scholarly journals Generation of All-in-Focus Images by Noise-Robust Selective Fusion of Limited Depth-of-Field Images

2013 ◽  
Vol 22 (3) ◽  
pp. 1242-1251 ◽  
Author(s):  
Said Pertuz ◽  
Domenec Puig ◽  
Miguel Angel Garcia ◽  
Andrea Fusiello
Keyword(s):  
Depth Of Field ◽  
Selective Fusion ◽  
Noise Robust ◽  
Limited Depth

scholarly journals Can Liquid Lenses Increase Depth of Field in Head Mounted Video See-Through Devices?

2021 ◽  
Vol 7 (8) ◽  
pp. 138
Author(s):  
Marina Carbone ◽  
Davide Domeneghetti ◽  
Fabrizio Cutolo ◽  
Renzo D’Amato ◽  
Emanuele Cigna ◽  
...  
Keyword(s):  
Control System ◽  
Clinical Practice ◽  
Augmented Reality ◽  
Time Of Flight ◽  
Depth Of Field ◽  
Liquid Lenses ◽  
Good Potential ◽  
Distance Sensor ◽  
Limited Depth ◽  
Lens Optics

Wearable Video See-Through (VST) devices for Augmented Reality (AR) and for obtaining a Magnified View are taking hold in the medical and surgical fields. However, these devices are not yet usable in daily clinical practice, due to focusing problems and a limited depth of field. This study investigates the use of liquid-lens optics to create an autofocus system for wearable VST visors. The autofocus system is based on a Time of Flight (TOF) distance sensor and an active autofocus control system. The integrated autofocus system in the wearable VST viewers showed good potential in terms of providing rapid focus at various distances and a magnified view.

scholarly journals Construction of All-in-Focus Images Assisted by Depth Sensing

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1409 ◽  
Author(s):  
Hang Liu ◽  
Hengyu Li ◽  
Jun Luo ◽  
Shaorong Xie ◽  
Yu Sun
Keyword(s):  
Image Fusion ◽  
Imaging System ◽  
State Of The Art ◽  
Depth Map ◽  
Depth Of Field ◽  
Depth Sensor ◽  
Depth Sensing ◽  
Focus Image ◽  
Limited Depth ◽  
Image Fusion Method

Multi-focus image fusion is a technique for obtaining an all-in-focus image in which all objects are in focus to extend the limited depth of field (DoF) of an imaging system. Different from traditional RGB-based methods, this paper presents a new multi-focus image fusion method assisted by depth sensing. In this work, a depth sensor is used together with a colour camera to capture images of a scene. A graph-based segmentation algorithm is used to segment the depth map from the depth sensor, and the segmented regions are used to guide a focus algorithm to locate in-focus image blocks from among multi-focus source images to construct the reference all-in-focus image. Five test scenes and six evaluation metrics were used to compare the proposed method and representative state-of-the-art algorithms. Experimental results quantitatively demonstrate that this method outperforms existing methods in both speed and quality (in terms of comprehensive fusion metrics). The generated images can potentially be used as reference all-in-focus images.

scholarly journals Extending Depth of Field in LC-SEM Scenes by Partitioning Sharpness Transforms

2008 ◽  
Vol 16 (2) ◽  
pp. 18-21
Author(s):  
H. Hariharan ◽  
A. Koschan ◽  
B. Abidi ◽  
D. Page ◽  
M. Abidi ◽  
...  
Keyword(s):  
Depth Of Field ◽  
Entire Area ◽  
Area Of Interest ◽  
Nondestructive Evaluations ◽  
Focus Image ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Limited Depth ◽  
Scanning Electron

When imaging a sample, it is desirable to have the entire area of interest in focus in the acquired image. Typically, microscopes have a limited depth of field (DOF) and this makes the acquisition of such an all-in-focus image difficult. This is a major problem in many microscopic applications and applies equally in the realm of scanning electron microscopy as well. In multifocus fusion, the central idea is to acquire focal information from multiple images at different focal planes and fuse them into one all-in-focus image where all the focal planes appear to be in focus.Large chamber scanning electron microscopes (LC-SEM) are one of the latest members in the SEM family that has found extensive use for nondestructive evaluations. Large objects (~1 meter) can be scanned in micro- or nano-scale using this microscope. An LC-SEM can provide characterization of conductive and non-conductive surfaces with a magnification from 10× to 200,000×. The LC-SEM, as with other SEMs, suffers from the problem of limited DOF making it difficult to inspect a large object while keeping all areas in focus.

Development of a High Sensitivity Three-Axis Force/Torque Sensor for Microassembly

2005 ◽  
Author(s):  
Scott E. Rose ◽  
James F. Jones ◽  
Eniko T. Enikov
Keyword(s):  
Design Theory ◽  
Force Feedback ◽  
High Sensitivity ◽  
Depth Of Field ◽  
Sensor Calibration ◽  
High Magnification ◽  
Torque Sensor ◽  
Robotic Microassembly ◽  
Assembly Tasks ◽  
Limited Depth

There is a growing need for multi-axis force torque (F/T) sensors to aid in the assembly of micro-scale devices. Many current generation robotic microassembly systems lack the force-feedback needed to facilitate automating common assembly tasks, such as peg-in-hole insertions. Currently, most microassembly operations use vision systems to align components being assembled. However, it is difficult to view high aspect ratio component assemblies under high magnification due to the resulting limited depth-of-field. In addition, this difficulty is compounded as assembly tolerances approach dimensions resolvable with optics or if the mating parts are delicate. This paper describes the development of a high sensitivity F/T sensor. Optimal design theory was applied to determine the configuration that would result in the most sensitive and accurate sensor. Calibration experiments demonstrated that the sensor can resolve down to 200μN and possibly less.

