Machine vision camera vs commercial DSLR

[chulminy]

HI.

I'm finding high resolution cameras for stereoscopic application (expriment).

Does anyone know what differeence between machine vision camera and commercial DSLR?

Aside from frame rate and possibility of computer connection/control, commercial DSLR has better pixel resolution than one for machine vision if they are similar price.  

I don't know why there are very few application using commercial DSLR. 

Is there any difference between Raw files? I mean I don't know whether the Raw file from cannon or Nikon and one from machine vision sensor are different. 

I read below article in this forum but I'm still wondering pros and cons to use commercial DSLR as experimental purpose?

(http://forums.ni.com/t5/Machine-Vision/Can-I-use-Multiple-DSLR-cameras-with-my-LCD-application/td-p/...

Thanks

[MoviJOHN]

Without a doubt, a professional DSLR will deliver great images, even by machine vision standards, and there are certainly applications where using one would be as good, or better than using a machine vision camera.

Machine vision cameras usually include hardware which targets very specific requirements, such as triggering, pixle binning, frame rate control, high speed transfer interfaces (GigE and CameraLink...).  The DLSR cameras fall short in these other areas.  It's debatable. 

[Klemen]

Hello,

try checking this out (this is not an advertisment!!! ):

http://www.scannerkiller.com/

They call it a scanner killer!

I saw this on a conference exhibition a couple years ago (using two DSLR cameras). The processing time was quite long, but that was really some high resolution 3D data.

Best regards,

K

[MikeeB]

Never use a DSLR for a machine vision application. Even a professional DSLR is meant to take and image every second for an 10 minute shoot. It will then get a lot of downtime. A machine vision camera is intended to take a shot every second 24 hours a day and 7 days a week. Think of the mechanical action of the mirror that must move out of the image path in a DSLR. The image may be higher resolution, but actual pixel sizes will shrink as your resolution goes up so your light sensitivity will drop. Mounting of the DSLR is hard as it is in essence a portable device and the tripod mount is inherently bad for permanent mounting. Lenses will also come into play as the MTF of a DSLR is not going to be very high when compared to a machine vision lens. 

Overall a machine vision camera will last longer, give more accurate, sensitive results in a repeatable fashion. The DSLR will give a higher number of pixels, its actual resolution on the resultant image will not be as high as you think due to many many factors.

Mike

[GuenterMueller]

Thanks Mike for the pretty detailled explanation with the focus on the right issues.   I will send a link to your post whenever this question is (again ) passed to me.

[SeeInTheSeas]

Hi Mike - I'm new to machine vision cameras and had the same questions as the OP. Your answer is very helpful. Has anything changed in the past 11 years? Would your advice change for different applications (e.g., low light)? Thanks!

[AmitShachaf]

Hi,

I am actually integrating Olympus DSLR in one of my solutions. 

There are multiple considerations that you need to take when going the DSLR direction.

1. Disadvantage - Most DSLR has mechanical shutter. DSLR sensor doesn't have electronic shutter in low speed. Mechanical shutter is rated to 50K images at low level DSLR to 500K on the professional expensive ones. The new Nikon top of the line full frame camera has only electronic shutter. But that is exceptional new camera.

2. Disadvantage - Not all DSLR cameras has good communication standard that can push the images into PC in real time. The processor in the camera is designed to save very fast to memory card. Not to USB interface.

3.  Disadvantage - Not all DSLR cameras has good SDK to program with. You have to make sure you have good SDK.

4. Advantage - You can use the autofocus system of DSLR. Usually very good an precise. 

5. Advantage - You have great selection of lenses with internal auto focus. 

6. Advantage - If you use DSLR you have very good encapsulation of autofocus + saving to SD Card in very high frame rate. 

Summary - For some application DSLR can be a real good solution. Great image quality + Good auto focus + Saving to SD card + Showing the Image on HDMI display. But for machine vision when the camera is sending images 24/7 in full rate. DSLR will go out of commission very fast.