Leaf damage detection and pencil drawing based on image processing techniques

Abstract

Leaf Damage Detection and Pencil Drawing Based on Image Processing Techniques Hitimana Eric Division of Electronics and Information Engineering (Computer Engineering) Advised by Oubong Gwun, PhD Digital image processing is an area characterized by the need for extensive experimental work to establish the viability of the proposed solutions to a given problem. The given problem to deal with can be either in computer vision or computer graphics applications. This thesis proposes two methods to handle problems in computer vision application for pest damage detection and estimation from leaf image and from Computer graphics, for rendering an automatic color pencil sketch with hatching lines from an input image.

vii Image segmentation is the most challenging issue in computer vision applications, and most difficulties of crops management in agriculture are the lack of appropriate and accurate methods for detecting the leaf damage for pests’ treatment. An automatic method for leaf damage detection and severity estimation by avoiding defoliation is proposed. After enhancing the contrast of the original image using LUT based gamma correction, the image is processed to remove the background, and the output leaf is clustered using Fuzzy c-means segmentation method in V channel of YUV color space to maximize all damages detection, and finally, the severity damage of leaf is measured in terms of ratio of leaf pixel distribution between the normal and the detected leaf damage. The results are compared to the current researches and the accuracy is obvious either in the background removal or damage detection. From the point of view, the proposed method can be recommended to famers as a solution of the current naked eye detection method resulting to errors and time costing. On the other hand, Non-Photorealistic Rendering (NPR) techniques in computer graphics to render an image can be created by making use of image editing and authoring tools. However, these tools are known to bring about high production cost along with increasing the time and labor charge. This thesis also proposes an automatic generation of pencil sketch rendition with hatching lines algorithm. From the input color image, the hatching lines are

viii generated where their directions depend on the choice of the orientation by motion blurring; shaded image with contour generated using Kirsch operator is produced to control the hatching texture on the final pencil sketch result. The algorithm also can come up with a colored pencil sketch where the color components are got from the original image. The method can be used as an editing tool for computer arts, advertising industrial or technical design, etc