.

Author: cshanahan1

specreduce/background.py

@@ -98,16 +98,27 @@ def __post_init__(self):
             dispersion axis
         crossdisp_axis : int
             cross-dispersion axis
+        mask_treatment : string
+            The method for handling masked or non-finite data. Choice of `filter`,
+            `omit`, or `zero-fill`. If `filter` is chosen, masked/non-finite data
+            will be filtered during the fit to each bin/column (along disp. axis) to
+            find the peak. If `omit` is chosen, columns along disp_axis with any
+            masked/non-finite data values will be fully masked (i.e, 2D mask is
+            collapsed to 1D and applied). If `zero-fill` is chosen, masked/non-finite
+            data will be replaced with 0.0 in the input image, and the mask will then
+            be dropped. For all three options, the input mask (optional on input
+            NDData object) will be combined with a mask generated from any non-finite
+            values in the image data.
         """
 
         # Parse image, including masked/nonfinite data handling based on
-        # choice of `mask_treatment`. returns a Spectrum1D
+        # choice of `mask_treatment`. Any uncaught nonfinte data values will be
+        # masked as well. Returns a Spectrum1D.
         self.image = self._parse_image(self.image)
 
-        # _parse_image returns a Spectrum1D. convert this to a masked array
-        # for ease of calculations here (even if there is no masked data).
-        # Note: uncertainties are dropped, this should also be addressed at
-        # some point probably across the package.
+        # always work with masked array, even if there is no masked
+        # or nonfinite data, in case padding is needed. if not, mask will be
+        # dropped at the end and a regular array will be returned.
         img = np.ma.masked_array(self.image.data, self.image.mask)
 
         if self.width < 0:
@@ -120,6 +131,9 @@ def __post_init__(self):
 
         bkg_wimage = np.zeros_like(self.image.data, dtype=np.float64)
         for trace in self.traces:
+            # note: ArrayTrace can have masked values, but if it does a MaskedArray
+            # will be returned so this should be reflected in the window size here
+            # (i.e, np.nanmax is not required.)
             windows_max = trace.trace.data.max() + self.width/2
             windows_min = trace.trace.data.min() - self.width/2
             if windows_max >= self.image.shape[self.crossdisp_axis]:
@@ -136,6 +150,7 @@ def __post_init__(self):
                                            self.crossdisp_axis,
                                            self.image.shape)
 
+
         if np.any(bkg_wimage > 1):
             raise ValueError("background regions overlapped")
         if np.any(np.sum(bkg_wimage, axis=self.crossdisp_axis) == 0):

specreduce/core.py

@@ -139,7 +139,6 @@ def _mask_and_nonfinite_data_handling(self, image, mask):
         # nothing needs to be done. input mask (combined with nonfinite data)
         # remains with data as-is.
 
-
         if mask_treatment == 'zero-fill':
             # make a copy of the input image since we will be modifying it
             image = deepcopy(image)

specreduce/tests/test_background.py

@@ -24,13 +24,13 @@ def test_background(mk_test_img_raw, mk_test_spec_no_spectral_axis,
 
     # all the following should be equivalent, whether image's spectral axis
     # is in pixels or physical units:
-    bg1 = Background(image, [trace-bkg_sep, trace+bkg_sep], width=bkg_width)
+    bg1 = Background(image, [trace - bkg_sep, trace + bkg_sep], width=bkg_width)
     bg2 = Background.two_sided(image, trace, bkg_sep, width=bkg_width)
     bg3 = Background.two_sided(image, trace_pos, bkg_sep, width=bkg_width)
     assert np.allclose(bg1.bkg_image().flux, bg2.bkg_image().flux)
     assert np.allclose(bg1.bkg_image().flux, bg3.bkg_image().flux)
 
-    bg4 = Background(image_um, [trace-bkg_sep, trace+bkg_sep], width=bkg_width)
+    bg4 = Background(image_um, [trace - bkg_sep, trace + bkg_sep], width=bkg_width)
     bg5 = Background.two_sided(image_um, trace, bkg_sep, width=bkg_width)
     bg6 = Background.two_sided(image_um, trace_pos, bkg_sep, width=bkg_width)
     assert np.allclose(bg1.bkg_image().flux, bg4.bkg_image().flux)
@@ -74,7 +74,7 @@ def test_background(mk_test_img_raw, mk_test_spec_no_spectral_axis,
     stats = ['average', 'median']
 
     for st in stats:
-        bg = Background(img, trace-bkg_sep, width=bkg_width, statistic=st)
+        bg = Background(img, trace - bkg_sep, width=bkg_width, statistic=st)
         assert np.isnan(bg.image.flux).sum() == 2
         assert np.isnan(bg._bkg_array).sum() == 0
         assert np.isnan(bg.bkg_spectrum().flux).sum() == 0
@@ -101,7 +101,7 @@ def test_warnings_errors(mk_test_spec_no_spectral_axis):
     with pytest.warns(match="background window extends beyond image boundaries"):
         Background.two_sided(image, 7, 5, width=6)
 
-    trace = ArrayTrace(image, trace=np.arange(10)+20)  # from 20 to 29
+    trace = ArrayTrace(image, trace=np.arange(10) + 20)  # from 20 to 29
     with pytest.warns(match="background window extends beyond image boundaries"):
         with pytest.raises(ValueError,
                            match="background window does not remain in bounds across entire dispersion axis"):  # noqa
@@ -112,8 +112,8 @@ def test_warnings_errors(mk_test_spec_no_spectral_axis):
     with pytest.raises(ValueError, match="width must be positive"):
         Background.two_sided(image, 25, 2, width=-1)
 
