The X-Cam and ISPS Projects




Overview Webcams Software Results
Overview PERT Optical Math
Olin-NASA Research Olin College NASA Goddard Space Flight Center Constellation-X

X-Cam Project: Results

Camera Modification

Rendering the camera capable of seeing x-rays turned out to be fairly straightforward, as we had anticipated. For each camera, we simply unscrewed the lens, then gently pried off the very thin film of glass covering the CMOS chip. The latter part was slightly difficult, in that it was such a delicate job. We broke one camera during this step by severing many very miniscule wires that ran underneath the glass cover.

 

Seeing X-rays

After removing the lens and glass, we were eager to see if we could detect x-rays. We first tried a Fe55 source, but it ended up being too weak to detect. We then resorted to using an x-ray gun, which did produce detectable x-rays. We saw the x-rays by isolating the camera in a darkroom and pointing the gun directly at the CMOS chip.

 

Data Processing

The entire chip was lit up when the x-ray gun was pointed at it, so we used some post-processing in MatLab to change the brightness threshold for the image produced by the camera. Every pixel with a brightness above the threshold was made white, and the rest were left black, producing a spot of white (where the x-ray hit) on a background of black. This allowed us to narrow down where exactly on the chip an x-ray was hitting, assuming that its location was the center of the spot. We wrote MatLab code that tweaks the threshold value until a spot of an acceptable size is obtained, and then another script which finds the centroid of that spot to yield a more precise designation of the location of an x-ray event.  Our final program can be downloaded by clicking here.