Detection parametersΒΆ

The detection execution parameters can be viewed/changed by accessing the params dictionaries of the DetectTrails class.

import lfd.detecttrails as detect
foo = detect.DetecTrails(run=2888, camcol=1, filter='i', field=139)

A special debug key can be set to True for any of the individual steps of the algorithm which will produce a very verbose output to stdout as well as save snapshots of the processed image in intermediate steps to a location pointed to by DEBUG_PATH environmental variable.

import lfd.detecttrails as detect
foo = detect.DetecTrails(run=2888, debug=True)

or, individually

foo.params_removestars["debug"] = True
foo.params_bright["debug"] = True
foo.params_dim["debug"] = True

The verbose output contains printed statements of acceptance tests such as average angles, difference in image positions between fitted lines etc. Additionally a number of images that help identifying the detection limiting factors are saved as well. For the bright detection step the following images are saved:

  • equBRIGHT - equalized 8bit int image with known objects masked out
  • dilateBRIGHT - equalized and dilated image
  • contoursBRIGHT - rectangles that pass the tests are drawn on the image
  • boxhoughBRIGHT - rectangles with corresponding fitted lines (set 1)
  • equhoughBRIGHT - processed image with second set of fitted lines (set 2)

while the dim detection step in debug mode produces the following set of images:

  • equDIM - equlized, 8bit img, removed objects, increased brightness
  • erodedDIM - equalized and eroded image without known objects
  • openedDIM - equalized, eroded and dilated image without known objects
  • contoursDIM - accepted rectangles
  • equhoughDIM - processed img with with the first set of fitted lines
  • boxhoughDIM - rectangles image with the second set of fitted lines

For the full list of parameters, their types and descriptions see the following tables sections. To get a better understanding of detection parameters contoursMode, contoursMethod, minAreaRectMinLen and lwTresh see fit_minAreaRect(). For nlinesInSet, thetaTresh, linesetTresh see check_theta(). For removestars params see doc remove_stars().