Quantitative Endoscopy: Initial Accuracy Measurements

2000 ◽  
Vol 109 (2) ◽  
pp. 128-132 ◽  
Author(s):  
Theodore O. Truitt ◽  
Roger A. Adelman ◽  
Dan H. Kelly ◽  
J. Paul Willging
Keyword(s):  
Object Size ◽  
Absolute Distance ◽  
Image Size ◽  
Absolute Size ◽  
Actual Object ◽  
Endoscopic Images ◽  
Endoscopic Image ◽  
The Mean ◽  
The Absolute ◽  
Size Estimates

The geometric optics of an endoscope can be used to determine the absolute size of an object in an endoscopic field without knowing the actual distance from the object. This study explores the accuracy of a technique that estimates absolute object size from endoscopic images. Quantitative endoscopy involves calibrating a rigid endoscope to produce size estimates from 2 images taken with a known traveled distance between the images. The heights of 12 samples, ranging in size from 0.78 to 11.80 mm, were estimated with this calibrated endoscope. Backup distances of 5 mm and 10 mm were used for comparison. The mean percent error for all estimated measurements when compared with the actual object sizes was 1.12%. The mean errors for 5-mm and 10-mm backup distances were 0.76% and 1.65%, respectively. The mean errors for objects <2 mm and ≥2 mm were 0.94% and 1.18%, respectively. Quantitative endoscopy estimates endoscopic image size to within 5% of the actual object size. This method remains promising for quantitatively evaluating object size from endoscopic images. It does not require knowledge of the absolute distance of the endoscope from the object, rather, only the distance traveled by the endoscope between images.

Gravity as a Monocular Cue for Perception of Absolute Distance and/or Absolute Size

Perception ◽  
1992 ◽  
Vol 21 (1) ◽  
pp. 69-76 ◽  
Author(s):  
John S Watson ◽  
Martin S Banks ◽  
Claes von Hofsten ◽  
Constance S Royden
Keyword(s):  
Wave Motion ◽  
Moving Objects ◽  
Formal Analysis ◽  
Free Fall ◽  
Absolute Distance ◽  
Absolute Size ◽  
The Absolute ◽  
Pendulum Wave

When the motion of an object is influenced by gravity (eg free fall, pendulum, wave motion), that influence may provide a cue to computing the absolute distance and/or size of the object. Formal analysis supports the claim that the distance and size of moving objects are generally computable with reference to the gravitational component of motion. Informal evidence from judgments of realism in films is consistent with this gravity-cue hypothesis.

Photoperiodism in the ewe: 2. The effects of various patterns of decreasing daylength on the onset of oestrus in clun forest ewes

1970 ◽  
Vol 12 (1) ◽  
pp. 115-123 ◽  
Author(s):  
M. J. Ducker ◽  
C. J. Thwaites ◽  
J. C. Bowman
Keyword(s):  
Control Group ◽  
Absolute Size ◽  
Abrupt Decrease ◽  
The Mean ◽  
The Absolute

SUMMARYIn six light-proofed buildings experiments were conducted with Clun Forest ewes to determine whether the date of first oestrus was affected by the absolute size of reduction in the case of an abrupt decrease in daylength and by the rate of reduction in the case of a given total decrease in daylength.The mean number of days from the onset of the light treatments to first oestrus (the reaction interval) for ewes receiving gradual decreases in daylength of 3·5, 7·2 or 10·9 min/day from 1 July were 66·4, 53·7 or 33·6 days, respectively. The reaction interval for ewes receiving abrupt decreases in daylength of 3·75, 7·75 or 11·75 hr on 1 July were 59·5, 44·8 or 33·6 days, respectively. A control group of ewes at pasture on natural daylength had a mean reaction interval of 66·2 days.It is concluded that the various light treatments applied significantly affected the date of onset of oestrus in Clun Forest ewes.

Photoperiodism in the ewe. 3. The effects of various patterns of increasing daylength on the onset of anoestrus in Clun Forest ewes

1970 ◽  
Vol 12 (3) ◽  
pp. 465-471 ◽  
Author(s):  
M. J. Ducker ◽  
J. C. Bowman
Keyword(s):  
Control Group ◽  
Vaginal Smears ◽  
Abrupt Increase ◽  
Absolute Size ◽  
Rate Of Increase ◽  
The Mean ◽  
The Absolute

SUMMARYIn light-proofed buildings experiments were conducted with six groups each of ten Clun Forest ewes to determine whether the onset of anoestrus was affected by the absolute size of increase in the case of an abrupt increase in daylength, and by the rate of increase in the case of a given total increase in daylength. The mean number of days from the onset of the light treatments to the cessation of oestrus (the reaction interval) for ewes receiving gradual increases in daylength of 3·5, 7·2 or 10·9 min per day from 23 December were 79·8, 84·1 and 75·7 days respectively. The reaction interval for ewes receiving abrupt increases in daylength of 3·75, 7·75 or 11·75 hr on 23 December were 86·3, 76·5 and 61·5 days respectively. A control group of ten ewes at pasture on natural daylength had a reaction interval of 93·6 days.The results show that increasing daylength largely controls the mean date of onset of aneostrus in Clun Forest ewes. The greater the increase in daylength the sooner the onset of anoestrus occurs.The observations on vaginal smears indicate that photoperiodic changes, whilst affecting the oestrous status of the ewe, may have no effect on ovulation.

