Red LED Blurry

epirb wrote on 5/21/2006, 2:30 PM

looking for suggestions on how to reduce the blur I am getting on shots of a panel with red LED meters on it.
When the image is in focus , (looking at the lettering in the image),
it seems if its the image sensor.
I've tried it with both my cams and still about the same, with
FX 1 3ccd, and AU1 CMOS.
Do you think shutter speed might help? Both were shot at 60 and the panels are dificult to light evenly due to there textured semi gloss finish, so more light and going up on the S/S would be hard.
Maybe a filter of some sort?
Dont know if its a freq issue or wavelength or what, but it bugs me as this is all HDV and everything else is sharp.
Its more noticable on moving frames, bet heres a frame capture:

BLUR

Comments

farss wrote on 5/21/2006, 2:49 PM

Two things.
The red plastic in front of the LED displays will produce some diffusion by itself. Secondly red has the worst subsampling.
Also (sorry this is 3 things), the LED displays are multiplexed i.e. they're going on and off at a high frequency, we don't see it but it can interact with the shutter and the field rate of the camera to cause all sorts of problems.
One way around this would be to composite a new display into the frame however if the camera is moving that'd take quite a bit of work unless you had something like AE with motion tracking.

If the shot is static and the display is 'winking' then using motion blur can cure these problems, that's assuming you have nothing else moving in the frame.
If you do then render out a new file with lots of motion blur, bring that back and use say the Cookie Cutter so only the problem part of the frame is seen, i.e. the MB is only being applied to the LED displays.

Bob.

JJKizak wrote on 5/21/2006, 4:21 PM

Edit that section of the video as a still or series of stills then superimpose red text over the original text. All done.

JJK

epirb wrote on 5/21/2006, 6:03 PM

thanks for the advice guys, two issues, both moving shot issues.
One is a zoom into that shot, I might try it with a still and zoom with that.
the other is I am also showing the meters change/fluctuate and change.
there are actually 6 meters total with voltage,frequency,amperage.
these have to be shown as breakers(loads are applied).
I'll take your advice and see what I come up with,and let you know.

johnmeyer wrote on 5/21/2006, 6:57 PM

The blur is normal. That's the way LEDs emit light. If you want it to look crisper, you'll have to fake it as advised in the other posts. If the video is moving, you can also select the red using the secondary color corrector, set saturation to zero, and play around with the Limit Luminance control. You will be able to turn the fuzzy edges to a shade of gray. I used these settings:

Limit Saturation: Low 61.0; High 162.0; Smooth 12.9;

Limit Hue: Center 92.7; Width 4.8; Smooth 0.0;

Limit Luminance: Low 43.2; High 255.0; Smooth 0.0

Crank the saturation (in the top of the dialog) way up, and the gamma way down.

Serena wrote on 5/21/2006, 8:23 PM

One question that hasn't been addressed: does it matter? The still frame you posted shows the LED displays just fine. As johnmeyer said, LEDs have a diffusing surround to increase their angle of visibility. Judging by the frame you posted, spend your time elsewhere.

Spot|DSE wrote on 5/21/2006, 8:48 PM

you can also light the shot using diffused light so that the LED is not as bright. This won't help the reflective areas surrounding the LED, but you'll be surprised at what a little bit of diffuse light will do.
I'm assuming you're shooting HDV w/your FX?

Xander wrote on 5/22/2006, 9:51 AM

Also, some LEDs emit a small amount of InfraRed light, which some camera sensors pick up as red coloring.