Search

Wireless capsule endoscopy (WCE) enables noninvasive and painless direct visual inspection of a patient's whole digestive tract, but at the price of long time reviewing large amount of images by clinicians. Thus, an automatic computer-aided technique to reduce the burden of physicians is highly demanded. In this paper, we propose a novel color feature extraction method to discriminate the bleeding frames from the normal ones, with further localization of the bleeding regions. Our proposal is based on a twofold system. First, we make full use of the color information of WCE images and utilize K-means clustering method on the pixel represented images to obtain the cluster centers, with which we characterize WCE images as words-based color histograms. Then, we judge the status of a WCE frame by applying the support vector machine (SVM) and K-nearest neighbor methods. Comprehensive experimental results reveal that the best classification performance is obtained with YCbCr color space, cluster number 80 and the SVM. The achieved classification performance reaches 95.75% in accuracy, 0.9771 for AUC, validating that the proposed scheme provides an exciting performance for bleeding classification. Second, we propose a two-stage saliency map extraction method to highlight bleeding regions, where the first-stage saliency map is created by means of different color channels mixer and the second-stage saliency map is obtained from the visual contrast. Followed by an appropriate fusion strategy and threshold, we localize the bleeding areas. Quantitative as well as qualitative results show that our methods could differentiate the bleeding areas from neighborhoods correctly.

Ulcer is one of the most common symptoms of many serious diseases in the human digestive tract. Especially for the ulcers in the small bowel where other procedures cannot adequately visualize, wireless capsule endoscopy (WCE) is increasingly being used in the diagnosis and clinical management. Because WCE generates large amount of images from the whole process of inspection, computer-aided detection of ulcer is considered an indispensable relief to clinicians. In this paper, a two-staged fully automated computer-aided detection system is proposed to detect ulcer from WCE images. In the first stage, we propose an effective saliency detection method based on multi-level superpixel representation to outline the ulcer candidates. To find the perceptually and semantically meaningful salient regions, we first segment the image into multi-level superpixel segmentations. Each level corresponds to different initial region sizes of the superpixels. Then we evaluate the corresponding saliency according to the color and texture features in superpixel region of each level. In the end, we fuse the saliency maps from all levels together to obtain the final saliency map. In the second stage, we apply the obtained saliency map to better encode the image features for the ulcer image recognition tasks. Because the ulcer mainly corresponds to the saliency region, we propose a saliency max-pooling method integrated with the Locality-constrained Linear Coding (LLC) method to characterize the images. Experiment results achieve promising 92.65% accuracy and 94.12% sensitivity, validating the effectiveness of the proposed method. Moreover, the comparison results show that our detection system outperforms the state-of-the-art methods on the ulcer classification task.

Purpose: Wireless capsule endoscopy (WCE) opens a new door for the digestive tract examination and diagnosis. However, the examination of its video data is tedious. This study aims to assist a physician to interpret a WCE video by segmenting it into different anatomic parts in the digestive tract., Methods: A two level WCE video segmentation scheme is proposed to locate the boundary between the stomach, small intestine, and large intestine. In the rough level, the authors utilize color feature to draw a dissimilarity curve for a WCE video and obtain an approximate boundary. Meanwhile, training data for the fine level segmentation can be collected automatically between the two approximate boundaries of organs to overcome the difficulty of training data collection in traditional approaches. In the fine level, color histogram in the HSI color space is used to segment the stomach and small intestine. Then, color uniform local binary pattern (CULBP) algorithm is applied for discrimination of the small intestine and large intestine, which includes two patterns, namely, color norm and color angle pattern. The CULBP feature is robust to variation of illumination and discriminative for classification. In order to increase the performance of support vector machine, the authors integrate it with the Adaboost approach. Finally, the authors refine the classification results to segment a WCE video into different parts, that is, the stomach, small intestine, and large intestine., Results: The average precision and recall are 91.2% and 90.6% for the stomach/small intestine classification, 89.2% and 88.7% for the small/large intestine discrimination. Paired t-test also demonstrates a significant better performance of the proposed scheme compared to some traditional methods. The average segmentation error is 8 frames for the stomach/small intestine discrimination, and 14 frames for the small/large intestine segmentation., Conclusions: The results have demonstrated that the new video segmentation method can accurately locate the boundary between different organ regions in a WCE video. Such a segmentation result may enhance the efficiency of WCE examination.

