land-of-kain

(umi'n no kuni)

Notebook: Yoga 900 ISK

My computer circus now includes a 13" Yoga 900 ISK (not ISK2, those have RAID mode only, which requires a BIOS update before installing Linux). Keyboard includes programmer-friendly Pos1/End/PgUpDown keys, 3200x2000 touch screen requires 150% scaling and runs on Intel HD 520 GPU, USB Type C port (which includes DisplayPort) is 3.0 only, which means 5/10Gps and 10/100W power. The hinge is nice, and Ubuntu 16.04 Xenial runs well enough.

HTC Vive: Lighthouse Tracking

Road to VR points to a Oliver Kreylos analysis of the HTC Vive (VR headset), in particular its tracking: Two lasers at diagonal ends of the room emit vertical and horizontal laser lines at 60Hz, and photodiodes all around the VR headset use the known timing to calculate the head position and orientation at 120Hz. GizModo has an intro. Compared to Oculus Rift and Playstation VR which have light emitters on the headset and an optical tracker in front of the user, this system can "look" in all directions at once, improving accuracy.

960fps Phone Camera: Sony Xperia XZ

Petapixel reports on the Xperia XZ phone whose camera shoots 720p@960fps, using an about 6mm Sony Exmor RS sensor (a new variant of the IMX300) with stacked RAM. Includes phase auto focus and an f/2.0 aperture, as well as a 2x optical zoom (only the perpendicular 5x zoom by Oppo is better). See also: DSLR basics.

8K Video Camera: Red Helium

The RED Helium sensor inside the Epic S35 films 16-bit RAW with 8K at 30fps, which amounts to up to 275MB per second; so bring a big SSD. PetaPixel reports that the low-light sensitivity is as good as the Sony A7r II. Costs 30K as Epic, and 50K as the 75fps RED Weapon S35.

Aperture, Shutter, ISO: Camera Basics explained with Particles

PetaPixel reports on a Some Stuff Explained video tutorial about camera basics using nice particle animations: Increasing the amount of photons perceived by the camera either by opening the aperture, increasing the shutter time or increasing sensor sensitivity.

Interactive Music Theory

Music theory is usually not physics-based, for historic reasons. In contrast, the light note project shows how sound waves translate into harmonies and musical scales, yielding a beginner's scientific approach to making music.

Underwater Slow Motion Explosions

PetaPixel and Sploid report on slow-motion underwater explosions (video) recorded by the Slow-mo guys, using a Phantom V2511 (costs 150K EUR) at 28Kfps and at 120Kfps, respectively. The initial photon blast is followed by a gas bubble, which eventually collapses again, yielding a second photon blast.

SSH Keys Upgrade: Elliptic Curve

Every few years, it has to be done: Upgrade your SSH keys, this time to elliptic curve 25519 by DJB. Fortunately, you can add the new keys to .ssh and then successively reconfigure all servers while keeping the old keys in the meantime. Or, in short: ssh-keygen -o -a 100 -t ed25519.

Studio Lighting Breakdown: Bonsai Furniture

Karl Taylor scribbles on a professional foto (video) to break down how he designed the lighting of the shot, featuring a person and a sofa, and more importantly all the right shadows and soft/hard lighting at the right spots.

Text Analysis: 6 Shapes of Stories

Nerdcore and Discover report on semi-automated text analysis of western literature by Uni Vermont [USA], which reveals 6 basic story shapes: Linear (rags to riches and vice versa), one hump (man in a hole vs. Oedipus) and two humps (Cinderella vs. Icarus). They used mechanical turk on text snippets to rate emotional scores.

Blackbird: Motion Capture (MoCap) for Cars

Nerdcore and Core 77 report on the Blackbird electric car by the mill: Just a black body with markers and sensors, its form can be adjusted to resemble the target car, and traction, speed and other properties can be programmed. After filming, a digital chassis is then inserted in post-production.

Hacker's Guide to Aging

Hackaday writes about strategies to counter-act the effects of to getting old: Using a light with magnifier or a similar head band to see more clearly, a fume extractor and mobile arm rests to minimize hand tremors, writing down ever more stuff, and even eye surgery and meds where necessary.

Multi-spectral Camera with Single Lens

Photonics and Heise [de] link to a Fraunhofer IPMS (Institute for Photonic Microsystems) press release on a camera prototype with two image sensors on different spectral bands behind a single lens. While details are scarce, apparently a specialized mirror steers light rays from different bands towards either sensor.

Lightfield Video Camera: Lytro Cinema

After the lightfield photo camera Lytro Illum (80 Mrays) comes the Lytro Cinema video camera (755 Mrays at 300fps), as Engadget reports. This means refocusing and, more importantly, better depth information for 4K (~8 MP) over ~90 micro lenses. The effect: Refocus effects that are not possible in actual lens hardware, and better 3d data for visual artists to work CG with. Unlike the 1K EUR Illum, the Cinema will be in the 100K EUR price range.

The Blackest Black

Peta Pixel reports on the blackest black: Surrey Nanosystems have invented a material named VantaBlack consisting of vertically aligned carbon nanotubes that bounce photons inside them until they turn into thermal energy. At 0.035% reflectance, e.g. the dot of a standard red laser pointer just vanishes. For comparison, very dark black coating arrives at around 1% reflectance.

Cinematic Lighting Examples

On Peta Pixel, Doug Jackson recounts examples of him getting still frames from cinematic movies, and analyzing them in terms of how the lighting was produced and which effect was intended. The primary tools are stage lighting equipment and various types of reflectors. Portrait lighting is covered by Felix Barjou.