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Old 01-06-2012, 11:26 AM   #21
Anthony
 
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Default Re: Reality check: Dark Vision and Hyperspectral Vision

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Originally Posted by vicky_molokh View Post
Apparently Infravision is switchable (switching between IR and VS), but Ultravision is not. Funny, that. Especially given that VS+IR is as reasonable a spectrum as VS+UV.
VS+Thermal is a pretty unlikely spectrum -- VS is 400-700 nm (factor of 1.75), VS+UV is about 250-700 nm (factor of 2.8), VS+Thermal is 400-10,000 nm (factor of 25). VS+NIR is a perfectly reasonable spectrum, most night vision gear actually picks up near IR, but it's usually a different sensor for longer than 2,000 nm or so.

Still, it's not like you can't just keep both sets of eyes open; the only animals I know of with IR vision (pit vipers) don't have to close their eyes to use thermal, since they don't see thermal with their eyes anyway.
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Old 01-06-2012, 11:35 AM   #22
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Default Re: Reality check: Dark Vision and Hyperspectral Vision

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Originally Posted by vicky_molokh
Apparently Infravision is switchable (switching between IR and VS), but Ultravision is not. Funny, that. Especially given that VS+IR is as reasonable a spectrum as VS+UV.
Eh? Are you getting that from Basic?

VS is normal vision?
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Old 01-06-2012, 11:55 AM   #23
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Default Re: Reality check: Dark Vision and Hyperspectral Vision

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Originally Posted by Not another shrubbery View Post
Eh? Are you getting that from Basic?

VS is normal vision?
VS = Visible Spectrum.

From Basic Set, final paragraph of UV and IRV respectively:

You can see both visible light and UV: 10 points.
You can switch freely between normal vision and Infravision: 10 points.
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Old 01-06-2012, 12:09 PM   #24
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Default Re: Reality check: Dark Vision and Hyperspectral Vision

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Originally Posted by vicky_molokh
From Basic Set, final paragraph of UV and IRV respectively:

You can see both visible light and UV: 10 points.
You can switch freely between normal vision and Infravision: 10 points.
I have never even noticed the phrasing difference before now. I wouldn't read much into it... since the values for the enhanced vision/alternate vision are the same for both traits, it seems clear that the intention is the difference (if any) between the two spectrums is negligible.
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Old 01-06-2012, 12:11 PM   #25
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Default Re: Reality check: Dark Vision and Hyperspectral Vision

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Originally Posted by vicky_molokh View Post
VS = Visible Spectrum.

From Basic Set, final paragraph of UV and IRV respectively:

You can see both visible light and UV: 10 points.
You can switch freely between normal vision and Infravision: 10 points.
That is odd. I guess the idea when writing IRV was to make the built-in vision ability work like switching the IR feature on and off on your night-vision goggles, except these are your eyes. Or maybe it was deemed that generally you wouldn't need IR when VS was present. Then again, obviously it'd be annoying to have to toggle between them all the time, even if it is a free action as I read it.

I'd say it's a +0% switch to have it either work as written (switch freely) or work like UV (VS + IR all the time). After all, you can theoretically just declare you're switching back and forth all the time. The benefit of having it on all the time - seeing clearly via the VS which also gives you colours, and being able to detect heat sources (or the suspicious lack of heat, as in creatures with no body heat trying to pass as normal) all at once - seems like it balances out with the possibility of being temporary blinded by a sudden intense burst of IR light that people without IRV might only perceive as warmth.
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Old 01-06-2012, 01:16 PM   #26
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Default Re: Reality check: Dark Vision and Hyperspectral Vision

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Originally Posted by Not another shrubbery View Post
I have never even noticed the phrasing difference before now. I wouldn't read much into it... since the values for the enhanced vision/alternate vision are the same for both traits, it seems clear that the intention is the difference (if any) between the two spectrums is negligible.
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Originally Posted by JCurwen3 View Post
That is odd. I guess the idea when writing IRV was to make the built-in vision ability work like switching the IR feature on and off on your night-vision goggles, except these are your eyes. Or maybe it was deemed that generally you wouldn't need IR when VS was present. Then again, obviously it'd be annoying to have to toggle between them all the time, even if it is a free action as I read it.

I'd say it's a +0% switch to have it either work as written (switch freely) or work like UV (VS + IR all the time). After all, you can theoretically just declare you're switching back and forth all the time. The benefit of having it on all the time - seeing clearly via the VS which also gives you colours, and being able to detect heat sources (or the suspicious lack of heat, as in creatures with no body heat trying to pass as normal) all at once - seems like it balances out with the possibility of being temporary blinded by a sudden intense burst of IR light that people without IRV might only perceive as warmth.
Yeah, I'm with you two on the opinion that it should / could be bought as non-switchable two-in-one.

