PURPOSE To evaluate the repeatability of wavefront measurements using the NIDEK OPD-Scan. METHODS A total of 179 eyes from 90 healthy volunteers (57 women and 33 men) with no corneal or lenticular pathology and normal visual acuity were enrolled in this study. Mean patient age was 39 years (range: 17 to 85 years). All patients underwent four consecutive measurements by one examiner with the N...

Robot performance criteria of position repeatability are studied. Weight-to-payload ratio is in manipulating robots significantly higher than in human operators. Bracing strategy improving the robot performances is introduced in the paper. The strategy copies human behavior during fine motion operations. A comparison is made between the robot and the human operator performing approximately the ...

In this paper, we show that salient regions, detected by a biologically motivated attention system, have a considerably higher repeatability than features detected by standard detectors (Harris-Laplacians and DoG features). If a scene contains a salient region, which differs in one of several possible features from the rest of the scene, the repeatability is close to 100%. In settings in which ...

A theoretical study is performed to understand the accuracy and repeatability of multiple pulse sequences in quantifying glutamine concentration at 3T. Variable repeatability (12% to >50%) and significant bias (-30% to +70%) is noted for the seven pulse sequences considered. Data acquired in vivo using three of the pulse sequences used for simulations matches the predicted repeatability well. F...

In the last decade, we observed a great interest in evaluation of local visual features in the domain of images. The aim is to provide researchers guidance when selecting the best approaches for new applications and data-sets. Most of the state-of-the-art features have been extended to the temporal domain to allow for video retrieval and categorization using similar techniques to those used for...

The extent of necrosis is the main determining factor in the outcome of osteonecrosis of the femoral head and is best measured by MRI. Using statistical analyses, we have evaluated the accuracy and repeatability of seven different methods of measuring the extent of necrosis, of which three demonstrate good or acceptable accuracy. For the general observer their repeatability is poor; only for ex...

Introduction: In vivo proton magnetic resonance spectroscopic imaging (MRSI) has a proven track record as a research tool and shows clinical promise in a range of diseases including brain tumours [1, 2], stroke [3, 4], epilepsy [5, 6] and multiple sclerosis [7, 8]. To enable reliable clinical (diagnostic and longitudinal) use, the repeatability of the technique must be quantified. Whilst studie...

In this paper, we report on passive alignment with sub-micron precision of two photonic chips on a silicon optical bench. An effective design principle to minimize the tolerance chain is presented and applied to a case study. The chips have been successfully manufactured and individual characterization of the chips revealed that all critical dimensions were within or close to specs. Sub-pixel a...

The aim of this study was to define the most appropriate static balance measurement protocol for comparisons between young and elderly subjects. A group of young healthy and a group of elderly subjects (n = 2 x 28) volunteered. They performed eight quiet stance tasks in which they were first screened for being able or not to complete a 30 s trial. Additionally, the body sway mechanical paramete...