Topics

• First-order and second-order motion
• Stereoscopic vision

Related topics in Clinical aspects of vision and visual cognition

• The ageing visual system

First-order and second-order motion

The world is made up a a rich variety of visual cues that provide us with important information about the properties of objects in the world and when these objects move, they give rise to vivid perceptions of motion. The characteristics of objects are typically divided into two categories. For moving stimuli these categories are referred to as 'first-order' and 'second-order' motion. First-order motion occurs when a moving object differs from its surrounding in terms of luminance. Second-order motion exists when an object differs from its surroundings in terms of more complex textural cues such as contrast, orientation or the size of its surface markings. There are lots of different types of second-order motion and it has been suggested that they exist to augment the first-order information available to us. This project is part of Dr Hutchinson's research programme. Her research in this area examines how the visual system exploits and combines first-order and second-order cues to provide us with an accurate and holistic representation of movement in the world.

Stereoscopic vision

Since our eyes are laterally offset in our heads, we receive two slightly different images of the world. The differences between these images, known as binocular disparities, provide useful information about the 3D layout of our visual world. Our visual systems use binocular disparities as a depth cue. The visual cortex contains mechanisms that detect and process binocular disparities to produce a vivid impression of the 3D environment, known as stereoscopic depth perception. Such perceptions are of the 3D shapes of visible surfaces and their location in depth relative to each other and to the self.

Part of Dr. Duke’s research program examines how the visual system achieves stereoscopic perception. This research has been examining, e.g. 1) How the visual system exploits different components of disparity to obtain information about the layout of the world and the position of the eyes in the head. 2)  How this information is used in conjunction with information from other sources. 3) How stereoscopically defined 3D properties such as lengths and angles are represented in visually perceived space.