Howto: move camera board to FPGA?

peepo

Re: Image Processing Demo:

What does the camera board do?

ie the camera sensor is attached to the camera board, which provides pins to LOGI-Pi.

but one can buy the same sensor with ffc to hirose connector.

so why not integrate into FPGA?

in order to understand the process...

jpiat

Hi,

you are right in saying that this particular sensor is available on a FCC cable and could be directly connected to the FPGA pins but we want to keep this camera as a module to the general purpose platform that is the LOGI-Pi/Bone. There are also other sensor that can be use with the logi-cam adapter (see arducam for a list of sensors with compatible pinout). These other sensors are not tested with the logi-pi/bone but are compatible electrically.

We are also working on a new camera board that uses less pins and provide higher performances. We hope to share details on this pretty soon.

Regards,

Jonathan Piat

peepo

I was looking at 1.3MP ov9655 which has a similar board.

where is the list of sensors with compatible pinouts you mention?

I found http://www.arducam.com/camera-modules/ but doesn't seem that helpful...

jpiat

I have some ov9655 module that i bought from ebay with a breakout board that convert the FCC cable into headers at the same format the ov7670.

same as :
http://www.ebay.fr/itm/OV9655-Camera-Board-Module-CMOS-Camera-Module-1-3MP-Camera-Chip-Development-Kit-/281524910365?pt=AU_B_I_Electrical_Test_Equipment&hash=item418c31391d

This module being pin compatible, it should be only a matter of writing the correct i2c configuration to the sensor to make it work with current logi demo.

Other module such as :
http://www.ebay.fr/itm/5-Mega-pixel-Camera-Module-OV5642-1080P-JPEG-Output-/271130719953?pt=LH_DefaultDomain_0&hash=item3f20a676d1
http://www.ebay.fr/itm/MT9V111-640-480-0-3-Mega-pixels-Camera-Module-much-better-than-OV7670-/281548559635?pt=LH_DefaultDomain_77&hash=item418d9a1513

should also work (untested).

If you have a look at the "Camera modules" section of http://www.arducam.com/arducam/ and then search for the sensor reference on ebay, you should get compatible modules.

Regards,

peepo

okay thanks for explanation.

 to be clearer about ffc hirose,

note Raspberry PiCam included this, and it gives 'flexibility'

in particular the sensor can be for instance be mounted perpendicular to board.

jpiat

The camera module of the raspberry pi uses LVDS signals between the camera sensor and the Rpi ( for pixels), allowing less conductors to be used and allowing to maintain a better signal integrity on "long" flat-cables.

The logi-camera module use a parallel bus and the lines between the sensor and the processing platform needs to be short, or otherwise the communication is more sensitive to noise.

You can still use a 20 pin flat cable such as http://www.ebay.fr/itm/CUSTOM-LENGTH-20-pin-2x10-way-IDC-RIBBON-CABLE/331440277725?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item4d2b6148dd

 but with a female and a male connector to extend the range of the camera. You should not go longer than 10cm and shield the cable as much as possible.

We are working on a solution to have a camera module with better range of motion.

peepo

comms issue: on the RPi there is also a ffc between the camera sensor and the camera board,

thanks for the introduction to what camera boards do,

I'd like a link or to see a simple more detailed introduction, as this is currently missing from the project, afaict.

thanks again

Jonathan

jpiat

Sure, this is something we should add to the wiki.

If you want to understand the signals coming out of the camera and how they are interfaced in the FPGA you can have a look at :
http://www.element14.com/community/groups/fpga-group/blog/2014/12/17/gradient-filter-implementation-on-an-fpga--part-1-interfacing-an-fpga-with-a-camera

peepo

yup, a fantastic article!

peepo

re: a new camera board that uses less pins and provide higher performances.

would I be right to assume this new camera board will not be CSI-2?

my understanding is that for say 5MP sensor CSI-2 is more or less required because parallel sensor has problems delivering data fast enough,

and as I cannot find open source FPGA CSI-2 this seems to be a significant hurdle for a high performance camera sensor.

looking forward to Part 2 interfacing an fpga with a camera...

jpiat

We don't have the ports to connect a CSI-2 camera (LVDS bus with one line for differential clock and two lines for differential data), but we have the SATA port that is capable of doing communication with some of the camera available. The goal is not to move to a higher resolution but to move to a camera designed fro computer vision (the Pi-Camera is for video capture, the ov7670 is a low cost mobile phone sensor and they both have a rolling shutter) with a higher VGA frame-rate.

CSI-2 is a physical specification for a camera bus, and most FPGA can deal with it, as it just require LVDS clocks, data lines and hardware deserializer.

Part 2 is coming, but still requires some work ...

peepo

well the OV10625 seems suitable:

http://www.ovt.com/download_document.php?type=sensor&sensorid=165

but how to source?

mjones

Hi @peepo  

Many times you have to buy the bare sensors and design a custom pcb.  Many of the popular sensors are avaialble on ebay, but it doesnot appear that this one is.  Also, sometime the vendor will have a development module, but you would have to check with them and they are usually quite expensive.

What specs are you looking for?  We may have a module in the works that would work for ou?

peepo

LVDS working example could be good as there are many sensors and boards available.

my specs are simple: I'm looking for global shutter and sync for stereo capability,
cheap as possible given that Spartan6 embedded has limited data capacity, maybe qvga*30fps or vga?

Can you please provide some further information on what you are considering, your 'module in the works'?

thanks again

Jonathan

mjones

Hi @peepo

Have a look at the MT9V034.  We  currently have a prototpye running, but the camera design is not our highest priority and we don't know how to proceed as the current logi-cam does not pass fcc/ce testing based upon the use of the low cost OEM (2 layer) OV7670 board.  In order for E14 to carry "LOGI" boards they require full compliance and high speed devices are not easy to get passed.  Especially when they are interconnected with long and un-impedance matched connectors (.1" headers).  

We may release new "development" only boards that are purely sub-assemblies or modules.  This would alleviate the high burden and the FCC/CE testing which significantly increase the design costs.  For such low volume products this may make sense.

If you are interested I can post the current MT9V034 pcb files which you can build your own camera board.  

SquareOne

hi,

if your MT9V034 board is ready i am interested in that . how about the drivers have you implemented  drivers for that and integrated in to logibone

mjones

Hi @SquareOne  We are making progress on the board with a newer version that will support daisy chained modules.  We are not sure how we are going to release the cameras at this point along with some other new product.  I can give you design files if you would like to prototype your own?