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r3 | ozzloy | 2007-07-16 16:26:08 -0700 (Mon, 16 Jul 2007) | 3 lines
creating a subdir for eigenFaces
The project's ultimate goal is to make a chemical sensor. That's useful for bomb detection. but this has been done, so why do it again? traditional chemical sensors are one-time use. a paper strip exposed to a particular agent will turn from the color it is to some other color. the paper actively changes and does not return to its original state upon removal of the agent. the sensors developed by mike sailor called rugate filters passively change color. they will change color as a result of changes in the environment. they will react to many agents. the rugate filters will yield the same color pattern when exposed to the same environment. this means they can repeatedly detect increased levels of a toxin. we do not have to discard rugate filters after one use. as a result, rugate filters can potentially be continuously monitoring the environment for changes in chemical levels. this requires that the filter be monitored for long amounts of time. a low cost camera provided by avaak can wirelessly report its findings back to a central computer capable of interpreting the changes in the image and determining the chemicals present in the environment.

my project involves collecting pictures of these sensors reacting to known concentrations of chemicals. each picture is a data point. i must categorize the changes. after quantifying the changes from picture to picture, i must determine if the change is correlated with the change in the chemicals of the environment. to determine where the changes in the pictures are the largest, i used principal component analysis, PCA. the cross between PCA and image analysis is called "eigen faces" because it was used with pictures of faces and yielded a high degree of success.

at this point i have collected a bunch of pictures and must start finding out where they change the most for a given change in the chemical environment. typically this change will be from 0 ppm to 50k ppm of one analyte.