The EMVA 1288 Standard helps you select a good camera for your system. But we believe that looking beyond the EMVA 1288 Standard helps you get a great camera for your system.
The EMVA 1288 Standard was developed by a working group of sensor and camera manufacturers (Adimec included), vision users, and research institutes within the European Machine Vision Association (EMVA) to define a unified method to measure, compute, and present specifications for cameras and image sensors used for machine vision applications.
The specification parameters that are currently covered are:
- Spectral sensitivity
- Signal/Noise Ratio (maximal SNR, dynamic range, dark noise)
- Inhomogeneities (DSNU, PRNU)
- Defect pixels
For a good explanation about these parameters: http://www.wiley-vch.de/berlin/journals/op/10-01/OP1001_S53-S54.pdf.
At Adimec we support industry standards as they offer customers more options and consistent information. The EMVA 1288 standard has achieved the original goal of providing a fair and quantitative way to compare some of the parameters of machine vision cameras. There are many cameras available, and we understand it is hard to distinguish them, as they can appear similar on paper. The standard also provides camera manufacturers some useful criteria in the development of camera products.
BUT, does it help you decide on the right camera for your application?
With the addition of automated testing equipment on the market (http://www.vision-systems.com/articles/2009/03/comparing-sensors-and-cameras.html and http://www.vision-systems.com/articles/print/volume-16/issue-1/departments/technology-trends/emva-1288-standard-camera-test-systems-go-on-show-at-vision.html) many believed that the machine vision camera selection process had been reduced to reviewing a few test reports. We believe the standard is valuable but not a simple solution.
For example, the relationship between the parameters measured in the standard and the needs of your specific application still needs to be determined. Even if you determine camera A has better linearity than that for Camera B – what do you require for your measurement? There are of course price consequences for the best performance, so you want to know what you need and not simply which is better in order not to over-design your system. You will likely still need to evaluate several cameras to determine how they behave and perform in your system.
Some other big factors to consider are the consistency and reliability of the cameras and sensors which is not addressed in the standard. How does the camera perform over time? How repeatable are different cameras in the same series? For a key component of the system, the life cycle management of the supplier is also important as unexpected changes can be disastrous.
The EMVA 1288 standard may help you narrow down your selection, make a comparison on purely camera specs (or image sensor specs most of the time), and understand camera technology better (all great things), but it does not eliminate the need for an in-house evaluation of the camera and a thorough consideration of the company behind the product.