Novia Ann Weiman

User Evaluation Of Cursor-Positioning Devices For 3-D Display Workstations

This paper reports a human-factors evaluation of cursor-positioning devices for 3-dimensional (3-D) display workstations. Five input devices were compared in terms of cursor-positioning time and error with two 3-D display systems: a true 3-D stereoscopic display system and a conventional display system using linear perspective to convey depth information. For both 3-D display systems, the results indicated that vector-oriented input devices produced lower cursor-positioning errors and faster cursor-positioning time than either plane-oriented or free-space input devices. Several implementations of vector-oriented input devices are discussed.

An Evaluation Of Input Devices For 3-D Computer Display Workstations

This paper reports several results from an on-going research program designed to examine the utility of alternate input device technologies for 3-dimensional (3-D) computer display workstations. In this paper, operator performance levels on a 3-D cursor-positioning task were compared using three input devices: (1) a trackball that allowed unrestricted (i.e., free-space) movements within the display space, (2) a mouse that provided selectable two-axis (i.e., plane) movements, and (3) a set of thumbwheels that provided separate controls for orthogonal single-axis (i.e., vector) movements. In addition, the input device evaluation was conducted for two operationally distinct 3-D display techniques: (1) a linear perspective encoding of image depth information and (2) a field-sequential stereoscopic encoding of depth information. Results are discussed in terms of input device selection and general design considerations for the user interface to 3-D computer workstations.

Assessing visual gray-scale sensitivity on a CRT

Current imaging display systems are capable of digitizing an image to eight bits of gray scale (256 levels). For demanding imaging applications such as X-ray images or satellite images more levels of gray scale may be required to extract fine details in the complex images. Obviously the digitization process should not result in the loss of critical information. Conversely the extension of gray scale capability beyond eight bits is associated with a marked increase in system expense and development resources. The desire, then, is to provide all the visual information that the human observer is capable of detecting without over-designing the system beyond the capacity of human vision.