TGP variables

[-Cipher-]

Hello people

can someone explain what is the definition of each one of these variables in a targeting pod
-Gain
-Level
-Contrast
-Brightness

as far as I've understood the Gain and Level are only related to IR-Imagery
gain is the sensitivity of the sensor to heat and IR-signature and gain does something with the background

Contrast is used to intensify the brightness i.e as we increase the contrast , dark parts get darker and brighter spots get brighter such as shadows getting darker

I would be glad if somebody explain the definition of each of those because I don't know if I know right
if it's possible please  suggest me some sources , pdfs or books to assist 

Sincerely

[twistking]

2 hours ago, -Cipher- said:

Hello people

can someone explain what is the definition of each one of these variables in a targeting pod
-Gain
-Level
-Contrast
-Brightness

as far as I've understood the Gain and Level are only related to IR-Imagery
gain is the sensitivity of the sensor to heat and IR-signature and gain does something with the background

Contrast is used to intensify the brightness i.e as we increase the contrast , dark parts get darker and brighter spots get brighter such as shadows getting darker

I would be glad if somebody explain the definition of each of those because I don't know if I know right
if it's possible please  suggest me some sources , pdfs or books to assist 

Sincerely

You are correct about Gain. It's basically signal amplification.
Level should be brightness of the signal basically. Note that increasing Gain is not the same as increasing signal brightness/Level. If you have an image processing software like photoshop you can think of Gain as "Exposure" and Level as "Brightness". If you are not familiar with image science, maybe just read about Exposure and Brightness or play around with Exposure vs Brightness in any image software...

Contrast is just that. Contrast. I think the contrast value is the contrast for the screen (MFD) and does not change the signal itself.

Brightness should be brightness of the screen (MFD). If you think in photoshop terms, "Brightness" would then be equivalent to changing your actual monitor brightness instead of changing the image file...

*edit* These aspects can be a bit weird, because if you think about it, you have a simulation of a virtual signal on a virtual screen (MFD) on a physical screen (your monitor or VR headset). In DCS you really only need (MFD) Brightness to change the virtual display for night or day flying. So when the sun sets, put the brightness down, so you are not blinded (and vice versa).
If you want to optimize the FLIR picture you can use manual Gain, but i rarely do that. It's only really needed when auto-gain struggles in some high contrast situations. You could then further fine tune with Level to avoid signal clipping.
I never use contrast, because i believe this is only a setting for the screen - not for the signal. Would have to check about that next time i fly. Which module are you flying by the way (there might be small differences between different modules)?

*edit2* random google search for exposure vs brightness (gain vs level): https://www.youtube.com/watch?v=Cs72Ksja0vk haven't watched it, but i'm sure it's fine.

 

Edited August 16, 2022 by twistking

[-Cipher-]

15 hours ago, twistking said:

You are correct about Gain. It's basically signal amplification.
Level should be brightness of the signal basically. Note that increasing Gain is not the same as increasing signal brightness/Level. If you have an image processing software like photoshop you can think of Gain as "Exposure" and Level as "Brightness". If you are not familiar with image science, maybe just read about Exposure and Brightness or play around with Exposure vs Brightness in any image software...

Contrast is just that. Contrast. I think the contrast value is the contrast for the screen (MFD) and does not change the signal itself.

Brightness should be brightness of the screen (MFD). If you think in photoshop terms, "Brightness" would then be equivalent to changing your actual monitor brightness instead of changing the image file...

*edit* These aspects can be a bit weird, because if you think about it, you have a simulation of a virtual signal on a virtual screen (MFD) on a physical screen (your monitor or VR headset). In DCS you really only need (MFD) Brightness to change the virtual display for night or day flying. So when the sun sets, put the brightness down, so you are not blinded (and vice versa).
If you want to optimize the FLIR picture you can use manual Gain, but i rarely do that. It's only really needed when auto-gain struggles in some high contrast situations. You could then further fine tune with Level to avoid signal clipping.
I never use contrast, because i believe this is only a setting for the screen - not for the signal. Would have to check about that next time i fly. Which module are you flying by the way (there might be small differences between different modules)?

*edit2* random google search for exposure vs brightness (gain vs level): https://www.youtube.com/watch?v=Cs72Ksja0vk haven't watched it, but i'm sure it's fine.

