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Comment Lightfields capture 4D to observe 3D (Score 2) 46

The trick lies in the fact that the picture is a projection, not the scene. There do exist 3D displays, which are volumetric, but a lightfield display doesn't replicate the objects, only the light passing through the screen. This is just like a hologram (although digital lightfield processing is far from the fidelity of chemical holography). The more commonly advertised "3D" screens approximate the effect for two points that represent your eyes, which breaks down in several ways: The points may be misplaced, such as looking at the screen from anywhere but dead center at the right distance and with the estimated interpupilary distance (yeah, that's not happening, particularly with multiple viewers); this is common for TVs and such. For HMDs and VR, a growing issue is that the points are not points at all; your pupils have a shape, and dynamic optics used to focus (accomodate). That's what these displays are designed to address. A related issue in turn is that cinematographers are used to using blurring effects to suggest focus, which will conflict if you're not looking exactly where you were expected to.

Light field imaging really does operate in 4D; two dimensions of position and two dimensions of angle. Normal stereoscopic imagery means using two cameras, each of which takes 2D angular images (e.g. the pixels represent a direction from the camera), and having them placed separately; this gives you a single step of third dimension, which is intended to exactly match the offset between your eyes. It's only an estimation as eyes have more axis of adjustability, including vergence and accomodation, and the direction of your eyes does affect your interpupilary distance for the same reason a panoramic camera setup needs a depth offsetting gimbal; the front end optics are in front of the rotation axis. Common stereoscopic displays like TVs and cinema have this as one of the less inaccurate tradeoffs, however, as the mere fact they don't know where you are (and there are frequently multiple watchers) means they can't show your perspective (if they did, you would see a wider field if you sat closer). A lightfield camera like a Lytro uses a lens array to distinguish such places on the lens itself. From that data you could focus to render 2D images, but a true lightfield display (like this one from Standford, the microlens projection system from MIT, or the very similar HMD shown by Nvidia) leaves that task to your eye's normal accomodation. Some lightfield systems simply use multiple cameras in an array; a few are designed for 3D and thus only have a linear array. Due to the unsolved problem of video transfer of true 4D lightfields, this is the category most 3D panoramic content falls in, which restricts the user to panning only (no yaw, little tilt, no translation) to avoid serious distortion.

If you look at a stereoscopic image, and move your head a little, you see the scene shearing to make objects further away move the same direction; this effect is because the images shown to your eyes were made for a different perspective. An eye tracking stereoscopic display could avoid this (sadly, the New 3DS does not), and a true light field display would not need to; it already displays different perspectives in different directions. In principle you'd require a capture array the size of your screen, but display prototypes avoid that simply by using CG, and it's also less of a problem for VR than cinema. A common application has been lenticular 3D pictures, which frequently have 5 or more perspectives.

Comment Re: Yep, they were... (Score 1) 369

Even the DMCA has exceptions regarding interoperability, which this falls under, and using a third party peripheral is not a copying act. If you want to stretch it, this is more akin to buying an off-brand gameboy cartridge; but even there copyright wasn't enough for the draconian desires of the maker, which is why every cartridge is forced to display the brand logo on startup. This was because trademark law was more enforceable, but that abuse is invalid in many regions due to the aforementioned interoperability concerns. There are lots of things wrong with DMCA, but trying to equate third party accessories with copying is pretty nasty FUD, not truth.

In Keurig's position, the thing to do would be to remove the defect from newly built machines, publish a tag to be used on unbranded cups, and preferably also make that tag available as a free sticker at retailers for people who're already burnt by the defective machines.

Comment Re:Have they not heard (Score 3, Interesting) 358

They have heard of adblock. In fact, when I specifically requested to pay them so they could pay the content creators without showing me ads, they refused and even mentioned ad blocking. Note my motivation in that sentence; this is actually a feature requested by some of us. This announcement got my hopes up just a bit, but it remains to be seen if it's like the offline watching, which was riddled with strange restrictions, never worked properly, and was quietly removed. I see they're still talking about that in the future tense.

Comment Re:Not much said (Score 1) 137

Thanks for the quote.. it's interesting to note that he's implying that others won't cooperate with them on regulating the 'net. The truth on that claim would be somewhere between them making unreasonable (whether impractical or unpalatable - we've seen what sort of regulation they do on their own) demands, this statement being false, or the "China hopes to" weasel language being key - allowing that they never tried. Not much said indeed.

