Johnson's Criteria
Encyclopedia
Johnson's criteria, or the Johnson criteria, created by John Johnson
, describe both image- and frequency-domain approaches to analyzing the ability of observers to perform visual tasks using image intensifier technology
. It was an important breakthrough in understanding the performance of visual devices that it would provide the basis guiding the development of future systems. Using Johnson's criteria, many predictive models for sensor technology have been developed that predict the performance of sensor systems under different environmental and operational conditions.
systems enabled the measurement of visual thresholds following World War II
. The 1950s
also marked a time of notable development in the performance modeling of night vision imaging systems. From 1957 to 1958, Johnson, a United States Army Night Vision & Electronic Sensors Directorate (NVESD) scientist, was working to develop methods of predicting target detection, orientation, recognition, and identification. Working with volunteer observers, Johnson used image intensifier equipment to measure the volunteer observer's ability to identify scale model
targets under various conditions. His experiments produced the first empirical data on perceptual thresholds that was expressed in terms of line pair
s. In the first Night Vision Image Intensifier Symposium in October 1958, Johnson presented his findings in a paper entitled "Analysis of Image Forming Systems", which contained the list that would later be known as Johnson's criteria.
across a target, in terms of several tasks:
These amounts of resolution give a 50 percent probability
of an observer discriminating an object to the specified level.
Additionally, the line pairs refer to lines being displayed on an interlaced CRT monitor. Each line pair corresponds to 2 pixels of a film image, or an image displayed on an LCD monitor.
John Johnson
-Artists and entertainers:*John Johnson , English lutenist and composer*John Johnson , trombonist and percussionist with Simply Red*John Johnson , American television reporter and anchor*J...
, describe both image- and frequency-domain approaches to analyzing the ability of observers to perform visual tasks using image intensifier technology
Technology
Technology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures. The word technology comes ;...
. It was an important breakthrough in understanding the performance of visual devices that it would provide the basis guiding the development of future systems. Using Johnson's criteria, many predictive models for sensor technology have been developed that predict the performance of sensor systems under different environmental and operational conditions.
History
Night visionNight vision
Night vision is the ability to see in low light conditions. Whether by biological or technological means, night vision is made possible by a combination of two approaches: sufficient spectral range, and sufficient intensity range...
systems enabled the measurement of visual thresholds following World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. The 1950s
1950s
The 1950s or The Fifties was the decade that began on January 1, 1950 and ended on December 31, 1959. The decade was the sixth decade of the 20th century...
also marked a time of notable development in the performance modeling of night vision imaging systems. From 1957 to 1958, Johnson, a United States Army Night Vision & Electronic Sensors Directorate (NVESD) scientist, was working to develop methods of predicting target detection, orientation, recognition, and identification. Working with volunteer observers, Johnson used image intensifier equipment to measure the volunteer observer's ability to identify scale model
Scale model
A scale model is a physical model, a representation or copy of an object that is larger or smaller than the actual size of the object, which seeks to maintain the relative proportions of the physical size of the original object. Very often the scale model is used as a guide to making the object in...
targets under various conditions. His experiments produced the first empirical data on perceptual thresholds that was expressed in terms of line pair
Line pair
A line pair can be more than one thing.-In philately:A line pair in philately is a coil pair of postage stamps bearing an inked line between the two stamps. There are at least two kinds of these:*A guide line pair has a guide line between the stamps...
s. In the first Night Vision Image Intensifier Symposium in October 1958, Johnson presented his findings in a paper entitled "Analysis of Image Forming Systems", which contained the list that would later be known as Johnson's criteria.
Criteria
The minimum required resolution according to Johnson's criteria are expressed in terms of line pairs of image resolutionImage resolution
Image resolution is an umbrella term that describes the detail an image holds. The term applies to raster digital images, film images, and other types of images. Higher resolution means more image detail....
across a target, in terms of several tasks:
- Detection, an object is present (1.0 +/– 0.25 line pairs)
- Orientation, symmetrical, asymmetric, horizontal, or vertical (1.4 +/– 0.35 line pairs)
- Recognition, the type object can be discerned, a person versus a car (4 +/– 0.8 line pairs)
- Identification, a specific object can be discerned, a woman versus a man, the specific car (6.4 +/– 1.5 line pairs)
These amounts of resolution give a 50 percent probability
Probability
Probability is ordinarily used to describe an attitude of mind towards some proposition of whose truth we arenot certain. The proposition of interest is usually of the form "Will a specific event occur?" The attitude of mind is of the form "How certain are we that the event will occur?" The...
of an observer discriminating an object to the specified level.
Additionally, the line pairs refer to lines being displayed on an interlaced CRT monitor. Each line pair corresponds to 2 pixels of a film image, or an image displayed on an LCD monitor.