scholarly journals Large Depth-of-Field Integral Microscopy by Use of a Liquid Lens

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3383 ◽  
Author(s):  
Anabel Llavador ◽  
Gabriele Scrofani ◽  
Genaro Saavedra ◽  
Manuel Martinez-Corral
Keyword(s):  
Numerical Aperture ◽  
Optical Power ◽  
Axial Position ◽  
Depth Of Field ◽  
Depth Range ◽  
Liquid Lens ◽  
New Apparatus ◽  
Depth Ranges ◽  
Limited Depth ◽  
At Will

Integral microscopy is a 3D imaging technique that permits the recording of spatial and angular information of microscopic samples. From this information it is possible to calculate a collection of orthographic views with full parallax and to refocus computationally, at will, through the 3D specimen. An important drawback of integral microscopy, especially when dealing with thick samples, is the limited depth of field (DOF) of the perspective views. This imposes a significant limitation on the depth range of computationally refocused images. To overcome this problem, we propose here a new method that is based on the insertion, at the pupil plane of the microscope objective, of an electrically controlled liquid lens (LL) whose optical power can be changed by simply tuning the voltage. This new apparatus has the advantage of controlling the axial position of the objective focal plane while keeping constant the essential parameters of the integral microscope, that is, the magnification, the numerical aperture and the amount of parallax. Thus, given a 3D sample, the new microscope can provide a stack of integral images with complementary depth ranges. The fusion of the set of refocused images permits to enlarge the reconstruction range, obtaining images in focus over the whole region.

scholarly journals Spectral tomographic imaging with aplanatic metalens

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Chen Chen ◽  
Wange Song ◽  
Jia-Wern Chen ◽  
Jung-Hsi Wang ◽  
Yu Han Chen ◽  
...  
Keyword(s):  
Imaging System ◽  
Imaging Modality ◽  
Chromatic Dispersion ◽  
Visible Spectrum ◽  
Imaging Systems ◽  
Depth Of Field ◽  
Tomographic Images ◽  
Mechanical Scanning ◽  
Conventional Systems ◽  
Limited Depth

Abstract Tomography is an informative imaging modality that is usually implemented by mechanical scanning, owing to the limited depth-of-field (DOF) in conventional systems. However, recent imaging systems are working towards more compact and stable architectures; therefore, developing nonmotion tomography is highly desirable. Here, we propose a metalens-based spectral imaging system with an aplanatic GaN metalens (NA = 0.78), in which large chromatic dispersion is used to access spectral focus tuning and optical zooming in the visible spectrum. After the function of wavelength-switched tomography was confirmed on cascaded samples, this aplanatic metalens is utilized to image microscopic frog egg cells and shows excellent tomographic images with distinct DOF features of the cell membrane and nucleus. Our approach makes good use of the large diffractive dispersion of the metalens and develops a new imaging technique that advances recent informative optical devices.

scholarly journals Surface defects measurement of ICF capsules under limited depth of field

2021 ◽  
Author(s):  
Renhui Guo ◽  
Hang Fu ◽  
Zhiyao Yin ◽  
Cong Wei ◽  
Xin Yang ◽  
...  
Keyword(s):  
Surface Defects ◽  
Depth Of Field ◽  
Limited Depth

scholarly journals Resolution Considerations for Photomacrography and Photomicroscopy

1996 ◽  
Vol 4 (4) ◽  
pp. 10-11
Author(s):  
Theodore M. Clarke
Keyword(s):  
Focal Plane ◽  
Numerical Aperture ◽  
Depth Of Field ◽  
Point Light Source ◽  
Maximum Resolution ◽  
Total Magnification ◽  
Point Light ◽  
Airy Disk ◽  
Limited Depth ◽  
Optimum Balance

My Inter/Micro-84 presentation and subsequent article in The Microscope dealt with optimizing diffraction limited depth of field in photomacrography and is referenced by Brian Bracegirdle in his “Scientific Photomacrography. My analysis was based upon the classical solution for the diffraction pattern image of a point light source, using the Rayleigh criterion of resolution. H. Lou Gibson's method of treating combined diffraction and geometric blurring away from the object focal plane was used. The calculations and the experimental results indicated that a final print resolution, for the object focal plane, of 7 lines/mm (.29 mm Airy disk) gives an optimum balance of depth of field and resolution. The 7 lines/mm criterion is equivalent to an Abbe criterion of total magnification equal to 440 times the numerical aperture. The 500 times numerical aperture Abbe criterion recommended for microscopists with very acute vision corresponds to a maximum resolution of 6 lines/mm in the final image.

The Broad Applications of the Scanning Electron Microscope

1969 ◽  
Vol 27 ◽  
pp. 20-21
Author(s):  
C. T. Nightingale ◽  
S. E. Summers ◽  
T. P. Turnbull
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Light Microscopy ◽  
Surface Topography ◽  
Great Depth ◽  
Resolving Power ◽  
Depth Of Field ◽  
Pictorial Representations ◽  
Scanning Electron

The ease of operation of the scanning electron microscope has insured its wide application in medicine and industry. The micrographs are pictorial representations of surface topography obtained directly from the specimen. The need to replicate is eliminated. The great depth of field and the high resolving power provide far more information than light microscopy.

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