Author Topic: Insanely high speed slit scan method?  (Read 913 times)

PaulBryanTV

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Insanely high speed slit scan method?
« on: October 21, 2017, 08:47:08 AM »
Hi David and others!
Just wondering after reading a lot of articles online about photo finishes, is it possible to make the Chronos read out a 1x720px image at even higher speeds for stuff such as high velocity weapons etc? So we could create high res 'frozen in time' style images from the footage using something like Slit Cam?

As the bullet or projectile would travel through the horizontal axis creating a full image of itself, so we only need the vertical resolution?
Would this make the camera be able to record insanely high speeds?
Is it even possible? Just an idea.

tesla500

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Re: Insanely high speed slit scan method?
« Reply #1 on: October 21, 2017, 11:15:47 AM »
This could be done, yes. The limitation right now is that the video encoder doesn't support resolutions below 96 pixels height. To get around that, we can add black bars to the video to remain within the encoder limitation. Once Raw/uncompressed saving is done, this won't be a problem at all.

There's also a frame rate limit above which the camera becomes export controlled, I believe the number is 200,000fps but I have to check. But the image sensor itself is capable of well above that when running at 1 pixel height.

David

PaulBryanTV

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Re: Insanely high speed slit scan method?
« Reply #2 on: October 21, 2017, 11:30:41 AM »
Does it support width of less than 96px? As a vertical pixel strip of maximum resolution height with a 1px width is what most would use.
For example a side profile shot of a bullet in mid air from left to right.

If you can incorporate this in some manner I think it would be awesome. Especially for content creators and photographers in the high speed niche.
Theoretically whats the maximum fps the sensor could handle? I think if you can put even a basic test feature of this in, you'd REALLY turn some heads in the industry.
Something like a 500K fps slitscan would lead to some INCREDIBLE images being made, particularly for ballistics / explosives.
« Last Edit: October 21, 2017, 11:36:33 AM by PaulBryanTV »

gyppor

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Re: Insanely high speed slit scan method?
« Reply #3 on: October 21, 2017, 01:23:26 PM »

There's also a frame rate limit above which the camera becomes export controlled, I believe the number is 200,000fps but I have to check. But the image sensor itself is capable of well above that when running at 1 pixel height.

David

It seems that as of 2011,  cameras capable of >1,000,000fps or <1us exposure AND >125fps were subject to controls. I can't seem to find a more recent version of the document:

http://www.international.gc.ca/controls-controles/about-a_propos/expor/guide-2011.aspx?lang=eng


From the document, on the list of controlled items:

1-6.A.3.a. Instrumentation cameras and specially designed components therefor, as follows:

[...]

4. Electronic framing cameras having a speed exceeding 1,000,000 frames/s;
5. Electronic cameras having all of the following:

    An electronic shutter speed (gating capability) of less than 1 μs per full frame; and
    A read out time allowing a framing rate of more than 125 full frames per second;



On another note... Is the new firmware going to include the black stripes top and bottom for higher frame rates? :-p

PaulBryanTV

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Re: Insanely high speed slit scan method?
« Reply #4 on: October 22, 2017, 05:20:19 AM »
Pretty sure all of that would be EXTREMELY easy to get around with Open Sourcing stuff with easy implementation methods / software?

BiduleOhm

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Re: Insanely high speed slit scan method?
« Reply #5 on: October 22, 2017, 05:39:13 AM »
Yep, software limit it to whatever the export limit is and then those who want to go higher just need to change a value or two in a config/header/whatever file and maybe re-compile the thing if the change isn't in a config file.

hydraulicpresschannel

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Re: Insanely high speed slit scan method?
« Reply #6 on: November 13, 2017, 06:54:04 AM »
At least with the Phantom cameras the limit when export difficulties start is 1 000 000 fps

AimedResearch

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Re: Insanely high speed slit scan method?
« Reply #7 on: November 27, 2017, 08:07:42 PM »
Hi David and others!
Just wondering after reading a lot of articles online about photo finishes, is it possible to make the Chronos read out a 1x720px image at even higher speeds for stuff such as high velocity weapons etc? So we could create high res 'frozen in time' style images from the footage using something like Slit Cam?

As the bullet or projectile would travel through the horizontal axis creating a full image of itself, so we only need the vertical resolution?
Would this make the camera be able to record insanely high speeds?
Is it even possible? Just an idea.

You mean like this?: (see attachment)

Max

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Re: Insanely high speed slit scan method?
« Reply #8 on: November 27, 2017, 08:19:31 PM »
Does it support width of less than 96px? As a vertical pixel strip of maximum resolution height with a 1px width is what most would use.
For example a side profile shot of a bullet in mid air from left to right.

If you can incorporate this in some manner I think it would be awesome. Especially for content creators and photographers in the high speed niche.
Theoretically whats the maximum fps the sensor could handle? I think if you can put even a basic test feature of this in, you'd REALLY turn some heads in the industry.
Something like a 500K fps slitscan would lead to some INCREDIBLE images being made, particularly for ballistics / explosives.

After the updates, yes it would be possible, but with speed, you will need to decrease the exposure time, so if you were to expose at half a million FPS the amount of light required for the exposure would be insane.

There is also another issue, we can't export anything easily with capability over 200,000fps because it becomes a federally regulated product, mainly because it is a tool that can be used easily for nuclear research.   :o

Edit:
Sorry, misinterpreted what you said, Due to sensor capabilities we can't narrow the sensor field below 336 pixels horizontally with framerate benefits, but you can do 336x1 for a slit shot once we get the blackspace working.
Cheers,
Max
« Last Edit: November 27, 2017, 08:29:07 PM by Max »

AimedResearch

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Re: Insanely high speed slit scan method?
« Reply #9 on: November 27, 2017, 08:22:45 PM »
PaulBryanTV,

The high-speed imaging industry uses high-speed streak cameras in the way you just described.  With the Chronos 1.4, you would run into a problem with the exposure needed to pull it off.  To get good detail to build an image from lines you would probably need 750ns exposures or faster.  Even if you ran the Chronos at the fastest exposure, you wouldn't have the light.  If you ran the camera at 1-million fps you would be forced to have a <1us exposure.

The picture I posted above was captured with a 500ns flash and a relatively inexpensive Nikon DSLR.  Projectile is exiting 6 inches of gel.  A flash unit like this could be utilized with a Chronos with full exposure at any given resolution (1/frame rate) or frame rate to capture a similar image.