MACHINE LEARNING OF HANDWRITTEN NANDINAGARI CHARACTERS USING VLAD VECTORS

• Main Authors: Prathima Guruprasad, Jharna Majumdar
• Format: Article
• Language: English
• Published: ICT Academy of Tamil Nadu 2017-11-01
• Series: ICTACT Journal on Image and Video Processing
• Subjects: Handwritten Nandinagari Characters; Invariant Features; Scale Invariant Feature Transform; Image Vectorization; Indexing and Retrieval
• Online Access: http://ictactjournals.in/ArticleDetails.aspx?id=3235
• ISSN: 0976-9099; 0976-9102

This paper provides an early attempt to train and retrieve handwritten Nandinagari characters using one of the latest techniques in visual feature detection. The data set consists of over 1600 handwritten Nandinagari characters of different fonts, size, rotation, translation and image formats. In the Learning phase, we subject them to an approach where their recognition is effective by first extracting their key interest points on the images which are invariant to Scale, rotation, translation, illumination and occlusion. The technique used for this phase is Scale Invariant Feature Transform (SIFT). These features are represented in quantized form as visual words in code book generation step. Then the Vector of Locally Aggregated Descriptors (VLAD) is used for encoding each of the Image descriptors in the database. In the recognition phase, for query image, SIFT features are extracted and represented as query vector .Then these features are compared against the visual vocabulary generated by code book to retrieve similar images from the database. The performance is analysed by computing mean average precision .This is a novel scalable approach for recognition of rare handwritten Nandinagari characters with about 98% search accuracy with a good efficiency and relatively low memory usage requirements.