I wonder what they match to? How much of a face covered by a hijab is required for a match?

https://news.yahoo.com/chinese-facial-recognition-technology-helping-152536986.html

Chinese facial recognition technology helping Iran to identify women breaking strict dress code: Report

… Shajarizadeh is one of several observers of Iran who fear that the country's Islamist regime has begun to weaponize facial recognition technology to find and punish women who flaunt laws about their dress and appearance in public, a setback for activists amid months of protesting for women's rights and regime change.

The fears that Iran could be using the technology come a year after such a system was proposed by Iranian lawmakers. Their calls were heard by the head of the government agency responsible for enforcing morality laws, who in a September interview said facial recognition would be used "to identify inappropriate and unusual movements," and a "failure to observe hijab laws."