Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?

+ - YouTube Live Streams Now Support HTML5 Playback And 60fps Video

Submitted by Anonymous Coward
An anonymous reader writes: YouTube today announced it is enabling HTML5 playback for live streams. At the same time, live streams can now be viewed at 60 frames per second (fps). A few puzzle pieces had to come together to make this possible. On October 29, YouTube quietly turned on 60fps support for videos uploaded on that date and later. While clips uploaded before that date remain at 30fps, new videos shot at 60fps suddenly started playing back at their proper framerate.

Comment: Re:Not Holograms (Score 1) 99

by Arkh89 (#49588623) Attached to: Microsoft Announces Windows Holographic Platform

I can construct a 2D image that has proper DOF cues.

Yes, you can construct it but it your eye is still focusing on a plane and the depth cues you are feeding it (them) do not match this. If you "force" your vision on something blurry, the device better has some way to find out this and tell it to the rendering engine. Retinal tracking allows the rendering engine to know what part of the scene is observed (in the center of the FoV) which helps for finding the actual depth and focusing parameters.

Yet, whatever tricks you use, the crystalline lens will always come back at the same position to have the in-focus image while you will perceive a change in DoF. This is another mismatch some people will perceive and there is no way to correct for it in stereo-vision. LFD might be slightly better at this but holography is the ultimate solution here.

I don't think that a stereo-based device you can use, with discomfort, for may be one hour and before getting really nauseous will have a good commercialization potential.

Comment: Re:Not Holograms (Score 1) 99

by Arkh89 (#49587811) Attached to: Microsoft Announces Windows Holographic Platform

Each retina collects photons on a surface and with a single eye you get a 2D image*. Your brain combines the images from your eyes in very complex ways to create a 3D internal model, but as far as what needs to get shined into your eyes, it's just the 2D image constructed on your retina that matters.

That is incorrect. There are numerous 3D depth perception cues, among which are stereo-vision, depth of field (things far from what you are looking at appear blurry) and prior knowledge of the objects size (knowing the average size of a car, you know that if you see it "small", then it must be far away). With only one eye, the last two are perfectly valid. The very last one is very simple to reproduce but the depth of field is far from being trivial to implement. For VR head set such as the Oculus, you would need retinal tracking, map to the corresponding depth of the observed object and adapt the rendering of the whole scene to this depth of field (with of course, very small latency), see http://3dvis.optics.arizona.edu/research/research.html. Having different cues in a system can cause serious discomfort to a large portion of the population.

Comment: Re:Not Holograms (Score 1) 99

by Arkh89 (#49586781) Attached to: Microsoft Announces Windows Holographic Platform

but the chances are it's not actually holographic.

You can be certain about it. There is no real-time holographic display as of today. For LFDs (Light Field Display), NVidia had a prototype a few years back and it is reasonable to think that Magic Leap is pursuing something similar. Yet, I don't think the technology is mature enough to be able to generate dense light fields needed for high quality scene rendering.

Comment: Re:Quick note (Score 4, Informative) 37

by Arkh89 (#49540751) Attached to: Virtual Telescope Readied To Image Black Hole's 'Ring of Fire'

Nope, you need the reference phase to still be coherent with the observed object (temporal and spatial), so the interference is only possible between two parts of the same wave (of light), different in space (think two pinholes in a plane through which you collect the light) and/or in time (think delay line, let one part of the line you collected run a longer distance). The first is the famous Young's double slit experiment, the second is the Michelson interferometer.

Also, for reference : frequency of the visible EM fields is in the order of 300THz (300,000GHz).

Comment: Quick note (Score 5, Informative) 37

by Arkh89 (#49539791) Attached to: Virtual Telescope Readied To Image Black Hole's 'Ring of Fire'

This telescope operate in the radio bands (sub-millimeter) and not in the visible. That's why it is easy to make interferometry over very long base line. In the visible domain this is very tricky to realize over a couple of 100m (such as with the VLTI).

You can think of it as completing piece by piece the Fourier transform of the image you want to observe. Every pair of telescope gives you a measurement in the so-called UV plane (spatial frequencies). The furthest the observations point are (the telescopes) the smaller details you can get. Except this is only valid if you can measure the amplitude and phase of the electromagnetic radiation (or find a way to reconstruct it in some way). This is easy in the radio bands. But this oscillation is just too fast with visible wavelength and thus, we can not record and adjust offline, we have to interfere the waves right away...

