The effect of dynamically changing visibility conditions on target acquisition is considered. A m... more The effect of dynamically changing visibility conditions on target acquisition is considered. A model is described that takes as input the statistical characterization ofthe obscurant and the physical.
Understanding infrared clutter through fixation point analysis. [Proceedings of SPIE 2224, 142 (1... more Understanding infrared clutter through fixation point analysis. [Proceedings of SPIE 2224, 142 (1994)]. Stanley R. Rotman, Marta L. Kowalczyk, Joan F. Cartier, J. Chang. Abstract. A model is proposed for determining the effect ...
Both edged-based and textural-based metrics can help us understand the effect of clutter in image... more Both edged-based and textural-based metrics can help us understand the effect of clutter in images that a human observer is searching in order to acquire targets. By studying the actual fixation points of the observers, we can determine which features distract or confuse an observer in his attempt to acquire the true target.
The standard single-target acquisition model used in military applications for human target acqui... more The standard single-target acquisition model used in military applications for human target acquisition using infrared systems has been extended to the multitarget scenario. It incorporates three possible versions, depending on the underlying causes for the nonunity detection probability at infinite time and the degree of correlation between targets.
There has been an increase in attempts to quantitatively measure clutter in the background of vis... more There has been an increase in attempts to quantitatively measure clutter in the background of visual and infrared scenes; this parameter is crucial for determining the probability of detection of military targets in actual battlefield conditions. We analyze several clutter metrics by comparing the location of fixation points with the spatial distribution of the areas of high clutter. We determine that a strong correlation does exist.
The threshold energy for the chemiluminescent reaction between NO and O3 to give NO&a... more The threshold energy for the chemiluminescent reaction between NO and O3 to give NO*2 and O2 has been measured using a photon detection crossed molecular beam machine. A supersonic NO beam was crossed at 90° by a quasieffusive ozone beam allowing better collision energy resolution than in previously published work. The data were fit using a cross section function of
IEEE Transactions on Aerospace and Electronic Systems, 1994
... Proceedings of the SID, 21, 3 (1980), 229-246. On the detection of signals embedded in natura... more ... Proceedings of the SID, 21, 3 (1980), 229-246. On the detection of signals embedded in natural scenes. Perception & Psychophysics, 39, 2 (1986), 87-95. Target acquisition model development: Effect of realistic terrain. Hughes ...
: The contribution of lightning to the global tropospheric NO sub x budget is estimated. The inje... more : The contribution of lightning to the global tropospheric NO sub x budget is estimated. The injection height of the NO sub x as well as its latitudinal distribution is provided for use in 2-D atmospheric models. Several components of the NO sub x production ...
A high resolution molecular beam measurement of the energy spectra of O3 photolysis products was ... more A high resolution molecular beam measurement of the energy spectra of O3 photolysis products was performed at 266 nm. (AIP)
A high resolution molecular beam measurement of the energy spectra of O3 photolysis products was ... more A high resolution molecular beam measurement of the energy spectra of O3 photolysis products was performed at 266 nm. (AIP)
The catalytic destruction of stratospheric ozone by the oxides of nitrogen is believed to be an i... more The catalytic destruction of stratospheric ozone by the oxides of nitrogen is believed to be an important part of the global ozone balance. The lack of sufficient measurements of NOx concentrations has impeded efforts to quantify this process. Recent measurements of stratospheric nitrogen dioxide from ground-based stations as well as aircraft and balloons have provided a first approximation to a global distribution of NO2 vertical columns at sunset. These observed vertical columns have been translated into time-dependent vertical NO2 profiles by means of a one-dimensional atmospheric photochemical model. Using recent observations of air temperature and ozone along with this information, the independent instantaneous (one second) rates of ozone production from oxygen photolysis P(O3), of ozone destruction from pure oxygen species (Chapman reactions) L(Ox ), and of ozone destruction by nitrogen oxides L(NOx ) were estimated over the three-dimensional atmosphere. These quantities are displayed as zonal average contour maps, summed over various latitude zones, summed over various altitude bands, and integrated globally between 15 and 45 km. Although the global summation between 15 and 45 km by no means tells the complete story, these numbers are of some interest, and the relative values are: P(O3), 100; L(Ox ), 15; L(NOx ), 45±15. It is to be emphasized that this relative NOx contribution to the integrated ozone balance is not a measure of the sensitivity of ozone to possible perturbations of stratospheric NOx ; recent model results must be examined for current estimates of this sensitivity.
