Witch machine vision camere and lens


#1

Hello,
I see a lot of machine visioncamera’s passing.
Witch one do you recommend and witch lens for 16 mm and normaal 8 mm.
I dont have a clou.
thx,
Wim


#2

In the realms of affordability for most people, the Schneider Componon (-S) 50mm lens, mounted backwards will give you excellent results, in a small form factor at a reasonable price.
To get better results is certainly possible, but you will be paying 10x as much.
The 50 will work from Regular8 up to 35mm and is very sharp, with great colour rendition. I typically run it at f4-f7 or so, once you get past f11 we find we get softness due to diffraction softening.

As for a machine vision camera, I’d recommend one of the Point Grey Research USB3 or Gig-E cameras. We tested nearly 100 cameras and the PGR ones have less noise and better dynamic range than other manufacturers, even when the sensor was identical. They seem to put a lot of effort into the electronics design, to keep the noise low. The PGR cameras had siginificantly better results than the Imaging Source cameras for example, and we can only put this down to better design on the electronics side.
Also the internal processing seems to be better on the PGR cameras. The trigger is also more reliable than most other brands we tested. In other words, they just worked and gave good results, whereas the others had image quality and other issues (some had ghosting, tearing, dropped frames, more noise, interference problems, heat issues etc.) or were just flaky for use where dropping a frame is a big problem.

They have an affordable line with the Chameleon and Blackfly range, and larger sensors and resolution in the more expensive Grasshopper range.
Make sure you pick up the interface/trigger cable and tripod mount-plate when ordering the cameras as you will most certainly want those.

There are cheap webcams, and cheap sensors out there, but most are more hassle than they are worth, and you end up spending more as you buy one, then end up buying something else, and then a third when you hit it’s limitations and so on.

Look for at least 3.4 micron pixel size if you want decent response in the dark areas, ideally 5 micron or larger. Anything under 3 microns will give poor dynamic range, regardless of what the marketing material might say, the pixels are just not large enough to capture enough photons.


#3

Great summary, Peter. I’ll be coming back to this myself when I"m ready to order new equipment. One question - how does one mount a lens backwards?


#4

Most lenses have a thread on the front to take filters, so you simply use an adapter that suits the filter diameter of the lens.
If you put “reverse lens adapter” into ebay, you will see a range of them.


#5

Peter, I’ve looked on ebay and find two Componon 50mm lenses. The “-S” version seems to have an aperture of f2.8 but there’s another variant without the “-S” that has f4.0. Is there any real difference between the two for this application? The f4 version seems to be 1/3-1/2 the price.


#6

Since I tend to capture at around f5.6 anyway, probably not, but I haven’t had the f4.0 lens myself for testing.


#7

Hi, Peter. Thanks for the interesting post. I have a question about lenses for cameras like PGR. Wide angle lenses (approx 120 degrees) needeed for the purpose of building SLAM system. Which one (or manufacter) you could recommend ? Guess focal length should be fixed and it should be 2 mm (for such an angle). Also guess another crucial parameter for such lenses is distortion. Btw, lets assume lens should have C-Mount bayonet and suitable for SONY IMX174 sensor.


#8

I assume by SLAM you mean a Simultaneous Localisation and Mapping setup?
I don’t have any experience with wide angle lenses for machine vision cameras, I’d talk to Point Grey or Lumenera for some recommendations.


#9

Hello

I do not no if this is the right place to ask this. But i try.
I have for a few years used DFK 31BU03 camera. The camera was trigged with a 5 volt puls from the projector. Now i have bought a point grey grasshopper camera. But i do not understand how to trigger this camera. Which GPI0 pin should i use and how many volts. Have asked pointgrey but the not get responded.

Mats


#10

Matt,
As described eartlier, My super8 setup uses a film plate from a B&H projector which matches the film frame. That means that there are no sprocket holes in the frame scans for software such as your extraction software.
My first choice for film movement was the intermittant option based on stepper motor moving the film, Having read your posts, the continuous motion option with mechanical trigger and LED flash seems to be better, avoiding frame float. However, I am concerned about the ability to trigger the machine vision camera at the right time, repeatable at a reasonable rate. In addition, I am very week on the computer capture software end of the process, and how to string all the .jpg images together. I have been using the NCH “debut” software to display the frames while working the kinks out of the lens, framing, issues. Is there an inexpensive software package that you recommend?
Lastly, doing a little research, I ended up with a 12mm FL, S mount, M12 lens with my 5mp machine camera which gives a full frame at approx 25mm spacing from the film frame. Do you know of a barrel extension for m-12 lens? I am using a paper tube which lacks mechanical stability and adjustability for focus.
Sorry about mixing topics, as they are all related.
Lastly, What color temp LED package do you recommend?
Thanks,
Tuneturkey


#11

Matt,
in all the forum posts, i have not read anything about shutter speed for either the DSLR or a machine camera.
If using the constant moving film approach, the camera shutter must be able to capture a clear and focused image.
With the machine camera, the global shutter does not appear to be adjustable. What do you recommend for the camera shutter speed and how do yo set it?
Or am I missing something, and if you use a machine camera with global shutter, the flash duration controls the exposure.
Help!
Tuneturkey


#12

@tuneturkey sorry for not responding sooner. I don’t have any advise as far as extension barrels are concerned. But there are some other posts about that. Heres one with a picture:

http://forums.kinograph.cc/t/image-sensor-optical-components/44/49?u=matthewepler

As for the shutter speed, this is totally dependent a few factors:

  1. Distance of camera from film
  2. Speed of film
  3. Light source brightness

The flash duration can be controlled by the microcontroller in the Kinograph setup. In some versions, people just leave it on since it doesn’t get that hot. In other words, the flash is not as much a factor as the others listed below.

Basically you would just do some experimentation to find what settings work. If you need more technical details, you could look at the specifications of your camera’s imaging sensor and find out what distance/time relationship will result in pixel blur when photographing a moving object.

M


#13

Matt,
Thanks for the response.
your assessment regarding film speed is in line with what I have read. I was hoping to get some pearls of wisdom based on your experimentation.
I am still working with a sensor by Leopard Imaging ( www.leopardimaging.com) which is modestly priced, 5mp CMOS,
much like the Pi camera, except USB. Take a look at the site as they carry a full range of sensors.
I have completed my hardware setup and am looking at frame processing for super8 film. have you made any progress in converting your processing software for use with 8mm?
My telecine setup uses parts and pieces from a bell and Howell Projector, including the film gate, pressure device and aperture opening from the projector. That means that all you see is the film frame, no sprocket holes. I have followed your design and using the projector sprocket wheels attached a roller limit switch for actuating the camera shutter.
With this I had hoped to run the film slowly per your design (2 fps or so). However, the camera film blur issue comes into play, and also even if successful, how do I process the resulting frames into a movie file.
There is alot of real complicated stuff on the forum, but not a lot of material we simple people can deal with.
I will photograph my setup (which is crude) but may be of value for others lacking the explicit technical know how!
I have used most of your design details with stepper motor driving a sprocket which pulls the film across the gate, the LED setup, and more.
I have a lot of other questions to ask, but the forum back and forth is some what slow.
Don’t misinterpret by comments, the forum is great and I have learned a great deal from it.
Thanks,
tuneturkey


#14

@tuneturkey feel free to email anytime with more questions if you’re looking for a faster response: matthewepler@gmail.com


#15

I’m not sure if it matches your requirements exactly, but how about this low-cost visionsensor?


#16

Cool little camera! We cannot use a front-light system, however. The image must be back-lit. Also, the dynamic range for this camera is likely lower than we want it to be. But the company does look interesting. Thanks for sharing!