it provides the FREX and STROBE signals which can be used for multi-camera synchronize capture with proper camera driver firmware.
No, as that is not the official Raspberry Pi camera board.Borisnov wrote:Might the Raspberry Pi Camera Rev.C from Arducam offer a spark of hope?
http://www.arducam.com/raspberry-pi-cam ... rformance/it provides the FREX and STROBE signals which can be used for multi-camera synchronize capture with proper camera driver firmware.
You can try tweaking MMAL_PARAMETER_VIDEO_FRAME_RATE on the respective devices. It allow steps of 1/256fps, although there is some rounding in the sensor driver too due to the way framerate control is done in the sensor. Have fun writing the control loop!ivannaz wrote:Regarding this idea of software frame synchronization, I see that I could start the cameras from a LAN trigger and perhaps achieve a ms level sync.
But if we have continuous image acquisition afterwards, is it possible to induce a small camera delay in one of the raspberries, should the program in this particular unit finds is it too much advanced compared to a reference unit?
Through the current mmal calls, I mean. I am not asking for GPU code changes. The idea here would be to keep an array of raspberries more or less (+/- 1ms) in sync, so if we start them in sync, and a few of them slowly skew due to small clock difference, we could compensate during acquisition.
We can, of course, stop everything and start again, but will loose a few frames in this process. Is there an alternative besides the already mentioned concept of hardware hacking the clocks?
While it's certainly true that you can get some additional and uneven exposure, where this comes in handy is when the flash illumination is significantly greater than the ambient light. OV FREX, or Global Reset can be used quite effectively, especially with Xenon, but even with LED depending on the lighting dynamics. In darker ambient condition, it can be utilized to take very well exposed photos.6by9 wrote: The FREX pin is a global reset of all pixels. Line 1 will then start reading out at the end of the configured exposure time, but readout is the same as in rolling shutter mode. If you don't have an external shutter, then the lower lines will have a steadily increasing exposure time as the frame is read out.
Therefore FREX is not a feasible feature to use with the standard Pi Camera.
Google "ov5647 datasheet" and you'll get the hit http://www.seeedstudio.com/wiki/images/ ... 7_full.pdfprutchi wrote:I recently purchased an Arducam Rev.C OV5647 camera for the Raspberry Pi. I can confirm that it works just as the official Raspberry Pi camera, but also has a separate set of pads with pinouts for the STROBE and FREX signals. However, Arducam does not yet have a way for activating the firmware register that enables these lines.
Has anyone been able to find a way of turning on STROBE and FREX functionality?
Where did you purchase this? Do you know where I can get one (shipped to me in USA) ? The US-based Arducam distributor, Marlin P. Jones http://www.mpja.com/ does not list this particular board.prutchi wrote:I recently purchased an Arducam Rev.C OV5647 camera for the Raspberry Pi.
After a thought, I'll relent a little.6by9 wrote:As the STROBE and FREX lines are not exposed on the Foundation's Pi camera board there is little motivation in me adding that sort of functionality to the firmware.
Hello Kozuch,Kozuch wrote:How do I feed an external clock signal to the camera? Do I physically have to remove the Y1 or is it enough to cut the power supply line on the camera's flat cable (=remove supply from Y1) and bring new clock to the little round test point next to Y1?
Do they not have contacts at Omnivision? If they're shipping OV modules I would have expected them to have, and OV do have Apps Engineers there just to support customer projects.Kozuch wrote:Those are SPI cameras that can connect to RPi too. Both the sensors they use have the FREX feature and Lee is willing to enable the feature on the 5 Mpix camera that exposes a FREX pin. However, he has exactly the same problem as we have - he needs help with camera register settings. So if anyone is willing to help with registers for FREX on OV5642 help is welcome. You can contact Lee at admin<thisisatsign>arducam.com.
How about the flash driver? viewtopic.php?f=43&t=83484DaveSemm wrote:Has anyone made progress with a simple way to add flash support for this camera? Or is that not going to happen?
Thanks! I will try it out!6by9 wrote:How about the flash driver? viewtopic.php?f=43&t=83484DaveSemm wrote:Has anyone made progress with a simple way to add flash support for this camera? Or is that not going to happen?
It doesn't use the strobe pin, but provides the option to trigger an external light source for stills captures with appropriate exposure compensation (requires a preflash).