Abstract
The growing number of surveillance cameras installed for crime prevention in various city locations capture images that might reveal private information, such as images of human faces, of car license numbers, and of windows, without permission. We previously reported a Hierarchical Masked image Filtering (HMF) technique that can mask and restore such objects in a captured image [1]. The object detection used for masking the privacy-related images uses the Haar-like [2] feature algorithm in the OpenCV library. We have now improved the HMF masking performance by developing a fast object detection method that is used instead of the Haar-like algorithm.
In this paper, we describe HMF based on the morphological pattern spectrum. This pattern spectrum can be used to mask not only a front face image but also a profile image. The use of this HMF reduced the processing time by about 62% compared with that of the Haar-like algorithm.
