I worked in imaging for medical diagnostic support and dark complexions are just plainly more difficult to analyse because of restricted illumination times and limited contrast. Sensors got much better in recent years though.

The indications in question were extremely rare for black people on the other hand. Another use case was the detection of Vitiligo, which is significantly more easy on black people. There was a great demand for therapies because patients are stigmatized for different reasons, especially in Africa because the symptoms can look similar to some deadly diseases.

There is a lot of discrimination in imaging, but it doesn't have to do with race and more with the creation of binary images.

As for facial recognition. I see some use cases for convenience, but it would be far more effective to disallow widespread application because of the numerous unsolved problems. So I see the move from IBM positively, even if they continue their work. In the end I believe face reg to be possible without bias, but I don't have these propped up security needs.