Zoom Objective Research Articles

Optofluidic zoom system with increased field of view and less chromatic aberration.

Imaging systems are widely used in many fields. However, there is an inherent compromise between field of view (FOV) and resolution. In this paper, we propose an optofluidic zoom system with increased FOV and less chromatic aberration, which can realize switching between large FOV and high resolution. The proposed system consists of a liquid prism, a zoom objective, an image sensor and image processing module, which can realize optical zoom and deflection. The proposed system achieves non-mechanical optical zoom from f = 40.5 mm to f = 84.0 mm. Besides, the angular resolution of zoom objective is up to 26"18 at f = 84.0 mm. The deflection range is ±10°, and the whole FOV of proposed system can reach up to 30.3°. The proposed system is compact and easy to machine. In addition, we reduce chromatic aberration produced by the liquid prism significantly. The proposed system can be used in monitor system, target tracking system, telescope system and so on.

3D microscope image acquisition method based on zoom objective.

Microscopy is being pursued to obtain richer and more accurate information, and there are many challenges in imaging depth and display dimension. In this paper, we propose a three-dimensional (3D) microscope acquisition method based on a zoom objective. It enables 3D imaging of thick microscopic specimens with continuous adjustable optical magnification. The zoom objective based on liquid lenses can quickly adjust the focal length, to expand the imaging depth and change the magnification by adjusting the voltage. Based on the zoom objective, an arc shooting mount is designed to accurately rotate the objective to obtain the parallax information of the specimen and generate parallax synthesis images for 3D display. A 3D display screen is used to verify the acquisition results. The experimental results show that the obtained parallax synthesis images can accurately and efficiently restore the 3D characteristics of the specimen. The proposed method has promising applications in industrial detection, microbial observation, medical surgery, and so on.

Deep Learning Enables Optofluidic Zoom System with Large Zoom Ratio and High Imaging Resolution

Due to the relatively low optical power of a liquid lens, it is usually difficult to achieve a large zoom ratio and a high-resolution image simultaneously in an optofluidic zoom imaging system. We propose an electronically controlled optofluidic zoom imaging system combined with deep learning, which achieves a large continuous zoom change and a high-resolution image. The zoom system consists of an optofluidic zoom objective and an image-processing module. The proposed zoom system can achieve a large tunable focal length range from 4.0 mm to 31.3 mm. In the focal length range of 9.4 mm to 18.8 mm, the system can dynamically correct the aberrations by six electrowetting liquid lenses to ensure the image quality. In the focal length range of 4.0-9.4 mm and 18.8-31.3 mm, the optical power of a liquid lens is mainly used to enlarge the zoom ratio, and deep learning enables the proposed zoom system with improved image quality. The zoom ratio of the system reaches 7.8×, and the maximum field of view of the system can reach ~29°. The proposed zoom system has potential applications in camera, telescope and so on.

Zoom Objective Structured Clinical Exams: Virtually the Same as the Real Thing?

Objective structured clinical exams (OSCE) are used to train and assess resident foundational family-centered communication skills incorporating key stakeholders. In 2020 encounters were conducted virtually. We sought to compare standardized patient (SP) and family faculty (FF) assessment across OSCE and virtual OSCE (VOSCE) formats. The intern classes of 2019 and 2020 completed a live OSCE and VOSCE respectively where they disclosed an error to an SP. The 10 minute encounter was observed by an FF and facilitator followed by a 20 minute debrief. The SP and FF completed a behavioral checklist to evaluate skill mastery. Eighteen (90%) of the 20 interns completed the encounter each year. Total mastery scores were significantly higher for SP assessment than for FF assessment in both OSCE [68% vs 46% (z=-3.005, P < .05)] and VOSCE formats [68% vs 53% (z=-2.105, P < .05)]. Total mastery scores of SPs across OSCE and VOSCE formats did not significantly differ, nor did FF scores based on evaluation format. Our current experience suggests VOSCEs are a viable alternative to in person sessions given the comparable assessment across the two modalities. The ease of participating in virtual sessions may provide a way to more easily partner with key stakeholders.