 

 

Thank you for your reply and sorry for my latency in response
I got all the modules with optical sensors except Harrier , JF-17 and Gazelle 
so as I have understood so far 
this might be a scenario which we may need manual display and flir optimization 
in a dark night mission cold start ; we should adjust the brightness and contrast for use of the MFD relative to the lighting condition and then as we use the flir if we need more brightness instead of touching the brightness knob we make the adjustments with "Level" variable

one last thing for me to fully understand is the conditions of gain adjustments
"if we are looking at an environment where the temperature difference between the warm and cold objects are relatively high i.e 
a snowy day with ground covered with snow
in this situation if we spot a human since the temperature of human body is way higher than the rest of the picture , flir can easily spot and we can easily discriminate the human from most of the things in scene
so in a scenario like this is it better to increase the gain to pickup warmer objects more easily??
vice-versa we have a town in hot desert full of people , dogs and many hot objects.....should we decrease the gain and give it a little of level?
correct me if I'm wrong 

[twistking]

... disregard

Edited August 17, 2022 by twistking

[twistking]

  

2 hours ago, -Cipher- said:

Thank you for your reply and sorry for my latency in response
I got all the modules with optical sensors except Harrier , JF-17 and Gazelle 
so as I have understood so far 
this might be a scenario which we may need manual display and flir optimization 
in a dark night mission cold start ; we should adjust the brightness and contrast for use of the MFD relative to the lighting condition and then as we use the flir if we need more brightness instead of touching the brightness knob we make the adjustments with "Level" variable

one last thing for me to fully understand is the conditions of gain adjustments
"if we are looking at an environment where the temperature difference between the warm and cold objects are relatively high i.e 
a snowy day with ground covered with snow
in this situation if we spot a human since the temperature of human body is way higher than the rest of the picture , flir can easily spot and we can easily discriminate the human from most of the things in scene
so in a scenario like this is it better to increase the gain to pickup warmer objects more easily??
vice-versa we have a town in hot desert full of people , dogs and many hot objects.....should we decrease the gain and give it a little of level?
correct me if I'm wrong 

I have the A-10, F-18 and F-16 when it comes to TGP equipped aircraft. Just in case that there might be differences in the implementation.

Yes, the MFD brightness is used to set the MFD to a brightness that suits the ambient light the same way you turn your smartphone display brighter when you are out in the sun. It should not have any influence on the signal. Set it up so that it's "appropriate". You also need thsi when you are not dealing with TGP, but have other stuff up on the MFD.
Contrast should be the same, only that you don't really have to use it. In real life displays can loose contrast over their lifetime, so it might be good to increase the contrast to compensate for that. Your computer screen has a contrast setting too, but you probably never use it. It is mainly "set and forget" (or "leave it at default and forget").

If the MFD brightness is set up appropriately for the ambient light it would technically be correct to use gain and level to adjust the FLIR image, however in DCS i find it often quicker to just change the MFD brightness. I guess you would not do this in real life. In DCS there isn't that big of a negativ effect of doing it. It's the weird simulation of a screen on a screen... So while it's technical a big difference, in DCS it's not.

With the Gain and Auto-Gain i suspect that in real life manual Gain is more useful, since you will encounter more difficult conditions where Auto-Gain will struggle more. In DCS i only found one situation where manual Gain is needed and that is when you have sunlight and cloud-shadows in the same scene and the Auto-Gain exposes for the shadow, while you want to see the sunlit area or vice versa. In these situations part of the images are blown out and get completely white or black since the dnymaic range is not enough. With manual gain you can expose for the area you want. Alternatively you can just zoom in until the Auto-Gain exposes for the area you are looking at.

Generally when you have good contrast between targets and landscape auto-gain should work fine. It gets difficult when you have no or low contrast between targets and landscape. In these conditions you could try to play around with manual Gain AND levels to improve the contrast of the whole scene, which might be helpful to see targets a bit easier, but it won't magically increase the contrast between target and background.

*edit* to play around wit manual gain, i'd suggest a mission around noon or early afternoon (high sun) and a single layer of clouds. This gives you massive contrast in TV and FLIR and might be good to toy around with manual gain. Start zoomed out and notice how auto-gain changes exposure depending on where you aim at and how some areas are totally over- or udnerexposed, while manual gain gives you full control.

Edited August 17, 2022 by twistking

[-Cipher-]

Thanks a lot @twstking for your time clarifying to me