scholarly journals CONTENT-BASED AUTOFOCUSING IN AUTOMATED MICROSCOPY

2010 ◽  
Vol 29 (3) ◽  
pp. 173 ◽  
Author(s):  
Peter Hamm ◽  
Janina Schulz ◽  
Karl-Hans Englmeier
Keyword(s):  
Phase Contrast ◽  
A Priori ◽  
A Priori Knowledge ◽  
Differential Interference Contrast ◽  
Field Phase ◽  
Bright Field ◽  
Automated Microscopy ◽  
Focus Plane ◽  
Object Features ◽  
Image Frequency

Autofocusing is the fundamental step when it comes to image acquisition and analysis with automated microscopy devices. Despite all efforts that have been put into developing a reliable autofocus system, recent methods still lack robustness towards different microscope modes and distracting artefacts. This paper presents a novel automated focusing approach that is generally applicable to different microscope modes (bright-field, phase contrast, Differential Interference Contrast (DIC) and fluorescence microscopy). The main innovation consists in a Content-based focus search that makes use of a priori knowledge about the observed objects by employing local object features and Boosted Learning. Hence, this method turns away from common autofocus approaches that apply solely whole image frequency measurements to obtain the focus plane. Thus, it is possible to exclude artefacts from being brought into focus calculation as well as locating the in-focus layer of specific microscopic objects.

Coelomomyces canadense stat. et comb. nov. (Blastocladiales: Coelomomycetaceae) from Psectrocladius sp. G (Diptera: Chironomidae)

1978 ◽  
Vol 56 (18) ◽  
pp. 2303-2306 ◽  
Author(s):  
Richard A. Nolan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Contrast ◽  
Field Phase ◽  
Species Status ◽  
Bright Field ◽  
Latin Diagnosis ◽  
Taxonomic Criterion ◽  
Sporangial Wall ◽  
Scanning Electron

Resistant sporangia of Coelomomyces chironomi var. canadense Weiser and McCauley were examined by bright-field, phase-contrast, and scanning electron microscopy (SEM). The use of SEM facilitated the observation of previously undescribed complex furrows in the sporangial wall. The taxonomic criterion for varietal status is discussed, and the variety is elevated to species status. Coelomomyces canadense (Weiser and McCauley) Nolan stat. et comb. nov. is described with an emended Latin diagnosis.

scholarly journals New Design for a Versatile Field Microscope

2013 ◽  
Vol 21 (3) ◽  
pp. 26-29 ◽  
Author(s):  
Yuval Goren
Keyword(s):  
Present Article ◽  
Phase Contrast ◽  
Dark Field ◽  
Optical Field ◽  
Field Conditions ◽  
Historical Background ◽  
Laboratory Research ◽  
Field Phase ◽  
Bright Field

The present article presents a new concept for a light optical field microscope developed after two decades of attempts to find a portable, yet versatile and capable, instrument for extra-laboratory research. Emphasis was put on a portable microscope with polarizing capabilities, yet versatile enough to perform in other configurations. After testing almost every available model made during the last century, the Goren microscope, as it is called now, was developed and tested in various field conditions. The new design, fashioned as two prototypes, is expected to be inexpensive if commercially produced. Still, it can be readily modified to perform as a bright-field, dark-field, phase-contrast, or polarizing instrument. The historical background of field microscopes is briefly presented in context of this new invention.

Imaging of Silicon (111) at 1.92Å Resolution using a 100keV STEM

1990 ◽  
Vol 48 (1) ◽  
pp. 34-35
Author(s):  
Peirong Xu
Keyword(s):  
High Resolution ◽  
Phase Contrast ◽  
Threshold Energy ◽  
Dark Field ◽  
Observation Time ◽  
Operating Voltage ◽  
Pole Piece ◽  
Field Phase ◽  
Bright Field ◽  
Annular Dark Field

Atomic structure imaging using bright field phase contrast at less than 2Å resolution has become routinely possible in medium and high voltage microscopes (>200 keV). Radiation damage at these elevated voltages can be serious and this limits the length of useful observation time. For example, the knock-on threshold energy for silicon is 120-190keV. Recently, a VG HB501A STEM equipped with a newly developed ultra-high resolution pole piece (Cs=0.7mm) has demonstrated the capability of achieving sub-2Å resolution in imaging the (111) silicon latticer using both bright field (BF) and annular dark field (ADF) modes at an operating voltage of l00keV (Fig.1).A thin silicon specimen was prepared through successive steps of chemical etching, anodic etching and reactive ion etching. Large flat thin areas about 100Å thick were produced in the specimen. Since there is no tilting mechanism for the stage used with this ultra-high resolution pole piece, the specimen was not oriented exactly along the (111) zone axis as indicated by CBED but was less than 1-2° off.

Phase-randomized laser illumination for microscopy

1977 ◽  
Vol 23 (1) ◽  
pp. 335-343
Author(s):  
R. Hard ◽  
R. Zeh ◽  
R.D. Allen
Keyword(s):  
Phase Contrast ◽  
Monochromatic Light ◽  
Dark Field ◽  
Spectral Studies ◽  
Field Phase ◽  
Bright Field ◽  
Laser Illumination ◽  
Argon Ion Laser ◽  
Ion Laser ◽  
Argon Ion

A simple apparatus is described that phase randomizes the output of a continuous argon ion laser, so that it may be used as a source of high intensity, monochromatic light for microscopy. The phase-randomizing device can be used with any laser, polarized or unpolarized, and of any desired power output and wavelength, including dye lasers for spectral studies. The randomizing system can be adapted to any light microscope and any optical system including bright-field, phase-contrast, Nomarski differential-interference, dark-field, and split-beam interference systems such as the Jamin-Lebedeff System. It can be used for a variety of photometric and photographic studies. The 514-nm wavelength appears to be relatively harmless to a variety of cells.

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