Combination of Wavelet Transform and Morphological Filtering for Enhancement of Magnetic Resonance Images

Author(s):  
Akansha Srivastava ◽  
Alankrita ◽  
Abhishek Raj ◽  
Vikrant Bhateja
1999 ◽  
Author(s):  
Gordon E. Sarty ◽  
M. Stella Atkins ◽  
Femi Olatunbosun ◽  
Donna Chizen ◽  
John Loewy ◽  
...  

2015 ◽  
Vol 27 (03) ◽  
pp. 1550024
Author(s):  
Saba Zahmati ◽  
Mohammad Mahdi Khalilzadeh ◽  
Mohsen Foroughipour

In recent years, multi-scale transform application in image processing especially for magnetic resonance (MR) images has been raised. Wavelet transform is introduced as a useful tool in image processing and it is capable of effectively removing noise from magnetic resonance images. The main problem with wavelet transform is that it is not able to distinguish one dimensional (1D) or higher dimentional discontinuities in images. In other words, since the wavelet transform is two dimensional (2D), it is considered as a separable transform, it is solely able to identify pointwise discontinuity in images. A proposed solution for this issue is an inseparable transform which is named curvelet. Time frequency transform based noise elimination methods, usually rely on thresholding. There are two important factors involved in thresholding: (1) a method to determine the threshold limit, (2) the implementation of the threshold. In curvelet method, by setting a hard threshold at low levels of noise the obtained similarity index is 0.9254. The proposed method for noise elimination and edge detection in this paper is applying curvelet transform in combination with wavelet transform, which on average leads to 10% improvement compared with wavelet method. The results show the efficiency of this method in different parts of image processing on simulated and actual MR images.


2019 ◽  
Vol 4 (5) ◽  

The present study aimed to investigate the design of a computer-assisted pathology system for diagnosis and clustering of cancerous lesions in magnetic resonance imaging of breast, using computer code in MATLAB software. In the analysis of breast segmentation by Atlas method, mass tumors 4 and non-mass tumors 5 are identified and segmented. Characteristics of the morphology, kinetics and matrix of the gray level co- occurrence of the tumors are extracted. In this study, a new feature called “dual-tree complex wavelet transform (DTCWT” was extracted and five characteristics associated with this type of property were extracted. After extracting these properties, the feature vectors were assigned to the clustering with different kernels and the combined clustering, which combine the linear discriminate analysis method and the nearest neighbor, and clustering of the tumors was performed into two benign and malignant categories. Using the new feature introduced in this study and applying it to the SVM cluster, AZ values for mass tumors, non-mass tumors and their combination were 0.71, 0.77 and 0.70, respectively, and by applying it to the combined cluster s LDA and NN-k were 0.70, 0.44 and 0.69, respectively. Also, in the Atlas-based segmentation, the FCM cluster was used for them first time. The use of this cluster caused that there is no empty cluster and the accuracy of the results would increase. In the feature extraction section, the feature of dual-tree complex wavelet transform (CWT-DT) was applied for the first time in magnetic resonance images of the breast and on mass and non-mass tumors and a combination of them was applied. Detection and extraction of non-mass tumors is the main challenge of this study, and applying the proposed feature group of non-mass tumors created an acceptable result, and the value of AZ increased compared to previous studies.


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