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A Closer Look At The AimTrak (with video goodness)
RandyT:
I took down my earlier post, because I assumed after the fact that the CMOS sensor was unable to ever see two emitter boards at once, unless it was a good distance from the screen. When aimed at the center of the screen, the CMOS sensor would absolutely need to have more than one set of emitters in frame for any of the advanced stuff related to multiple emitters to be done.
I think there's not enough information about the hardware available, specifically the field-of-view of the CMOS sensor / lens, to know whether this system can be improved at all. Andy mentioned something about a cell phone camera earlier, so I did some testing with my (t)rusty old Motorola Q. One thing that is very interesting is that I can get the entire monitor in frame, with some extra space above and below for emitters from about 27" in front of the emitters. This is about 2' closer than where I need to use the Aimtrak for it to work well, so I am going to have to make the assumption that the camera on the Q cell phone has a bit of a wide angle lens. I suspect that such a lens would be very undesirable on the Aimtrak, due to the distortion inherent with inexpensive wide angle lenses, so it probably has a much narrower field of view, which provides a more uniform image.
If this isn't the case, however, I'm having a hard time understanding why a second set of emitters, with a reversed pattern (i.e. same board, flipped) or not, wouldn't allow one to get quite a bit closer than is currently possible.
RandyT
AndyWarne:
--- Quote from: RandyT on October 23, 2009, 10:45:03 pm ---I took down my earlier post, because I assumed after the fact that the CMOS sensor was unable to ever see two emitter boards at once, unless it was a good distance from the screen. When aimed at the center of the screen, the CMOS sensor would absolutely need to have more than one set of emitters in frame for any of the advanced stuff related to multiple emitters to be done.
I think there's not enough information about the hardware available, specifically the field-of-view of the CMOS sensor / lens, to know whether this system can be improved at all. Andy mentioned something about a cell phone camera earlier, so I did some testing with my (t)rusty old Motorola Q. One thing that is very interesting is that I can get the entire monitor in frame, with some extra space above and below for emitters from about 27" in front of the emitters. This is about 2' closer than where I need to use the Aimtrak for it to work well, so I am going to have to make the assumption that the camera on the Q cell phone has a bit of a wide angle lens. I suspect that such a lens would be very undesirable on the Aimtrak, due to the distortion inherent with inexpensive wide angle lenses, so it probably has a much narrower field of view, which provides a more uniform image.
If this isn't the case, however, I'm having a hard time understanding why a second set of emitters, with a reversed pattern (i.e. same board, flipped) or not, wouldn't allow one to get quite a bit closer than is currently possible.
RandyT
--- End quote ---
You said that you can get all four corners on the screen at a distance of 27in.
Now imagine a line drawn from the phones center axis, to the screen (or even fit a laser pointer to the phone). Move the phone until the pointer reaches the edge of the screen. You will not be able to see all four corners on the camera picture.
Now move back until you are able to get the pointer to hit all four corners while still being able to see the opposite corner on the picture...
Actually you will need to move back twice the distance.
If the sensor can work using one LED, at least for part of its field, then the disctance does not have to be doubled. Adding another board below the screen might increase the vertical field of view if the sensor could use either the top or botom board, but would not affect the horizontal field of view. Its true that the lower sensor might provide more information, at least when the camera can see both boards. But its not practical because at certain locations of the pointer, the camera will only be able to see one LED (ie one of the four LED groups) and would not know which one its looking at unless there is active control of each LED as in the Sega system.
brandon:
--- Quote from: AndyWarne on October 24, 2009, 04:52:39 am ---
--- Quote from: RandyT on October 23, 2009, 10:45:03 pm ---I took down my earlier post, because I assumed after the fact that the CMOS sensor was unable to ever see two emitter boards at once, unless it was a good distance from the screen. When aimed at the center of the screen, the CMOS sensor would absolutely need to have more than one set of emitters in frame for any of the advanced stuff related to multiple emitters to be done.
