Push up fps by droping colors
Posted: 05 January 2010 07:53 AM   [ Ignore ]
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Who knows something about firmware of this camera ?
I think there is possible to pushing more fps from PS3Eye when we lose information about color.
(If cmos sensor is a bayer paterrn may be is possibility to boost resolution too)
My PS3Eye will arrive to me about end of the week and now I’m very interested, where may I find information about it.
Does somebody try something like this?


I’m sorry if I wrote this in wrong place.

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Posted: 06 January 2010 12:41 PM   [ Ignore ]   [ # 1 ]
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valoos - 05 January 2010 07:53 AM

Who knows something about firmware of this camera ?
I think there is possible to pushing more fps from PS3Eye when we lose information about color.
(If cmos sensor is a bayer paterrn may be is possibility to boost resolution too)
My PS3Eye will arrive to me about end of the week and now I’m very interested, where may I find information about it.
Does somebody try something like this?


I’m sorry if I wrote this in wrong place.

valoos, unfortunately we are pushing the limits of the camera’s sensor already. According to the specs it only goes up to 60fps at 640x480. If you look at the frame rates list in the SDK, we even have implemented 75fps at 640x480, but that already is starting to introduce some artifacts in the output image. We are also pushing the USB transfer rates pretty high at this point. So I’m afraid even if we could get faster frame rates the USB will start dropping more and more frames.

AlexP

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Posted: 06 January 2010 04:18 PM   [ Ignore ]   [ # 2 ]
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Hi,

I am new here, but this topic is very interesting and I have a question releated to valoos’s post. If it is true than CMOS sensor is a bayer pattern or smth similliar, this will mean that every color pixel is combined from four grayscale pixels, am I right? If yes, it is possible to get four times resolution using raw pixel color data, loosing color information and ends with a 1280x960 grayscale frame. Everything in software without changing USB transfer rate. It is possible?

Thanks and sorry for my English.

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Posted: 06 January 2010 05:05 PM   [ Ignore ]   [ # 3 ]
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Futhark - 06 January 2010 04:18 PM

Hi,

I am new here, but this topic is very interesting and I have a question releated to valoos’s post. If it is true than CMOS sensor is a bayer pattern or smth similliar, this will mean that every color pixel is combined from four grayscale pixels, am I right? If yes, it is possible to get four times resolution using raw pixel color data, loosing color information and ends with a 1280x960 grayscale frame. Everything in software without changing USB transfer rate. It is possible?

Thanks and sorry for my English.

It is true that the PS3Eye CMOS sensor’s pixels are arranged in bayer pattern. Unfortunately, the whole bayer pattern thing is a trick.
The total number of bayer pixels in the PS3Eye is actually 640x480. It is true that every four of these create one color pixel. Unfortunately you don’t get four times the resolution since there are only 640x480 pixels available.
In another words if for a given CMOS sensor they say that is has 1MP (bayer pattern CMOS sensor), this means that it has exactly 1MP of Bayer pixels and not real color pixels. The real color pixels are generated by dynamic color interpolation.
So the only difference between 640x480 grayscale sensor and 640x480 color sensor is not the number of pixels but the R, G, B filters that are ‘painted’ onto color CMOS sensing pixels.
So to answer your question, you can’t get 1280x960 resolution from this camera since it only has 640x480 true pixels.

AlexP

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Posted: 07 January 2010 10:29 AM   [ Ignore ]   [ # 4 ]
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So, the interpolation process goes on the camera side? I was sure that fps limit of this stuff is only from USB bandwidth limit. (from this reason was born my idea of cuting data, for example drop the color information)
So, the only one way to push more fps from it is cool down the sensor ... :D

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Posted: 07 January 2010 12:18 PM   [ Ignore ]   [ # 5 ]
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valoos - 07 January 2010 10:29 AM

So, the interpolation process goes on the camera side? I was sure that fps limit of this stuff is only from USB bandwidth limit. (from this reason was born my idea of cuting data, for example drop the color information)
So, the only one way to push more fps from it is cool down the sensor ... :D

So as you said, since camera CMOS sensor pixels are already in the bayer configuration, there is no way to drop the colors (other than skipping the pixels, thus decimating the image).
The CMOS sensor, as any other semiconductor, has the max operating speed rating and I guess cooling it down will probably help with noisy image at higher framerates, but that still does not solve the max running clock issue. Basically we are talking here about overclocking the CMOS sensor chip. I have already done this with 75fps and as you can see the image is usable but there are some artifacts already visible in there. Pushing it higher than this is possible (I experimented with this in my early driver development), but it introduces even more artifacts and makes the image pretty much unusable. Also, as the exposure time gets shorter you will need more incoming light to the sensor to get the normal brightness image. If you try to compensate for this by adjusting the gain value, this will add even more noise to the resulting image. So it is a trade off.
I suggest you get our CL-Eye SDK and test this with the supplied API. I haven’t tried cooling the CMOS sensor and running it at 75fps, but I’m very interested to hear about the results.
If you are willing to try this out, please post your findings here. We might be able to push even higher framerates (>75) out of the sensor if this works.

AlexP

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