Global Threshold Using Otsu and Active Contour for Detection of Malaria Parasites in Thick Blood Smear

Department of Electrical and Information Engineering, Faculty of Engineering, Universitas Gadjah Mada, Yogyakarta Indonesia

^* Corresponding author: adinugroho@ugm.ac.id

Abstract

Malaria is a disease caused by the plasmodium parasite and has caused many fatalities. In general, identifying malaria parasite infection can be done by visually observing thick and thin blood smears through microscopic devices. Identification of parasites in thick blood preparations has a higher level of difficulty than thin blood preparations. In thick blood preparations, various objects such as artefacts and noise have a structure similar to the structure of parasitic objects. This paper aims to develop a parasite detection method based on image processing in thick blood smears, consisting of two main stages. First is to improve image quality by applying contrast value stretching, converting green channels, and refining each image. Second is to segment the plasmodium parasite using global threshold Otsu and active contour followed by several morphological operations. The proposed method produces a high sensitivity of 98.06% with an average negative false rate of 1.4%. With the sensitivity level obtained, it can be interpreted that most of the parasitic objects have been detected correctly in one blood sample image.