Optimizing the depth of field for short object distance of capsule endoscope

Ou-Yang, Mang; Huang, Shih-Wei; Su, Wei-Kai; Feng, Han-Ming; Chen, Zhao-Yu; Wu, Hsin‐Mao; Kuo, Yi-Ting

doi:10.1117/12.762504

Cited by 5 publications

(5 citation statements)

References 1 publication

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“…17. 7,22 5 Discussion and Conclusions In this work, images captured by the RICE system were processed and reconstructed using MATLAB software (MathWorks, Natick, MA). First, the image compression problem that is caused by the cone mirror is considered.…”

Section: Image Reconstruction In Cartesian Coordinatesmentioning

confidence: 99%

Image stitching and image reconstruction of intestines captured using radial imaging capsule endoscope

Ouyang

Jeng

et al. 2012

Opt. Eng

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This study investigates image processing using the radial imaging capsule endoscope (RICE) system. First, an experimental environment is established in which a simulated object has a shape that is similar to a cylinder, such that a triaxial platform can be used to push the RICE into the sample and capture radial images. Then four algorithms (mean absolute error, mean square error, Pearson correlation coefficient, and deformation processing) are used to stitch the images together. The Pearson correlation coefficient method is the most effective algorithm because it yields the highest peak signal-to-noise ratio, higher than 80.69 compared to the original image. Furthermore, a living animal experiment is carried out. Finally, the Pearson correlation coefficient method and vector deformation processing are used to stitch the images that were captured in the living animal experiment. This method is very attractive because unlike the other methods, in which two lenses are required to reconstruct the geometrical image, RICE uses only one lens and one mirror.

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Section: Image Reconstruction In Cartesian Coordinatesmentioning

confidence: 99%

Image stitching and image reconstruction of intestines captured using radial imaging capsule endoscope

Ouyang

Jeng

et al. 2012

Opt. Eng

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“…The parameter r denotes the inner radius; C is the diameter of the image circle and equals the length of the diagonal of the CCD; and x is the shell thickness (0.7 mm) plus the thickness of the liquid in the intestines (0.4 mm). This object distance ensures that the optical module can correctly capture images of the intestines and that the quality of the images is not affected by the liquid that is attached to the intestines; so, x is 1.1 mm [13]. Table 2 shows the specifications of the doublet lenses in the FICE.…”

Section: Design Of Optical Lensesmentioning

confidence: 99%

Design and analysis of radial imaging capsule endoscope (RICE) system

Ou-Yang¹,

Jeng²

2011

Opt. Express

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In this study, a radial imaging capsule endoscope (RICE) system is designed, which differs from a conventional front imaging capsule endoscope (FICE) system. To observe the wrinkled intima of the intestine, which spreads without folding around the circumference of the capsule when a capsule endoscope with a diameter that slightly exceeds that of the intestine passes through it, the RICE uses a cone mirror, a radial window shell, and a focus optical module that comprise the radial imaging system. This concept was demonstrated in a packaged optical simulator. The RICE optical model also has been established and verified by many simulations and experiments. In minimizing the sagittal and tangential aberrations, the optical module of the RICE has achieved an F-number of 4.2, a viewing angle of 65.08°, and an RMS radius of the 4th to 6th fields of less than 17 um. A comparison of these characteristics with those of the focus optical module that is used in FICE lenses reveals that the spot size is 50% larger for each field, and the modulation transfer function (MTF) is remarkably improved from 7% to 36% at 100 lp/mm on the 5th field of the sagittal plane.

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“…In general, three main types of endoscopic systems are used: rigid endoscopes, flexible endoscopes and capsule endoscopes. Rigid endoscopes consisting of a set of lens modules and an image sensor are commonly used in the clinic examinations, such as gynecology and laparoscopy for internal medicine [1]. In the conventional endoscopic system, the depth-of-field (DOF), the distance between the nearest and farthest objects in a scene that appears clear in an image, is fixed and limited due to the fixed focusing properties of lens modules of endoscopes.…”

Section: Introductionmentioning

confidence: 99%

An endoscopic system adopting a liquid crystal lens with an electrically tunable depth-of-field

Chen¹,

Lin²

2013

Opt. Express

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Conventional endoscopic systems consisting of several solid lenses suffer from a fixed and limited depth-of-field (DOF). For practical applications, conventional endoscopes mechanically change the distance between the solid lenses of a lens module in order to change the focusing plane and DOF to see clearly in a scene. In this paper, we demonstrate an electrically tunable endoscopic system adopting a liquid crystal lens. By means of tunable focusing properties of the LC lens as a positive lens and a negative lens, the object at different objective distances can be imaged to the image sensor clearly and the corresponding depth-of-field can also help to enlarge the total spatial depth perception in a scene. The optical mechanism is discussed. In the experiments, under adjustment of three discrete lens powers of the LC lens, the viewing range or total spatial depth perception of the endoscopic system is from 76.4 mm to 12.4 mm which is 2x improved compared to the conventional one without LC lens. We believe this study can be extended to the applications of industrial and medical endoscopes.

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Optimizing the depth of field for short object distance of capsule endoscope

Cited by 5 publications

References 1 publication

Image stitching and image reconstruction of intestines captured using radial imaging capsule endoscope

Image stitching and image reconstruction of intestines captured using radial imaging capsule endoscope

Design and analysis of radial imaging capsule endoscope (RICE) system

An endoscopic system adopting a liquid crystal lens with an electrically tunable depth-of-field

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