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Nakhon Sawan, Thailand

Choogorn T.,Nakhon Sawan Rajabhat University | Mahattanakul J.,Mahanakorn University of Technology
IET Circuits, Devices and Systems

This study presents distortion analysis of the fully differential Gm-C filters in which the imbalance of the differential input voltages is taken into consideration. Closed-form equations expressing distortions of differential-mode (DM) output voltages as functions of DM and common-mode input voltages are developed. It was found that the HD3 of the DM output voltage is independent of the input imbalance. On the contrary, the HD2 of the DM output voltage is directly dependent upon the input imbalance. Simulation results are shown to be in good agreement with the analytical results. © The Institution of Engineering and Technology 2013. Source

Khankasikam K.,Nakhon Sawan Rajabhat University
Journal of Information Science and Engineering

Binary image is the essential format for document image processing, and the operation of the subsequent steps depends on the quality of the binarization process. The objective of this research is to propose a new binarization method based on adaptive multilayer- information for restoration of degraded historical document images. This paper focuses on degraded Thai historical document images, which are in the form of handwritten and machine-printed documents images. The proposed method consists of five stages including noise elimination, majority pixel analysis, degradation of the background layer estimation, thresholding and vicinity analysis. The experiments are performed on 480 degraded Thai historical document images provided by National Library of Thailand. The experimental results demonstrate that the proposed method performs better than five well-known adaptive binarization methods. Source

Khankasikam K.,Nakhon Sawan Rajabhat University
7th International Conference on Digital Information Management, ICDIM 2012

The objective of this research is to investigate the feasibility of using Conway's game of life to solve the problem on printed Lanna character recognition. Pattern recognition can be defined as the objects identification on the basis of information available about it. The problem on character recognition has been discussed to find out the best solution and various recognition methods have been implemented. Conway's game of life has a capability to generate a new identity pattern, which is a stable state, from predefined pattern. The proposed framework consists of three modules: preparation, training and recognition. The experiments are carried on 1,200 printed Lanna characters, which randomly selected from documents written in Lanna language. The system performs the number of match 1,142 characters or 95.15%, while mismatch 27 characters or 2.25% and rejecting 31 characters or 2.58%. © 2012 IEEE. Source

Khankasikam K.,Nakhon Sawan Rajabhat University
Applied Mechanics and Materials

The objective of this paper is to develop methodology that can recognize the Lanna handwritten character on historical documents by using character feature extraction technique. Historical documents are national treasures. Insignificant effort has been made to preserve Lanna historical documents. Other nations such as Egypt, China and Greece are investing a large effort in restoring and preserving their national historical documents. As a starting point, the focus is on using one Lanna historical document for performing experiments and verifying recognition methods available in this research area. The proposed system consists of three modules, which are image preprocessing module, feature extraction module and character recognition module. The details of each module are following: first, the input image is transformed into a suitable image for feature extraction module. Second, the proposed system extracts character features from the image. Finally, the extracted character information, which is kept in form of bit string, is calculated a similarity value for recognition result. The experiment was conducted on more than 4,000 Lanna handwritten characters by using 10-fold cross-validation classification method which is using 3,600 for training characters and 400 for testing character. The cross-validation process is repeated 10 times, with each of the 10 subsets used exactly once as the validation data. The precision of the proposed system is around 89.73 percent. © (2013) Trans Tech Publications, Switzerland. Source

Kitthawee U.,Kasetsart University | Pathaveerat S.,Kasetsart University | Srirungruang T.,Nakhon Sawan Rajabhat University | Slaughter D.,University of California at Davis
Biosystems Engineering

One of the most important problems affecting the successful marketing of fresh young coconut fruit is bruising. Bruising frequently occurs during postharvest operations due to excessive compressive force and impact. A survey showed that the majority (50-100%) of young coconuts in wholesale or retail markets in Thailand was bruised. Bruised areas of <100 mm2 and bruise counts of 4 per fruit were predominant. The mechanical bruising of young coconut was characterised by browning in the husk tissue under the skin. Bruise volume was linearly correlated with either compression or impact energy above the bruise threshold limit. Good correlation was observed between the probability of bruise occurrence and compression or impact energy below the bruise threshold. Based on the variations in the minimum energy level required to bruise the fruit, young coconut fruit is much more susceptible to bruising occurrence under impact than under compression. © 2011 IAgrE. Source

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