Intensity variation over time with different exposure times.

<p>The graph shows the average intensity of images taken every minute and stored on the SD card with different exposure times (1 ms, 5 ms, 10 ms, 50 ms, 100 ms, and 500 ms). The microscope was placed in a dark box with the external battery-powered LED light switched on. Even after 3 days of constant illumination, the image intensity at longer exposure times is sufficient for brightfield microscopy. Lateral drift of the time series, calculated as a cross-correlation of successive images, shows a sudden jump in value after about 8 hours, likely due to the opening of a door.</p> <p>(PDF)</p>