HMI Experimental Smoother-Based Tracking

Michael Turmon, JPL, November 2010

The movies below are made with the current HMI masks, which use magnetogram information only (no intensity information).

In contrast to the tracks reported elsewhere, the track movies here use a more computationally-intensive joint space/time smoothing. The smoothing looks forward in time, as well as backward. This allows the track boundaries to evolve more smoothly.

I made these movies as a test of concept only. The tracker parameters in these movies were not carefully tuned, and a couple of design decisions cut algorithm complexity, but are sub-optimal for high-latitude regions.

So, please don't take the particulars of which region was grouped with which other region as having much significance.

I do hope these movies illustrate the benefits of temporal smoothing to make patches that don't frivolously expand and contract.

Movie Layout

The movies have 1024x1024 frames; they may be cropped by the inline movie player in your browser. If this is getting in the way, download the movie and play it locally.

The disk is gray, and pixels labeled as "active" within the gray disk are black. The colored blobs represent the full content of different HARPs; small clumps of black pixels that are outside the HARP's are below-threshold. The color of the HARP-blob is related to its track number (counting up from one).

The white bounding box surrounding the HARP encircles all within-HARP pixels.

For display purposes, I rotated the images (which have p-angle 180) to make north appear up, and rotation from left-to-right, as expected.

Text Insets

All four corners of the movie have text insets.

Top left: frame number in overall image sequence.

Bottom left: Number of HARPs in this frame, and time and date of T_REC.

Top right: For the top half of the image, shows the HARP ID of the current region sets. A "^" next to the ID means it is the largest on the disk, and a "v" means it is the smallest.

Bottom right: Region list for the bottom half of the image, in format just described.

Next to the track number appears a colored square corresponding to the track shown.

Files Here

Tag Size Starts at Ends at Notes
2010-07-03 1.6M 2010/07/01_12:48 2010/07/03_06:36 No Notes
2010-08-10 3.6M 2010/08/10_12:00 2010/08/12_05:48 No Notes
2010-09-01 2.6M 2010/09/01_12:00 2010/09/03_05:48 No Notes


In these movies, the detection threshold for finding an AR is too high, so we miss some concentrations of activity that would correspond to NOAA ARs. So, these movies are not directly comparable to the existing HMI patch movies.

It takes about 10 frames at the beginning and end of the sequence before the patches stabilize. This is a simple edge effect due to the temporal smoothing.