I suppose one way to determine why the generated captchas are so unreadable would be if the captchas that didn't complete correctly (or were skipped with the Reload button) are automatically saved somewhere along with the failed attempts, the correct answer, the level of distortion and any other data that can help find a pattern and fix the problem. In this way perhaps a balance could be found between readability and security.
One solution that I found interesting is the one proposed in
>>7665 to make the letters use an cursive/ronde font. This would not require applying as much distortion (since most OCR programs do not recognize this typeface, or only partially at best) while at the same time maintaining an easy-to-read font (at least for those who have completed primary school).
A similar way to achieve this would be using the mathematical type letters:
https://en.wikipedia.org/wiki/Mathematical_Alphanumeric_Symbols?useskin=vector#Latin_letters Mainly the script/calligraphy ones, perhaps also intermixing some Fraktur letters such as 𝔞, 𝔅/𝔟, 𝔠, 𝔇, 𝔢, 𝔣, 𝔨, ℜ, 𝔘/𝔲 and 𝔛/𝔵.
>>7891
>add image captcha as an alternative to text captcha.
Wouldn't that affect the accessibility of the site? I mean, it's not like blind users can participate in the chan (at least not with the current captcha), but maybe someday the admins will want to add an audio captcha or something (which might be difficult to implement with an image captcha).
>https://github.com/Kamuso/captchouli
The problem with that Go module/package in particular is that it would need to be connected to Lynxchan somehow (which is written in Node.js). I found
https://github.com/zealic/go2node although I don't know if it is the best solution.