Smidlee said:
daroamer said:
Smidlee said:
bobbert said:
Smidlee said:
bobbert said:
Smidlee said:
Well for one thing , kinect doesn't see things in 3-D no more than another other web cam. The claim Kinect "sees" in 3D is a little misleading as most people think 3D as like how they see. Kinect cam sees a completely flat image. There are ways to try tracking something 3d on a flat image . For example Move uses the size of the ball on the image to determine where the move controller is in Z-axis. The more pixels the ball image uses the closer the ball is relative to the camera. Kinect tracking the Z axis how the strength of IR light bouncing off an object.
I can think of two major disadvantages of Kinect tracking you sitting vs standing up.
1) You are closer to surrounding objects including what you can sitting on. (standing puts distance between you and other objects) While our brain can do this with ease even with one eye close yet it's a lot tougher for and computer to do this.
2) Your images itself takes up less pixels on the camera which means Kinect is recieving less information.
So while Kinect may work sitting down I doubt it will be able to track as well as standing up. This is good reason Microsoft wanted developers to develop games at least at launch standing up.
|
really? so any camera can see 3D as well as kinect's RGB camera near-IR emitter & IR sensor? Both cameras are working at all times. You might want to actually look at the kinect compenent list before acting like you know how that Z-axis tracking works. Your hypotheses might be more believable
|
I watch the video of how Kinect works and they make it clear this is how it works. The problem with using RGB camera when it comes to depth is most homes has multiply light sources makes is extremely difficult to track Z axis. Our brain can do this with ease with just one eye even though you don't see true 3D with one eye. The brain uses lines, lighting, shapes, etc. Even super computers have trouble take two images and make a true 3D image with any kind of speed like our brain does.
Kinect software is the tough part as it takes all those pixels and guesses the position of the player's body.
|
You obviously have no idea what you're talking about. All of the videos are very generic descriptions, and I have seen some that are so WAAAAAAAY off of what is happening that it's funny.
First, we have the primesensor-like unit:

And unless you know how to do fourier transforms, I can't even begin to describe to you how it works for detecting 3D. Also, more details about the chip:

Notice the optional RGB, that is because it is using a standard RGB camera like a standard webcam. Instead of just using depth, MS is using the RGB camera to get depth and color, taking advantage of that optional output. From what I read, there is discrepancy on whether they use IR light or light that is considered not IR, but outside the visible spectrum of 99.999% of humans.
Now, does that seem like your normal webcam? Well wait, there's more. There's a camera that detects IR, with a filter blocks out visible light (probably including the near-IR light emitted from the primesense setup). This is to determine whether the object in front of you is human or not, where different body parts are, etc.
Also, random lights in different parts of the room are not going to effect detection. The way you described it made me laugh so hard. The bright lighting has more to do with the noise of the detector. I'm sure it's a very high SNR detector, and that's why it's a low megapixel rating. There's a reason why you can get a point-and-shoot camera with a 16MP rating, yet it is difficult to find a professional camera with more than a 10MP rating. As the light detected by the detector goes up, the blips of noise become large hunks of noise. The problem with your lamp idea is that the lens will focus all of that light to a small portion of the detector and have a little effect on the noise of the rest of the image. It's when you flood the entire room with light that you will have an issue.
Thanks for taking the time to read this and clarifying your BS. Now please stop talking out of your ass. Also don't tell someone that they're wrong when you obviously have no freaking clue yourself.
|
They have stated that Kinect works in the dark and low light thus it does not track you with the RGB cam. (Your brain can easily see depth with just one eye so it is possible to detect depth with RGB range.) It's just more simple if you track with only one color ... thus IR light. Notice the RGB cam is right beside the IR cam; as close as possible so the images are same. RGB cam is to put your image (other images) on screen while IR cam does the tracking.
This still doesn't show Kinect sees 3D no more that a RGB cam. Thus it misleading to claim Kinect sees 3D as there is difference between detecting depth (one eye) which Move and TrackIR does with a different method and seeing 3D (two eyes).
|
This is simply wrong.
It's not tracking "colour" at all. It's tracking DEPTH. It's working more like sonar, the Kinect IR transmitter is bathing the room with IR light, that light is bouncing back to the depth sensor. The closer something is to the camera, the brigher it appears. Look at the IR image again, as stuff moves away from the camera it gets darker. It's clearly evident that the brightest thing in the image is the pillow or whatever on the bottom right and the darkest thing is the far wall.
If you were to light the scene with a bright light on the wall behind the people, an RGB camera would see them as darker than the background and according to you it would think the wall was closer than they are. The IR camera would still see the scene with the correct depth as it's not seeing visible light at all, it's ignoring all those wavelengths.
The ability to read the depth of the scene is what allows it generate a 3D map of the scene.
|
IR is a color just not one your eyes sees which is the point of uses IR over normal light. There are animals that can see IR though. IR works the same way as red. I have seen a video a few months ago where I could see a table in the distance showed up as bright as the players in front of Kinect. They said the software is programed to ignore the table since it looking for players figures which again points out why standing up is ideal. IR light also bouncing off objects differently (I have IR reflectors) including people. They had trouble tracking dark skin people at first because the fact IR bounces off darker skin different.
|
No, IR is light, but it's is not colour. Colour is classified as the visual (to us) part of the spectrum. Animals that "see" in IR are seeing heat.
Your response does not refute any of what I said. You can clearly see the depth of the scene above is not related in any way to the RGB image, as you claim. Close objects are light, far objects are dark.
You said it's possible to detect depth with an RGB camera and that it's really no different than what IR is doing. This is incorrect or at the least extremely misleading. For any kind of real world application trying to read depth for an entire scene with an RGB camera would be completely useless, especially in this case, so the point is completely moot. Move is doing something similar to this but it requires fully lit coloured balls for accurate tracking and it's only tracking that 1 point.
This is completely different to what Kinect is doing. IR is used because it most objects don't react to it in the same way that they do with visible light, almost all the light is being reflected back. The depth sensor, in combination with the IR emitter, is able to create an accurate depth map of the room by using the inverse square law to determine how far away something is depending on the reflected light it is picking up. You're right that it's not seeing in 3D but I don't see where Microsoft ever claimed it was a 3D camera, simply that it was depth camera that used that depth map to create a 3D map of the player, which is completely accurate.
Kinect is not the only depth sensing camera out there and there is a reason they are called DEPTH SENSORS.
"Depth cameras (such as those from PrimeSense1, 3DV [28], and Canesta2) are able to directly sense range to the nearest physical surface at each pixel location. They are unique in that they enable inexpensive real time 3D modeling of surface geometry, making some traditionally difficult computer vision problems easier. For example, with a depth camera it is trivial to composite a false background in a video conferencing application. Microsoft’s Kinect device3 builds on PrimeSense technology and computes a skeletal model of a player for motion-driven gaming. While such cameras are now rare, the release of Kinect is likely to make depth cameras inexpensive and widely available."