30-09-2021, 01:50 PM
(This post was last modified: 30-09-2021, 01:53 PM by Mike Watterson.)
Apart from having worked with Video and TV for the day job, on and off from 1973 to 2008 and the interest in Vintage R&TV (from 1966) I researched the concepts for an SF series with Aliens I started in 1989 and seriously was working on from 2012 till now.
1) Our colour TV only really works for humans and not perfectly for all humans. Even on Earth different creatures have different colour perception in our visible spectrum. Some creatures really only have monochrome, some like dogs have a very different response basically two "primaries". Some birds have IR vision. Some birds and insects can see UV (some women may have this tetrachromacy but the UV is mostly blocked from the retina). The pigeon may be pentachromatic. See below about Rods & Cones.
2) Frame rate. Guinea pigs need to spot movement so it might be why their perception of motion is much higher than ours which kicks in about 12 fps but some of us can see 50Hz flicker, but only at the edge of vision. Regular TV might be simply separate frames to guinea pigs.
3) Organisation. Leaving aside mechanical scanning and film frames, or colour, even a purely electronic system needs to serialise image transfer either on cable, RF or inside the electronics. You either do rows and then the pixels along the rows (R to L or vices versa), or columns and then the pixels on a column (Up to Down or vice versa). Obviously if you start with scanning film frames as an electronic source the same applies, except a movie projector inherently wants vertical spools (Stills can use either and has done), so you have rows first and the order depends on the film transport direction, which seems to have been an arbitrary choice.
4) Cameras vs display. A camera is a lot trickier than a display. Your display can have a brighter source if mechanical. Mechanical cameras and Philo Farnsworth's camera only sense light at one pixel element at a time as it's scanned, so as the resolution is increased it's quickly uselessly insensitive. A suitable electronic camera needs to accumulate charge from the light during the entire frame. It's true that the sensor sensitivity does drop as the resolution is increased, but you can keep the pixel element the same size and use a larger image area and bigger lenses. Not possible with the mechanical cameras and Philo Farnsworth's camera. So you can imagine an Alien civilisation that uses film cameras, doesn't have Baird's clever processing and wet scanning in the camera, but has electronic displays.
Rods and Cones. Generally rods are thought to be more or less insensitive to hue (but are not be the same range of spectrum in different creatures here) and Cones do colour, somehow. Colour perception is always overlapping curves. So a set of R G and B LEDs matched to peaks may give a good simulation. More colours or wider band sources may be better, but LEDs will produce some colours more saturated than filters on LCD or phosphors. OLED may use phosphors and filters. LCDs might use R G B LED backlights, CCFL tube backlights (mercury discharge + phosphor) or "white" LEDs (really blue to violet or UV with phosphors) or in a projector: LEDs, incandescent lamp or xenon discharge.
There are three theories as to how the Cones actually work . Unlike a single tube/chip camera they may not use pigments (a filter).
So Aliens and us can use the same monochrome TV system if the frame rate is high enough, but colour TV would be rubbish unless the aliens had multiple sentient creatures or have a culture encompassing multiple worlds. It's possible to have a wideband camera and display system with very many more colour channels than three. Of no value to the majority of people here. I'll not bore with details of one possible implementation.
Maxwell may have been the first to realise a simple "trick" three colour system would work for humans and Newton decided a rainbow has seven colours because he liked the mystical connotations of seven. A rainbow has maybe thousands of colours to our perception and we can "see" some colours not actually in a rainbow or white light or in any spectrum. If a signal has red and blue components of the spectrum) but no components in the green area, then we see colours that don't exist in any monochromatic light. The Cyan Yellow Magenta (or C Y M K) models used for colour photography and printing in subtractive or overlay mode use this trick to produce images that look realistic to life to use. The earliest colour film used R G B random starch based filters on one layer so was very insensitive. Using C Y M layers for a negative was a massive improvement. The "holy grail" for a bistable colour display alternative to monochrome eink (which is opaque) is to have bistable layers that are clear or C Y or M over a bottom monochrome eink. This would also work for brighter projectors with LCD. The coloured layers could be 1/3rd resolution or less of the monochrome.
