Visual search efficiency depending on spatial layout of stimuli in volumetric image

In medical imaging, large sets of two-dimensional images are used for evaluating anatomical structures. Observers experience high cognitive load due to necessity of memorizing information and data is not seen in a real volume. A volumetric multi-planar display is a promising technology that can eliminate above mentioned issues by producing images in a real three-dimensional space. Therefore, the goal of our study was to investigate how well individuals perceived a difference in spatial localization of visual stimuli and describe its impact on visual search performance in three-dimensional digital space. Participants searched for a target stimulus which was located closer to the observer comparing to other stimuli in different depth segments of a display and provided subjective evaluation of the task difficulty. The results revealed that on average visual attention could be deployed without significant differences on all four depths segments in terms of response time and quality. But at the same time, eccentricity of stimuli influenced considerably the performance which can be related to higher cognitive load due to limitation of visual acuity and attention in the peripheral visual field. To be added, subjective evaluation of perceived task difficulty matched well response time and accuracy in visual search. The obtained results leaded to the conclusion that spatial layout of stimuli in horizontal and vertical dimension had a bigger impact on visual search performance comparing to the third dimension on a volumetric multi-planar display.