Tumor in digestive tract is a common disease and wireless capsule endoscopy (WCE) is a relatively new technology to examine diseases for digestive tract especially for small intestine. This paper addresses the problem of automatic recognition of tumor for WCE images. Candidate color texture feature that integrates uniform local binary pattern and wavelet is proposed to characterize WCE images. The proposed features are invariant to illumination change and describe multiresolution characteristics of WCE images. Two feature selection approaches based on support vector machine, sequential forward floating selection and recursive feature elimination, are further employed to refine the proposed features for improving the detection accuracy. Extensive experiments validate that the proposed computer-aided diagnosis system achieves a promising tumor recognition accuracy of 92.4% in WCE images on our collected data.

This article presents a computer-aided detection system for capsule endoscopy (CE) images using contourlet-based color textural features to recognize tumors in the digestive tract. As tumor exhibits rich information in color texture, a novel color texture feature based on contourlet transform is proposed to describe characteristics of tumor in CE images. The proposed features are a hybrid of contourlet transform and uniform local binary pattern, yielding detailed and robust color texture features in multi-directions for CE images. Sequential floating forward search approach is further applied to refine the proposed features. With support vector machine for classification, comprehensive experiments on our present data reveal an encouraging accuracy of 93.6% for tumor detection in CE images using the proposed features.

Objective: Capsule endoscopy is useful in the diagnosis of small bowel diseases. However, the large number of images produced in each test is a tedious task for physicians. To relieve burden of physicians, a new computer-aided detection scheme is developed in this study, which aims to detect small bowel tumors for capsule endoscopy., Methods and Materials: A novel textural feature based on multi-scale local binary pattern is proposed to discriminate tumor images from normal images. Since tumor in small bowel exhibit great diversities in appearance, multiple classifiers are employed to improve detection accuracy. 1200 capsule endoscopy images chosen from 10 patients' data constitute test data in our experiment., Results: Multiple classifiers based on k-nearest neighbor, multilayer perceptron neural network and support vector machine, which are built from six different ensemble rules, are experimented in three different color spaces. The results demonstrate an encouraging detection accuracy of 90.50%, together with a sensitivity of 92.33% and a specificity of 88.67%., Conclusion: The proposed scheme using color texture features and classifier ensemble is promising for small bowel tumor detection in capsule endoscopy images., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Wireless capsule endoscopy (WCE) has been gradually applied for inspecting the gastrointestinal (GI) tract. However, WCE can only provide monocular view. Moreover, only a small part of GI wall is visible frame by frame due to the limited illumination and irregular motion of the capsule endoscope. The perception of entire GI structure could be hard even for the experienced endoscopists. A realistic friendly three dimension view is needed to help the physicians to get a better perception of the GI tract. In this paper, we present a method to reconstruct the three dimension surface of the intestinal wall by applying the SIFT feature detector and descriptor to a sequence of WCE images. Epipolar geometry is employed to further constrain the matching feature points in order to obtain a more accurate 3D view. The experiments on real data are presented to show the performance of our proposed method.

Capsule endoscopy (CE) has been widely used to diagnose diseases in human digestive tract. However, a tough problem of this new technology is that too many images to be inspected by eyes cause a huge burden to physicians, so it is significant to investigate computerized diagnosis methods. In this paper, a new computer-aided system aimed for bleeding region detection in CE images is proposed. This new system exploits color texture feature, an important clue used by physicians, to analyze status of gastrointestinal tract. We put forward a new idea of chrominance moment as the color part of color texture feature, which makes full use of Tchebichef polynomials and illumination invariant of hue/saturation/intensity color space. Combined with uniform local binary pattern, a current texture representation model, it can be applied to discriminate normal regions and bleeding regions in CE images. Classification of bleeding regions using multilayer perceptron neural network is then deployed to verify performance of the proposed color texture features. Experimental results on our bleeding image data show that the proposed scheme is promising in detecting bleeding regions.

Wireless capsule endoscopy (WCE) has been gradually employed in hospitals because it can directly view the entire small bowel of a human body for the first time. However, a troublesome problem related to this new technology is that too many images produced by WCE will take a lot of efforts for doctors to inspect. In this paper, we propose a comparative study of shape features aiming for intestinal polyp detection for WCE images. As polyps exhibit strong shape characteristics, also a powerful clue used by physicians, we investigate two kinds of shape features, MEPG-7 region-based shape descriptor and Zernike moments, in our study. With multi-layer perceptron neural network as the classifier, experiments on our present image data show that it is promising to employ both Zernike moments and MEPG-7 region-based shape descriptor as the shape features to recognize the intestinal polyp regions, and a better performance is obtained by the Zernike moments based shape features.