Regarding colours: AFAIK, IRV has colours too - objects don't emit/reflect IR radiation uniformly across the spectrum; different do more or less in various sections of the spectrum, just like various objects reflect VS light non-uniformly. Okay, not 'just like', but you get the idea.
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Old 01-06-2012, 01:35 PM   #27
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Default Re: Reality check: Dark Vision and Hyperspectral Vision

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[...]However, thermal sensors usually have trouble spotting objects that aren't significantly warmer than the sensor, and because all room-temperature objects glow more or less equally, contrast is lousy; undead wouldn't be invisible to IR, but they might well have a couple levels of chameleon against it.
I've seen plenty of IR photos with very low contrast between similar-temperature things, but I wonder how much the situation could be improved (at potentially high cost for technological solutions). From the images I've seen, it looks like most IR imagers basically sample a single wavelength (or get one signal from many combined wavelengths) and produce a grayscale image. How much could the image be improved if the imager had 3-4 sensors that each detected different wavelengths and could then produce multiple channels? With multiple channels, you could use Tone Mapping algorithms to merge the images while still keeping the contrast from all the images.
In fact, I've always wondered why (as far as I know) IR images only use the (presumably) single IR channel and don't even bother using VS-range channels (cheap to image) with tone mapping to provide more detail under all conditions.
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Old 01-06-2012, 01:50 PM   #28
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Default Re: Reality check: Dark Vision and Hyperspectral Vision

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Originally Posted by Extrarius View Post
I've seen plenty of IR photos with very low contrast between similar-temperature things, but I wonder how much the situation could be improved (at potentially high cost for technological solutions). From the images I've seen, it looks like most IR imagers basically sample a single wavelength (or get one signal from many combined wavelengths) and produce a grayscale image. How much could the image be improved if the imager had 3-4 sensors that each detected different wavelengths and could then produce multiple channels?
Unless there's significant differences in emissivity at different wavelengths, which isn't the case for most materials in the thermal infrared band, it doesn't do very much for you.
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Originally Posted by vicky_molokh View Post
You can see both visible light and UV: 10 points.
Which is grossly overpriced, but the advantage probably also does too much. Ponder how to more appropriately redo senses. Some thoughts:
  • Enhanced Color Perception: 1
    You see more colors than a normal person, though the range of wavelengths you can see is unchanged. Grants +1 per level to vision tests related to color perception. The main combat use is to counter camouflage and chameleon effects. Without ECP, characters see only three colors regardless of their actual visual range, though those colors don't have to be the same as human vision colors.
  • IR Vision(Near): 2
    You can see near infrared, in the 700-1,400 nm range. Allows seeing and using infrared flashlights and some infrared beams in the relevant wavelengths, and grants +2 night vision when the ambient light source is a fire or incandescent bulb. This substantially increases your ability to spot hot objects, objects as cool as 500 degrees are visible in darkness and at 1,000 degrees are faintly visible in daylight.
  • IR Vision(Short): 5
    As Near, but you can see down to 3,000 nm, and the bonus is +4 for firelight. Objects at room temperature glow visibly if the background light is sufficiently dim, in total darkness you're at -3 to spot boiling objects, -5 to spot human body temperature, -7 for room temperature objects, -8 for freezing objects.
  • UV Vision(Near): 1
    You can see near ultraviolet, in the 250-400 nm range. This allows using ultraviolet flashlights and seeing ultraviolet beams; it has few other applications, since ultraviolet light propagates poorly in the atmosphere and with natural sources is inevitably much dimmer than visual light. UV vision is a good excuse for enhanced color perception, but does not include it by default.

Last edited by Anthony; 01-06-2012 at 02:17 PM.
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Old 01-06-2012, 01:53 PM   #29
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Default Re: Reality check: Dark Vision and Hyperspectral Vision

Possibly because false-colour imaging tricks human visual systems into doing stupid stuff, and human brains into doing stupid stuff. You can overcome it when you're sitting at a desk analyzing telescope data or satellite imagery, but when you're in a combat situation (which IIRC most of this tech was initially developed for) you don't want to have random eye-brain interface farts.

Well, that and 3 different sensors costs more than 3x one sensor, makes the assembly bigger, gives it more parts to fail, and makes the software more complicated which means more expensive and more likely to have bugs.

Which might be a bigger factor, even with civilians without life-or-death situations on the line.
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