As the popularity of the digital Web-cam¡Athese devices are more and more cheaper and powerful. We can apply computer vision techniques with camera and projector to build a more convenient presentation system. In presentation, sometimes due to the position of projector, the images appear the perspective distortion (keystone distortion). The user should manually adjust the position of projector or use the keystone corrections of the projector. But when the distortion is not trapezium, the built-in keystone corrections are not suitable in this situation. We present a computer-vision based method that uses a Web-cam to calibrate the keystone distortion. The Web-cam takes the images that the projector projected on the wall. If the Web-cam observes keystone distortions of the projected images, we use a geometric transform that pre-warps the images in the projector frame, such that these images appears rectangle with known aspect ratio after being projected on the wall. Besides, we implement the virtual buttons that allow users to interact with the computer. The virtual buttons means that when the camera detect the laser point is on the virtual buttons, computer triggers the event as the virtual button being pushed. This paper uses point-matching pairs to obtain the homography between camera image frame and source image frame. The homography, that is the fundamental of calibrating perspective distortions also help us to search the position of the laser point.

The aim of this research is to examine the conceptual design issues concerned with integrating product capabilities that can only be generated at the micro- scale (through feature sizes generally of the order of 100nm to 100μm) directly into 3-dimensional products at the macro-scale. Such macro-scale products could accordingly contain internal devices that are too small to be seen or touched by unaided human designers, which begs the question as to how to enable designers to work with objects which are beyond direct human experience, and how can the necessary collective discussion take place within teams of designers, and between these teams and those responsible for product manufacture? This thesis examines and tests a concept that theoretical 2-dimensional diagrams of function may be transformed into 3-dimensional working structures using procedures allied to those used by graphic designers to create solid objects from 2-dimensional prototype geometries through, for example, extrusion or rotation. Applying such procedures to theoretical diagrams in order to transform them into scalable 3-dimensional devices is not yet in general use at the macro-scale, but with increasing recognition of the unique capabilities of the micro- scale the idea may grow in appeal to alleviate the difficulties of conceiving of functional structures that, when built, will be too small to experience directly. Furthermore this design method, through its basis upon a common currency of functional diagrams, may overcome many of the problems of describing and discussing the design and manufacture of normally intangible objects in 3 dimensions. Finally, it is shown through the example of a novel Red Blood Cell / Plasma Separation Device that the geometric transformation process can lead to the design of functional structures which would not readily be arrived at intuitively, and that may be effectively and efficiently integrated into host products.