Sains Malaysiana 55(8)(2026): 1262-1271

http://doi.org/10.17576/jsm-2026-5508-03

 

Crescent Moon Segmentation via Histogram Percentiles and Simplified K-Means Algorithm

(Segmentasi Bulan Sabit melalui Persentil Histogram dan Algoritma K-Means Ringkas)

 

SYED ALI SYED AHMAD YUNUS¹, NAZHATULSHIMA AHMAD^2,*, IBRAHIM MOHAMED¹, ROSLI SALLEH³ & MOHD SAIFUL ANWAR MOHD NAWAWI⁴

 

¹Institute of Mathematical Sciences, Faculty of Science, University of Malaya, Malaysia

²Department of Physics, Faculty of Science, University of Malaya, Malaysia

³Department of Computer System and Technology, Faculty of Computer Science and Information Technology, University of Malaya, Malaysia

⁴Department of Fiqh and Usul, Academy of Islamic Studies, University of Malaya, Malaysia

 

Diserahkan: 3 Februari 2026/Diterima: 29 Julai 2026

 

Abstract

Detection of crescent moon in digital images is of interest to researchers and practitioners involved in crescent moon sighting activities. The ability to detect the crescent moon shape, if it exists, will contribute to the decision making related to the local Islamic calendar based on the observation method and support the expected visibility of the crescent moon using the calculation method. However, under the syariah (Islamic law) consideration, any crescent moon detection procedure on the original image should not ‘create what is not’ during the image processing. Hence, in this paper, we propose a new crescent moon shape detection procedure by increasing the contrast of the image without changing its original feature. This is done by segregating the ordered pixel intensity values of the image according to their quartiles and maximizing the contrast in each quartile.  Next, another procedure is proposed to segment the crescent moon from the background. These procedures are applied on selected crescent moon images taken at Teluk Kemang Observatory Station, Negeri Sembilan, Malaysia. We found that the procedures are able to detect the crescent moon shape if it exists in the image, and segment it from the background. More importantly, false detection is also avoided. The results are very important to support the local Islamic religious authority in making the final decision on the beginning of important Islamic events that depends on the visibility of the crescent moon in Malaysia.

Keywords: Feature extraction; image contrast; Islamic calendar; object segmentation; quartile plots

 

Abstrak

Pengesanan anak bulan dalam imej digital adalah perkara yang menarik minat para penyelidik dan pengamal yang terlibat dalam aktiviti cerapan anak bulan. Keupayaan untuk mengesan bentuk anak bulan, sekiranya wujud akan menyumbang kepada proses membuat keputusan berkaitan dengan kalendar Islam tempatan berdasarkan kaedah cerapan serta menyokong jangkaan kebolehnampakan anak bulan menggunakan kaedah pengiraan. Namun, dari sudut pertimbangan syariah, sebarang prosedur pengesanan anak bulan pada imej asal tidak seharusnya ‘mencipta sesuatu yang tiada’ semasa pemprosesan imej. Oleh itu, dalam kertas ini kami mencadangkan satu prosedur baharu untuk mengesan bentuk anak bulan dengan meningkatkan kontras imej tanpa mengubah ciri asalnya. Kaedah ini dilakukan dengan memisahkan nilai keamatan piksel imej mengikut kuartil dan memaksimumkan kontras dalam setiap kuartil. Seterusnya, satu lagi prosedur dicadangkan untuk mengasingkan anak bulan daripada latar belakang. Prosedur ini diaplikasikan pada imej anak bulan terpilih yang diambil di Balai Cerap Teluk Kemang, Negeri Sembilan, Malaysia. Kami mendapati bahawa prosedur ini berupaya mengesan bentuk anak bulan sekiranya ia wujud dalam imej, serta mengasingkannya daripada latar belakang. Lebih penting lagi, kesalahan dalam pengesanan juga dapat dielakkan. Hasil kajian ini sangat penting untuk menyokong pihak berkuasa agama Islam tempatan dalam membuat keputusan muktamad mengenai permulaan peristiwa penting Islam yang bergantung kepada kebolehnampakan anak bulan di Malaysia.

Kata kunci: Ciri pengekstrakan; kalendar Islam; kontras imej; plot kuartil; segmentasi objek

 

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*Pengarang untuk surat-menyurat; email: n_ahmad@um.edu.my