Improving target detection with nonlinear magnification in visual inspection

Abstract

This experiment examined the effect of nonlinear magnification and foveal loading on the detection of peripheral visual targets. Peripheral objects were scaled using cortical magnification factors, and the foveal task was to determine mirror symmetry for pairs of figures. The results showed that nonlinear magnification had the effect of equating target detection performance at the centre and the periphery. The improved detection performance was present in both with and without foveal loading conditions, with the greatest performance improvement occurring for the farthest peripheral targets. These results suggest the potential usefulness of variable resolution projection displays designed to match the psychophysical properties of the human visual system and reduce the tunnel vision effect found in visual inspection and vigilance tasks in manufacturing industries. However, because of a lateral masking effect, it seems necessary to concurrently magnify the inter-object spacings as well as the object sizes to achieve better overall effectiveness with such variable resolution displays.

Effects of magnification methods and magnifier shapes on visual inspection

“…The proposition of using the differential magnification methods arose due to the ineffectiveness of scaling stimulus in the vicinity of fixation and the effectiveness of the nonlinear magnification using cortical magnification factors on target detection performance Chan and Ma, 2006). Furthermore, more peripheral objects were enclosed on the differential nonlinear magnifying lens, when compared with the linear and differential linear magnifying lenses (Lee and Chan, 2008).…”

“…Some empirical studies on magnification have been conducted to investigate ways of improving target detection performance using linear magnification and nonlinear magnification (Chan and Courtney, 1998;Ma et al, 2004;Chan and Ma, 2006) methods. The results demonstrated that further detailed investigation is required to improve understanding of the search component of the inspection processes using magnification, and to explore the methods of enhancing search performance through consideration of magnification interface factors.…”

“…Ma et al (2004) and Chan and Ma (2006) used a cortical magnification factor to explore and evaluate nonlinear magnification. It was found that, similar to linear magnification, target detection performance with nonlinear magnification, was better with scaled stimuli than that with non-scaled stimuli.…”

Effects of Auditory Cues for Linear and Differential Magnification Methods on Visual Inspection Performance

“…These studies include examination of human search performance under different test conditions, such as level of background luminance, contrast, and the presence of glare; the relationship between search time and peripheral visual acuity; visual field mapping; the effects of training and job aids on visual inspection; the modeling of visual search; and the application of visual search model to map display design. Nevertheless, only a relatively small number of studies (Chan & Ma, ; Ma, Chan, & Courtney, ; Vos, ) have dealt with the ergonomics issues associated with object magnification. In particular, the effects of magnification interface factors on visual search have not been addressed to any great extent in the literature.…”