What to consider when interpreting an EMVA1288 report
The EMVA1288 standard is a great standard – it assures that everybody speaks the same language. So you avoid having to ask questions like: how do you define your dynamic range, temporal dark noise, or saturation capacity. Or if you forget to ask that question and you find out later that you where not talking about the same definition. That could even cause bigger confusion.
EMVA1288 thus removes the fuzz about definitions of important quantities that are used to characterize a camera.
However, this does not mean you can just ask a camera manufacturer to provide you with the EMVA1288 report for a specific camera. Some camera manufacturers might provide you one but in general asking that question won’t give you the right information. The report you get is probably measured with the standard camera settings that are probably okay for most people or at least provide a good enough outcome on some of the characteristics covered in the EMVA1288 reports.
And if you are reading this blog more often you already know that a camera can be optimized to your application. This is the reason that a single camera model does not have one but a multitude of EMVA1288 reports, and they are all true.
To give you an example, some sensors provide the possibility to adjust a parameter called programmable gain amplifier (PGA). This parameter applies a, in general, analog gain to the detected video signal. In some cases this gain causes a lower noise floor compared to using digital gain or if you do not apply any gain at all. In our new Adimec 50 MPx S-50A30 camera, we allow the user to use this gain. So we performed some EMVA1288 measurements to find out what would be the profit. The results are listed in below table.
|Gain||Overal system gain||Temporal dark noise||SNRmax||Absolute sensitivity threshold||Saturation capacity||Dynamic range|
|1||0.282 DN/e-||8.12 e-||41.4 dB||8.70 e-||13651 e-||63.9 dB|
|4 (PGA)||1.090 DN/e-||7.75 e-||35.4 dB||8.27 e-||3435 e-||52.4 dB|
|4 (Digital)||1.085 DN/e-||8.69 e-||35.4 dB||9.21 e-||3481 e-||51.5 dB|
As you can see, this already gives 3 different EMVA1288 reports for 1 camera. If your application would need a large saturation capacity then you would not be happy with reading from the other two reports. However, if you are fighting the sensors detection limit or if you require a minimal temporal dark noise you might actually be interested to read the other reports. Although the differences are small with a gain of one you could at least learn that when applying a gain it would be better to use the PGA instead of applying digital gain.
So the take home message is that the EMVA1288 standard is a great standard as it defines a language with which we can speak about camera characteristics and everybody knows or can look up what definition of that characteristic you use. You could probably say EMVA1288 is like a dictionary. However you have to keep in mind that a camera can often be configured in several ways. One camera can thus have multiple EMVA1288 reports that are all true. If EMVA1288 is the dictionary it still matters how you choose your words just like with any language!
Do you need help translating any system requirements to EMVA1288 measurements? Contact our support engineers.