Influence of noise on tracking performance using SCPF with 50 particles. These data correspond to frames 42, 50, 52, 55, 61, and 77 of Movie 1. The original movie (SNR = 7.5) was degraded by artificial addition of white noise to produce a range SNRs: (a) SNR = 4.2, (b) SNR = 2.3, (c) SNR = 1.7, and (d) SNR = 1.5. The bounding boxes measure 10 × 130 pixels throughout. The panels show the tracking results overlaid on the image of the moving neurofilament, with insets showing the object tracking area at higher magnification. The position of the bounding box relative to the image of the filament is an indication of the tracking performance. Note that the tracking performance is good with SNRs as low as 1.7, but significant errors are apparent with SNR = 1.5 (note the bounding boxes in red in (d) are shifted relative to those in (a)–(c), which is most noticeable in the insets).