+ - iOS WiFi Bug Allows Remote Reboot Of All Devices In Area 2

Submitted by BronsCon
BronsCon writes: A recently disclosed flaw in iOS 8 dubbed "No iOS Zone" allows an attacker to create a WiFi hot spot that will cause iOS devices to become unstable, crash, and reboot, even when in offline mode. Adi Sharabani and Yair Amit of Skycure are working with Apple for a fix; but, for now, the only workaround is to simply not be in range of such a malicious network.

+ - Drone Killed Hostages From U.S. and Italy 1

Submitted by HughPickens.com
HughPickens.com writes: The NYT reports that President Obama has offered an emotional apology for the accidental killing of two hostages held by Al Qaeda, one of them American, in a United States government counterterrorism operation in January, saying he takes “full responsibility” for their deaths. “As president and as commander in chief, I take full responsibility for all our counterterrorism operations,” including the one that inadvertently took the lives of the two captives, a grim-faced Obama said in a statement to reporters in the White House briefing room. The White House earlier released an extraordinary statement revealing that intelligence officials had confirmed that Warren Weinstein, an American held by Al Qaeda since 2011, and Giovanni Lo Porto, an Italian held since 2012, died during the operation. Gunmen abducted Warren Weinstein in 2011 from his home in Lahore, Pakistan. They posed as neighbors, offered food and then pistol-whipped the American aid worker and tied up his guards, according to his daughter Alisa Weinstein.

The White House did not explain why it has taken three months to disclose the episode. Obama said that the operation was conducted after hundreds of hours of surveillance had convinced American officials that they were targeting an Al Qaeda compound where no civilians were present, and that “capturing these terrorists was not possible.” The White House said the operation that killed the two hostages “was lawful and conducted consistent with our counterterrorism policies” but nonetheless the government is conducting a “thorough independent review” to determine what happened and how such casualties could be avoided in the future.

Comment: News for nerds? (Score 5, Informative) 28

by Arkh89 (#49525793) Attached to: How False Color Astronomy Works

They are more art than science, providing an illusion of reality.

Nope, they are coded with the relation color = abundance of atomic component. Colors are a stimulus, they do not exist outside of all of our brains. What is real is the wavelength, and that, for instance, the transition of an electron from the 3rd to 2nd layer of the structure of the Hydrogen atom will emit a photon at 656nm, which we call red.

One disadvantage of the FITS format is that raw images typically need to be manipulated to show anything.

Nothing to do with the FITS format. That's the same type of information all RAW formats have : unprocessed data, as close as possible to the signal coming from the sensor after quantization, with ideally no processing, offset or other adjustments performed.

It made for great imagery, but wasn’t a true representation of how Jupiter looks.

Our vision is also subjective, it permanently adapt to lightning and ambient color conditions. There is no such thing as a true image representation. Especially in the mentioned case (a magazine), where it is desirable to have an image which pops the eye rather than a blob of washed out colors.

So what's the news here?

+ - LAUSD OKs Girls-Only STEM School, Plans Boys-Only English Language Arts School

Submitted by theodp
theodp writes: Citing statistics that showed a whopping 46 more boys than girls passed the AP Computer Science Exam in 2011-12, the 640,000+ student Los Angeles Unified School District (LAUSD) on Tuesday approved a waiver to enable the District to operate a single-gender, all-girls STEM School called the Girls Academic Leadership Academy (GALA). Students in GALA will follow a six year sequence of computer courses starting in middle school that will culminate in AP Computer Science Principles. "Fewer females take AP courses in math, science, or computer science, and they are not as successful as males in receiving passing scores of 3, 4 or 5," argued the General Waiver Request (PDF, 700+ pages). "An all girls environment is reasonably necessary for the school to improve the self-confidence of girls in their academic abilities, especially in STEM areas where an achievement gap currently exists. GALA's admissions shall also comply with AB 1266 to ensure male students who identify as female are admitted to the school." The school's CS-related Partners include the UCLA Exploring Computer Science Program, as well as Google-bankrolled Girls Who Code, Black Girls Code, and NCWIT. One of the reasons the all-girls STEM school reportedly got the green light is that its backers satisfied federal regulations requiring a "substantially equal school" for excluded male students by submitting a plan for a companion all-boys school that would emphasize English Language Arts, where they often fall short of girls' test scores, rather than GALA's focus on STEM. One suspects the no-fan-of-gender-restricted-public-schools ACLU may call BS on this maneuver.