ishihara

Generates pseudoisochromatic plates — the dotted circles with a numeral hidden in the colour separation — from a seed, so the same seed gives the same plate on any machine, forever.

Install it Source Take a test

0.1.2 · pip install ishihara · MIT · reproducible from a seed

What it does

Generates pseudoisochromatic plates — the dotted circles with a numeral hidden in the colour separation — from a seed, so the same seed gives the same plate on any machine, forever.

pip install ishihara
ishihara --seed 4211 --figure 74

Why the seed matters

Plates in the wild are generated with an unseeded random number generator, which means no two runs produce the same test and no result can be compared with another. A screening tool whose stimulus changes between subjects is measuring the stimulus as much as the subject.

What it is not

Not a diagnosis, and not a calibrated instrument. A screen is not a lightbox: the plate you generate is only as honest as the display it lands on, and the calibration limits are published rather than glossed over. The underlying method is deposited with a DOI.

PyPI Source OpticQuiz

How it works

Install itpip install ishihara.
Pick a seed and a figureishihara --seed 4211 --figure 74.
Get the same plate anywhereThe seed is the plate. Run it on another machine next year and it is identical.

What it does

Reproducible from a seedThe entire point. Plates in the wild are generated with an unseeded RNG, so no two runs produce the same test.

Comparable resultsA screening tool whose stimulus changes between subjects is measuring the stimulus as much as the subject.

Published methodThe generation method is deposited with a DOI.

Deficiency typesPlates targeted at protan, deutan and tritan separation.

Honest about the screenA display is not a lightbox, and the calibration limits are published rather than glossed.

Not a diagnosisScreening. The pages that matter say so.

Specifications

Install	pip install ishihara
Version	0.1.2
Licence	MIT
Output	Plate images from a seed
Source	vince-gonzalez/ishihara

Questions

Can I use these to diagnose someone?: No. It is screening, and a screen is not a calibrated instrument.
Why does the seed matter so much?: Because without it, two people take two different tests and the results cannot be compared with each other or with themselves.