Design of Lightweight and Miniaturized Zoom Objective Optical System with Wide Band

Design of Lightweight and Miniaturized Zoom Objective Optical System with Wide Band

Continuous optical zoom microscope with extended depth of field and 3D reconstruction

Microscope such as fluorescence microscope, confocal microscope and two-photon microscope plays an important role in life science, laser processing and other fields. However, most microscopes only have discrete zoom rates. In this paper, a continuous optical zoom microscope with extended depth of field and 3D reconstruction is demonstrated for the first time. It consists of a zoom objective lens, a microscope holder, an adjustable three-dimensional object stage, an Abbe condenser and an LED light source. The zoom objective lens is composed of several liquid lenses and solid lenses. By adjusting the applied voltage to the liquid lens, the proposed microscope can achieve a large continuous magnification from 10? to 60?. Moreover, an improved shape from focus (SFF) algorithm and image fusion algorithm are designed for 3D reproduction. Based on the liquid lenses, the axial focusing position can be adjusted to obtain images with different depths, and then the extended depth of field and 3D reconstruction can be realized. Our experimental results demonstrate the feasibility of the proposed microscope. The proposed microscope is expected to be applied in the fields of pathological diagnosis, biological detection, etc.

Biomimetic Vision for Zoom Object Detection Based on Improved Vertical Grid Number YOLO Algorithm.

With the development of bionic computer vision for images processing, researchers have easily obtained high-resolution zoom sensing images. The development of drones equipped with high-definition cameras has greatly increased the sample size and image segmentation and target detection are important links during the process of image information. As biomimetic remote sensing images are usually prone to blur distortion and distortion in the imaging, transmission and processing stages, this paper improves the vertical grid number of the YOLO algorithm. Firstly, the light and shade of a high-resolution zoom sensing image were abstracted, and the grey-level cooccurrence matrix extracted feature parameters to quantitatively describe the texture characteristics of the zoom sensing image. The Simple Linear Iterative Clustering (SLIC) superpixel segmentation method was used to achieve the segmentation of light/dark scenes, and the saliency area was obtained. Secondly, a high-resolution zoom sensing image model for segmenting light and dark scenes was established to made the dataset meet the recognition standard. Due to the refraction of the light passing through the lens and other factors, the difference of the contour boundary light and dark value between the target pixel and the background pixel would make it difficult to detect the target, and the pixels of the main part of the separated image would be sharper for edge detection. Thirdly, a YOLO algorithm with an improved vertical grid number was proposed to detect the target in real time on the processed superpixel image array. The adjusted aspect ratio of the target in the remote sensing image modified the number of vertical grids in the YOLO network structure by using 20 convolutional layers and five maximum aggregation layers, which was more accurately adapted to “short and coarse” of the identified object in the information density. Finally, through comparison with the improved algorithm and other mainstream algorithms in different environments, the test results on the aid dataset showed that in the target detection of high spatial resolution zoom sensing images, the algorithm in this paper showed higher accuracy than the YOLO algorithm and had real-time performance and detection accuracy.

Design and Implementation of Virtual Reality Interactive Product Software Based on Artificial Intelligence Deep Learning Algorithm

The aim of this study is to improve the interactive needs of artificial intelligence in the virtual reality environment. Based on the in-depth study of the interactive needs of virtual reality, a virtual reality interactive glove based on nine-axis inertial sensor and realized by artificial intelligence deep learning algorithm is designed. The AI deep learning algorithms employed include the KNN, SVM, Fuzzy, PNN, and DTW algorithms. Static gesture recognition is relatively simple, dynamic gesture recognition needs to a dynamic real-time gesture sequence data starting point and end point planning, by building the directed graph structure, quickly retrieving the global optimal solution, and determining gesture starting point, with dynamic planning to solve the minimum distance between two points, avoid the graph, and improve efficiency. The results showed that by 50 gestures such as select object, attract object, zoom object, rotate object, shoot small box, exhale menu, and close the menu, the recognition rate is 100%, 94%, 96%, 100%, 92%, 100%, and 100%. The motion data of finger and palm are captured by nine axis sensor, and the gesture recognition is carried out by using artificial intelligence deep learning algorithm. It is proved that the artificial intelligence deep learning algorithm can effectively realize the design of virtual reality interactive product software.

