Streak detection steps. The top left image shows a quadrant of a raw CCD file. The size of the image is 2048 × 2066 pixels, corresponding to 204.8 × 206.6 arcseconds. Asteroids are marked with red arrows, and the remaining streaks are cosmic rays. The top right image is the same file after having cosmic rays removed. This image is then fed to StreakDet, which results in a segmented image, shown in the bottom left. The bottom right image shows the final streaks found by StreakDet. As can be seen, there are many false-positive detections. The brightest pixels in an image are often caused by cosmic rays, and after they are removed, the scaling of the image changes. For this reason, after cosmic ray removal, the image appears brighter than before the cosmic rays were removed.