1) Our colour TV only really works for humans and not perfectly for all humans. Even on Earth different creatures have different colour perception in our visible spectrum. Some creatures really only have monochrome, some like dogs have a very different response basically two "primaries". Some birds have IR vision. Some birds and insects can see UV (some women may have this tetrachromacy but the UV is mostly blocked from the retina). The pigeon may be pentachromatic. See below about Rods & Cones.
2) Frame rate. Guinea pigs need to spot movement so it might be why their perception of motion is much higher than ours which kicks in about 12 fps but some of us can see 50Hz flicker, but only at the edge of vision. Regular TV might be simply separate frames to guinea pigs.
3) Organisation. Leaving aside mechanical scanning and film frames, or colour, even a purely electronic system needs to serialise image transfer either on cable, RF or inside the electronics. You either do rows and then the pixels along the rows (R to L or vices versa), or columns and then the pixels on a column (Up to Down or vice versa). Obviously if you start with scanning film frames as an electronic source the same applies, except a movie projector inherently wants vertical spools (Stills can use either and has done), so you have rows first and the order depends on the film transport direction, which seems to have been an arbitrary choice.
4) Cameras vs display. A camera is a lot trickier than a display. Your display can have a brighter source if mechanical. Mechanical cameras and Philo Farnsworth's camera only sense light at one pixel element at a time as it's scanned, so as the resolution is increased it's quickly uselessly insensitive. A suitable electronic camera needs to accumulate charge from the light during the entire frame. It's true that the sensor sensitivity does drop as the resolution is increased, but you can keep the pixel element the same size and use a larger image area and bigger lenses. Not possible with the mechanical cameras and Philo Farnsworth's camera. So you can imagine an Alien civilisation that uses film cameras, doesn't have Baird's clever processing and wet scanning in the camera, but has electronic displays.
Rods and Cones. Generally rods are thought to be more or less insensitive to hue (but are not be the same range of spectrum in different creatures here) and Cones do colour, somehow. Colour perception is always overlapping curves. So a set of R G and B LEDs matched to peaks may give a good simulation. More colours or wider band sources may be better, but LEDs will produce some colours more saturated than filters on LCD or phosphors. OLED may use phosphors and filters. LCDs might use R G B LED backlights, CCFL tube backlights (mercury discharge + phosphor) or "white" LEDs (really blue to violet or UV with phosphors) or in a projector: LEDs, incandescent lamp or xenon discharge.
There are three theories as to how the Cones actually work . Unlike a single tube/chip camera they may not use pigments (a filter).
So Aliens and us can use the same monochrome TV system if the frame rate is high enough, but colour TV would be rubbish unless the aliens had multiple sentient creatures or have a culture encompassing multiple worlds. It's possible to have a wideband camera and display system with very many more colour channels than three. Of no value to the majority of people here. I'll not bore with details of one possible implementation.
Maxwell may have been the first to realise a simple "trick" three colour system would work for humans and Newton decided a rainbow has seven colours because he liked the mystical connotations of seven. A rainbow has maybe thousands of colours to our perception and we can "see" some colours not actually in a rainbow or white light or in any spectrum. If a signal has red and blue components of the spectrum) but no components in the green area, then we see colours that don't exist in any monochromatic light. The Cyan Yellow Magenta (or C Y M K) models used for colour photography and printing in subtractive or overlay mode use this trick to produce images that look realistic to life to use. The earliest colour film used R G B random starch based filters on one layer so was very insensitive. Using C Y M layers for a negative was a massive improvement. The "holy grail" for a bistable colour display alternative to monochrome eink (which is opaque) is to have bistable layers that are clear or C Y or M over a bottom monochrome eink. This would also work for brighter projectors with LCD. The coloured layers could be 1/3rd resolution or less of the monochrome.
