A hyperspectral imaging system is proposed for early study of skin diagnosis. A stable and high hyperspectral image quality is important for analysis. Therefore, a light guide sleeve (LGS) was designed for the embedded on a hyperspectral imaging system. It provides a uniform light source on the object plane with the determined distance. Furthermore, it can shield the ambient light from entering the system and increasing noise. For the purpose of producing a uniform light source, the LGS device was designed in the symmetrical double-layered structure. It has light cut structures to adjust distribution of rays between two layers and has the Lambertian surface in the front-end to promote output uniformity. In the simulation of the design, the uniformity of illuminance was about 91.7%. In the measurement of the actual light guide sleeve, the uniformity of illuminance was about 92.5%.
Oral cancer is a serious and growing problem in many developing and developed countries. To improve the cancer screening procedure, we developed a portable light-emitting-diode (LED)-induced autofluorescence (LIAF) imager that contains two wavelength LED excitation light sources and multiple filters to capture ex vivo oral tissue autofluorescence images. Compared with conventional means of oral cancer diagnosis, the LIAF imager is a handier, faster, and more highly reliable solution. The compact design with a tiny probe allows clinicians to easily observe autofluorescence images of hidden areas located in concave deep oral cavities. The ex vivo trials conducted in Taiwan present the design and prototype of the portable LIAF imager used for analyzing 31 patients with 221 measurement points. Using the normalized factor of normal tissues under the excitation source with 365 nm of the central wavelength and without the bandpass filter, the results revealed that the sensitivity was larger than 84%, the specificity was not smaller than over 76%, the accuracy was about 80%, and the area under curve of the receiver operating characteristic (ROC) was achieved at about 87%, respectively. The fact shows the LIAF spectroscopy has the possibilities of ex vivo diagnosis and noninvasive examinations for oral cancer.
Oral cancer is one of the serious and growing problem in many developing and developed countries. The simple oral visual screening by clinician can reduce 37,000 oral cancer deaths annually worldwide. However, the conventional oral examination with the visual inspection and the palpation of oral lesions is not an objective and reliable approach for oral cancer diagnosis, and it may cause the delayed hospital treatment for the patients of oral cancer or leads to the oral cancer out of control in the late stage. Therefore, a device for oral cancer detection are developed for early diagnosis and treatment. A portable LED Induced autofluorescence (LIAF) imager is developed by our group. It contained the multiple wavelength of LED excitation light and the rotary filter ring of eight channels to capture ex-vivo oral tissue autofluorescence images. The advantages of LIAF imager compared to other devices for oral cancer diagnosis are that LIAF imager has a probe of L shape for fixing the object distance, protecting the effect of ambient light, and observing the blind spot in the deep port between the gumsgingiva and the lining of the mouth. Besides, the multiple excitation of LED light source can induce multiple autofluorescence, and LIAF imager with the rotary filter ring of eight channels can detect the spectral images of multiple narrow bands. The prototype of a portable LIAF imager is applied in the clinical trials for some cases in Taiwan, and the images of the clinical trial with the specific excitation show the significant differences between normal tissue and oral tissue under these cases.
The pupil response to light can reflect various kinds of diseases which are related to physiological health. Pupillary abnormalities may be influenced on people by autonomic neuropathy, glaucoma, diabetes, genetic diseases, and high myopia. In the early stage of neuropathy, it is often asymptomatic and difficulty detectable by ophthalmologists. In addition, the position of injured nerve can lead to unsynchronized pupil response for human eyes. In our study, we design the pupilometer to measure the binocular pupil response simultaneously. It uses the different wavelength of LEDs such as white, red, green and blue light to stimulate the pupil and record the process. Therefore, the pupilometer mainly contains two systems. One is the image acquisition system, it use the two cameras modules with the same external triggered signal to capture the images of the pupil simultaneously. The other one is the illumination system. It use the boost converter ICs and LED driver ICs to supply the constant current for LED to maintain the consistent luminance in each experiments for reduced experimental error. Furthermore, the four infrared LEDs are arranged nearby the stimulating LEDs to illuminate eyes and increase contrast of image for image processing. In our design, we success to implement the function of synchronized image acquisition with the sample speed in 30 fps and the stable illumination system for precise measurement of experiment.