Design of 20 mm~200 mm zoom objective lens for polarization imaging system

变焦物镜是偏振成像系统的重要组成部分，目前因变焦物镜使用较多非球面而导致价格较为昂贵。为了降低偏振成像系统变焦物镜的加工成本，设计了一款用于偏振成像系统的20 mm~200 mm变焦物镜。采用正组补偿，利用Zemax优化变焦系统，最终系统仅使用7片球面透镜，并达到良好像质，系统调制传递函数（MTF）在120 lp/mm处大于0.3，畸变小于4%，系统凸轮曲线平滑无断点。系统公差分析结果表明，公差范围设置为：镜片表面光圈公差为2，镜片或空气中心厚度公差为±0.02 mm，透镜表面中心倾斜公差为±0.025°，透镜装调公差为±0.025 mm，透镜折射率偏差为0.002，公差设置符合元件加工和系统装调工艺，对降低偏振成像系统成本具有一定的参考价值。

Raman and Photoluminescence Spectroscopy with a Variable Spectral Resolution.

Raman and photoluminescence (PL) spectroscopy are important analytic tools in materials science that yield information on molecules’ and crystals’ vibrational and electronic properties. Here, we show results of a novel approach for Raman and PL spectroscopy to exploit variable spectral resolution by using zoom optics in a monochromator in the front of the detector. Our results show that the spectral intervals of interest can be recorded with different zoom factors, significantly reducing the acquisition time and changing the spectral resolution for different zoom factors. The smallest spectral intervals recorded at the maximum zoom factor yield higher spectral resolution suitable for Raman spectra. In contrast, larger spectral intervals recorded at the minimum zoom factor yield the lowest spectral resolution suitable for luminescence spectra. We have demonstrated the change in spectral resolution by zoom objective with a zoom factor of 6, but the perspective of such an approach is up to a zoom factor of 20. We have compared such an approach on the prototype Raman spectrometer with the high quality commercial one. The comparison was made on ZrO2 and TiO2 nanocrystals for Raman scattering and Al2O3 for PL emission recording. Beside demonstrating that Raman spectrometer can be used for PL and Raman spectroscopy without changing of grating, our results show that such a spectrometer could be an efficient and fast tool in searching for Raman and PL bands of unknown materials and, thereafter, spectral recording of the spectral interval of interest at an appropriate spectral resolution.

Design of thermal imaging continuous-zoom optical system

The report tells about the design of a middle wave infrared continuous-zoom imaging optical system. To capture the image in an «eye-type» infrared optical system a multi-element sensor is used. To increase the contrast of the thermal image the sensor is equipped with a cold aperture. The use of an optical system based on the continuous-zoom lens makes it possible to solve the problems of object detection and identification more effectively but requires taking into account some features of varifocal lenses. The optical system being analyzed in the report includes front zoom objective system and secondary imaging system. The front zoom optical system is composed of four groups and provides the focal length that is continuously changed with a large zoom ratio (15–20X) under the condition of a constant total length of the system. The secondary imaging system is designed for zoom system exit stop and sensor cold stop conjugation. The design technique represents analytical expressions and equations to obtain optical parameters of the front and secondary system components and the motion curves for movable groups.

A new strategy for measuring the grain height uniformity of a grinding wheel

The grain height uniformity of a grinding wheel is a critical parameter in the optimization of the grinding process. A new strategy based on an optical system with a narrow depth-of-field microscope was proposed to determine the peak height of each grain for the evaluation of grain height uniformity based on statistical parameters: standard deviation and skewness. A zoom objective lens was used for a two-step measurement strategy. After planning the measurement path, each grain was vertically scanned, and grain heights were directly extracted according to local minimum image entropies. Grain heights of a #35/40 monolayer brazed grinding wheel were measured and evaluated by statistical parameters. The evaluation results of height uniformity are mean: 360.8 μm, standard deviation: 85.8 μm and skewness: −1.93 for all grains on the grinding wheel. Height uniformity at different depths and subregions of the grinding wheel was also analyzed. Experimental results indicate that the proposed method can measure grain heights on a whole surface or large area without the time-consuming reconstruction of wheel topography and can conveniently analyze height uniformity from different aspects.

