Color notes - references, links, and unsorted stuff: Difference between revisions

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You could argue that the amounts of rods and cones argues you might be able to get up to ''hundreds'' of megapixels.
You could argue that the amount of rods says you should be able to get up to ''hundreds'' of megapixels.
They won't all be firiing at the same time, though, but maybe still 100MP?
They won't all be firing at the same time, though, but maybe still 100MP, optimistically?


A little more practically, the optic nerve carries maybe a million things, arguing for roughly 1MP.
A little more practically, the optic nerve carries maybe a million things, arguing for roughly 1MP.[citation needed]
We've been shown to distinguish translates to roughly ~1MP in the fovea[citation needed]
 
And we've been shown to distinguish what roughly translates to ~1MP in the fovea[citation needed]




The thing is that this is not a simple, uniform, linear system (like image sensors are, for reasons of physics, and the sanity of everyone that has to deal with them).
The thing is that this is not a simple, uniform, linear system (like image sensors are, for reasons of physics, and the sanity of everyone that has to deal with them).


So a more practical 'what do experiments show that we can distinguish' angular resolution is around 1 arcminute, and that's ''only'' in the fovea -- which covers roughly 10 degrees of your vision (...roughly, it's a falloff).
In fact, one of the reasons we saccade all over the place while looking is that only the fovea has good resolution


So if you count the sharpness of what you are looking at directly,  
So a more practical 'what do experiments show that we can distinguish' angular resolution is around 1 arcminute, and that's ''only'' in the fovea -- which covers roughly 10 degrees of your vision (...roughly, it's a falloff; the best vision is in a tighter peak, maybe less than 3 degrees?{{verify}}).
it's only on the order of single megapixels - and both color ''and'' resolution is ''worse'' in the periphery
 
 
So if you count the sharpness of what you are looking at ''directly'', it's only on the order of single megapixels.
 
Both color ''and'' resolution is ''worse'' in the periphery.




https://en.wikipedia.org/wiki/Peripheral_vision
https://en.wikipedia.org/wiki/Peripheral_vision
https://en.wikipedia.org/wiki/Fovea_centralis
https://en.wikipedia.org/wiki/Fovea_centralis


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Revision as of 15:57, 4 March 2024

The physical and human spects dealing with audio, video, and images

Vision and color perception: objectively describing color · the eyes and the brain · physics, numbers, and (non)linearity · color spaces · references, links, and unsorted stuff

Image: file formats · noise reduction · halftoning, dithering · illuminant correction · Image descriptors · Reverse image search · image feature and contour detection · OCR · Image - unsorted

Video: format notes · encoding notes · On display speed · Screen tearing and vsync


Audio physics and physiology: Sound physics and some human psychoacoustics · Descriptions used for sound and music

Noise stuff: Stray signals and noise · sound-related noise names · electronic non-coupled noise names · electronic coupled noise · ground loop · strategies to avoid coupled noise · Sampling, reproduction, and transmission distortions · (tape) noise reduction


Digital sound and processing: capture, storage, reproduction · on APIs (and latency) · programming and codecs · some glossary · Audio and signal processing - unsorted stuff

Music electronics: device voltage and impedance, audio and otherwise · amps and speakers · basic audio hacks · Simple ADCs and DACs · digital audio · multichannel and surround
On the stage side: microphones · studio and stage notes · Effects · sync


Electronic music:

Electronic music - musical terms
MIDI · Some history, ways of making noises · Gaming synth · microcontroller synth
Modular synth (eurorack, mostly):
sync · power supply · formats (physical, interconnects)
DAW: Ableton notes · MuLab notes · Mainstage notes


Unsorted: Visuals DIY · Signal analysis, modeling, processing (some audio, some more generic) · Music fingerprinting and identification

For more, see Category:Audio, video, images

"What's the resolution of the human eye?"

Unsorted

http://en.wikipedia.org/wiki/Deep_Color

http://en.wikipedia.org/wiki/XvYCC

Grayscale conversion from RGB

✎ This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.

The easiest conversion to grayscale is a simple average, (r+g+b)/3, but this is not very perception-accurate.


There are various RGB standards that mention grayscale conversion as weighing of the channels. In some cases this is based on perception, in some it correction for RGB primaries used in the standard (probably based on phosphors?).

These include:

  • ITU-601-1 and a few others use nearly identical numbers, 0.298954*R + 0.586434*G + 0.114612*B (apparently originating from CIE-XYZ 1931(verify))
  • EBU/ITU 3213 (PAL(verify))): 0.222*R + 0.707*G + 0.071*B
  • BT/ITU-709 (NTSC(verify))): 0.213*R + 0.715*G + 0.072*B
  • ...more


The best choice depends mostly on what sort of RGB you have.

It can also depend on specicic wishes. Consider how photographers sometimes use specific colored lenses (or nearly-equivalent photoshop filters) for specific effects, such as lessening the visibility of freckles, making skies more contrasted, and such.


Undetailed so far

Mostly colour spaces, colour models, and transforms. Again, these are not necessarily accurate.

  • HSV, HSB, HSL/HLS, HSI - hue, saturation, and brightness/level/luminisity/intensity. * IHS,
  • NTSC YIQ, NTSC CMY
  • YUV, YIQ, YCbCr
  • CMY, CMYK
  • HMMD
  • StW, I1I2I3
  • Retinal Cone
  • Munsell
  • Karhonen-Loeve

And things I've read about them:

  • NTSC RGB seems to refer to the defined conversion from YIQ to RGB inside the TV.
  • SMPTE RGB apparently does the same but matches modern phosphors better.
  • IHS conversions seems inconsistently defined between books.
  • I1I2I3 is defined from an (unspecified?) RGB as I1=(R+G+B)/3, I2=(R-B)/2, I3=(2G-R-B)/4, so seems to be a luminance-and-opposite type of system.
  • CIE L*a*b* apparently agrees with Munsell's colour system well.


File format notes:

  • GIF stores RGB
  • JPG stores RGB, YCbCr, or CMYK (verify)
  • PNG is RGB (sRGB unless it stores an ICC profile)


http://color-management-swicki.eurekster.com/device+independent+color+space/


Web gamma: http://hsivonen.iki.fi/png-gamma/

http://www.libpng.org/pub/png/png-gammatest.html

http://www.libpng.org/pub/png/png-colortest.html

References and other links

Technical

General


CIE stuff


Illuminants


Psycho-ish


Formulae


Other



Websites

Online calculators

Color pickers

Color pickers / color schemes / color coordination, often for styles





Social scheming


Reference lists


Usability

(considering color blindness and such):

Other/unsorted




More links: http://www.tlbox.com/web_designers/color

Software

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