Judul: Feature Extraction Based on Color, Shape and Texture for Animal Image Retrieval.
Abstrak: The differences in color, shape, and texture characteristics between each animal cause difficulties in animal image retrieval. Therefore, specified technique is needed to obtain pattern from each animal’s feature so that image retrieval might works properly. One of the techniques to obtain the pattern done by feature extraction. This research tries to develop image extraction method in Content Based Image Retrieval approach by using three image visual features (color, shape, texture). In this research, Fuzzy Color Histogram (FCH) for color feature extraction is used through computing the membership function using Cauchy function. In FCH, one color may belong to two bins histogram or more with different membership functions. Then, shape feature is extracted using edge direction histogram, where each image is processed using Sobel edge detection, and then the direction is mapped into a defined bin histogram. For texture feature extraction, the process uses co-occurrence matrix with computing the values of energy, moment, entropy, maximum probability, contrast, correlation and homogeneity. Similarity value between image query and images in database is computed based on its features, those are color, shape, texture, and its combination. Recall and precision value resulted in this research shows the largest average precision value is obtained from searching process using index combination (color, shape, texture) of feature extraction. Keywords: feature extraction, Fuzzy Color Histogram, edge direction histogram, co-occurrence matrix
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Judul: Image Searching Using Heuristic Method for Image Retrieval System.
Abstrak: The development of image retrieval system and user demand for a fast and accurate search engine motivates research on finding efficient retrieval methods. Commonly, image searching process works through computing and comparing similarity value between input query and entire database images. This process is not efficient due to time-wasting during computation especially for large database. This research proposes heuristic method for image searching. The basic idea of this research deals with structural database content that reduces searching time. This research implements fitness landscape model. Fitness landscape is kind of directed graph whose labeled vertices and edges. Each node represents an image and each edge represents distance or similarity value of a node to other connected nodes. Similarity value between nodes are computed using combination of three image features, those are color, shape, and texture. Heuristic algorithm moves on these nodes with Breadth-First Search mechanism under certain constraints. Each visited node that fulfills the requirement will be retrieved as searching result. This retrieval result is then evaluated using recall precision parameter to get value of searching effectiveness. This experiment also computes retrieval time for each query. As the result, heuristic method obtains average retrieval time up to nine times faster compared with the non-heuristic one. Hence, this proposed method is promising to be used in image retrieval system because it provides fast image searching. Keywords: image searching, fitness landscape, heuristic, content based image retrieval.
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Judul: Penghambatan Degradasi Sukrosa Dalam Nira Tebu Menggunakan Gelembung Gas Nitrogen Dalam Reaktor Venturi Bersirkulasi
Abstrak: Degradasi sukrosa yang terkandung dalam nira tebu selama pengolahan disebabkan oleh reaksi inversi enzimatis dan aktivitas mikroba. Inversi sukrosa disebabkan oleh waktu tunggu (dowmtime) karena kerusakan peralatan pada saat proses berlangsung. Proses penghambatan degradasi sukrosa dalam nira tebu dapat dilakukan dengan gelembung gas inert menggunakan reaktor venturi bersirkulasi. Penelitian ini dilakukan untuk mendapatkan teknologi penghambatan degradasi sukrosa dalam nira tebu menggunakan gelembung gas nitrogen dalam reaktor venturi bersirkulasi. Penelitian dilakukan dengan memvariasikan laju alir nira pada 25 l/min, 20 l/min, dan 15 l/min, dengan kecepatan aliran gas nitrogen antara 0,02 m/det sampai 0,6 m/det menggunakan ukuran nozel 5 mm, 6 mm, dan 8 mm. Hasil penelitian menunjukkan gas hold-up yang terbentuk sangat baik untuk penghambatan degradasi sukrosa, dan menunjukkan adanya korelasi linier antara penghambatan sukrosa dengan gas hold-up. Laju penghambatan degradasi sukrosa pada laju alir nira 25 l/min dan kecepatan aliran gas nitrogen 0,6 m/det menggunakan ukuran nozel 6 mm dan suhu reaktor 70 oC memberikan penghambatan sebesar 4,2 %. Proses penghambatan degradasi sukrosa dengan menggunakan gelembung gas nitrogen dipengaruhi oleh gas hold-up dan ukuran gelembung yang terbentuk
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