The study of the methods for evaluating the matching rate of capsule endoscope pixels and its resolution effectiveness

Jia Xiaohang; Zhang Qinyuan; Yan Qinglai; Yang Shiming; Chen Debao

doi:10.12086/oee.2019.180112

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Jia Xiaohang, Zhang Qinyuan, Yan Qinglai, et al. The study of the methods for evaluating the matching rate of capsule endoscope pixels and its resolution effectiveness[J]. Opto-Electronic Engineering, 2019, 46(1): 180112. doi: 10.12086/oee.2019.180112

Citation:

Jia Xiaohang, Zhang Qinyuan, Yan Qinglai, et al. The study of the methods for evaluating the matching rate of capsule endoscope pixels and its resolution effectiveness[J]. Opto-Electronic Engineering, 2019, 46(1): 180112. doi: 10.12086/oee.2019.180112

The study of the methods for evaluating the matching rate of capsule endoscope pixels and its resolution effectiveness

1.
Zhejiang Institute of Medical Device Testing, Hangzhou, Zhejiang 310018, China
2.
Third Military Medical University, Chongqing 400037, China

Fund Project: Supported by National Key Research and Development Plan Fund (2016YFC0107000)

More Information

Corresponding author: Zhang Qinyuan, E-mail:zhang.qinyuan@163.com

Received Date 09 March 2018

Revised Date 21 May 2018

Published Date 01 January 2019

Abstract

Abstract

The evaluation for the matching level between the optical resolution and the pixels number on the full field of view of the capsule endoscope, and the evaluation methods for the resolution effectiveness of pixels number were established. This method selects the horizontal optical axis section as the meridian plane to analyze. The section passing through the planar array sensor is row or column scanned. The line resolution elements number, the line pixel efficiency, the center field matching rate, and the full field maximum matching rate were derived by the analysis unit using the optical resolution angle and the pixel element projection angle. The simple conversion method of resolution length and resolution angle on the spherical field of view can simplify the measurement. These parameters not only constitute the evaluation basis for matching ratio and resolution validity of the pixel number of the capsule endoscope, but also offer a reference for product design, analysis and modification.
- capsule endoscope /
- matching rate /
- resolution effectiveness /
- pixel

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References

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Overview

Overview

Overview: Based on clinical application, the capsule endoscope is designed as a wide field of view. However, the wide field of view will cause distortion. The distortion is easy to generate the matching inconsistency between the pixel element and the optical resolution element in the full field of view. Then the effectiveness of the pixels has declined. Furthermore, the distortion even causes the mismatching in some positions. The small intestine capsule endoscope is used to observe the surrounding field of view. The detection found that Moiré pattern occurred in the small intestine capsule endoscopy. Therefore, researches were carried out to establish the evaluation for the matching level between the optical resolution and the pixel number on the full field of view of the capsule endoscope, and the evaluation methods for the resolution validity of pixel number. This method selects the horizontal optical axis section as the meridian plane to analyze. The section passing through the planar array sensor is row or column scanned. The analytical method of the optical resolution angle continuation arrangement was adopted. Then the algorithm of line resolution element number was derived. The number of effective pixels of the line was described by the number of resolution elements. Then, the effective rate of line pixel number was obtained. The pixel element projection angle and the optical resolution angle were taken as the analytical units. The ratio between the pixel element projection angle and the optical resolution angle in the same field of view position was regarded as the line-matching ratio. Three basic functions for analysis were further extended, including the resolution angle density function, the relative function of line matching ratio and the density eigenfunction of pixel element projection angle. A simple measurement method was derived by using the simple conversion relations between a line segment and an included angle on a spherical field of view. Those three basic functions for analysis were obtained by fitting, so that the situation of the pixel element and the optical resolution element in every position, the matching details between two elements and the matching level between two elements in the full field of view were obtained. The parameters, including the line resolution element number, effective rate of line pixel number, center field of view matching ratio, maximum matching ratio of the full field of view and its position and other parameters, not only constitute the evaluation basis for matching ratio and resolution validity of the pixel number of the capsule endoscope, but also offer a reference for product design, analysis and modification.