  In this paper we develop FaceQvec, a software component for estimating the
conformity of facial images with each of the points contemplated in the ISO/IEC
19794-5, a quality standard that defines general quality guidelines for face
images that would make them acceptable or unacceptable for use in official
documents such as passports or ID cards. This type of tool for quality
assessment can help to improve the accuracy of face recognition, as well as to
identify which factors are affecting the quality of a given face image and to
take actions to eliminate or reduce those factors, e.g., with postprocessing
techniques or re-acquisition of the image. FaceQvec consists of the automation
of 25 individual tests related to different points contemplated in the
aforementioned standard, as well as other characteristics of the images that
have been considered to be related to facial quality. We first include the
results of the quality tests evaluated on a development dataset captured under
realistic conditions. We used those results to adjust the decision threshold of
each test. Then we checked again their accuracy on a evaluation database that
contains new face images not seen during development. The evaluation results
demonstrate the accuracy of the individual tests for checking compliance with
ISO/IEC 19794-5. FaceQvec is available online
(https://github.com/uam-biometrics/FaceQvec).
