Do-Hyeon Kim

Intensity surface stretching technique for contrast enhancement of digital photography

In this paper we propose a contrast enhancement technique which stretches the intensity surfaces of an image to improve the quality of a digital photo. The proposed method enhances the contrast of an image by stretching the intensity surface of the original image to the maximum range of the output image. This is done in proportion to the distances between the original intensity surface, and the upper and lower intensity surfaces respectively. The upper and lower intensity surfaces are generated adaptively from the original intensity surface by gaussian smoothing and gamma transform. In our experiments, digital color images in a variety of illumination conditions were used, and the proposed method was compared with other algorithms such as histogram stretching, histogram equalization, gamma correction, and retinex. From the results of the experiments, it was proven that the proposed algorithm further enhanced the contrast more than other methods and resulted in a more natural image without deterioration of gradation.

Fuzzy truck control scheme for obstacle avoidance

The fuzzy system can be a good solution when a mathematical model of the system is either unavailable or too complex. Truck backer-upper control problem is one example of a standard highly nonlinear control problem. Bearing this in mind the control scheme that considers obstacles near the truck is much more complex than other conventional approaches. In this paper a fuzzy truck control system for obstacle avoidance, using newly designed 33 fuzzy inference rules for steering control and 13 rules for speed control, is proposed. Through simulations of various real world situations, we observed that the proposed fuzzy controller could drive the truck to the goal smoothly while avoiding the obstacles, and showed a reasonably good trajectory. This flexible and applicable fuzzy control logic can be adapted to provide easy interaction with the driver for state-of-the-art intelligent cruise control systems.

Design an effective pattern classification model

This paper presents an effective pattern classification model by designing an artificial neural network based pattern classifiers for face recognition. First, a RGB image inputted from a frame grabber is converted into a HSV image. Then, the coarse facial region is extracted using the hue(H) and saturation(S) components except intensity(V) component which is sensitive to the environmental illumination. Next, the fine facial region extraction process is performed by matching with the edge and gray based templates. To make a light-invariant and qualified facial image, histogram equalization and intensity compensation processing using illumination plane are performed. The finally extracted and enhanced facial images are used for training the pattern classification models. The proposed hierarchical ART2 pattern classification model which has the Max-Min cluster selection strategy makes it possible to search clustered reference patterns effectively. Experimental results show that the proposed face recognition system is as good as the SVM model which is famous for face recognition field in recognition rate and even better in classification speed.

An Automated Outsole Inspection System Using Scale Block and Divide-and-Conquer Technique

We propose an outsole measurement/inspection system to improve the quality of the shoe product. It uses the Divide-and-Conquer technique to measure the length of shoes`outsole. First, it detects edge positions of outsole`s toe and heel from each image frame using an unique scale block we defined and calculates the outsole`s length as the distance of two edge positions. Then it compensates the total length of outsole using the side image of outsole. Next, it classifies the outsole as inferior goods if the measurement error is bigger than 5.8mm. As a result of testing with the various kinds of outsoles, it was shown that the 95% accuracy was acquired within 1mm allowable error range. In conclusion, the proposed inspection system is effective and useful in the measurement/inspection process of shoe product and any material object as well.