Sea Ice non-rigid motion and discontinuity estimation from satellite

images

Gowri SomanathVincent Ly

Dr. Chandra Kambhamettu

Department of Computer & Information Sciences

Dr. Cathleen GeigerDepartment of Geography

http://vims.cis.udel.edu

ACE Meeting May 9th 2012

Today

• Look at some results from motion segmentation and summary presentation– High activity, low activity– Thresholds and its effect on level of summary

• Possible further analysis• Next steps

Motion summary: visualizing flow characteristics using motion in an area

• The segments are demarcated by the thick black lines. The transparent grayscale color is only an indication of segments not anything else from the image.

• The arrows show the direction of motion (length and thickness scaled by motion magnitude). It is calculated from the average of all vectors within the segment.

• The white dot is placed at the centroid of the corresponding segment.

• The blue line is along the horizontal axis – which is the reference for all angular measurements.

• The green semi-circle indicates the lower and upper bounds on the angular component of the motion in the segment. The bounds are determined by mean and standard deviation of the angle of the motion (we use mean+std dev and mean-std dev). The start and end points of the green semi-circle indicate these limits.

Its hard to look at the dense motion vectors, so we present a ‘summary’ by segmenting the motion field into coherent regions with ‘similar motion’.

Motion ‘summary’ : set 1LIC

Motion magnitude

Summary image

Motion ‘summary’ : set 2LIC

Motion magnitude

Summary image

Motion ‘summary’ : set 4cLIC

Motion magnitude

Summary image

Motion ‘summary’ : set 5LIC

Motion magnitude

Summary image

Motion ‘summary’ : set 1 – parameter tweaksLIC

Motion magnitude

Possible analysis• Fix a threshold and study the ‘summary’ over a area from multiple

pairs (over time)– Do more segments mean more breakage?– Changes in patterns of motion – indicate something

interesting?

Need• Data to perform the above tests

Questions and suggestion?

Next step

• We need to revamp our GUI design to accommodate some of our newer products and ideas

• We may do more tests on the segmentation with existing data.