Zoom Ratio Research Articles

大变倍比近红外无焦激光扩束系统

To explore lightning properties,a near-infrared afocal continuous zoom laser beam expanding system with large zoom ratio was designed to simulate lightning spot elements with different sizes for the lightning scene in a laboratory.On the basis of Gaussian geometric method,the overall dimensions of the system was calculated and the diameters and focal powers of lenses were determined reasonably.By using ZEMAX optical design software,optical structural parameters of the system were optimized,then total performance of the system was analyzed and evaluated.As the results,the system shows a 13X beam expansion ratio and excellent emitting beams with higher energies,uniform spots,and diffraction-free rings,which meets the requirements for simulating lightning properties.Furthermore,the central wavelength of the afocal laser beam expanding system is 777.4 nm,the incident laser beam with a diameter of 1.0 mm is continuously adjustable by a stepper motor and the emitted beam diameter ranges from φ0.8 mm to φ10.6 mm.The beam expanding system has some advantages of fewer lenses,simple structures and smoothly zoom trajectory,and it is suitable for simulating lighting elements with different sizes.

Optical design of infrared continuous-zoom lenses

An infrared continuous zoom system is designed.The simple system has a large relative aperture with high transmittance,large continuous zoom ratio,and wide wave band.By introducing a diffractive surface and an aspheric surface,the modulation transfer function(MTF) of the system is above 0.6 for all continuous zoom ratios at the spatial frequency of 14lp/mm.As the system only contains 4 lenses,the transmittance is higher than 80%,and the zoom ratio of the system could also reach 8 continuously.As the color and the off-axis aberration are well corrected,the experiment indicates that the image quality of the continuous zoom system is pretty well.

이종 입체 영상 카메라의 광학 특성 일치화

본 논문에서는 이종 입체 카메라 시스템의 광학적 특성을 일치화하여 동일한 품질의 입체영상을 생성하는 기술을 제안한다. 이종 입체 카메라의 광학적 특성에는 크게 줌, 심도, 초점이 있으며 이들의 차이는 결과적으로 입체영상의 품질에 영향을 주어 사람의 시각 피로를 발생시키는 요인이 된다. 본 논문에서 제안하는 광학 특성 일치화 기술은 이종 카메라의 줌 영상을 일치한 후 동일 피사체에 대해 초점을 맞추고 심도를 일치화하는 과정으로 이루어진다. 이를 위하여 이종 입체 카메라의 줌 영상의 비교 알고리즘을 통하여 줌 렌즈에 대한 룩업테이블(LUT)을 작성하였다. 그리고 입체 영상의 에지(edge)에서 초점 정보를 추출하여 심도를 일치화하였다. 광학적 특성 일치화 실험을 위하여 직교방식의 리그를 제작하고 서로 다른 사양의 HD급 카메라를 이용하여 입체 카메라 장치를 구성하였다. 줌 일치화 및 심도 일치화에 대한 실험 결과로 시각 피로를 줄일 수 있는 입체 영상 생성이 가능함을 보였다.

A holographic projection system with an electrically tuning and continuously adjustable optical zoom

A holographic projection system with optical zoom is demonstrated. By using a combination of a LC lens and an encoded Fresnel lens on the LCoS panel, we can control zoom in a holographic projector. The magnification can be electrically adjusted by tuning the focal length of the combination of the two lenses. The zoom ratio of the holographic projection system can reach 3.7:1 with continuous zoom function. The optical zoom function can decrease the complexity of the holographic projection system.

Design of Compact Infrared Zoom Lens System

Infrared zoom lens system with cooled focal plane array (FPA) detector is widely used in military application. Relevant information about optical design can be got easily, but research on infrared zoom lens system with low cost and high image quality for commercial application is less. This paper design a Compact infrared zoom lens system with only four lenses, using an uncooled focal plane array (FPA) with 384×288 pixels with zoom ratio 3:1. Because of large F number and less lenses, transmission of the whole zoom system is greatly improved. NETD and MRTD of infrared system will be satisfying by this compact design. There is no special surface such as diffractive surface, HOE in zoom lens system, and only Ge and Znse infrared materials are chosen which result in lower production cost of infrared zoom lens system for commercial applications.

A Pico Projection System With Electrically Tunable Optical Zoom Ratio Adopting Two Liquid Crystal Lenses

A pico projection system with electrically tunable optical zoom ratio adopting two liquid crystal (LC) lenses is first demonstrated. The projected image of the system is not only continuously focused, but also zoomed simultaneously by adjusting the focal lengths of LC lenses electrically. The related optical principle is discussed and a liquid-crystal-on-silicon (LCOS)-based pico projection system was used to demonstrate the designed concept. This study opens a new window in realizing pico projectors with electrically tunable optical zooms.