The effect of global clutter is discussed from the vantage point of selecting the best model for ... more The effect of global clutter is discussed from the vantage point of selecting the best model for background IR scenery. Methods based on the human visual system and on the latest models for image composition are discussed.
The effect of dynamically changing visibility conditions on target acquisition is considered. A m... more The effect of dynamically changing visibility conditions on target acquisition is considered. A model is described that takes as input the statistical characterization of the obscurant and the physical characteristics of the target; the output is the probability of detection as a function of time. Analysis indicates that the variation of the obscurant as a function of time greatly affects the predicted target detection times and, hence, the utility of the infrared system in realistic scenarios.
Many of the standard considerations for the modeling of infrared target acquisition of stationary... more Many of the standard considerations for the modeling of infrared target acquisition of stationary targets in a single field of view must be altered when considering target acquisition in the actual battlefield. Sensors are scanning, targets are moving, and a complex background is present. A metric is needed to determine acquisition efficacy which is considerably more complex than the standard analysis. In this paper, we will discuss several of the issues involved. The use of a single detectable frequency to model the target acquisition process is not sufficient. We consider the replacement of this model with one consisting of an integral of the target spectrum, taking into account the spatial frequency modulation transfer function dependence of the imaging system. Psychophysical experiments are presented; the results of this experiment verify our approach that the maximum spatial frequency criterion is not sufficient to determine the target acquisition probability.
The target acquisition rate P(0) is given for a single-target single-observer scenario by the Cen... more The target acquisition rate P(0) is given for a single-target single-observer scenario by the Center for Night Vision and Electro-Optics (CNVEO) search model. In this paper, an attempt is made to extend this model to cases in which P(0) changes due to statistical fluctuations in the atmosphere. The effect on both single- and multiple-observer detection times is described.
The search strategy in field-of-regard infrared target acquisition is considered. Three methods o... more The search strategy in field-of-regard infrared target acquisition is considered. Three methods of choosing the sequence of fields-of-view to be searched in the field-of-regard are considered: random, `windshield-wiper' and `typewriter'. The effect of the speed of the scan on the blurring of the target image is considered. The results are used to predict the performance of actual military systems.
The effect of dynamically changing visibility conditions on target acquisition is considered. A m... more The effect of dynamically changing visibility conditions on target acquisition is considered. A model is described that takes as input the statistical characterization ofthe obscurant and the physical.
Understanding infrared clutter through fixation point analysis. [Proceedings of SPIE 2224, 142 (1... more Understanding infrared clutter through fixation point analysis. [Proceedings of SPIE 2224, 142 (1994)]. Stanley R. Rotman, Marta L. Kowalczyk, Joan F. Cartier, J. Chang. Abstract. A model is proposed for determining the effect ...
Both edged-based and textural-based metrics can help us understand the effect of clutter in image... more Both edged-based and textural-based metrics can help us understand the effect of clutter in images that a human observer is searching in order to acquire targets. By studying the actual fixation points of the observers, we can determine which features distract or confuse an observer in his attempt to acquire the true target.
The standard single-target acquisition model used in military applications for human target acqui... more The standard single-target acquisition model used in military applications for human target acquisition using infrared systems has been extended to the multitarget scenario. It incorporates three possible versions, depending on the underlying causes for the nonunity detection probability at infinite time and the degree of correlation between targets.
There has been an increase in attempts to quantitatively measure clutter in the background of vis... more There has been an increase in attempts to quantitatively measure clutter in the background of visual and infrared scenes; this parameter is crucial for determining the probability of detection of military targets in actual battlefield conditions. We analyze several clutter metrics by comparing the location of fixation points with the spatial distribution of the areas of high clutter. We determine that a strong correlation does exist.
The threshold energy for the chemiluminescent reaction between NO and O3 to give NO&a... more The threshold energy for the chemiluminescent reaction between NO and O3 to give NO*2 and O2 has been measured using a photon detection crossed molecular beam machine. A supersonic NO beam was crossed at 90° by a quasieffusive ozone beam allowing better collision energy resolution than in previously published work. The data were fit using a cross section function of
IEEE Transactions on Aerospace and Electronic Systems, 1994
... Proceedings of the SID, 21, 3 (1980), 229-246. On the detection of signals embedded in natura... more ... Proceedings of the SID, 21, 3 (1980), 229-246. On the detection of signals embedded in natural scenes. Perception & Psychophysics, 39, 2 (1986), 87-95. Target acquisition model development: Effect of realistic terrain. Hughes ...
