Page 283 - Fundamentals of Light Microscopy and Electronic Imaging

Figure 14-7
Image view and corresponding text file of two fluorescent microtubule filaments. Each pixel
value (described in analogue-to-digital units or ADUs) indicates the number of incident
photoelectrons during the exposure. Notice that where the two filaments cross, the pixel
value becomes doubled. The CCD camera used here is capable of resolving up to 4096 gray
levels within a single image frame.