Perceptual evaluation of color transformed multispectral imagery

Abstract

Color remapping can give multispectral imagery a realistic appearance. We assessed the practical value of this technique in two observer experiments using monochrome intensified (II) and long-wave infrared (IR) imagery, and color daylight (REF) and fused multispectral (CF) imagery. First, we investigated the amount of detail observers perceive in a short timespan. REF and CF imagery yielded the highest precision and recall measures, while II and IR imagery yielded significantly lower values. This suggests that observers have more difficulty in extracting information from monochrome than from color imagery. Next, we measured eye fixations during free image exploration. Although the overall fixation behavior was similar across image modalities, the order in which certain details were fixated varied. Persons and vehicles were typically fixated first in REF, CF, and IR imagery, while they were fixated later in II imagery. In some cases, color remapping II imagery and fusion with IR imagery restored the fixation order of these image details. We conclude that color remapping can yield enhanced scene perception compared to conventional monochrome nighttime imagery, and may be deployed to tune multispectral image representations such that the resulting fixation behavior resembles the fixation behavior corresponding to daylight color imagery. Downloaded From: http://opticalengineering.spiedigitallibrary.org/ on 05/16/2015 Terms of Use: http://spiedl.org/terms

Improved Color Mapping Methods for Multiband Nighttime Image Fusion

“…The sample-based mapping is highly specific for different types of materials in the scene and can therefore easily be adapted to the task at hand, such as optimizing the visibility of camouflaged targets. In a recent study [72], we observed that multiband nighttime imagery that has been recolored using this look-up-table based color transform conveys the gist of a scene better (i.e., to a larger extent and more accurately) than each of the individual infrared and intensified image channels. Moreover, we found that this recolored imagery conveys the gist of a scene just as well as regular daylight color photographs.…”

“…Moreover, we found that this recolored imagery conveys the gist of a scene just as well as regular daylight color photographs. In addition, targets of interest such as persons or vehicles were fixated faster [72].…”

Evaluation of fused imagery using eye movement-based measures of perceptual processing

“…A C C E P T E D M A N U S C R I P T 32 We computed correlation coefficients to quantify the extent to which each of the image characteristics accounted for the performance of sensor conditions. For each Sensor (6) x Distance (3) setting in Experiment 2a and 2b, we computed the average image metric and performance value (averaged across Position and Character, and then averaged across subjects).…”

“…Toet et al [32] examined eye movement behaviour during visual search of colour-fused nearinfrared/visible spectrum images as well as component single-band images. The authors examined the total fixation duration, number of fixations, and fixation rate (i.e.…”

“…A C C E P T E D M A N U S C R I P T 7 Eye movement recordings have proved to be an important tool in the study of visual search of natural scenes (for reviews see [26][27][28][29]), but there have been only a few applications of this technique to the domain of infrared sensors and image fusion [30][31][32][33]. In a study by Krebs,Scribner,and McCarley [33], eye tracking was used to obtain measures of scanpath length during visual search of infrared and fused scenes.…”