I think there's not enough information about the hardware available, specifically the field-of-view of the CMOS sensor / lens, to know whether this system can be improved at all. Andy mentioned something about a cell phone camera earlier, so I did some testing with my (t)rusty old Motorola Q. One thing that is very interesting is that I can get the entire monitor in frame, with some extra space above and below for emitters from about 27" in front of the emitters. This is about 2' closer than where I need to use the Aimtrak for it to work well, so I am going to have to make the assumption that the camera on the Q cell phone has a bit of a wide angle lens. I suspect that such a lens would be very undesirable on the Aimtrak, due to the distortion inherent with inexpensive wide angle lenses, so it probably has a much narrower field of view, which provides a more uniform image.
If this isn't the case, however, I'm having a hard time understanding why a second set of emitters, with a reversed pattern (i.e. same board, flipped) or not, wouldn't allow one to get quite a bit closer than is currently possible.
RandyT
--- End quote ---
You said that you can get all four corners on the screen at a distance of 27in.
Now imagine a line drawn from the phones center axis, to the screen (or even fit a laser pointer to the phone). Move the phone until the pointer reaches the edge of the screen. You will not be able to see all four corners on the camera picture.
Now move back until you are able to get the pointer to hit all four corners while still being able to see the opposite corner on the picture...
Actually you will need to move back twice the distance.
If the sensor can work using one LED, at least for part of its field, then the disctance does not have to be doubled. Adding another board below the screen might increase the vertical field of view if the sensor could use either the top or botom board, but would not affect the horizontal field of view. Its true that the lower sensor might provide more information, at least when the camera can see both boards. But its not practical because at certain locations of the pointer, the camera will only be able to see one LED (ie one of the four LED groups) and would not know which one its looking at unless there is active control of each LED as in the Sega system.
--- End quote ---
I wonder if the Sega system has all LEDs "steady on" but strobes them when its unsure which LED its looking at... Because if the sensor can only refresh at, say 60hz then each corner would only be updated every 15hz and that would cause noticeable lag. I know that's not really helpful in regard to the AimTrak but I'm curious :)
RandyT:
--- Quote from: AndyWarne on October 24, 2009, 04:52:39 am ---You said that you can get all four corners on the screen at a distance of 27in.
Now imagine a line drawn from the phones center axis, to the screen (or even fit a laser pointer to the phone). Move the phone until the pointer reaches the edge of the screen. You will not be able to see all four corners on the camera picture.
--- End quote ---
Obviously. but I can still see the center area where the emitters are positioned, which is really the only thing that's important.
--- Quote ---But its not practical because at certain locations of the pointer, the camera will only be able to see one LED (ie one of the four LED groups) and would not know which one its looking at unless there is active control of each LED as in the Sega system.
--- End quote ---
I'm not suggesting the more complex implementation as others are. There is middle ground that I'm not sure you are seeing, so I'll give you a scenario and a question;
Given the notion that the center screen position of the camera shows an emitter at very near the top of the image and one at very near the bottom of the image, at what point could the gun not be able to accurately determine the current emitter if the logic were :
Two Emitters = Don't Care
Above Emitter = Lower Emitter
Below Emitter = Upper Emitter
given the limitation of left to right off-screen reload shots only?
AndyWarne:
--- Quote from: RandyT on October 24, 2009, 12:50:09 pm ---
Obviously. but I can still see the center area where the emitters are positioned, which is really the only thing that's important.
I'm not suggesting the more complex implementation as others are. There is middle ground that I'm not sure you are seeing, so I'll give you a scenario and a question;
Given the notion that the center screen position of the camera shows an emitter at very near the top of the image and one at very near the bottom of the image, at what point could the gun not be able to accurately determine the current emitter if the logic were :
Two Emitters = Don't Care
Above Emitter = Lower Emitter
Below Emitter = Upper Emitter
given the limitation of left to right off-screen reload shots only?
--- End quote ---
Dont understand at all. The camera cant always see the center area, it moving with the gun...If its pointing at the top of the screen it loses the bottom emitter and vice versa. The cameran can only see both when the gun is aimed near the center of the screen.