The effective use of stereoscopic display systems is dependent, in part, on reliable data describing binocular fusion limits and the accuracy of depth discrimination for such visual display devices. These issues were addressed in three experiments, as were the effects of interocular cross talk. Results showed that limits of fusion were approximately 27.0 min arc for crossed disparity and 24.0 min arc for uncrossed disparity. Subjects were extremely accurate in distinguishing the relative distance among four groups of stimuli, were able to identify a pair of stimuli colocated at the same depth plane within each group, and were fairly accurate in scaling stimuli along the depth dimension. The mean error in using disparity as a depth cue was approximately 2.2 min arc. Interocular cross talk had little effect on fusion limits for 200-ms stimulus presentations but significantly affected fusion for longer (2 s) presentations that enabled vergence responses to be executed. Depth discrimination performance was essentially unaffected by interocular cross talk; however, cross talk significantly influenced subjective ratings of image quality and visual comfort.

No abstract

The use of color LCDs in medical imaging is growing as more clinical specialties use digital images as a resource in diagnosis and treatment decisions. Telemedicine applications such as telepathology, teledermatology, and teleophthalmology rely heavily on color images. However, standard methods for calibrating, characterizing, and profiling color displays do not exist, resulting in inconsistent presentation. To address this, we developed a calibration, characterization, and profiling protocol for color-critical medical imaging applications. Physical characterization of displays calibrated with and without the protocol revealed high color reproduction accuracy with the protocol. The present study assessed the impact of this protocol on observer performance. A set of 250 breast biopsy virtual slide regions of interest (half malignant, half benign) were shown to six pathologists, once using the calibration protocol and once using the same display in its "native" off-the-shelf uncalibrated state. Diagnostic accuracy and time to render a decision were measured. In terms of ROC performance, Az (area under the curve) calibrated = 0.8570 and Az uncalibrated = 0.8488. No statistically significant difference (p = 0.4112) was observed. In terms of interpretation speed, mean calibrated = 4.895 s; mean uncalibrated = 6.304 s which is statistically significant (p = 0.0460). Early results suggest a slight advantage diagnostically for a properly calibrated and color-managed display and a significant potential advantage in terms of improved workflow. Future work should be conducted using different types of color images that may be more dependent on accurate color rendering and a wider range of LCDs with varying characteristics.

No abstract

Past work has shown that facilitation of reflex blinking accompanies cardiac deceleration when the attention of subjecLs is directed to a reflex-eliciting stimulus. The present studies showed that when warning stimuli directed attention instead to weak (tactile) stimuli presented simultaneously with reflex-eliciting (acoustic) stimuli, cardiac deceleration was still present but reflex magnitude was unchanged or inhibited. However, latency to reflex onset remained facilitated, i.e., latency and magnitude changes were discordant. The findings were interpreted as evidence for two independent processes: a process capable of selectively enhancing or attenuating sensory input and a non-selective process presumably facilitating motor pathways.