The ambiguity and complexity of medical cerebrovascular image makes the skeleton gained by conventional skeleton algorithm discontinuous, which is sensitive at the weak edges, with poor robustness and too many burrs. This paper proposes a cerebrovascular image skeleton extraction algorithm based on Level Set model, using Euclidean distance field and improved gradient vector flow to obtain two d...

With the rapid development of image production and applications, image security has become very important. Traditional image encryption algorithms, such as Arnold transform is used widely, but it has the defect of long transform periodicity, which costs large time and computation memory. Therefore, based on the analysis of the defect of traditional image scrambling methods, a novel hybrid encry...

A multi-stage approach is presented for thresholding document images, along with its application. The proposed method is based on two stages. Global thresholding is used in first stage to give a preliminary result. A second stage then refines the threshold value based on local spatial characteristics of the regions formed in the first stage. It automatically customizes the thresholding of regio...

Contrast enhancement plays a crucial role in the field of image processing. Histogram equalization is a simple and automatic method for contrast enhancement. Conventional contrast-enhancement techniques, such as histogram specification and contrast stretching, require manual parameters to achieve satisfactory results. To automatically produce enhanced results for low-contrast images, a new hist...

We present a new method for texture image classification using Basic Gray Level Aura Matrices (BGLAMs). Given an unseen texture image, our approach classifies it into one of the pre-learned classes, each of which is characterized using BGLAMs. There are two stages in our algorithm: a learning stage and a classification stage. In the first stage, models of texture classes are learned from the BG...

A novel method is proposed for exact Legendre moment computation for gray level images. A recurrence formula is used to compute exact values of moments by mathematically integrating the Legendre polynomials over digital image pixels. This method removes the numerical approximation errors involved in conventional methods. A fast algorithm is proposed to accelerate the moment’s computations. A co...

Visual cryptography is a kind of image encryption technology. It is characterized by the process of decryption that is overlapping the encrypted images and restores the secret by the human vision. Kafri and Keren proposed three random grid algorithms to encrypt a binary secret image in 1987. The advantage of their research is that the encrypted images with random grid will not be excessive expa...

Automatic thresholding of the gray-level values of an image is very useful in automated analysis of morphological images, and it represents the first step in many applications in image understanding. Recently it was shown that by choosing the threshold as the value that maximizes the entropy of the l-dimensional histogram of an image, one might be able to separate, effectively, the desired obje...

A color estimation method for a gray-level image is proposed by giving a few color pixels. It is known that a density value in the gray-level image will be calculated by linear combination of an RGB vector of the color image. The problem dealt with in this study can be formulated as an ill-posed problem which searches for an RGB vector from a density value as a solution. By assuming a restricte...

For some gray-level images, the boundary between the foreground and the background is perceived in correspondence with the locally maximal changes in gray-level through the image. In this framework, this paper proposes a method to extract the objects of interest from an image and, hence, to distinguish the foreground from the background, starting from a partition of the image obtained by means ...