An automated chimpanzee identification system using face detection and recognition

Abstract

Due to the ongoing biodiversity crisis, many species including great apes like chimpanzees are on the brink of extinction. Consequently, there is an urgent need to protect the remaining populations of threatened species. To overcome the catastrophic decline of biodiversity, biologists and gamekeepers recently started to use remote cameras and recording devices for wildlife monitoring in order to estimate the size of remaining populations. However, the manual analysis of the resulting image and video material is extremely tedious, time consuming, and cost intensive. To overcome the burden of time-consuming routine work, we have recently started to develop computer vision algorithms for automated chimpanzee detection and identification of individuals. Based on the assumption that humans and great apes share similar properties of the face, we proposed to adapt and extend face detection and recognition algorithms, originally developed to recognize humans, for chimpanzee identification. In this paper we do not only summarize our earlier work in the field, we also extend our previous approaches towards a more robust system which is less prone to difficult lighting situations, various poses, and expressions as well as partial occlusion by branches, leafs, or other individuals. To overcome the limitations of our previous work, we combine holistic global features and locally extracted descriptors using a decision fusion scheme. We present an automated framework for photo identification of chimpanzees including face detection, face alignment, and face recognition. We thoroughly evaluate our proposed algorithms on two datasets of captive and free-living chimpanzee individuals which were annotated by experts. In three experiments we show that the presented framework outperforms previous approaches in the field of great ape identification and achieves promising results. Therefore, our system can be used by biologists, researchers, and gamekeepers to estimate population sizes faster and more precisely than the current frameworks. Thus, the proposed framework for chimpanzee identification has the potential to open up new venues in efficient wildlife monitoring and can help researches to develop innovative protection schemes in the future.

Towards Automated Visual Monitoring of Individual Gorillas in the Wild

“…Recent progress in the emerging field of animal biometrics [36], in particular in ape facial recognition [47,12,46,16] promises to overcome some of these obstacles and make broad-scale, real-world applications a realistic prospect.…”

“…Loos et al [45,46] proposed the first pipeline for identification of chimpanzees. Only images showing near-frontal chimpanzee faces serve as suitable input to the technique to guarantee feature comparability.…”

“…For their experiments, Freytag et al prepare an extended version of the chimpanzee dataset by Loos and Ernst [46], covering 24 individuals on 2109 images. The images of this C-Zoo dataset are cropped faces.…”

Sloop: A pattern retrieval engine for individual animal identification

“…There are several notable systems including ECOCEAN [26], face-recognition-based systems for chimpanzees and gorillas [27] and the African Penguin Recognition System (APRS) [18]. The latter two can be applied to different species, particularly as APRS is further motivated by biometrics for Turing patterns [28].…”

SURF-based mammalian species identification system

“…The system for automatic species identification presented here takes advantage of existing object recognition methods applied in the field of biology, in particular for plant species [15] and chimpanzee individuals [8]. Plants are identified from their leaves using the inner distance and from their bark using multi-block local binary patterns, while human face recognition algorithms are adapted for chimpanzee identification, combining local descriptors and holistic global features and making use of a decision fusion scheme.…”