As far as I understand you have images

of the skin, say from arms. Not from the scalp.

Three methods come in mind for removing

the hair: outlier detection (statistics), or

edge detection (Canny algorithm), or

clustering in RGB histograms: hairs should

cause small sharp peaks.

After recognition you can replace the hairs

by an interpolated hue from the near environment.

A more sophisticated approach would try

to identify the hair as an object and could

follow the trajectories of the hairs for

doing the removal.

Regards,

Joachim