The image fusion is combination of two or more images into one image. The fusion of multi-band spectral images has been in many applications, such as thermal system, remote sensing, medical treatment, etc. Images are taken with the different imaging sensors. If the sensors take images through the different optical paths in the same time, it will be in the different positions. The task of the image registration will be more difficult. Because the images are in the different field of views (F.O.V.), the different resolutions and the different view angles. It is important to build the relationship of the viewpoints in one image to the other image. In this paper, we focus on the problem of image registration for two non-pinhole sensors. The affine transformation between the 2-D image and the 3-D real world can be derived from the geometrical optics of the sensors. In the other word, the geometrical affine transformation function of two images are derived from the intrinsic and extrinsic parameters of two sensors. According to the affine transformation function, the overlap of the F.O.V. in two images can be calculated and resample two images in the same resolution. Finally, we construct the image registration model by the mapping function. It merges images for different imaging sensors. And, imaging sensors absorb different wavebands of electromagnetic spectrum at the different position in the same time.
In recent years, transparent display is an emerging topic in display technologies. Apply in many fields just like mobile device, shopping or advertising window, and etc. Electrowetting Display (EWD) is one kind of potential transparent display technology advantages of high transmittance, fast response time, high contrast and rich color with pigment based oil system. In mass production process of Electrowetting Display, oil defects should be found by Automated Optical Inspection (AOI) detection system. It is useful in determination of panel defects for quality control. According to the research of our group, we proposed a mechanism of AOI detection system detecting the different kinds of oil defects. This mechanism can detect different kinds of oil defect caused by oil overflow or material deteriorated after oil coating or driving. We had experiment our mechanism with a 6-inch Electrowetting Display panel from ITRI, using an Epson V750 scanner with 1200 dpi resolution. Two AOI algorithms were developed, which were high speed method and high precision method. In high precision method, oil jumping or non-recovered can be detected successfully. This mechanism of AOI detection system can be used to evaluate the oil uniformity in EWD panel process. In the future, our AOI detection system can be used in quality control of panel manufacturing for mass production.
The difference of spectral distribution between lesions of epithelial cells and normal cells after excited fluorescence is one of methods for the cancer diagnosis. In our previous work, we developed a portable LED Induced autofluorescence (LIAF) imager contained the multiple wavelength of LED excitation light and multiple filters to capture ex-vivo oral tissue autofluorescence images. Our portable system for detection of oral cancer has a probe in front of the lens for fixing the object distance. The shape of the probe is cone, and it is not convenient for doctor to capture the oral image under an appropriate view angle in front of the probe. Therefore, a probe of L shape containing a mirror is proposed for doctors to capture the images with the right angles, and the subjects do not need to open their mouse constrainedly. Besides, a glass plate is placed in probe to prevent the liquid entering in the body, but the light reflected from the glass plate directly causes the light spots inside the images. We set the glass plate in front of LED to avoiding the light spots. When the distance between the glasses plate and the LED model plane is less than the critical value, then we can prevent the light spots caused from the glasses plate. The experiments show that the image captured with the new probe that the glasses plate placed in the back-end of the probe has no light spots inside the image.
The intraocular pressure (IOP) that can diagnose or track glaucoma generally because it is one of the physiology parameters that are associated with glaucoma. But IOP is not easy and consistence to be measured under different measure conditions. Besides, diabetes is associated with diabetic autonomic neuropathy (DAN). Pupil size response might provide an indirect means about neuronal pathways, so the abnormal pupil size may relate with DAN. Hence an infrared videopupillography is needed for tracking glaucoma and exploring the relation between pupil size and DAN. Our previous research proposed an infrared videopupillography to monitoring the pupil size of different light stimulus in dark room. And this 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 can be mounted on any eyeglass frame. But it can modulate only two dimensions, we cannot zoom in/out the eyes. Moreover, the eye diameter curves were not smooth and jagged because of the light spots, lone eyelashes, and blink. Therefore, we redesign the optical path of our device to have three dimension modulation. Then we can zoom in the eye to increase the eye resolution and to avoid the LED light spots. The light spot could be solved by defining the distance between IR LED and CCD. This device smaller volume and less prices of our previous videopupillography. We hope this new infrared videopupillography proposed in this paper can achieving early detection about autonomic neuropathy in the future.
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.
KEYWORDS: Color reproduction, Eye, Image quality, Electrical engineering, Medicine, Visual system, Visualization, Digital image processing, Current controlled current source, 3D image processing
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.
