How big is the difference between FOM 1661 and 1979?

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Till now, in our comparability blogs we have now in contrast ECHO to a GEN3 and different GEN2s. You possibly can learn all about it here.

Nevertheless, we have now by no means in contrast ECHO vs ECHO to reply a query “how large is the distinction between FOM 1600 and FOM 1900?“. Now, we’ll attempt to cowl that query with examples.

Specification of Check Models

Allow us to begin by evaluating specification sheets of the chosen take a look at models. As you’ll be able to see in desk under one unit is with FOM 1661 and one other is FOM 1979.

A000743

Spots rating*	8/10
FOM	1661
Decision	67
SN	24,79
Acquire	10022
EBI	0,05
Picture alignment	0,04

A000745

Spots rating*	7/10
FOM	1979
Decision	67
SN	29,54
Acquire	10831
EBI	0,07
Picture alignment	0,31

Let´s discuss FOM

Official definition – FOM or the Determine of Advantage, is a quantity calculated by multiplying the signal-to-noise ratio (SNR) by the decision of an evening imaginative and prescient picture intensifier. FOM quantity permits rapidly estimate basic efficiency degree of the particular evening imaginative and prescient picture intensifier, and consequently the evening imaginative and prescient machine constructed round it.

Principally:

FOM = SNR x Decision.

How a lot does FOM really have an effect on efficiency?

Since decision for ECHO tubes is just about the identical throughout completely different gadgets (normally round 65-68), then the principle distinction in FOM comes for the Sign‐to‐Noise Ratio.

What’s Sign‐to‐Noise Ratio (SNR)?

Sigal-to-noise Ratio definition by Phtonis:

Therefore, the upper is the determine of SNR, the much less noise / extra sign you get in low mild environments.

Let’s put that to check!

Beneath you’ll be able to see footage taken with test-devices in numerous low-light environments. So you’ll be able to choose outcomes your self.

As you see we should agree that there’s barely extra noise on the left footage the place machine has decrease SNR.

On this image above we are able to already discover extra important distinction in picture high quality in low mild circumstances. Within the image on the best aspect you’ll be able to nearly see completely different objects on the background, however on the left aspect it’s extra blurry. However let’s see another shot …

What has occurred right here? Why decrease FOM unit has extra clear image? It nearly appears that unit with increased FOM is unfocused. The reply is that the unit on the best has increased picture allignment. The decrease the allignment, the extra focus you may get out of your machine.

A Comparability Video of Check Gadgets (FOM 1661 vs FOM 1979)

Conclusion

Primarily based on the video and the images above, we are able to all agree that increased FOM unit performs barely higher in low mild environments. However, the distinction is just not large, even when evaluating devises with such completely different FOM scale. To be hones, except you examine models side-by-side, you’ll most likely not even discover the distinction. The distinction in picture high quality is just not as dramatic as evaluating normal GEN2 to ECHO.

As well as, we have now noticed to this point that the upper FOM ECHO models are normally a bit extra spotty or have another non-desirable attribute increased (EBI, Picture Alignment). Why? As a result of if the unit goes above FOM 1800+, then firstly this unit is taken into account to be 4G. If throughout evaluation some the attribute doesn’t meet the 4G necessities, then it’s labeled as ECHO machine.

In our case with the test-device with FOM 1979 – the picture alignment is a bit too excessive for the unit to be thought of for 4G. So, it was labeled as ECHO as a substitute.

Questions? One thing doesn’t make sense?
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