Advancing further the theory of the optimal edge detector, as has been developed by Canny and Spacek, we derive the 'definitive' optimal edge operator. We show that the cubic spline approximation is, in practice, as good as the optimal edge detector.

The sipping of ink through the pages of certain double-sided handwritten documents after long periods of storage poses a serious problem to human readers or OCR systems. This paper addresses this problem through the recovery of content on the front side of a page from the interfering image caused by the handwriting on the reverse side. First, by adapting the Gaussian stochastic model, the inter...

This paper presents a new method for edge detection using one-dimensional processing. The Discrete Hilbert Transform of a Gaussian function is used as an edge detection lter. The image is smoothed using 1-D Gaussian along the horizontal (or vertical) scan lines to reduce noise. Detection lter is then used in the orthogonal direction, i.e., along vertical (or horizontal) scan lines to detect the...

Edge detection is one of the most critical tasks in automatic image analysis. There exists no universal edge detection method which works well under all conditions. This paper shows the new approach based on the one of the most efficient techniques for edge detection, which is entropy-based thresholding. The main advantages of the proposed method are its robustness and its flexibility. We prese...

A relaxation algorithm for the computation of optic flow at edge elements (edgels) is presented. Flow is estimated only at intensity edges of the image. Edge elements, extracted from an intensity image, are used as the basis for the algorithm. A matching strength or weight surface is computed around each edgel and neighbourhood support obtained to enhance the matching strength. A principal mome...

By expansion of digital multimedia and networking technology, the problem of ownership protection has become increasingly important. Digital watermarking is an efficient way for copyright protection of digital images. Traditional watermarking techniques degrade the quality of host image by embedding a watermark logo. Facing this problem, a new watermarking approach called zero-watermarking has ...

In this paper, we have proposed a system based on KL Transform to recognize different hand gestures. The system consists of five steps: skin filtering, palm cropping, edge detection, feature extraction, and classification. Firstly the hand is detected using skin filtering and palm cropping was performed to extract out only the palm portion of the hand. The extracted image was then processed usi...

The National Archives of Singapore keeps a large volume of historical handwritten documents. One common problem with the archives is that over the years, ink sipped through the pages of these documents such that characters on the reverse side become visible and interfere with the characters on the front side. This paper addresses this problem and develops a novel algorithm to extract clear text...

A method to study the changes in the retinal vasculature of diabetic patients is proposed. Generalized fractal dimension followed by canny edge detection method is used to classify diabetic people from healthy one. Statistical analysis is also done to verify the classification results.

Our fuzzy classifier detects classes of image pixels corresponding to gray level variation in the various directions. It uses an extended Epanechnikov function as a fuzzy set membership function (FSMF) for each class where the class assigned to each pixel is the one with the greatest fuzzy truth of membership. This classification is done first, after which a competition is run as a second step ...