Automatic Craniofacial Anthropometry Landmarks Detection and Measurements for the Orbital Region

Abstract

Facial landmarks detection is undoubtedly important in many applications in computer vision for example the face detection and recognition. In craniofacial anthropometry, consistent landmarks localization as per standard definition of the craniofacial anthropometry landmarks is very important in order to get accurate craniofacial anthropometry data. In this article we demonstrated an automatic detection of craniofacial anthropometry landmarks at the orbital region. 3D images of 100 respondents' were photogaphed using Vectra-3D in controlled environment. Craniofacial measurements of 30 3D images were measured using VAM software. Two data sets of left and right eyes positive training data were created to train 'en' and 'ex' haar cascade classifiers. These classifiers were used to detect and locate the inner (en) and outer (ex) eye corners. We automatically measured the left and right eye fissures length (en-ex), the intercanthal (en-en) and the biocular (ex-ex) width. Statistical analysis was performed on the measurements taken by Vectra 3D and by our software with paired t-test and calculated the ICC indices. We observed quite amount of false positive detections. We removed the false positive and predicted the eye corners. Our classifiers able to detect and locate the 'en' and the 'ex' in 59 out of 60 test images. Our results show accurate detection of 'ex' and 'en' craniofacial landmarks as per standard definition. The paired t-test showed that all four (4) measurements are no significant difference with the p values on 95% confidence level are above 0.05. The ICC indices for the measurements were from 0.4 to 0.78. In conclusion, our trained enHaar and exHaar cascade classifiers were able to automatically detect the 'en' and 'ex' craniofacial anthropometry landmarks in controlled environment. The measurements were clinically no significant differences with the mean different were less than 1 mm in both eye fissures and intercanthal except the biocular width ( 1.16 mm). The consistency of the measurements between the two methods are good for the intercanthal width and moderate for the biocular width and for both eye fissure lengths.