Good Illumination Research Articles

이중 현미경 구조를 이용한 마이크로 렌즈 및 핀홀 어레이 기반 병렬 공초점 시스템

The three-dimensional measurement method of confocal systems is a spot scanning method which has a high resolution and good illumination efficiency. However, conventional confocal systems had a weak point in that it has to perform XY axis scanning to achieve FOV (Field of View) vision through spot scanning. There are some methods to improve this problem involving the use of a galvano mirror [1], pin-hole array, etc. Therefore, in this paper we propose a method to improve a parallel mode confocal system using a micro-lens and pin-hole array in a dual microscope configuration. We made an area scan possible by using a combination MLA (Micro Lens Array) and pin-hole array, and used an objective lens to improve the light transmittance and signal-to-noise ratio. Additionally, we made it possible to change the objective lens so that it is possible to select a lens considering the reflection characteristic of the measuring object and proper magnification. We did an experiment using 5X, 2.3X objective lens, and did a calibration of height using a VLSI calibration target.

Study on the Synthesis, Characterization of p-CuSCN/n-Si Heterojunction

The p-CuSCN/n-Si heterojunction is fabricated by depositing CuSCN films on n-Si (111) films substrate using successive ionic layer adsorption and reaction (SULAR). CuSCN films show 􀀂-phase structure by virtue of X-ray diffraction (XRD) spectroscopy. ZnO/CuSCN heterojunctions exhibit good diode characteristics and photovoltaic effects with illumination form its current-voltage (I-V) measurements. The linear relationship of 1/C2 versus voltage curve implies that the built-in potential Vbi and the conduction band offset of the heterojunctions were found to be 2.1eV and 1.5eV, respectively. The forward conduction is determined by trap-assisted space charge limited current mechanism. At forward bias voltages, the electronic potential barrier is larger than holes in the p-CuSCN/n-Si heterojunction interface. In this voltage area, a single carrier injuction is induced and the main current of p-CuSCN/n-Si heterojunction is hole current. In addition, a band diagram of ZnO/CuSCN heterojunctions is also proposed to explain the transport mechanism. This heterojunction diode can be well used to light emission devices and photovoltaic devices.

Optimizing spherical light-emitting diode array for highly uniform illumination distribution by employing genetic algorithm

A numerical optimization method (genetic algorithm) is employed to design the spherical light-emitting diode (LED) array for highly uniform illumination distribution. An evaluation function related to the nonuniformity is constructed for the numerical optimization. With the minimum of evaluation function, the LED array produces the best uniformity. The genetic algorithm is used to seek the minimum of evaluation function. By this method, we design two LED arrays. In one case, LEDs are positioned symmetrically on the sphere and the illuminated target surface is a plane. However, in the other case, LEDs are positioned nonsymmetrically with a spherical target surface. Both the symmetrical and nonsymmetrical spherical LED arrays generate good uniform illumination distribution with calculated nonuniformities of 6 and 8%, respectively.

Transoral robotic surgery of the central skull base: preclinical investigations

In this study we explored possible applications of the da Vinci system in approaching the skull base at optic chiasm level on two cryopreserved cadavers, using an entirely transoral robotic technique (TORS). We used a standard 12 mm endoscopy and 8 mm terminals. Bone drilling was performed manually. The da Vinci system is equipped with very good illumination and 3D viewing, thus providing excellent vision and great maneuverability even in the less accessible areas of the skull. Our experience demonstrates that an entirely transoral skull base robotic approach to this complex anatomical region has many advantages as compared to traditional techniques.

The Research of the Lane Detection Algorithm Base on Vision Sensor

The intelligent vehicle is an important area country in recent years of painstaking research in Intelligent Transportation System, which become the focus of the study, based on the visual structure of the road environment recognition. Aiming at the robust and real time problems of lane detection in the visual navigation system of intelligent vehicles, a robust lane detection method is proposed for the structured road. It can provide for intelligent vehicle automatically to maintain lane and changing lanes traveling lane information necessary to make smart vehicle to achieve a smooth, safe driving. Due to the complexity of the road itself, the complexity of the road image, Therefore, the pre-road established certain assumptions and these assumptions and the detection algorithm is combined to further improve the algorithm efficiency. Simulation test of the collected road images results show that the lane detection method designed in this study is stable enough to show the lane Position for engineering application not matter in good or poor illumination road condition.

An Image Automatic Matching Method Based on FAST Corner and LBP Descriptor

An automatic image matching based on Features from Accelerated Segment Test (FAST) corner detector and Local Binary Patterns (LBP) Descriptor is proposed in this paper. Firstly, constructing gauss pyramid of the reference image and the image to match, then detecting and extracting the FAST corner points of both images, and calculating the LBP descriptors of the corner points, following by searching match point pairs by K-D tree. Thirdly, using random sample consensus algorithm to remove error point pairs and then calculate the geometry transform coefficients. Lastly, executing the geometry transform to get the matching image. Experimental result proves that this method has higher matching accuracy, higher matching efficiency, good scale invariance and illumination invariance.