Generally, the instrument of color measurement can be divided into spectrophotometer and color
meter. The former instrument use prism or grating to separate the light, it can achieve high
accuracy but a higher price. The latter instrument use color filter, however there is no spectrum
information with it. This article establishes a color measuring system and uses eigen-spectrum
method in double light sources to calibrate the spectrum. The measuring system includes
tri-stimulus sensors which were made by color filter. The tungsten lamp and Xenon lamp are used
to be light source. The advantage of this measuring system is the higher accuracy and the lower
cost. The eigen-spectrum method can calibrate the spectrum in less eigenvector. This method used
singular value deposition to obtain basis function of spectrum set, which can be obtained by
measuring. Because the range of the spectrum set was 380nm to 780nm, the eigenvector per
nanometer from 380nm to 780nm can be obtained. In general, the color spectrum can be obtained
with less eigenvector. The color difference in L*a*b* color space from 31.2398 down to 2.48841,
and reconstructs the spectrum information.
The purpose of color measuring instrument is judging the color information by scientific method, which may
instead of the human's eyes. Generally, the instruments of color measuring have two kinds, spectrophotometer
and color meter. The former measures spectrum by usage of prism or grating to separate the light, this could
achieve high accuracy but with a higher price. The latter obtains tristimulus from color filter; however there is no
spectrum information with it. This article establishes a color measuring system and uses eigenspectrum method
to correct the average inaccuracy. The measuring system includes tristimulus sensors which were made by color
filter, and Xenon lamp as light source. The advantage of this measuring system is the higher accuracy and the
lower cost. The eigenspectrum method can correct the average inaccuracy in less eigenvector, which can save
the time. This method used singular value deposition to obtain basis function of spectrum set, which can be
obtained by measuring. Because the range of the spectrum set was 380nm to 780nm, the eigenvector per
nanometer from 380nm to 780nm can be obtained. In general, the color spectrum can be obtained with less
eigenvector. This article establishes a color measuring system, which has three sensors and uses Xenon lamp as
light source, to acquire the color spectral reflectance. This article also uses the eigenspectrum methods to
correct the average color difference in L*a*b* color space,which from 31.2398 down to 4.8401, and reconstructs
the spectrum information.
KEYWORDS: Black bodies, Light sources, Color difference, CIE 1931 color space, Light sources and illumination, Body temperature, Curium, RGB color model, LCDs, Manufacturing
Color temperature(CT) conversion of triprimary color display from one white point to another on the Planckian's locus
with the maximal brightness has been proposed. However, whether converting an original white point to another white
point on the isotemperature line will enlarge maximal brightness more than converting an original white point to another
white point on the Planckian's locus needs to be determined. This paper proposes a new algorithm to enlarge maximal
brightness by calling the center of gravity method of color mixing in the acceptable color difference range while the CT
is converted. From the prior study, we find that the apexes of color gamut boundary move along the line of center gravity
of primaries while the total brightness varies, where the line of center gravity of primaries is linked by the color points
mixed by two or more full primary colors and one partial primary color. And in CIE 1931 color space, the color gamut
boundary expanding from white point as total brightness decreasing will touch the isotemperature line with its apexes.
Therefore, the best point of CT conversion of tri-primary color display with more maximal brightness is determined by
the isotemperature line and the line of center gravity of primaries. Further, the theory extends to multi-primary color
displays. Lastly, the simulations prove that converting a white point to another on the isotemperature line enlarges
maximal brightness more than converting a white point to another on Planck's locus.
A new feedback readout circuit of microbolometers for sensing radiant power is proposed in this paper. Due to excellent
thermal characteristics of microstructure on infrared application recently, the readout circuits of the microsensors would
not concern the responsivity only, but should also take offset voltage cancellation, digitalization, and signal-to-noise ratio
under considerations. Although Wheatstone bridge readout circuit has been widely used in resistive thermal sensor
readout for several decades, its nonlinear output voltage acting as the offset voltage still perplex us, as well as its
digitalization and signal-to-noise ratio could be unsatisfied for microbolometer applications. Hence, we present the
feedback readout which could optimize the key factors simultaneously and increase the responsivity without any layout
modification of the bridge structure on Infrared Focal Plane Array (IRFPA) microbolometer chip. The results revealed
that the balanced parameter, frequency, equal to 0.5 would be the best condition for these requirements instead of the
balanced parameter equal to unity by intuition traditionally. Compared to traditional Wheatstone bridge readout circuit,
the feedback readout circuit would improve the responsivity of 2.86 times, immunize the offset voltage exactly, obtain a
very large OVRR, and reduce the noise of the readout circuit of 5.6 dB. These significantly important results will
improve significantly the performance of the readout circuit, and speed up the commercialization of infrared focal plane
array of microbolometers.
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