Comment Re:Write-only code. (Score 1) 757

Neither. The first calls compute() only once per orn, and the second makes the list population clearer (and less error prone). So go for

borbs = [b for b in map(compute, orns) if b > 12]

The map can be replaced with another comprehension or generator expression, but at that point I'd place the filter condition on a separate line to call attention to it. This particular combination is a weakness in the comprehension syntax because the output expression can't be named for use in a condition, so we must nest. Breaking it up in two stages may also be viable.

Comment Re:Assignement in Python (Score 1) 729

No, these are not different operations; you just altered references in different places (first in your locals, second in a list that you held two references to). I see people getting similarly confused about vector or elementwise operations in Matlab, frequently resorting to blindly slapping on a period.

Comment Re:Powershell (Score 3, Informative) 729

- sizeof(string) (I may have got the name of the function wrong) returns the length of a single byte rather than the length of the entire string.

A number of things misleading here, which do stem from C's archaic background: Firstly, sizeof is not a function (those parenthesis are not needed and only make it confusingly resemble a function call), it is a rather special operator both in that it looks like a name and operates on types instead of values. There is no string type at all. There are two types frequently used as strings, char arrays and char pointers; only in the case of the array would sizeof return the storage size (which is larger than the string length, unless you've already encountered a buffer overflow). Otherwise you get the size of a pointer, notably also since arrays cannot be passed around but get translated into pointers. In neither case do you get the size of a character.

Of course, the more you explain about C the less sensible it appears. ;)

Comment Re:People say they want them, but no one buys them (Score 1) 544

I imagine part of that is from targeting them as some sort of budget phones. I tried the Blackberry Q10 because it was the only decent (i.e. not an obvious downgrade) keyboard phone even made in recent years, only to find they cut corners, particularly for the keyboard (it has markings they never implemented in software, and mechanical issues, and the bright idea to not allow answering a call with a button - the capacitive screen is unreliable when a raindrop comes near). My previous phone was an HTC Desire Z, which was decent besides a subpar screen, but is now severely outdated with no successor. I really wanted to get a Nokia N950, but Nokia decided they didn't want to sell it, and then I wanted a Jolla, but they decided both on a subpar screen and to not make the keyboard accessory (75 of them were made, so it's hardly because none was designed). I'm a little tired of meeting "there's no demand" when I am asking for things. It's a bit like the old Unix error message "go away, you don't exist", only more oblivious to the irony.

Comment As a Q10 owner... (Score 1) 139

The square screen layout is not news (but it is problematic, with several websites breaking themselves out of spite or incompetence). The larger size got us a keyboard that looks simply too wide, not adding any of the keys we were missing; you could get used to that, but it has nothing to do with the primary problems. Blackberry used to sell on corporate support, working keyboards, and an integrated pointing device. As of the BB10 versions, it feels rather half-developed - that vaunted keyboard has markings that are not supported by the software, the pointing device is missing (the touchscreen basically mocks us by adding another layer with the popup ring), and the build quality is not the best (I have keys losing their clickyness, and I had to return one phone because the same issue made keys unusable). How on earth they decided on a keyboard device to make it impossible to answer a call with a button - and on top of that, make the end call function *move* on the screen - I'll never understand. It's quite possible this new model improves on things with the touch detection in the keyboard, but as it is I'd rather switch to Nokia E72 than take another chance with BB. While chasing fashion all manufacturers, even Jolla, seem to have agreed to not produce another practical PDA.

Comment Re:No Way! (Score 1) 261

I have a simple explanation for a large chunk of its popularity - cinemas take a higher price for them, and therefore only show top tier movies in 2D if forced to. I went to the cinema yesterday to see Maleficent, and had to select 3D; there was no alternative. There was a choice in what 3D glasses to get; expensive single-use ones, ridiculously expensive ones that don't fit over glasses (still cheapo plastic film ones, mind you), or suffer the consequences of double picture at double brightness. The film itself made aggressive use of stereoscopic depth coupled with depth of field blur, which is a sensory conflict that continuously bugs me, and included misrendered video where the two pictures did not match, which bugs everyone. This is why 3D gets so many complaints; it's generally badly done and forced on people (try Hugo for a better film, including better stereoscopy). Meanwhile people who like the effect, which I do, aren't getting choices either; get a Fujifilm W3 (2010), because there's nothing else. Want more than 640x720 at 24fps? Tough - oh, and note that they sacrifice horisontal resolution for horisontal parallax, reducing the benefit as well as the quality, even worse if viewed on an interlaced panel like the LG polarized TVs which cut vertical resolution in half. Curved TV screens on the other hand really is a gimmick.

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Never buy what you do not want because it is cheap; it will be dear to you. -- Thomas Jefferson