Pre‐processing, registration and selection of adaptive optics corrected retinal images

In this paper, the aim is to demonstrate enhanced processing of sequences of fundus images obtained using a commercial AO flood illumination system. The purpose of the work is to (1) correct for uneven illumination at the retina (2) automatically select the best quality images and (3) precisely register the best images. Adaptive optics corrected retinal images are pre-processed to correct uneven illumination using different methods; subtracting or dividing by the average filtered image, homomorphic filtering and a wavelet based approach. These images are evaluated to measure the image quality using various parameters, including sharpness, variance, power spectrum kurtosis and contrast. We have carried out the registration in two stages; a coarse stage using cross-correlation followed by fine registration using two approaches; parabolic interpolation on the peak of the cross-correlation and maximum-likelihood estimation. The angle of rotation of the images is measured using a combination of peak tracking and Procrustes transformation. We have found that a wavelet approach (Daubechies 4 wavelet at 6th level decomposition) provides good illumination correction with clear improvement in image sharpness and contrast. The assessment of image quality using a 'Designer metric' works well when compared to visual evaluation, although it is highly correlated with other metrics. In image registration, sub-pixel translation measured using parabolic interpolation on the peak of the cross-correlation function and maximum-likelihood estimation are found to give very similar results (RMS difference 0.047pixels). We have confirmed that correcting rotation of the images provides a significant improvement, especially at the edges of the image. We observed that selecting the better quality frames (e.g. best 75% images) for image registration gives improved resolution, at the expense of poorer signal-to-noise. The sharpness map of the registered and de-rotated images shows increased sharpness over most of the field of view. Adaptive optics assisted images of the cone photoreceptors can be better pre-processed using a wavelet approach. These images can be assessed for image quality using a 'Designer Metric'. Two-stage image registration including correcting for rotation significantly improves the final image contrast and sharpness.

A non-rigid cardiac image registration method based on an optical flow model

According to non-rigid medical image registration, new method of classification registration is proposed. First, Feature points are extracted based on SIFT (Scale Invariant Feature Transform) from reference images and floating images to match feature points. And the coarse registration is performed using the least square method. Then the precise registration is achieved using the optical flow model algorithm. SIFT algorithm is based on local image features that are with good scale, rotation and illumination invariance. Optical flow algorithm does not extract features and use the image gray information directly, and its registration speed is faster. The both algorithms are complementary. SIFT algorithm is used for improving the convergence speed of optical flow algorithm, and optical flow algorithm makes the registration result more accurate. The experimental results prove that the algorithm can improve the accuracy of the non-rigid medical image registration and enhance the convergence speed. Therefore, the algorithm has some advantages in the image registration.

COH형 LED 패키지를 이용한 가로등 생산공정에 관한 연구

Recent high oil price results in the development of energy saving technology such as LED lighting system. Street-lighting system using COH LED package can save energy because the heat dissipation through cupper base is better than conventional technology. Studies on manufacturing processes of lighting system are insufficient even though LED package design and its heat analysis have been studied. This study focuses on the problem and solution of manufacturing processes such as LED packaging process, optimized emission angle, and LED bar dimension for mechanical assembly. As a result, we established better manufacturing alternatives of LED packaging and street-lighting system with higher lighting efficiency of 84 lm/W, as well as good illumination intensity of 39.7 lux at 6 m from lighting source.

Colposcopy: The scientific basis

Colposcopy was first introduced in 1925 in Germany by Hans Hinselman. A colposcopeworks on the hypothesis that by magnifying the cervix and applying good illumination, early stages of cervical cancer could be picked -up. Other workers in the field include Schiller, Papanicolou, and Ayres who all contributed to the early detection of cervical cancer. The basic issue is the transformation zone (TZ). It is an area that forms from squamous metaplasia of columnar epithelium. The area where the two epithelia meet is referred to as the squamo-columnar junction SCJ. It is the most important landmark in cytology and colposcopy, where 90% of cervical neoplasm originates. More units are incorporating colposcopy into their practice so as to improve care of women with abnormal smears. Therefore, understanding of the scientific basis of colposcopy is important in carrying out the procedure according to agreed international standards.