Methodology to design optical systems with curved sensors.

Curved sensors are a suitable technological solution to enhance the vast majority of optical systems. In this work, we show the entire process to create curved sensor-based optical systems and the possibilities they offer. This paper defines the boundaries of the reachable curvatures for a full range of monolithic sensors. We discuss how the curved focal plane shape is related to the imaged scenes and optical parameters. Two camera prototypes are designed, realized, and tested, demonstrating a new compact optical architecture for a 40deg compact objective as well as a wide-field fisheye zoom objective using a convex sensor to image a 180deg field of view.

Optical system design of 30 mm～300 mm light weight zoom objective

设计了一组长焦距轻量型变焦光学系统，焦距为30 mm ~ 300 mm, 视场角为1.1°~ 11.4°，F数为3.5。由于变焦系统焦距较长，并且需要在控制口径的前提下减轻质量，经过对变焦理论进行分析并结合实际情况，采用正组补偿，运用Zemax软件，对变焦系统同时进行像质优化与轻量化设计，优化过程中加入非球面，达到简化结构，提高像质的作用; 在不影响像面照度的情况下，对轴外光线进行了适当的拦光，使得有效口径尽量变小，同时对系统的部分透镜材料进行替换，平衡了高像质与轻质量间的矛盾，最终使系统的总体质量从937 g减小到584 g，且系统像质良好，轴上调制传递函数在120 lp/mm处大于0.3，轴外调制传递函数在120 lp/mm处大于0.2，各视场的调制传递函数在40 lp/mm处大于0.5，畸变小于1%。根据变焦运动方程，运用Matlab软件进行编程计算，得到反映变倍组与补偿组运动过程的凸轮曲线，在变焦的过程中像面比较稳定，调焦顺畅。

用高斯光学和三级像差理论求变焦距物镜的初始解

用高斯光学和三级像差理论求变焦距物镜的初始解

Electrically optofluidic zoom system with a large zoom range and high-resolution image.

We report an electrically controlled optofluidic zoom system which can achieve a large continuous zoom change and high-resolution image. The zoom system consists of an optofluidic zoom objective and a switchable light path which are controlled by two liquid optical shutters. The proposed zoom system can achieve a large tunable focal length range from 36mm to 92mm. And in this tuning range, the zoom system can correct aberrations dynamically, thus the image resolution is high. Due to large zoom range, the proposed imaging system incorporates both camera configuration and telescope configuration into one system. In addition, the whole system is electrically controlled by three electrowetting liquid lenses and two liquid optical shutters, therefore, the proposed system is very compact and free of mechanical moving parts. The proposed zoom system has potential to take place of conventional zoom systems.

Zoom microscope objective using electrowetting lenses.

We report a zoom microscope objective which can achieve continuous zoom change and correct the aberrations dynamically. The objective consists of three electrowetting liquid lenses and two glass lenses. The magnification is changed by applying voltages on the three electrowetting lenses. Besides, the three electrowetting liquid lenses can play a role to correct the aberrations. A digital microscope based on the proposed objective is demonstrated. We analyzed the properties of the proposed objective. In contrast to the conventional objectives, the proposed objective can be tuned from ~7.8 × to ~13.2 × continuously. For our objective, the working distance is fixed, which means no movement parts are needed to refocus or change its magnification. Moreover, the zoom objective can be dynamically optimized for a wide range of wavelength. Using such an objective, the fabrication tolerance of the optical system is larger than that of a conventional system, which can decrease the fabrication cost. The proposed zoom microscope objective cannot only take place of the conventional objective, but also has potential application in the 3D microscopy.

立体手术显微镜连续变焦大物镜设计

立体手术显微镜连续变焦大物镜设计

立体手术显微镜连续变焦大物镜设计

立体手术显微镜连续变焦大物镜设计

Zoom system for measurement of coherent backscattering of light in micro- and nanomaterials

We report on an optical system capable of detecting backscattering cones within a wide angular range—from less than mrad up to 500 mrad. It is based on an intermediate optical system placed between the sample and the CCD camera equipped with a 5 × zoom objective. The theory of operation is explained and experimental results are presented.