scholarly journals An independent distance estimate to the AGB star R Sculptoris

2018 ◽  
Vol 611 ◽  
pp. A102 ◽  
Author(s):  
M. Maercker ◽  
M. Brunner ◽  
M. Mecina ◽  
E. De Beck
Keyword(s):  
Scattered Light ◽  
Angular Size ◽  
Dust Particles ◽  
Phase Lag ◽  
Distance Estimate ◽  
Agb Stars ◽  
Absolute Distance ◽  
Absolute Size ◽  
Thermal Pulse ◽  
The Absolute

Context. Distance measurements to astronomical objects are essential for understanding their intrinsic properties. For asymptotic giant branch (AGB) stars it is particularly difficult to derive accurate distance estimates. Period-luminosity relationships rely on the correlation of different physical properties of the stars, while the angular sizes and variability of AGB stars make parallax measurements inherently inaccurate. For the carbon AGB star R Sculptoris, the uncertain distance significantly affects the interpretation of observations regarding the evolution of the stellar mass loss during and after the most recent thermal pulse. Aim. We aim to provide a new, independent measurement of the distance to R Sculptoris, reducing the absolute uncertainty of the distance estimate to this source. Methods. R Scl is a semi-regular pulsating star, surrounded by a thin shell of dust and gas created during a thermal pulse ≈2000 years ago. The stellar light is scattered by the dust particles in the shell at a radius of ≈19″. The variation in the stellar light affects the amount of dust-scattered light with the same period and amplitude ratio, but with a phase lag that depends on the absolute size of the shell. We measured this phase lag by observing the star R Scl and the dust-scattered stellar light from the shell at five epochs between June–December 2016. By observing in polarised light, we imaged the shell in the plane of the sky, removing any uncertainty due to geometrical effects. The phase lag gives the absolute size of the shell, and together with the angular size of the shell directly gives the absolute distance to R Sculptoris. Results. We measured a phase lag between the stellar variations and the variation in the shell of 40.0 ± 4.0 days. The angular size of the shell is measured to be 19.″1 ± 0.″7. Combined, this gives an absolute distance to R Sculptoris of 361 ± 44 pc. Conclusions. We independently determined the absolute distance to R Scl with an uncertainty of 12%. The estimated distance is consistent with previous estimates, but is one of the most accurate distances to the source to date. In the future, using the variations in polarised, dust-scattered stellar light, may offer an independent possibility to measure reliable distances to AGB stars.

scholarly journals A Multi-Channel Uncertainty-Aware Multi-Resolution Network for MR to CT Synthesis

2021 ◽  
Vol 11 (4) ◽  
pp. 1667
Author(s):  
Kerstin Klaser ◽  
Pedro Borges ◽  
Richard Shaw ◽  
Marta Ranzini ◽  
Marc Modat ◽  
...  
Keyword(s):  
Medical Image Analysis ◽  
Absolute Error ◽  
Magnetic Resonance Images ◽  
The Body ◽  
Whole Body ◽  
Image Size ◽  
Body Images ◽  
Image Translation ◽  
The Mean ◽  
Synthetic Ct

Synthesising computed tomography (CT) images from magnetic resonance images (MRI) plays an important role in the field of medical image analysis, both for quantification and diagnostic purposes. Convolutional neural networks (CNNs) have achieved state-of-the-art results in image-to-image translation for brain applications. However, synthesising whole-body images remains largely uncharted territory, involving many challenges, including large image size and limited field of view, complex spatial context, and anatomical differences between images acquired at different times. We propose the use of an uncertainty-aware multi-channel multi-resolution 3D cascade network specifically aiming for whole-body MR to CT synthesis. The Mean Absolute Error on the synthetic CT generated with the MultiResunc network (73.90 HU) is compared to multiple baseline CNNs like 3D U-Net (92.89 HU), HighRes3DNet (89.05 HU) and deep boosted regression (77.58 HU) and shows superior synthesis performance. We ultimately exploit the extrapolation properties of the MultiRes networks on sub-regions of the body.

