Public Member Functions
def	__init__
def	setdata
def	setoption
def	mark
def	getresult
def	save
def	plot
Public Attributes
	israster
	marker
	st

Detailed Description

The edgemarker is a helper tool to calibrate OTF observation
without explicit OFF scans. According to a few user-specified
options, the class automatically detects an edge region of the
map and mark integrations within this region as OFF.

The edgemarker supports raster pattern as well as other generic 
ones (e.g. lissajous, double circle). The constructor takes
one boolean parameter to specify whether scan pattern is raster
or not. This is because that edge detection algorithms for raster
and others are different.

Current limitation of this class is that it cannot handle some
complicated observed area. Typical case is that the area has
clear 'dent' (e.g. a composite area consisting of two diamond-
shaped areas that slightly overlap). In such case, the class
will fail to detect such feature.

Note that the class takes a copy of input data so that input
data will not be overwritten. Result will be provided as a
separate data whose contents are essentially the same as input
except for that some integrations are marked as OFF.

Here is typical usage:

   s = scantable( 'otf.asap', average=False )
   marker = edgemarker( israster=False )
   marker.setdata( s )
   marker.setoption( fraction='15%', width=0.5 )
   marker.mark()

   # get result as scantable instance
   s2 = marker.getresult()

   # save result on disk
   marker.save( 'otfwithoff.asap', overwrite=True )

Definition at line 6 of file edgemarker.py.

Constructor & Destructor Documentation

def asap.edgemarker.edgemarker.__init__	(	self,
		israster = `False`
	)

Constructor.

israster -- Whether scan pattern is raster or not. Set True
    if scan pattern is raster. Default is False.

Definition at line 44 of file edgemarker.py.

Member Function Documentation

def asap.edgemarker.edgemarker.getresult ( self )

Get result as scantable instance. Returned scantable is
copy of input scantable except for that some data are
marked as OFF as a result of edge detection and marking.

Definition at line 129 of file edgemarker.py.

Referenced by asap.edgemarker.edgemarker.plot(), and asap.edgemarker.edgemarker.save().

def asap.edgemarker.edgemarker.mark ( self )

Process data. Edge region is detected according to detection
parameters given by setoption(). Then, integrations within
edge region will be marked as OFF.

Definition at line 120 of file edgemarker.py.

def asap.edgemarker.edgemarker.plot ( self )

Definition at line 148 of file edgemarker.py.

References asap.edgemarker.edgemarker.getresult(), and asap.edgemarker.rotate().

Referenced by task_sdgrid.sdgrid_worker.finalize().

def asap.edgemarker.edgemarker.save	(	self,
		name,
		overwrite = `False`
	)

Save result as scantable.

name -- Name of the scantable.
overwrite -- Overwrite existing data if True. Default is
     False.

Definition at line 137 of file edgemarker.py.

References asap.edgemarker.edgemarker.getresult().

def asap.edgemarker.edgemarker.setdata	(	self,
		st
	)

Set data to be processed.

st -- Data as scantable instance.

Definition at line 55 of file edgemarker.py.

References asap.edgemarker.edgemarker.st.

def asap.edgemarker.edgemarker.setoption	(	self,
		args,
		kwargs
	)

Set options for edge detection. Valid options depend on
whether scan pattern is raster or not (i.e. constructor
is called with israster=True or False).

=== for raster (israster=True) ===
fraction -- Fraction of OFF integration in each raster
    row. Either numerical value (<1.0) or string
    is accepted. For string, its value should be
    'auto' or format 'xx%'. For example, '10%'
    is same as 0.1. The 'auto' option estimates
    number of OFFs based on t_OFF = sqrt(N) t_ON.
    Default is 0.1.
npts -- Number of OFF integration in each raster row.
Default is -1 (use fraction).

Note that number of integrations specified by the above
parameters will be marked as OFF from both ends. So, twice
of specified number/fraction will be marked as OFF. For
example, if you specify fraction='10%', resultant fraction
of OFF integrations will be 20%.

Note also that, if both fraction and npts are specified,
specification by npts will come before. 

=== for non-raster (israster=False) ===
fraction -- Fraction of edge area with respect to whole
    observed area. Either numerical value (<1.0)
    or string is accepted. For string, its value
    should be in 'xx%' format. For example, '10%'
    is same as 0.1. Default is 0.1.
width -- Pixel width for edge detection. It should be given
 as a fraction of the median spatial separation
 between neighboring integrations in time. Default
 is 0.5. In the most case, default value will be fine.
 Larger value will cause worse result. Smaller value
 may improve result. However, if too small value is
 set (e.g. 1.0e-5), the algorithm may not work.
elongated -- Set True only if observed area is extremely
     elongated in one direction. Default is False.
     In most cases, default value will be fine.

Definition at line 65 of file edgemarker.py.

References asap.edgemarker.edgemarker.israster.