The type of illumination systems and color filters used typically generate varying levels of color difference in capsule endoscopes, which influence medical diagnoses. In order to calibrate the color difference caused by the optical system, this study applied a radial imaging capsule endoscope (RICE) to photograph standard color charts, which were then employed to calculate the color gamut of RICE. Color gamut was also measured using a spectrometer in order to get a high-precision color information, and the results obtained using both methods were compared. Subsequently, color-correction methods, namely polynomial transform and conformal mapping, were used to improve the color difference. Before color calibration, the color difference value caused by the influences of optical systems in RICE was 21.45±1.09. Through the proposed polynomial transformation, the color difference could be reduced effectively to 1.53±0.07. Compared to another proposed conformal mapping, the color difference value was substantially reduced to 1.32±0.11, and the color difference is imperceptible for human eye because it is <1.5. Then, real-time color correction was achieved using this algorithm combined with a field-programmable gate array, and the results of the color correction can be viewed from real-time images.
The technology of electrowetting display (EWD) is the most important method for the traditional displays that can work more efficiently. When the voltage drives, the aperture ratio of the ink will reach 75% and the transmittance can reach 60%. Furthermore, the EWD technology has the advantages such as high transmittance, high switching speed, color performance, low power consumption, and etc. They make the advances of technology development for the transparent displays. However, due to the diffraction phenomenon resulted from periodic pixel structures, when the users observe the background object through the transparent display, the transmitted image will be blurred. In this paper, we recognized the problems by the simulation and constructed the optical model first. In order to avoid the diffraction, we use micro lens array to prevent the rays interfere on the micro structure, so that it will not produce the destructive and constructive interference, so the diffraction effect can be reduced. The micro lens array avoid the light touches the outer frame of EWD pixels. The simulations are simulate at different distance, and the distance of diffraction width is condensed to 91% with respect to the origin. In the future, this concept can apply in other transmitted images of transparent displays.
Glaucoma was diagnosed or tracked by the intraocular pressure (IOP) generally because it is one of the physiology
parameters that are associated with glaucoma. But measurement of IOP is not easy and consistence under different
measure conditions. An infrared videopupillography is apparatus to monitor the pupil size in an attempt to bypass the
direct IOP measurement. This paper propose an infrared videopupillography to monitoring the pupil size of different
light stimulus in dark room. The portable infrared videopupillography contains a camera, a beam splitter, the visible-light
LEDs for stimulating the eyes, and the infrared LEDs for lighting the eyes. It is lighter and smaller than the present
product. It can modulate for different locations of different eyes, and can be mounted on any eyeglass frame. An analysis
program of pupil size can evaluate the pupil diameter by image correlation. In our experiments, the eye diameter curves
were not smooth and jagged. It caused by the light spots, lone eyelashes, and blink. In the future, we will improve the
analysis program of pupil size and seek the approach to solve the LED light spots. And we hope this infrared
videopupillography proposed in this paper can be a measuring platform to explore the relations between the different
diseases and pupil response.
Current capsule endoscope uses one camera to capture the surface image in the intestine. It can only observe the abnormal point, but cannot know the exact information of this abnormal point. Using two cameras can generate 3D images, but the visual plane changes while capsule endoscope rotates. It causes that two cameras can’t capture the images information completely. To solve this question, this research provides a new kind of capsule endoscope to capture 3D images, which is 'A 3D photographic capsule endoscope system'. The system uses three cameras to capture images in real time. The advantage is increasing the viewing range up to 2.99 times respect to the two camera system. The system can accompany 3D monitor provides the exact information of symptom points, helping doctors diagnose the disease.
This study concerns the illumination system in a radial imaging capsule endoscope (RICE). Uniformly illuminating the object is difficult because the intensity of the light from the light emitting diodes (LEDs) varies with angular displacement. When light is emitted from the surface of the LED, it first encounters the cone mirror, from which it is reflected, before directly passing through the lenses and complementary metal oxide semiconductor (CMOS) sensor. The light that is strongly reflected from the transparent view window (TVW) propagates again to the cone mirror, to be reflected and to pass through the lenses and CMOS sensor. The above two phenomena cause overblooming on the image plane. Overblooming causes nonuniform illumination on the image plane and consequently reduced image quality. In this work, optical design software was utilized to construct a photometric model for the optimal design of the LED illumination system. Based on the original RICE model, this paper proposes an optimal design to improve the uniformity of the illumination. The illumination uniformity in the RICE is increased from its original value of 0.128 to 0.69, greatly improving light uniformity.
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.
This article mainly focuses on image processing of radial imaging capsule endoscope (RICE). First, it used the radial
imaging capsule endoscope (RICE) to take the images, the experimental used a piggy to get the intestines and captured
the images, but the images captured by RICE were blurred due to the RICE has aberration problems in the image center
and lower light uniformity affect the image quality. To solve the problems, image processing can use to improve it.
Therefore, the images captured by different time can use Person correlation coefficient algorithm to connect all the
images, and using the color temperature mapping way to improve the discontinuous problem in the connection region.
This paper is researching about the illumination system in ring field capsule endoscope. It is difficult to obtain the
uniform illumination on the observed object because the light intensity of LED will be changed along its angular
displacement and same as luminous intensity distribution curve. So we use the optical design software which is
Advanced Systems Analysis Program (ASAP) to build a photometric model for the optimal design of LED illumination
system in ring field capsule endoscope. In this paper, the optimal design of illumination uniformity in the ring field
capsule endoscope is from origin 0.128 up to optimum 0.603 and it would advance the image quality of ring field capsule
The index for evaluating the ability of color reproduction is required. The color distribution index (CDI) was proposed to
comment the display ability of color distribution of reproduction in CIE Lu'v' color space. A cell of Just Noticeable
Difference (JND) for luminance and chromaticity (u'v') was proposed to qualify whether the reproduced colors are in
some region of color volume of display. Human eye can perceive fewer colors at low luminance, however, the scalar of
chromaticity (u'v') JND at low luminance was the same with the one at other luminance. CDI will be distorted at low
luminance. In this paper, regarding perceptible vision at low luminance, we try to use chromaticity (a*b*) JND to replace
chromaticity (u'v') JND. The color distribution will be discussed in CIE La*b* color space. We find that CDI at low
luminance in CIE L*a*b* color space is higher than in CIE Lu'v' color space, as well as different gamma curves and
different bit depths affect CDI. The displays are going to keep approaching 100% true color reproduction; hence the
index for evaluating the ability of color reproduction is required.