: The contribution of lightning to the global tropospheric NO sub x budget is estimated. The inje... more : The contribution of lightning to the global tropospheric NO sub x budget is estimated. The injection height of the NO sub x as well as its latitudinal distribution is provided for use in 2-D atmospheric models. Several components of the NO sub x production ...
A high resolution molecular beam measurement of the energy spectra of O3 photolysis products was ... more A high resolution molecular beam measurement of the energy spectra of O3 photolysis products was performed at 266 nm. (AIP)
A high resolution molecular beam measurement of the energy spectra of O3 photolysis products was ... more A high resolution molecular beam measurement of the energy spectra of O3 photolysis products was performed at 266 nm. (AIP)
The catalytic destruction of stratospheric ozone by the oxides of nitrogen is believed to be an i... more The catalytic destruction of stratospheric ozone by the oxides of nitrogen is believed to be an important part of the global ozone balance. The lack of sufficient measurements of NOx concentrations has impeded efforts to quantify this process. Recent measurements of stratospheric nitrogen dioxide from ground-based stations as well as aircraft and balloons have provided a first approximation to a global distribution of NO2 vertical columns at sunset. These observed vertical columns have been translated into time-dependent vertical NO2 profiles by means of a one-dimensional atmospheric photochemical model. Using recent observations of air temperature and ozone along with this information, the independent instantaneous (one second) rates of ozone production from oxygen photolysis P(O3), of ozone destruction from pure oxygen species (Chapman reactions) L(Ox ), and of ozone destruction by nitrogen oxides L(NOx ) were estimated over the three-dimensional atmosphere. These quantities are displayed as zonal average contour maps, summed over various latitude zones, summed over various altitude bands, and integrated globally between 15 and 45 km. Although the global summation between 15 and 45 km by no means tells the complete story, these numbers are of some interest, and the relative values are: P(O3), 100; L(Ox ), 15; L(NOx ), 45±15. It is to be emphasized that this relative NOx contribution to the integrated ozone balance is not a measure of the sensitivity of ozone to possible perturbations of stratospheric NOx ; recent model results must be examined for current estimates of this sensitivity.
The effect of global clutter is discussed from the vantage point of selecting the best model for ... more The effect of global clutter is discussed from the vantage point of selecting the best model for background IR scenery. Methods based on the human visual system and on the latest models for image composition are discussed.
The effect of dynamically changing visibility conditions on target acquisition is considered. A m... more The effect of dynamically changing visibility conditions on target acquisition is considered. A model is described that takes as input the statistical characterization of the obscurant and the physical characteristics of the target; the output is the probability of detection as a function of time. Analysis indicates that the variation of the obscurant as a function of time greatly affects the predicted target detection times and, hence, the utility of the infrared system in realistic scenarios.
Many of the standard considerations for the modeling of infrared target acquisition of stationary... more Many of the standard considerations for the modeling of infrared target acquisition of stationary targets in a single field of view must be altered when considering target acquisition in the actual battlefield. Sensors are scanning, targets are moving, and a complex background is present. A metric is needed to determine acquisition efficacy which is considerably more complex than the standard analysis. In this paper, we will discuss several of the issues involved. The use of a single detectable frequency to model the target acquisition process is not sufficient. We consider the replacement of this model with one consisting of an integral of the target spectrum, taking into account the spatial frequency modulation transfer function dependence of the imaging system. Psychophysical experiments are presented; the results of this experiment verify our approach that the maximum spatial frequency criterion is not sufficient to determine the target acquisition probability.
The target acquisition rate P(0) is given for a single-target single-observer scenario by the Cen... more The target acquisition rate P(0) is given for a single-target single-observer scenario by the Center for Night Vision and Electro-Optics (CNVEO) search model. In this paper, an attempt is made to extend this model to cases in which P(0) changes due to statistical fluctuations in the atmosphere. The effect on both single- and multiple-observer detection times is described.
The search strategy in field-of-regard infrared target acquisition is considered. Three methods o... more The search strategy in field-of-regard infrared target acquisition is considered. Three methods of choosing the sequence of fields-of-view to be searched in the field-of-regard are considered: random, `windshield-wiper' and `typewriter'. The effect of the speed of the scan on the blurring of the target image is considered. The results are used to predict the performance of actual military systems.
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