Signal identification tools (masking and noise) for spectral line data.
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Signal identification tools (masking and noise) for spectral line data.

The Noise Spec

  • noise is a object linked to a SpectralCube characterizing its 3D noise properties

  • Noise is characterized by a scalar noise estimate scale, which typifies the noise for a cube. The scalar is broadcast to all points in the image or the cube using a 2D spatial rescaling and a 1D spectral rescaling parameter so that the noise scale is

    noise[x,y,z] = scale * spatial_norm[x,y] * spectral_norm[z]

  • The distribution defaults to a normal distribution with a zero center. Use scipy.stats function handlers to test and sample from the variation.

  • Instantiates from the representations (the width of a normal distribution), or (usually) from data (generates noise width estimates).

  • Generates SNR cube when combined with SpectralCube structure.

  • Allows smoothing for the noise behavior in the case for interfometers or other systems where the noise behavior is expected to be smooth (or flat?) with spatial or spectral.

The Mask Spec

  • rich object that knows basic ppv cube functionality

  • does not explicitly contain a linked data object, but accepts them as necessary in method calls (?noise linkage is to data?)

  • basic operations (combined with other): suggested - multiplication = intersection, addition = union, subtraction = xor, divison = madness. These need to be exposed, don't have to be operators.

  • masking methodology for basic user:

    • thresholding
    • thresholding + structuring element (extends "joint thresholding")
    • velocity field + width
  • basic mask manipulation methods

    • dilation

    • erosion

    • opening

    • closing

    • reject_island_on_condition - label then evaluate each island, reject on some condition. Possible link to some property calculator but also maybe to implement as a function pass. Potentially involves some .

      (e.g., area, extent, perimeter)

  • to/from disk in sensible way

  • interface with cube:

    • to produce vectorized data
    • to allow cube to be split into a set of smaller subcubes that span all contiguous assignment