Gary Ault, Shiwon Choe, David Emory, Benjamin Smith

Prof. Roger Blumberg, Visiting Lecturer in the Department of Computer Science

Prof. Leslie Welch, Dept. of Psychology, Brown University


Target Audience

The target audience for this project will be Brown students taking a psychological perception course. This project will be used as a supplement to the explanation of perceptual phenomena given in class that students would look at independently to illustrate points made in class. The project is not designed to replace actual lectures; it is designed to be a supplementary "exercise" for the students to utilize if they wish to do so.

Target Platform

Java-enabled PCs and Macs


For this project we will be writing a collection of interactive demonstrations that help illustrate concepts pertaining to human perception. Although the applets will be unified by some web-based content dealing with general issues in the study of perception, the focus of development will be on a series of independent components, each of which will deal with a particular topic pertaining to the study of perception. Along with Prof. Welch we have identified three major components which we plan to implement

  • Perception of a Two-Dimensional Representation of a 3D Scene
  • Perception of Human Motion
  • Perception of Color

Detailed Descriptions

1) Perception of a Two-dimensional Representation of a 3D Scene

The purpose of this component is to allow students to examine the nature of depth perception by modifying the elements in a 2D scene that give the impression of three-dimensional depth. The main window will show a two-dimensional picture of a three-dimensional scene drawn as line art. There will be a background clearly identifiable as such, with a number of objects (such as boats) situated within the scene. The objects will be of the same size if the scene actually existed in three dimensions, but in the two-dimensional picture, they will clearly look different objects that look smaller appear further off in the distance, as do objects that are at a higher level in the scene, as do objects that are obstructed by other objects.  To examine this phenomenon, the user will be able to adjust the relative height, size, and transparency of the various objects in order to examine what role height, size, and occlusion play in the perception of depth in a scene, as well as the "eye level" within the scene.  The images and background will be "line art" pictures, to remove the interference of such properties as color or texture as factors that affect this perceptual test. We may wish to add a feature where the user can change what the objects are from a specific list to see if certain depth illusions work if the user knows that all objects should be the same size (as in the case with the boats) that subsequently fail to work with objects without such size clues (such as a bunch of cubes).  This component will be written as a Java applet embedded in an HTML file that can be viewed over the web.

2) Perception of Human Motion

The basis for this component is a research project done by Brown CS Prof. Nancy Pollard while at the Georgia Tech Animation lab. This research resulted in a series of computer generated animations depicting human figures performing common motor skills such as running and bicycling. The animations were created by identifying key points in the human anatomy (joints, etc) and representing each with a white "dot" in the animation (set against a black background). Taken as a whole, these collections of animated dots can easily be identified as a representation the specific action being performed.  The interactive demonstration we write will allow users to control which dots are visible in the animation, which will affect the perception of the animation as a whole. (e.g., how would hiding the dots corresponding to key joints in the body affect the perception of the overall action?)  The applet will be written in Java, consisting primarily of the animation display and the interface for the on/off toggling of individual dots in the animation (probably through use of AWT checkboxes).

3) Perception of Color

This part of the project covers aspects of the color theory. The applets that will be developed will allow the students of Professor Welch's class to understand how perceptions of color are produced by cues and other aspects of a particular scene or environment. The students will be allowed to visualize what is seen by individuals whose vision is such in everyday life. There will be several models developed to display these ideas. These models will basically cover the color theory.  Color is only visible with light. These models will expand upon this premise and state how color comes into being with the interaction between light, the object, and the idea. The models that would be used are

  • The Color Wheel
  • Changes in color due to changes in various wavelengths
  • Perceptions of color in images (i.e. Picture of a fruit basket)

This component of project will be done mostly in Java, with the possible use of Director for additional user interface support.



2000 Brown University CS Department