Feature Analysers, Optical Illusions, and Figural Aftereffects

Perception ◽  
1977 ◽  
Vol 6 (4) ◽  
pp. 401-406 ◽  
Author(s):  
Tadasu Oyama
Keyword(s):  
Interaction Model ◽  
Size Ratio ◽  
Absolute Distance ◽  
Test Circle ◽  
Optical Illusions ◽  
Tuning Width ◽  
The Absolute ◽  
Delboeuf Illusion

Simple displacement models cannot explain some aspects of optical illusions and figural aftereffects. The orientation-detector interaction model proposed by Blakemore and others is more suitable to explain many aspects of the Zöllner illusion, positive and negative illusions, the effect of gap between the inducing and test lines, and the anisotropy of illusions. If we hypothesize size detectors whose tuning width and distribution steps are proportional to logarithmic size, interactions between them explain well the fact that the Delboeuf illusion and figural aftereffects of circles are determined by the size ratio of the inducing to test circle, not by the absolute distance between the contours of these circles.

The Race for Online Reputation: Implications for Platforms, Firms, and Consumers

2021 ◽  
Author(s):  
Mingwen Yang ◽  
Zhiqiang (Eric) Zheng ◽  
Vijay Mookerjee
Keyword(s):  
Adverse Event ◽  
Marketing Mix ◽  
Digital Economy ◽  
The Other ◽  
The Mean ◽  
The Absolute ◽  
The Cost ◽  
Online Reputation ◽  
Better Than

Online reputation has become a key marketing-mix variable in the digital economy. Our study helps managers decide on the effort they should use to manage online reputation. We consider an online reputation race in which it is important not just to manage the absolute reputation, but also the relative rating. That is, to stay ahead, a firm should try to have ratings that are better than those of its competitors. Our findings are particularly significant for platform owners (such as Expedia or Yelp) to strategically grow their base of participating firms: growing the middle of the market (firms with average ratings) is the best option considering the goals of the platform and the other stakeholders, namely incumbents and consumers. For firms, we find that they should increase their effort when the mean market rating increases. Another key insight for firms is that, sometimes, adversity can come disguised as an opportunity. When an adverse event strikes the industry (such as a reduction in sales margin or an increase in the cost of effort), a firm’s profit can increase if it can manage this event better than its competitors.

Effects of sampling regime on the mean and variance of home range size estimates

2006 ◽  
Vol 75 (6) ◽  
pp. 1393-1405 ◽  
Author(s):  
LUCA BÖRGER ◽  
NOVELLA FRANCONI ◽  
GIAMPIERO DE MICHELE ◽  
ALBERTO GANTZ ◽  
FIORA MESCHI ◽  
...  
Keyword(s):  
Home Range ◽  
Home Range Size ◽  
Range Size ◽  
Sampling Regime ◽  
Mean And Variance ◽  
The Mean ◽  
Size Estimates

scholarly journals The Luminosity Determination

1995 ◽  
Vol 10 ◽  
pp. 399-402
Author(s):  
A.E. Gómez ◽  
C. Turon
Keyword(s):  
Main Sequence ◽  
Small Volume ◽  
Absolute Magnitude ◽  
Fitting Procedure ◽  
Trigonometric Parallaxes ◽  
The Mean ◽  
The Absolute ◽  
Absolute Magnitudes ◽  
Kinematical Data ◽  
Magnitude Determination

The Hertzprung-Russel (HR) diagram luminosity calibration relies basically on three kinds of data: trigonometric parallaxes, kinematical data (proper motions and radial velocities) and cluster distances obtained by the zero-age main sequence fitting procedure. The most fundamental method to calculate the absolute magnitude is the use of trigonometric parallaxes, but up to now, accurate data only exist for stars contained in a small volume around the sun. Individual absolute magnitudes are obtained using trigonometric parallaxes or photometric and spectroscopic calibrations. In these calibrations the accuracy on the absolute magnitude determination ranges from ±0.m2 in the main sequence to ±0m5 in the giant branch. On the other hand, trigonometric parallaxes, kinematical data or cluster distances have been used to make statistical calibrations of the absolute magnitude. The standard error on the mean absolute magnitude calibrations ranges from ±0m3 to ±0m6 on the mean sequence, from ±0m5 to ±0m7 on thegiant branch and is of about 1mfor supergiants.Future improvements in the absolute magnitude determination will depend on the improvement of the basic data from the ground and space. A brief overview of the new available data is presented. In particular, the analysis of the first 30 months data of the Hipparcos mission (H30) (from the 37 months data of the whole mission) allows to perform a statistical evaluation of the improvements expected in the luminosity determination.

4. Results of Makerstoun Observations, No. III. On the Solar and Lunar periods of the Magnetic Declination.

1851 ◽  
Vol 2 ◽  
pp. 144-145
Author(s):  
J. A. Broun
Keyword(s):  
The North ◽  
Magnetic Declination ◽  
The Mean ◽  
The Absolute ◽  
Annual Period ◽  
North End

The absolute westerly declination at Makerstoun, for the mean epoch, June 1844 = 25° 17′·12.The annual motion of the north end of the needle towards the east = 5′·67.The annual periodof magnetic declination consists of a double oscillation, having nearly the following epochs of maxima and minima.

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