基于联合变换相关器的远红外变焦光学系统设计

In order to meet the requirement of tank sight and improve the ability of joint transform correlator in target tracking and recognition,an infrared continuous refractive zoom optical system for 8~12 μm wave-band is designed for 1 inch infrared CCD detector.The zoom system uses mechanical compensation.The relative aperture is invariant during the zoom process.The F number of the system is 2,and the zoom ratio is 4∶1.The focal length from 50 mm to 200 mm could be changed continuously.Variable magnification curve and compensation curve are smooth.The range of tank sight searching targets was expanded.The optical system image quality is evaluated with ZEMAX optical design software.The results have shown when spatial frequency is 17lp/mm,the MTF curve in the whole range of focal length are all above 0.55 which is closed to the diffraction limited curve.The stability of the image plane is well.The result of this system meets the requirement of technical specification.

An electrically tunable optical zoom system using two composite liquid crystal lenses with a large zoom ratio

An electrically tunable-focusing optical zoom system using two composite LC lenses with a large zoom ratio is demonstrated. The optical principle is investigated. To enhance the electrically tunable focusing range of the negative lens power of the LC lens for a large zoom ratio, we adopted two composite LC lenses. Each composite LC lens consists of a sub-LC lens and a planar polymeric lens. The zoom ratio of the optical zooming system reaches ~7.9:1 and the object can be zoomed in or zoomed out continuously at the objective distance of infinity to 10 cm. The potential applications are cell phones, cameras, telescope and pico projectors.

High-Speed Focusing Vision: Coupling of Image Processing System with Tunable Optics without Speed Bottleneck

Imaging optics is essential for a robot vision to acquire images, since it projects the image of remote object to its imager. In particular, dynamic control of imaging optics has been desired because it enables vision to measure new information, such as depth of scene, that single robot vision with static optics cannot obtain. Conventional imaging optics, however, takes around one second to change its optical property. Thus, measurement frequency of sensing method using dynamic control of optics was limited by the slow response. In this paper, high-speed focusing vision, that is composed of high-speed vision and high-speed imaging optics based on a Dynamorph Lens (DML), is proposed. DML is a liquid variable-focus lens that can dynamically focus by morphing liquid-liquid interface in millisecond order. Since both high-speed vision and high-speed imaging optics have millisecond response time, it can change its focus and zoom ratio almost every frame. High-speed focus-switch experiment in 2[ms] was observed using a developed prototype. High-speed autofocusing in 15.8[ms] by capturing and processing 14-images at different focal position, and continuous focusing on quickly moving object by switching focal position in every 5[ms] were successfully demonstrated to validate the high-speed focusing vision.

高变倍比变焦距系统设计

高变倍比变焦距系统设计

低成本高变倍光学变焦手机摄像镜头设计

低成本高变倍光学变焦手机摄像镜头设计

联合变换相关器远红外变焦距光学系统设计

Based on optical correlation theory and technical parameters of the optical system,an infrared zoom optical system with long wavebands is designed.The infrared materials germanium and AMTIR1 are selected for 8~ 12 μm long wave imaging system,15 times with a large zoom ratio,CCD pixels size of 45 μm × 45 μm.According to the optimization design of IR zoom optical system,MTF value is above 0.6,RMS radius of each field spot diagram close to Airy disk,wavefront aberration less than 1/4 wavelength when the cut-off frequency is 11 lp/mm.The stability of the image plane is well,the result of this system meets the requirement of technical specification and improves the ability of joint transform correlator in target tracking and recognition.

디지털 영상 안정화를 위한 오일러각 기반 전역 움직임 추정 모델

This paper treats the DIS (Digital Image Stabilization) problem subject to base motions such as translation, rotation and zoom. For the local motion estimation from a raw image, the Harris corner detection algorithm is exploited to extract feature points, and comparing those of consecutive images, the zoom ratio (scale factor) is computed. For the global motion estimation, an equivalent model is derived to account for a 3-dimensional composite motion from which the center point and Euler angle can be determined. Finally, the motion compensation follows. To show the effectiveness of the present DIS scheme, experimental results for synthetic images are illustrated.

Nonmechanical bifocal zoom telescope

We report on a novel zoom lens with no moving parts in the form of a switchable Galilean telescope. This zoom telescope consists of two flat liquid-crystal diffractive lenses with apertures of 10mm that can each take on the focal lengths of -50 and +100cm, with a spacing of 50cm and, hence, a zoom ratio of 4x. The lenses are driven using a low-voltage ac source with 1.6V and exhibit millisecond switching times. The spectral characteristic of this diffractive zoom system is evaluated for light sources of various bandwidths. Potential applications for this technology include a zoom lens with no moving parts for camera phones and medical imaging devices.

DESIGN OF INFRARED ZOOM SYSTEM WITH 4 REFLECTIVE MIRRORS

A relatively simple optical method based on Seidel aberration theory was presented for the design of mechanically compensated infrared reflective zoom systems with 4 mirrors. This research includes the study of image formation rules by a single mirror, the concept of the mechanical compensation method in zoom systems, and the derivation of analytical formulae for the Seidel aberration coefficients. The advantage of this method is that it allows the designer to achieve the initial structure parameters of the optical system (radii of curvature and separations between mirrors, etc.) by solving a set of Seidel aberration coefficient functions. Two design examples of 4-mirror zoom systems were given. The results show that the proposed method is feasible in the design of infrared reflective zoom systems with large zoom ratios.

