Camera selection

[Sahiru Hettiarachchi]

Getting there guys..... :D

Help me to select a camera for my machine. I need my machine to run somewhat faster so already I am thinking to upgrade it with ball screws and servo motors. So I think having a higher fps camera would benefit? Would that be the case?

I have selected two cameras on AliExpress. Help me decide with is better.

ELP IMX291 USB 3.0 Mini Webcam MJPEG 50fps 2MP 

Model - ELP-SUSB1080P01-MFV

Sensor - IMX291

Lens Size - 1/2.8 inch

Pixel Size - 2.9µm X 2.9µm
Max. Resolution -1920(H)X1080(V)
Compression format - MJPEG  / YUV2(YUYV)

Resolution & frame

1920X1080 MJPEG@ 50fps/ USB3.0 1920X1080 YUY2@ 50fps

1280X720 MJPEG@ 50fps / USB3.0 1280X720 YUY2@ 50fps

640X480MJPEG@ 50fps / USB3.0 640X480 YUY2@ 50fps

Price - $63.13

ELP OV9712 Sensor 1.0Megapixel12mm lens HD CMOS Mini Camera Board

Model - ELP-USB100W03M-L36

Sensor -  OV9712

Lens Size - 100W, 1.0megapixel

Pixel Size -
Max. Resolution - 1280X720
Compression format - MJPEG  / YUV2(YUYV)

Resolution & frame

1280 (H) x 720 (V) pixels    MJPEG 30fps      YUY2 10fps
960 (H)   x 720 (V) pixels    MJPEG 30fps      YUY2 15fps
800 (H)   x 600 (V) pixels    MJPEG 30fps      YUY2 20fps
640 (H)   x 480 (V) pixels    MJPEG 30fps      YUY2 30fps
352(H)    x 288 (V) pixels    MJPEG 30fps      YUY2 30fps
320 (H)   x 240 (V) pixels    MJPEG 30fps      YUY2 30fps
176(H)    x 144 (V) pixels    MJPEG 30fps      YUY2 30fps
160 (H)   x 120 (V) pixels    MJPEG 30fps      YUY2 30fps

Price -  $29.61

I have to have the camera wires like 5m long to connect to the PC. So would USB3.0 speeds work and would I reach such fps values. :/

Best Regards

[Jim Young]

High FPS is not really needed in a PnP machine. Most of the measurements are done with the object in focus being still. A 12 mm lens is going to be way too long of a focal length, unless your camera is far away from the parts, PCB. 

This is the camera I bought to replace the stock cameras on my LitePlacer, 6mm focal length -   ELP Mini 720p Webcam USB Camera Module 1.0Megapixel CMOS OV9712 HD Free driver industrial Camera for Machine Vision, 3d printer|Surveillance Cameras| - AliExpress

Reasonably priced and works fine for both top and bottom camera.

[mark maker]

Yes higher FPS is good, if everything else stays the same (resolution, color).

But I would not buy a variable zoom/focus lens. You need repeatable results in Computer Vision, so you want to select the right fixed focal-length lens and also set the focus once, then fix it using set screws. Also these zoom lenses might have more complex distortions that cannot be compensated as well. Finally, remember the camera is moved around on the head, hopefully with aggressive motion. The comparatively huge lens adds off-center weight, might add to stresses on the camera, worsen image vibrations, even cause some shifting or drift. All this is relevant in precision machine vision.

The recommended camera is the ELP 720p, but three is a FullHD model, that has a 720p mode with double the FPS, i.e. 60fps (I have this model):

http://www.elpcctv.com/full-hd-usb-camera-module-1080p-usb20-ov2710-color-sensor-support-mjpeg-with-36mm-lens-p-203.html  --> buy it with a longer lens!

The downside of this camera is that it needs a dedicated USB port on the PC. Two cannot be operated over the same root USB hub, because the needed bandwidth is too high at double the FPS.

I guess there are newer USB 3.0 models that do not have this restriction (likely the following is the camera that is inside that housing you linked):

http://www.elpcctv.com/elp-2mp-sony-imx291-plug-and-play-usb-30-cmos-machine-vision-cameras-for-medical-equipment-p-259.html

That one is just USB 2.0 but has 720p @ 120fps.

http://www.elpcctv.com/elp-high-speed-mjpeg-1080p-60fps-720p-120fps-cmos-ov4689-usb-camera-module-p-101.html

Just keep in mind that the OpenPnP recommendation is there for a reason. On unknown/new camera makes and models, the specs often sound good, but then some setting is missing (e.g. manual exposure) or the compression quality is worse. Time and again there have been disappointments. If have once tried a 120fps global shutter camera, that was nice but had a terrible bug in clipping overexposed parts, creating "psychedelic" false color elements. Unusable for computer vision.

Conversely, if you test a new model positively, please report your findings back here.😁

_Mark

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[vespaman]

I have (afaict) the ELP camera you linked to, but the bare board version of it. (https://www.aliexpress.com/item/32885928557.html?spm=a2g0o.order_list.order_list_main.39.21ef1802i6LAx0 ) (IIRC this is the one that Mark linked to) as upcam on my setup. I chose it because of the IMX291sensor which is good with low light and USB3.0, and can report that it works well.  (OpenPnP reports 49FPS 1920x1080p MJPG, but the YUV FPS is less spectacular). IMX29x is rolling shutter though, so it is not perfect in that sense. (Don't think OpenPnP really cares about this at the moment(?), but for future mabye Global shutter can be supported.

I have not tried with long USB cable. In general, 5 meters USB sound like on the border, esp with a passive ("normal") cable.

Maybe purchase a couple of different lenses while you are at it.

 - Micael

[Sahiru Hettiarachchi]

Thank you Mark, I have decided to go with this camera. It comes with a 5m cable too.

ELP High Speed High frame rate MJPEG1080P 60fps/ 720P 120fps/ 360P 260fps USB2.0 OmniVision OV4689 CMOS USB Webcam Camera Module

I will post my findings as soon as I receive them.

Also I thought to take on Micael's advice too and purchase some additional lenses too.