Designing LED array for uniform illumination distribution by simulated annealing algorithm

We propose a numerical optimization method designing LED array for achieving a good uniform illumination distribution on target plane. Simulated annealing algorithm is employed to optimize LED array arrangement. Using the method, we optimized three LED arrays with various luminous intensity profiles. In order to exhibit the design freedom of the method, we use some LEDs with different intensity value in the first and third array, respectively. By optimizing, the three arrays all produced highly uniform illumination distribution with the uniformity of 0.12, 0.23 and 0.13, respectively. It indicates our method can design various luminous intensity distribution LED arrays and design array consisting of LEDs with different intensity value. In addition, the method is simple and can optimize the LED array automatically by computer program. To the best of our knowledge, it is first time to use numerical optimization method to design the optimal LED array arrangement for uniform irradiance.

Intelligent Lighting Control for Vision-Based Robotic Manipulation

The ability of a robot vision system to capture informative images is greatly affected by the condition of lighting in the scene. This paper reveals the importance of active lighting control for robotic manipulation and proposes novel strategies for good visual interpretation of objects in the workspace. Good illumination means that it helps to get images with large signal-to-noise ratio, wide range of linearity, high image contrast, and true color rendering of the object's natural properties. It should also avoid occurrences of highlight and extreme intensity unbalance. If only passive illumination is used, the robot often gets poor images where no appropriate algorithms can be used to extract useful information. A fuzzy controller is further developed to maintain the lighting level suitable for robotic manipulation and guidance in dynamic environments. As carried out in this paper, with both examples of numerical simulations and practical experiments, it promises satisfactory results with the proposed idea of active lighting control.

Illumination Invariant Face Recognition Using Quaternion-Based Correlation Filters

Existing face recognition systems decrease their performance when face images are affected by lighting variations. Recently, several quaternionic representations of face image features and a quaternion-based correlation filter have been combined in order to cope with the effects of having non-properly illuminated face images. The use of this approach has the advantage of using only one training face image per person. In this paper, the original idea based on the unconstrained optimal trade-off quaternion filter (UOTQF) is extended and two additional different correlation filters in quaternionic domain are evaluate: a phase only quaternion filter (POQF) and a separable trade-off quaternion filter (STOQF). Three different quaternion-based correlation filters are designed and conjugated with four face feature extraction methods aiming at obtaining the best combination: a two-level discrete wavelet decomposition (DWT), image differentiation (DIF), discrete cosine transform (DCT) and local binary patterns (LBP). Verification and identification experiments confirms that when combining a quaternionic representation with a quaternion-based correlation filter, both with good discriminative power and illumination invariant properties, an improvement in face recognition accuracy is obtained.

Video-Assisted Resection in Mediofacial Lateral Tumors

Tumors that developed into the soft tissues of the cheek rising from the anterior prolongation of the parotid gland, minor salivary glands, and the masseter muscle are the most profitable with the use of video-assisted surgery.In the Department of Plastic Surgery at Argerich Hospital in Buenos Aires, Argentina, from 1999 to 2010, video-assisted approaches were used in the treatment of 158 patients, 16 of them presented tumors that developed into the tissues of the cheek.Intraoral approach such as natural orifice surgery was performed in 13 cases; in the other 3 cases, a preauricular incision was performed. Minor complications such as hematoma and transitory paresis of the superior buccal nerve were detected.Video-assisted technique offers both good illumination and excellent magnification, permitting not only a safe anatomic dissection by means of surgical maneuvers in avascular planes but also contributed to avoid injuries of facial nerve branches and secondary obstruction of the Stensen duct. On the other hand, when intraoral incisions are used, visible scarring is avoided; the uses of transoral areas are the most feasible approaches of natural orifice surgery.The outcome achieved with endoscopic techniques in mediofacial lateral areas has permitted to consider it as the first election in the surgical treatment in tumors that developed into the soft tissues of the cheek, offering more advantages than the classic approaches.

Heat development at nasal endoscopes' tips: Danger of tissue damage? A laboratory study

The aim of this study was to measure the temperature generated by light sources in conjunction with angulated endoscopes and to analyze whether the heat generated at the endoscopes' tips harbors potential damage to mucosa or highly sensitive structures like the optic nerve or brain when in direct contact, considering a beginning necrosis of human protein starting at 40°C. Laboratory setting, prospective. Brand new 4-mm, 0° and 30° rigid nasal endoscopes were measured each with halogen, xenon, and light-emitting diode (LED) light sources, respectively, at different power levels for tip contact temperature. The highest temperatures were reached with a xenon light source at a maximum of 44.3°C, 65.8°C, and 91.4°C at 33%, 66%, and 100% power levels, respectively, for 4-mm, 0° endoscopes. For 30° endoscopes, temperatures of 47.0°C, 75.1°C, and 95.5°C were measured at 33%, 66%, and 100% power levels (P < .001; 0° vs. 30°), respectively. At 5-mm distance from the tip, temperatures were below body temperature for all light sources (<36°C) at all power settings. Within 2 minutes after switching off light sources, temperatures dropped to room temperature (22°C). Xenon light sources have the greatest illumination potential; however, at only 33% power level, potentially harmful temperatures can be reached at the tips of the endoscopes. Power LED and halogen have the highest safety; however, only LED has very good illumination. In narrow corridors, direct contact to tissues or vital structures should be avoided, or endoscopes should be cooled during surgical procedures.