Compact MWIR Zoom System

On the basis of 320×240 cooled staring focal plane array(FPA) detector,a compact mid-wavelength infrared zoom system with six lenses is designed,The system consist of a mechanically compensate zoom system,a re-imaging system,and two reflectors,can realize 27.5～458 mm continuous zoom and satisfy 100% cold shield efficiency.The design results prove that the zoom system has high optical transmission,large zoom ratio,high resolution,small size and excellent image quality.

Compact Zoom Lens Design for a 5x Mobile Camera Using Prism

This study presents the compact zoom lens with a zoom ratio of 5x for a mobile camera by using a prism. The lens modules and aberrations are applied to the initial design for a four-group inner-focus zoom system. An initial design with a focal length range of 4.4 to 22.0 mm is derived by assigning the first-order quantities and third-order aberrations to each module along with the constraints required for optimum solutions. We separately designed a real lens for each group and then combined them to establish an actual zoom system. The combination of the separately designed groups results in a system that satisfies the basic properties of the zoom system consisting of the original lens modules. In order to have a slim system, we directly inserted the right-angle prism in front of the first group. This configuration resulted in a more compact zoom system with a depth of 8 mm. The finally designed zoom lens has an f-number of 3.5 to 4.5 and is expected to fulfill the requirements for a slim mobile zoom camera having high zoom ratio of 5x.

ディスプレイ―ＩＤＷ’０８を中心に―液晶レンズを用いたズームシステムの構成

A zoom lens system with no moving elements is reported. The system is composed of three lenses: one glass lens and two liquid crystal (LC) ones almost identical in structure. The focal length of the LC lenses is tunable from negative to positive with two independent applied voltages. The two LC lenses are placed on two sides of the glass lens, and the positions of all lenses are fixed. The image size is changed and the image position on the CCD image sensor plane is maintained by tuning the focal length of each LC lens. The lens power of the LC lenses ranges from −14.7 to 14.0 m−1. Clear images are obtained at various values of the applied voltages and the zoom ratio is approximately 1:2.

Zoom lens system without moving elements realised using liquid crystal lenses

A zoom lens system realised using two liquid crystal (LC) lenses is reported. No moving parts are contained in the system; the zoom function is achieved by adjusting the applied voltages on the LC lenses. A zoom ratio of approximately 1:1.5 is obtained.

The Significance of Cardiac Sympathetic Nervous System Abnormality in the Long-Term Prognosis of Patients with a History of Ventricular Tachyarrhythmia

Severe left ventricular dysfunction or cardiac sympathetic nervous system (SNS) abnormality predicts cardiac death in various heart diseases, including arrhythmogenic disorders. However, it is not clear whether SNS abnormality predicts sudden cardiac death during long-term follow-up in patients with a history of ventricular tachyarrhythmia. We hypothesized that SNS abnormality would be associated with recurrent ventricular arrhythmic events. 123I-metaiodobenzylguanidine (MIBG) scintigraphy was performed on 86 patients (mean age+/-SD, 46+/-19 y, 65.1% men) with a history of ventricular tachycardia or fibrillation. 123I-MIBG (111 MBq) was intravenously administered under resting conditions, and planar images were obtained 15 min and 4 h later (anterior view for 6 min; 512x512 matrices; zoom ratio, 1.0). SNS activity was assessed using the heart-to-mediastinum ratio on delayed imaging. During about 11 y of follow-up (mean+/-SD, 5.2+/-3.7 y), 3 patients (3.5%) had sudden cardiac death and 21 patients (24.4%) had sustained ventricular tachyarrhythmic events. SNS abnormality, defined as a heart-to-mediastinum ratio of less than 2.8, and left ventricular dysfunction, defined as a left ventricular ejection fraction of less than 50%, were associated with sudden cardiac death or recurrent ventricular tachyarrhythmic events (18/40 patients [45%] with SNS abnormality, vs. 6/46 patients [13%] without, P=0.004; 9/15 patients [60%] with left ventricular dysfunction, vs. 15/71 patients [21.1%] without, P=0.008). After adjustment for potential confounding variables such as age, sex, coronary risk factors, medication use, history of structural heart disease, and left ventricular function, SNS abnormality was a powerful predictor of recurrent arrhythmic events, with a hazard ratio of 3.6 [95% confidence interval, 1.4-9.2, P=0.007]). Further, SNS abnormality had incremental and additive prognostic power in combination with left ventricular dysfunction, with an adjusted hazard ratio of 4.4 [95% confidence interval, 1.9-9.9, P<0.0001]). SNS abnormality predicted recurrent ventricular tachyarrhythmic events during long-term follow-up. 123I-MIBG scintigraphic evaluations for SNS abnormality may be an option for screening patients at high risk for sudden cardiac death.