it via a web app that offers up randomly-generated answers to yes-or-no questions.

[Theory to Thing] offers up a basic statistical exploration of bias in the system, and shows how it can be mitigated to some degree, but we’d love a deeper dive into the maths to truly quantify how good this system is when it comes to randomness. We’ve featured deep dives on the topic before.

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