Impact of socioeconomic status on decayed, missing, filled teeth (DMFT) among state government employees in Shimla City, Himachal Pradesh

Objectives: To assess the impact of socioeconomic status (SES) on decayed, missing, filled teeth (DMFT) among state government employees in Shimla city, Himachal Pradesh. Design: Cross-sectional study. Materials and Methods: This study was conducted on 1008 dentate subject 705 (69.9%) males and 303 (30.1%) females out of 10908 government employees. Data regarding dentition status and treatment needs was recorded on a W.H.O. format 1997. Type III examination was conducted under good illumination by the investigator himself. Student's t -test or ANOVA was applied for statistical evaluation of means and the comparisons of proportions. P value ≤ 0.5 and ≤ 0.01 was considered statistically significant and highly significant respectively. Results: Total teeth examined were 29575 out of which 14.84% were decayed. Overall mean DMFT was 3.29 (1.86). Females were reported significantly higher ( P P P Conclusions: A preventive and curative oral health policy for the government employees in Shimla city needs to be planned and implemented to maintain their commitment in their official work. Also they must be educated the importance of oral health and methods how to maintain it.

Broadband Millimeter-Wave Short Backfire Antenna With Bowtie Exciter

A broadband millimeter-wave short backfire antenna with a rounded bowtie exciter is reported in this letter. Simulations and measurements show that the bowtie exciter can provide good illumination to a large antenna aperture, and the elliptical composite cavity can enhance the operating bandwidth to the most extent. Investigations show that the antenna can present a bandwidth from 27.6 to 42.5 GHz for -10-dB sidelobe level (SLL), from 27.6 to over 50 GHz for standing-wave ratio (SWR) ≤ 2, and a broadside gain of 14.3 ~ 18.2 dBi. Electric field distributions over the antenna aperture are given to clearly show its operating principles. Studies on six critical parameters are performed for practical designs.

Research on LED Lighting Secondary Light Distribution by Using a Freeform Lens

Application of semiconductor lighting is widespread, so its secondary light distribution design of the LED for lighting plays an important role. For LED road lighting applications, its uniformity of illumination need to meet certain requirements, a freeform surface using freeform optical lens was designed, in the secondary light distribution. Because of the application of freeform lens, LED lighting illumination uniformity has been improved. Lighting simulation and analysis, results indicate that based on freeform lens, LED lighting has good illumination uniformity, and has well research, development and application prospects.

Satisfaction Scale for Measuring Thermal Comfort and Illumination in Office

A suitable physical climate is needed if one wants to feel comfortable and ef ficient at work. The environment feels comfortable when you are barely aware of the climate conditions. It is only when temperature decreases and increases beyond ones' comfort limits that one becomes aware of discomfort. Artificial lighting is needed to provide task luminance and adequate visual environments to carry on the task when natural light is inadequate or not available. Good artificial illumination, prevent accidents, prospects health by minimizing eye strain and also contributes to the beauty in of fices. Hence, presence study was undertaken with an objective to develop scale for measuring thermal comfort and illumination in of fice. As the scale was found to be reliable and valid, the developed scale will serve as a scientific tool for the measurement of thermal comfort and illumination in offices.

Learning to discount transformations as the computational goal of visual cortex

AbstractIt has been long recognized that a key obstacle to achieving human-level object recognition performance is the problem of invariance. The human visual system excels at factoring out the image transformations that distort object appearance under natural conditions. Models with a cortex-inspired architecture such as HMAX as well as nonbiological convolutional neural networks are invariant to translation (and in some cases scaling) by virtue of their wiring. The transformations to which this approach has been applied so far are generic; a single example image of any object contains all the information needed to synthesize a new image of the transformed object. In contrast, viewpoint and illumination transformations depend on the object's 3D structure and material properties. These are normally consistent within, but not between, classes.Class-specific modifications of the HMAX model achieve good viewpoint and illumination tolerant performance in a one-shot identification task. Performance suffers when a model that is specialized for transformations of one class is tested on identification within a different class. In fact, viewpoint-pooling models employing templates from the wrong class perform worse on viewpoint invariant identification tasks than models that have no particular mechanisms for dealing with viewpoint at all. The same situation arises for illumination invariance. This is in stark contrast to the generic case where the model is invariant to all classes undergoing the transformation no matter what templates are used.