TABLE 1:
Cega thresholding values used for experimental data.
| Step | Optimal values estimated for experimental data | How to estimate values | Additional considerations for optimal use |
|---|---|---|---|
| Pixel calibration | Offset = 2293 and Gain = 71 | Estimated from series of dark frames from EMCCD camera (see Materials and Methods). | Data must be calibrated before Cega. Calibration is specific to the camera used. |
| Stationary model estimation | Sliding temporal window median filter = 31 frames. | Duration of >95% of moving motors of interest. | If tracking particles that move for long periods of time or periodically pause, choose a window size encompassing the duration of >95% of the particles of interest. |
| Motion model estimation | Spatiotemporal gaussian blur = 5 frames | Duration that >95% of moving motors remain within 2 adjacent pixels. | Smaller temporal kernel provides better computational efficiency. |
| KL divergence | No user defined parameters are required. | No user defined parameters are required. | Stationary and motion models are used as input. |
| Connectivity filter | 3 connected pixels >0.1 nats | Threshold set to 95th percentile of connectivity model. | Additive salt noise results in many false positives. This noise is removed before candidate finding by applying a threshold. |
| LoG filter | 3 × 3 neighborhood pixel sum from connectivity filter >5 nats. | Threshold set to 95th percentile of LoG model. | The LoG image sequence is used to find initial local minima. Then, connectivity image sequence values for these positions are used to threshold local minima appropriately. |