Anonymous asked in Science & MathematicsPhysics · 2 years ago

Would a camera that emits light be able to see in the dark?

I think this is how night vision cameras work, but my main concern is, would a lens that emits light also be able to interpret light. Or would that be too much interference?

I’m not actually working with cameras or anything, I was mostly thinking about superheroes that could turn into fire or light or have light coming from their eyes (and fictional robots with light up eyes.) In real life, would they be unable to see? Would they be blind even during the day? I can’t seem to find much on the internet about this...If you explain your answer please use technical terms I can research, thank you.

8 Answers

  • 2 years ago
    Favorite Answer

    I think technically the superheros could. The ones that full body glow in the IR probably emit hundreds of times more IR from their bodies than their eyes, so they could just use a cutoff above the amount emitted from the eyes at the eye surface.

    Also, why assume the IR comes from the retina, there is lots of inside the eyeball that could emit light besides the retina.

    Also, even on the retina you could have light emitter cells positioned between rods and cones. Some phones actually have screens that both emit light and can see at the same time. I saw two patents where they use light sensors between the pixels This search query ("patent phone screen detects light") mentions one at the top of the page and a little further on one from Apple.

    So that covers Johnny from Fantastic Four and Superman.

  • John P
    Lv 7
    2 years ago

    Night vision cameras which have light sources emit infra-red light from "lamps" near the camera lens, but not actually passing out through the camera lens.

    Mostly night vision cameras "see" the infra-red light emitted by living things and other sources of infra-red.

  • 2 years ago

    Technically, any light source IS NOT part of the camera. That side, MOST night vision cameras are sensitive to light levels not detectable to the human eye. MANY use infrared light, which is just outside of the visible spectrum of the human eye at the 'red' side. Some such cameras do have infrared light sources attached to them, but not all. Infrared frequencies are also associated with heat. Most living things emit enough infrared energy to be detected by infrared cameras.

  • 2 years ago

    Many camera systems use an IR Led to illuminate the scene in dark.

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  • 2 years ago

    Well, fundamentally, if the camera emits light then it is no longer dark. Night vision does not work by emitting some sort of light (that would generally make the night vision user a target, which is the opposite of what is desired). Night vision works by enhancing the intensity of the small amount of light that still exists (they get washed out, flooded by whiteness, if intense light is around). IR systems take infrared or longer wavelength light that is not visible to our eyes, and changes the wavelengths into ranges that our eyes can see. It is a false color image.

  • 2 years ago

    I have many security cameras that emit their own light. (Usually it is infra red but that is of little concern ).

    A ring of LED lights around the lens does the illumination. The light is not put through the lens because this would interfere with image formation.

  • Vaman
    Lv 7
    2 years ago

    I am not a technical person. Here is the idea of night vision camera. We have regular LCD cameras in our mobile. When the wave enters, it creates a charge separation. This charge separation is converted into visible light by equating one to one i.e. amount of charge separation to a given colour by you. These are called as charge coupled devices. You take a photo with ccd. Each wave of a given colour creates a charge separation of known amount. If you know the amount give a colour to it. The same thing can be done with infrared camera. First calibrate it for various infrared frequencies and then give a colour code to it. Any picture can be given any code that you like. In nut shell calibrate semi conductor for charge separation for various infrared frequencies. Assign colour codes. Now you have an infrared camera.

  • Anonymous
    2 years ago

    No, this isn't how night-vision works, that's how camera flashes work. In actual fact, you'll notice that the light-emitting portion (the flash) is offset slightly from the camera lens. That's because the output light can't come from the exact same spot as the camera lens that takes in the images. You can try to get the output flash and the input lens as close as possible, but at some point the flash will blind the lens if it's too close to each other.

    As for night vision cameras. That works differently. That uses body heat to light up the images. Body heat is also a type of light, but it's invisible to human eyes, it's called infrared light, meaning it's redder than the reddest colour you can see with your eyes. Human eyes may not be able to see these lights, but camera lenses certainly can. So pretty much all living things on Earth produce infrared heat, even yourself, and you can use this fact to act as a light source for your camera.

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