Hi Philip The issue you are describing is a general global issue with motion picture cameras and fluorescent light.
The easiest fix is to change FPS and shutter speed to match the flickering frequency or a multiple/division of it. Try a shutter speed (exposure time) of 1/50 (25 or 50 fps), if you need less motion blur try 1/100, 1/150... If you still see lower frequency flickering (frequency of 1Hz or less) then the power grid frequency is just a little bit off 50Hz and you have to fine-tune your exposure time. Since the Elphel camera can use any float value as exposure time you should be able to get perfectly flicker free footage with a little bit of fine tuning. Some more info on the internet: http://ezinearticles.com/?All-About-Fluorescent-Light-Flicker-in-Cameras!&id=3193172 Regards Sebastian On Mon, Dec 13, 2010 at 05:17, Oleg K Dzhimiev <[email protected]> wrote: > > ---------- Forwarded message ---------- > From: Philip Haynes <[email protected]> > Date: 12 December 2010 17:46 > Subject: Re: stereo camera: resizing and combined frames mode problems > To: Oleg K Dzhimiev <[email protected]> > > > Hi Oleg, > > We tried what you suggested and we saw no notable difference. > > Just so we are clear this issue has to do with power frequency. Fluorescent > lights > (in Australia) operate at 50 hz and we are getting severe image strobing. > > Philip > On 9/12/10 6:58 PM, "Oleg K Dzhimiev" <[email protected]> wrote: > > Hi Philip, > > We are working on fixing te correct resizing - it affects more areas in the > UI... there are some problems with switching between the modes. > But the phases in the firmware you've got should be fine. You can check that > bye putting sensors in a triggered mode > > 10359_controls.html - has such button > in telnet/ssh - "fpcf -i2cw16 48a0 41" - enable, "fpcf -i2cw16 48a0 0" - > disable > > As a result you should see 5 clear colored vertical bars. If the image is not > static - then let's try to trouble shoot this. > > Best regards, > Oleg > > On 9 December 2010 00:24, Philip Haynes <[email protected]> wrote: > > Hi Oleg, > > I also sent through a note on phasing. Do you have a comment on this? > > Much thanks, > > Philip > > > On 7/12/10 2:02 PM, "Oleg K Dzhimiev" <[email protected] > <http://[email protected]> > wrote: > > Yes – but you lose half the image. > Alternating means we get the full picture providing more data to start > building up a 3D geometry. A 1600x(2*1200) image would be desirable, but I > wasn’t aware possible. > > Yes 1600x(2*1200) is possible. > Technically the only difference is that the vertical sync signal is > interrupted for alternating and uninterrupted for combined. > But doing 'alternating mode' is more complicated for autoexposure (analyzes > the current frame to change exposure for the next one) and changing > parameters for example - and it is not supported right now in the camera (but > it is possible to enable it in the mux board so the camera will not know). > > Oleg > > > > > > _______________________________________________ > Support-list mailing list > [email protected] > http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com > _______________________________________________ Support-list mailing list [email protected] http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com
