This Demonstration is intended to be used for bio- and medical-imaging analysis. The program automatically creates thresholds for the given image, determining the segments of bright fluorescence. Click a segment and the computer will calculate the size (in pixels), the total fluorescence, and the fluorescence per pixel of the selected segment. You can vary the thresholding parameters, "foreground threshold" and "size threshold". You can switch between the two images that can be loaded using the "image number" buttons. To see all the calculated data, click the "data list" button.