To protect the environment and save human lives, the detection of various hazardous toxins of biological or chemical origin has been a major challenge to the researchers at Oregon State University. Living fish cells can indicate the presence of a wide range of toxins by reactions such as changing color and shape changes. A research team in Electrical and Computer Engineering Department is developing a hybrid detection device (Cytosensor) that combines biological reaction and digital technology. The functions of Cytosensor can be divided into three parts, which are real-time image acquisition, data processing and statistical data analysis. User-friendly Web-Based Distributed Applications (WBDA) for Cytosensor offer various utilities. WBDA allow the users to control and observe the local Cytosensor, search and retrieve data acquired by the sensor network, and process the acquired images remotely using only a web browser. Additionally, these applications minimize the user's exposure to dangerous chemicals or biological products. This thesis describes the design of a remote controller, system observer, remote processor, and search engine using JAVA applets, XML, Perl, MATLAB, and Peer-to-Peer models. Furthermore, the implementations of image segmentation technique in MATLAB and the Machine Vision Algorithm in JAVA for independent web-based processing are investigated. / Graduation date: 2003