[Issues] ConvolvedFrame, SegmentationImage and chip attribute

[Hans Vaith]

Dear all,

testing the ConvolvedFrame and the underlying convolution software, 
implemented by Johannes Koppenhöfer and Arno Riffeser, within AstroWISE, I 
ran into a problem when trying to create a SourceList from these frames. The 
problem arises from the fact that ConvolvedFrame has a chip attribute that 
will not be set, however, when a ConvolvedFrame is created by convolving a 
CoaddedRegriddedFrame, as the latter does not have a chip attribute. 

When, as part of making a SourceList, the method get_canonical_name() of class 
SegmentationImage is called, the following piece of code causes an error:

if hasattr(self.sourcelist.frame, 'chip'):
    canonical.chip_name       = self.sourcelist.frame.chip.name


In my local checkout of opipe I have added an additional check:

if hasattr(self.sourcelist.frame, 'chip'):
    if self.sourcelist.frame.chip != None:
        canonical.chip_name       = self.sourcelist.frame.chip.name

With this additional check the error does not occur.

Please let me know if this fix is acceptable, or if the problem should be 
tackled somewhere else.

Regards,
Hans