Title
Computer-aided colorectal tumor classification in NBI endoscopy using local features.
Abstract
An early detection of colorectal cancer through colorectal endoscopy is important and widely used in hospitals as a standard medical procedure. During colonoscopy, the lesions of colorectal tumors on the colon surface are visually inspected by a Narrow Band Imaging (NBI) zoom-videoendoscope. By using the visual appearance of colorectal tumors in endoscopic images, histological diagnosis is presumed based on classification schemes for NBI magnification findings. In this paper, we report on the performance of a recognition system for classifying NBI images of colorectal tumors into three types (A, B, and C3) based on the NBI magnification findings. To deal with the problem of computer-aided classification of NBI images, we explore a local feature-based recognition method, bag-of-visual-words (BoW), and provide extensive experiments on a variety of technical aspects. The proposed prototype system, used in the experiments, consists of a bag-of-visual-words representation of local features followed by Support Vector Machine (SVM) classifiers. A number of local features are extracted by using sampling schemes such as Difference-of-Gaussians and grid sampling. In addition, in this paper we propose a new combination of local features and sampling schemes. Extensive experiments with varying the parameters for each component are carried out, for the performance of the system is usually affected by those parameters, e.g. the sampling strategy for the local features, the representation of the local feature histograms, the kernel types of the SVM classifiers, the number of classes to be considered, etc. The recognition results are compared in terms of recognition rates, precision/recall, and F-measure for different numbers of visual words. The proposed system achieves a recognition rate of 96% for 10-fold cross validation on a real dataset of 908 NBI images collected during actual colonoscopy, and 93% for a separate test dataset.
Year
DOI
Venue
2013
10.1016/j.media.2012.08.003
Medical Image Analysis
Keywords
Field
DocType
Colorectal cancer,Colonoscopy,NBI,Pit-pattern,Bag-of-visual-words
Histogram,Computer vision,Pattern recognition,Bag-of-words model in computer vision,Computer-aided,Support vector machine,Artificial intelligence,Sampling (statistics),Magnification,Cross-validation,Mathematics,Visual Word
Journal
Volume
Issue
ISSN
17
1
1361-8415
Citations 
PageRank 
References 
15
0.91
78
Authors
10
Name
Order
Citations
PageRank
Toru Tamaki112030.21
Junki Yoshimuta2221.52
Misato Kawakami3150.91
Bisser Raytchev421233.11
Kazufumi Kaneda543986.44
Makoto Yoshida64612.34
Yoshito Takemura7221.85
Keiichi Onji8151.25
Rie Miyaki9193.40
Shinji Tanaka107216.85