To enhance the contrast and the details of the wireless capsule endoscopy images, which are used to diagnose the status of the human gastrointestinal tracts, we propose a tensor based diffusion method in this paper. After analyzing the structure tensor of the image in RGB color space, we focus on the properties of the nonlinear anisotropic diffusion. Then we design two diffusion strength functions to determine the anisotropic diffusion according to the local characteristics of the wireless capsule endoscopy images. Experimental results on real wireless capsule endoscopy images indicate effective enhancement of details and contrast by our new approach.

Wireless capsule endoscopy (WCE) has become a widely used diagnostic technique for the digestive tract, at the price of a large volume of data that needs to be analyzed. To tackle this problem, a new computer-aided system using novel features is proposed in this paper to classify WCE images automatically. In the feature learning stage, to obtain the representative visual words, we first calculate the color scale invariant feature transform from the bleeding, polyp, ulcer, and normal WCE image samples separately and then apply $K$ -means clustering on these features to obtain visual words. These four types of visual words are combined together to composite the representative visual words for classifying the WCE images. In the feature coding stage, we propose a novel saliency and adaptive locality-constrained linear coding (SALLC) algorithm to encode the images. The SALLC encodes patch features based on adaptive coding bases, which are calculated by the distance differences among the features and the visual words. Moreover, it imposes the patch saliency constraint on the feature coding process to emphasize the important information in the images. The experimental results exhibit a promising overall recognition accuracy of 88.61%, validating the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Wireless capsule endoscopy (WCE) needs computerized method to reduce the review time for its large image data. In this paper, we propose an improved bag of feature (BoF) method to assist classification of polyps in WCE images. Instead of utilizing a single scale-invariant feature transform (SIFT) feature in the traditional BoF method, we extract different textural features from the neighborhoods of the key points and integrate them together as synthetic descriptors to carry out classification tasks. Specifically, we study influence of the number of visual words, the patch size and different classification methods in terms of classification performance. Comprehensive experimental results reveal that the best classification performance is obtained with the integrated feature strategy using the SIFT and the complete local binary pattern (CLBP) feature, the visual words with a length of 120, the patch size of 8*8, and the support vector machine (SVM). The achieved classification accuracy reaches 93.2%, confirming that the proposed scheme is promising for classification of polyps in WCE images. [ABSTRACT FROM AUTHOR]

Abstract: Wireless capsule endoscopy (WCE) opens a new stage for diagnosing gastrointestinal tract diseases since it enables direct visualization of the small intestine for the first time. However, it requires a clinician’s long time inspection due to a great number of images produced by the procedure. Therefore, it may be beneficial to devise an automatic detection system to help clinicians identify problematic images. In this work, we attempt to design a computerized scheme aiming for polyp WCE image recognition though polyp in WCE images show great variations in appearance. This scheme utilizes a new texture feature to characterize WCE images, which integrates advantages of wavelet transform and uniform local binary pattern. With support vector machine (SVM) as a classifier, extensive experiments on our present image data, which consists of 600 normal WCE images and 600 polyp WCE images chosen from 10 patients, verify that it is promising to utilize the proposed scheme to detect polyp WCE images. [Copyright &y& Elsevier]

Abstract: Wireless capsule endoscopy (WCE) has been widely applied to diagnose diseases in human digestive tract due to its advantage that it can directly view the entire small intestine for the first time. However, many WCE images are rather dark, which challenge to analysis and diagnosis exerted by a clinician. To overcome this shortcoming so as to assist physicians, especially computer aided detection, we propose an adaptive contrast diffusion to enhance WCE images. Based on local analysis of WCE images, we put forward a new idea of contrast diffusion. Then, we employ contrast diffusion to enhance WCE images with an adaptive choice of the conductance parameter, which plays an important role in diffusion. Extensive experiments demonstrate that this new method exhibits promising performance of enhancement for WCE images, leading into a better visualization as well as an improved classification performance of WCE images using computerized methods. [Copyright &y& Elsevier]