Preliminary evaluation of display format effects on perceptibility in a low contrast ultrasound test object

1981 ◽  
Vol 8 (2) ◽  
pp. 155-157 ◽  
Author(s):  
F. Graham Sommer ◽  
Stelios C. Orphanoudakis ◽  
Kenneth J. W. Taylor
Keyword(s):  
Test Object ◽  
Preliminary Evaluation ◽  
Low Contrast ◽  
Display Format ◽  
Format Effects ◽  
Contrast Ultrasound

The Impact of Task Characteristics on Display Format Effects

1988 ◽  
Vol 32 (5) ◽  
pp. 352-356
Author(s):  
David R. Schwartz
Keyword(s):  
Human Performance ◽  
Task Complexity ◽  
Design Criterion ◽  
Task Characteristics ◽  
Regression Equations ◽  
Display Format ◽  
The One ◽  
Format Effects ◽  
The Impact ◽  
Performance Research

A study was conducted to determine how well the display format effects described by Tullis (1983, 1984) and the resulting prediction equations could be generalized to other display situations. Task complexity and visual monitoring load were identified as task variables which could potentially moderate the format effects and, thus, were varied factorially. The current study also sought to extend Tullis's findings to tasks where the use of several pieces of information from predictable display locations is required. In general, the data indicate the need to study Tullis's format dimensions more fully before using his regression equations to evaluate display designs for use outside the task situation in which the equations were developed. Also, subjects were unable to evaluate their performance accurately under alternative display designs. Their evaluations seemed to be determined mostly by the perceived ease with which information was extracted from the display. This outcome should serve as a warning to system designers. That is, empirical human performance research should be conducted when performance is the paramount design criterion and a validated prediction system, such as the one developed by Tullis for search, is not available.

Transfer of Resolution in the Production of Orthophotos

1970 ◽  
Vol 24 (4) ◽  
pp. 459-471
Author(s):  
Stanley H. Collins ◽  
Zdenek Kalensky
Keyword(s):  
Test Object ◽  
Glass Plate ◽  
Relative Importance ◽  
Low Contrast ◽  
Progressive Loss ◽  
Angle Of View ◽  
Made In

The progressive loss of resolution was determined for the various steps involved in producing optically-projected orthophoto prints. The first test object was a set of low-contrast annular targets placed at the focus of a collimator in the laboratory. A film negative, with images of the test object across both diagonals, was made in a Wild RC8 camera supported on a nodal slide. From this negative, glass plate diapositives were made in three different printers. A typical diapositive was selected and used as the test object for two different orthophoto projectors and a tilt-rectifying projector. The resulting negatives were printed by contact and by projection. A graph of resolution vs. angle-of-view is given for each stage of reproduction, and the relative importance of the loss of resolution in each stage is discussed.

Exploring Coronal Structures with SOHO

2000 ◽  
Vol 179 ◽  
pp. 403-406
Author(s):  
M. Karovska ◽  
B. Wood ◽  
J. Chen ◽  
J. Cook ◽  
R. Howard
Keyword(s):  
Solar Corona ◽  
Image Enhancement ◽  
Coronal Mass Ejections ◽  
Dynamical Evolution ◽  
Small Scale ◽  
Low Contrast ◽  
Contrast Structures ◽  
Scale Structures ◽  
Small Scale Structures ◽  
Coronal Structures

AbstractWe applied advanced image enhancement techniques to explore in detail the characteristics of the small-scale structures and/or the low contrast structures in several Coronal Mass Ejections (CMEs) observed by SOHO. We highlight here the results from our studies of the morphology and dynamical evolution of CME structures in the solar corona using two instruments on board SOHO: LASCO and EIT.

One Million Direct Magnification Microscopy

1971 ◽  
Vol 29 ◽  
pp. 166-167
Author(s):  
J. A. Hugo ◽  
V. A. Phillips
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Illumination Level ◽  
Level Of Detail ◽  
Photographic Emulsion ◽  
Low Contrast ◽  
Fluorescent Screen ◽  
Resolution Electron ◽  
Lattice Images ◽  
Electron Microscopes

A continuing problem in high resolution electron microscopy is that the level of detail visible to the microscopist while he is taking a picture is inferior to that obtainable by the microscope, readily readable on a photographic emulsion and visible in an enlargement made from the plate. Line resolutions, of 2Å or better are now achievable with top of the line 100kv microscopes. Taking the resolution of the human eye as 0.2mm, this indicates a need for a direct viewing magnification of at least one million. However, 0.2mm refers to optimum viewing conditions in daylight or the equivalent, and certainly does not apply to a (colored) image of low contrast and illumination level viewed on a fluorescent screen through a glass window by the dark-adapted eye. Experience indicates that an additional factor of 5 to 10 magnification is needed in order to view lattice images with line spacings of 2 to 4Å. Fortunately this is provided by the normal viewing telescope supplied with most electron microscopes.

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