Starfruit Shape Defect Estimation Based on Concave and Convex Area of a Closed Planar Curve

Dalam kertas kerja ini, sebuah perwakilan bentuk berdasarkan kawasan cekung dan cembung di sepanjang keluk tertutup dipersembahkan. Teknik yang dicadangkan dalam kertas kerja ini melibatkan proses anggaran kekelukan daripada keluk masukan dan juga proses pencarian titik kritikal pada keluk masukan tersebut. Dengan mengasingkan titik kritikal tersebut kepada kategori cekung dan cembung, pengiraan kawasan cekung dan cembung dilakukan. Daripada ciri–ciri statistik ini, dua permasalahan berkaitan dengan bentuk disiasat. Di sini, teknik yang dicadangkan diuji terhadap proses penganggaran kerosakan bentuk dan pengenalan bentuk pada buah belimbing. Pada kes pertama, kerosakan bentuk belimbing diukur dengan mengira kuasa cekung di mana kuasa cekung ini adalah selanjar dengan kerosakan bentuk tersebut. Untuk kes pengenalpastian bentuk pula, tangkai belimbing adalah objek untuk dikenal pasti dan tangkai belimbing ini akan diasingkan daripada bentuk belimbing kerana ia akan menyumbang kepada kesalahan pengiraan kerosakan bentuk belimbing. Bagi kedua–dua kes, teknik yang dicadangkan diuji dengan tiga teknik penganggaran kekelukan untuk memastikan keberkesanan teknik yang dicadangkan. Kata kunci: Perwakilan bentuk, kekelukan, titik kritikal, kawasan cekung dan cembung In this paper, a shape representation based on concave and convex area along a closed curve is presented. The proposed technique involves the process of the curvature estimation from the input curve and search for its corresponding critical points. By splitting the critical points into concave and convex categories, the concave and convex area are computed. From these statistical features, two problems related to the shape (curve) are investigated. Here, the proposed technique is tested on shape defect estimation and shape recognition of starfruit. In the first case, defect is measured by computing concave energy, which is proportional to the defect. For shape recognition, starfruit’s stem is identified and removed from the starfruit’s shape, as it will contributes false computation of defect measurement. For both cases, the proposed technique is tested with three different curvature estimation techniques to validate the results. Key words: Shape representation, curvature, critical point, concave and convex area

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