There are several LED layouts in use, but how do they differ and does it matter?
Resolution and noise
Eye resolution test
I have made a simple test image to test the resolution of your eyes on a phone, phablet, tablet, laptop or PC!
The most common result is it is pointless to go beyond around 1/12000 of the viewing distance
Be SURE it is shown in the screens native resolution. e.g. 960 pixels should fill half a FullHD display. (or use one of the added ones with your screens resolution)
Be SURE that your browser or your windows settings doesn’t do any scaling/zooming/smoothing, i.e. one pixel in the image is one pixel on the display. (If in doubt take a magnifying glass -or macro camera- and look closely on the screen, it should be like the mock-up later in this post)
It is the point where the single line pair is indistinguishable from the double line we are looking for (that is: where it looks like one continuous thick line)
You will most likely find the finest resolution using the red or green figure.
Use any prescribed glasses that you normally would for the distance – we are testing resolution, not focusing ability.
NOTE: If you got a PenTile display, usually the green will do fine! Have a look at this on different subpixel arrangements. Several pixel arrangement exists out there, that could have similar issues…
Principal ideas for smarter image sensor technology
Currently the limitation in the amount of photons that can be caught versus the noise, set a limit for the dynamic range.
But what if the sensor output could not be over saturated?
Continue reading “Principal ideas for smarter image sensor technology”
Digital camera sensor sizes – selling elastic bands by the metre
When a sensor is advertised/sold as 1/2.3″ most people would think that is the diagonal of the sensor. Well it is NOT! It might even vary drastically between manufacturers.
For historical reasons the diameter of a fictitious Vidicon tube with the same active area is what is advertised!!
![ccdsizes[1]](https://eskerahn.dk/wp-content/uploads/2015/05/ccdsizes1.gif)
From http://www.dpreview.com/news/0210/02100402sensorsizes.asp
Unfortunately, it is even more confusing than that…
Continue reading “Digital camera sensor sizes – selling elastic bands by the metre”
Superzoom and DOF plus TZ70 iZoom
It should be remembered that there are no miracles in superzoom!
And you should be careful on where your focus plane is, even if all in the frame to the human looks as ‘far away’.
Crop of 30x zoom:
(As usual, click to enlarge)
Megapixel-craze and tiny sensors & lenses. Myths & Facts
This is an attempt to replace some of the common myths, urban legends and misunderstandings with some facts.
(last updated 20181103)
There are at least three physical issues and one biological that are interesting:
1) Rayleigh’s criterion and sensor width.
F * √N < W , (N number of sensors in Mpixels, W in mm, red light F numerical aperture)
![AR-principles[1]](https://eskerahn.dk/wp-content/uploads/2015/05/AR-principles1-300x95.jpg)
![Airy_disk_spacing_near_Rayleigh_criterion[1]](https://eskerahn.dk/wp-content/uploads/2015/05/Airy_disk_spacing_near_Rayleigh_criterion1-196x300.png)
2) The eye’s real life resolution
Resolution beyond 1/12000 of viewing distance is pointless for most
3) Thermal noise.
Relative noise increases by 1/d, (+)almost √n and √T, (N number of sensors in Mpixels, d sensor diameter, T in kelvin, i.e. °C+273.15)
4) Effective pixel count
The effective pixel count falls with the amount of light, the less the pixel size the worse.
5) Stacking images
Stacking can compensate, but can not perform miracles.
6) Thickness of device versus sensor size
The angle of light to the sensor edges binds max sensor size to thickness.
Continue reading “Megapixel-craze and tiny sensors & lenses. Myths & Facts”