Combining Entropy Optimization and Sobel Operator for Medical Image Fusion

Fusing medical images is a topic of interest in processing medical images.This is achieved to through fusing information from multimodality images for the purpose of increasing the clinical diagnosis accuracy.This fusion aims to improve the image quality and preserve the specific features.The methods of medical image fusion generally use knowledge in many differentfields such as clinical medicine,computer vision,digital imaging,machine learning,pattern recognition to fuse different medical images.There are two main approaches in fusing image,including spatial domain approach and transform domain approachs.This paper proposes a new algorithm to fusion multimodal images.This algorithm is based on Entropy optimization and the Sobel operator.Wavelet transform is used to split the input images into components over the low and high frequency domains.Then,two fusion rules are used for obtaining the fusing images.Thefirst rule,based on the Sobel operator,is used for high frequency components.The second rule,based on Entropy optimization by using Particle Swarm Optimization(PSO)algorithm,is used for low frequency components.Proposed algorithm is implemented on the images related to central nervous system diseases.The experimental results of the paper show that the proposed algorithm is better than some recent methods in term of brightness level,the contrast,the entropy,the gradient and visual informationfidelity for fusion(VIFF),Feature Mutual Information(FMI)indices.

Grey Relevancy Degree and Improved Eight-Direction Sobel Operator Edge Detection

Edge detection is an important aspect to improve image edge quality in image processing. The purpose of edge detection is to identify the points in digital images with great brightness variation. However, the accuracy of traditional edge detection methods in edge extraction is low. For the actual image, the grey edge is sometimes not very clear, the image also contains noise. The detection result of the traditional Sobel operator is relatively accurate, but the detection result is rough and sensitive to noise. To solve the above problems, this paper proposes an improved eight-direction Sobel operator based on grey relevancy degree, which combines 5 × 5 Sobel operator with a grey relational degree and a new eight-direction grey relevancy method. The results show that this method can detect the useful information of edge more accurately and improve the anti-noise performance. However, the drawback is that the algorithm is not automatic.

Image segmentation of overlapping leaves based on Chan–Vese model and Sobel operator

To improve the segmentation precision of overlapping crop leaves,this paper presents an effective image segmentation method based on the Chan–Vese model and Sobel operator.The approach consists of three stages.First,a feature that identifies hues with relatively high levels of green is used to extract the region of leaves and remove the background.Second,the Chan–Vese model and improved Sobel operator are implemented to extract the leaf contours and detect the edges,respectively.Third,a target leaf with a complex background and overlapping is extracted by combining the results obtained by the Chan–Vese model and Sobel operator.To verify the effectiveness of the proposed algorithm,a segmentation experiment was performed on 30 images of cucumber leaf.The mean error rate of the proposed method is 0.0428,which is a decrease of 6.54%compared with the mean error rate of the level set method.Experimental results show that the proposed method can accurately extract the target leaf from cucumber leaf images with complex backgrounds and overlapping regions.

Movement Invariants-based Algorithm for Medical Image Tilt Correction

In this paper, the edge detection for a medical image is performed based on Sobel operator, and the bounding box is obtained, by which the effective medical sub-image is extracted. Then, the centroid and the normalized central moments of the medical sub-image are calculated, and the rotation angle a is obtained by minimizing the second-order central moment based on its rotation invariance. Finally, the whole medical image is rotated around the centroid by --a to correct the tilted image. F^rthermore, inspired by the uniformity degree of the image, the rotation angle ct is revised, which achieves a better correction effect and performance. The experimental results show that the proposed algorithms are fairly reliable and accurate for the determination of tilt angles, and are practical and effective tilt correction techniques.

A MODIFIED EDGE-ORIENTED SPATIAL INTERPOLATION ALGORITHM FOR CONSECUTIVE BLOCKS ERROR CONCEALMENT

This paper proposes a low-complexity spatial-domain Error Concealment (EC) algorithm for recovering consecutive blocks error in still images or Intra-coded (I) frames of video sequences. The proposed algorithm works with the following steps. Firstly the Sobel operator is performed on the top and bottom adjacent pixels to detect the most likely edge direction of current block area. After that one-Dimensional (1D) matching is used on the available block boundaries. Displacement between edge direction candidate and most likely edge direction is taken into consideration as an important factor to improve stability of 1D boundary matching. Then the corrupted pixels are recovered by linear weighting interpolation along the estimated edge direction. Finally the interpolated values are merged to get last recovered picture. Simulation results demonstrate that the proposed algorithms obtain good subjective quality and higher Peak Signal-to-Noise Ratio (PSNR) than the methods in literatures for most images.

Edge-Oriented Spatial Interpolation for Error Concealment of Consecutive Blocks

This paper proposes a low-complexity spatial-domain error concealment （EC） algorithm for recovering consecutive blocks error in still images or intra-coded （I） frames of video sequences. The proposed algorithm works with the following steps. Firstly the Sobel operator is performed on the top and bottom adjacent pixels to detect the most probable edge direction of current block area. After that one-dimensional （1-D） matching is used on the available block boundaries. Displacement between edge direction candidate and most probable edge direction is taken into consideration as an important factor to improve stability of 1-D boundary matching. Then the corrupted pixels are recovered by linear weighting interpolation along the estimated edge direction. Finally the interpolated values are merged to get last recovered picture. Simulation results demonstrate that the proposed algorithms obtain good subjective quality and higher PSNR than the methods in literatures for most images.

A fast method to detect blood vessel in retinal image

Due to the increasing number ot diabetic patients, the number of people affected by diabetic retinopathy isexpected to increase. Diabetic retinopathy is a complication of diabetes and the most serious frequent eye disease in the world. Large-scale retinal screening for diabetic patients is necessary to prevent visual loss and blindness. The analysis of digital retinal images, obtained by the fundus camera, is viewed as a feasible approach because retinal blood vessels have been shown to change in diameter, branching angles, or tortuosity as a result of diabetic retinopathy. The morphological change can help identify the different stages of diabetic retinopathy. In addition, the acquisition of retinal image is nonintrusive and low cost. Automatic segmentation of the retinal blood vessel is a prerequisite for this analysis.~3 This article presents a method to detect blood vessel based on sobel operators.4 Small and fast computation is the outstanding merit of this method.