Development of a Novel Automated Hair Counting System for the Quantitative Evaluation of Laser Hair Removal.
OBJECTIVE
We aimed to develop and validate a novel computer-assisted automated hair counting system for the quantitative evaluation of laser hair removal (LHR).


METHODS
We developed a computer-aided image processing system to count hairs on shaved skin and validated its performance through clinical trials. Five volunteers of Fitzpatrick skin type III-IV volunteered and were tested on both thighs. The system automatically detects hair and places a "+" sign on each hair site for every positive detection. This method allows clinicians to check whether a hair has been counted or not. We analyzed the difference in the hair counts between the proposed system (automatic) and those by human observers (manual).


RESULTS
The hair counts from the proposed system and the manual counts were compared. The percentage error between automatic and manual counting was <5% in each subject. The data of the two groups were statistically verified with Student's independent t-test. The averages were statistically equivalent between the two groups. The proposed system showed significant time saving in terms of counting.


CONCLUSIONS
A dependable, accurate, and fast method of counting hairs on shaved skin through a computer-aided image processing system was developed and validated. The "+" signs on the image to indicate detection allows clinicians to compare with the original image and detect any omission or redundancy. The proposed system is expected to be reliable in analyzing the results of multiple skin-related treatments, including LHR and hair transplantation. Further, it is expected to be widely applicable for use in the clinic.
1 Interdisciplinary Program for Bioengineering, College of Engineering, Seoul National University , Seoul, Korea.
Hyoung-Woo
HW
Lim
1 Interdisciplinary Program for Bioengineering, College of Engineering, Seoul National University , Seoul, Korea.
Minwoo
M
Cho
2 Department of Dermatology, Institute of Human-Environment Interface Biology, College of Medicine, Seoul National University , Seoul, Korea.
Dong-Hun
DH
Lee
3 JMO Dermatology , Seoul, Korea.
Wooseok
W
Koh
4 Department of Mechanical and Aerospace Engineering, Institute of Advanced Aerospace Technology, College of Engineering, Seoul National University , Seoul, Korea.
Youdan
Y
Kim
2 Department of Dermatology, Institute of Human-Environment Interface Biology, College of Medicine, Seoul National University , Seoul, Korea.
Jin Ho
JH
Chung
5 Department of Biomedical Engineering, College of Medicine, Seoul National University , Seoul, Korea.|6 Institute of Medical and Biological Engineering, Seoul National University , Seoul, Korea.
Sungwan
S
Kim
D001331:Automation; D002986:Clinical Trials as Topic; D005069:Evaluation Studies as Topic; D005260:Female; D006197:Hair / Q000000981:diagnostic imaging*; D006204:Hair Removal / Q000379:methods*; D064368:Healthy Volunteers; D006801:Humans; D007091:Image Processing, Computer-Assisted; D053685:Laser Therapy / Q000379:methods*; D008297:Male; D018709:Statistics, Nonparametric
dermatology; imaging/imaging science; laser irradiation; low-power; photomedicine