-def test_trace_inputs(mk_test_img_raw):
 
+def test_trace_inputs(mk_test_img_raw):
     """
     Tests for the input argument 'traces' to `Background`. This should accept
     a list of or a single Trace object, or a list of or a single (positive)
@@ -143,78 +143,84 @@ def test_trace_inputs(mk_test_img_raw):
     with pytest.raises(ValueError, match=match_str):
         Background(image, 'non_valid_trace_pos')
 
+
 class TestMasksBackground():
 
     """
     Various test functions to test how masked and non-finite data is handled
-    in `Background.
+    in `Background. There are three currently implemented options for masking
+    in Background: filter, omit, and zero-fill.
     """
 
     def mk_img(self, nrows=4, ncols=5, nan_slices=None):
         """
-        Make a simpleimage to test masking in Background.
-        Optionally add NaNs to data. Returned array is in u.DN.
+        Make a simple gradient image to test masking in Background.
+        Optionally add NaNs to data with `nan_slices`. Returned array is in
+        u.DN.
         """
 
-        img = np.tile((np.arange(1., ncols+1)), (nrows, 1))
+        img = np.tile((np.arange(1., ncols + 1)), (nrows, 1))
 
         if nan_slices:  # add nans in data
             for s in nan_slices:
                 img[s] = np.nan
 
         return img * u.DN
 
-    def test_fully_masked_column(self):
+    @pytest.mark.parametrize("mask", ["filter", "omit", "zero-fill"])
+    def test_fully_masked_column(self, mask):
         """
-        Test what happens when a full column is masked, not the entire
-        image. In this case, the background value for that fully-masked
-        column should be 0.0, with no error or warning raised.
+        Test background with some fully-masked columns (not fully masked image).
+        In this case, the background value for that fully-masked column should
+        be 0.0, with no error or warning raised. This is the case for
+        mask_treatment=filter, omit, or zero-fill.
         """
 
-        img = np.ones((12, 12))
+        img = self.mk_img(nrows=10, ncols=10)
         img[:, 0:1] = np.nan
 
-        bkg = Background(img, traces=FlatTrace(img, 6))
-
+        bkg = Background(img, traces=FlatTrace(img, 6), mask_treatment=mask)
         assert np.all(bkg.bkg_image().data[:, 0:1] == 0.0)
 
-
-    def test_fully_masked(self):
+    @pytest.mark.parametrize("mask", ["filter", "omit", "zero-fill"])
+    def test_fully_masked_image(self, mask):
         """
         Test that the appropriate error is raised by `Background` when image
         is fully masked/NaN.
         """
 
         with pytest.raises(ValueError, match='Image is fully masked.'):
             # fully NaN image
-            img = np.zeros((4, 5)) * np.nan
-            Background(img, traces=FlatTrace(self.mk_img(), 2))
+            img = self.mk_img() * np.nan
+            Background(img, traces=FlatTrace(self.mk_img(), 2), mask_treatment=mask)
 
         with pytest.raises(ValueError, match='Image is fully masked.'):
-            # fully masked image (should be equivilant)
+            # fully masked image (should be equivalent)
             img = NDData(np.ones((4, 5)), mask=np.ones((4, 5)))
-            Background(img, traces=FlatTrace(self.mk_img(), 2))
+            Background(img, traces=FlatTrace(self.mk_img(), 2), mask_treatment=mask)
 
         # Now test that an image that isn't fully masked, but is fully masked
-        # within the window determined by `width`, produces the correct result
+        # within the window determined by `width`, produces the correct result.
+        # only applicable for mask_treatment=filter, because this is the only
+        # option that allows a slice of masked values that don't span all rows.
         msg = 'Image is fully masked within background window determined by `width`.'
         with pytest.raises(ValueError, match=msg):
             img = self.mk_img(nrows=12, ncols=12, nan_slices=[np.s_[3:10, :]])
             Background(img, traces=FlatTrace(img, 6), width=7)
 
     @pytest.mark.filterwarnings("ignore:background window extends beyond image boundaries")
     @pytest.mark.parametrize("method,expected",
-                            [("filter", np.array([1., 2., 3., 4., 5., 6., 7.,
+                             [("filter", np.array([1., 2., 3., 4., 5., 6., 7.,
                                                   8., 9., 10., 11., 12.])),
-                              ("omit", np.array([0.,  2.,  3.,  0.,  5.,  6., 
-                                                  7.,  0.,  9., 10., 11., 12.])),
-                              ("zero-fill", np.array([ 0.58333333, 2., 3., 
-                                                       2.33333333, 5., 6., 7.,
-                                                       7.33333333, 9., 10., 11.,
-                                                       12.]))])
+                              ("omit", np.array([0., 2., 3., 0., 5., 6.,
+                                                 7., 0., 9., 10., 11., 12.])),
+                              ("zero-fill", np.array([0.58333333, 2., 3.,
+                                                      2.33333333, 5., 6., 7.,
+                                                      7.33333333, 9., 10., 11.,
+                                                      12.]))])
     def test_mask_treatment_bkg_img_spectrum(self, method, expected):
-        """ 
-        This test function tests `Backgroud.bkg_image` and 
+        """
+        This test function tests `Backgroud.bkg_image` and
         `Background.bkg_spectrum` when there is masked data. It also tests
         background subtracting the image, and returning the spectrum of the
         background subtracted image. This test is parameterized over all
@@ -227,8 +233,8 @@ def test_mask_treatment_bkg_img_spectrum(self, method, expected):
 
         # make image, set some value to nan, which will be masked in the function
         image1 = self.mk_img(nrows=img_size, ncols=img_size,
-                            nan_slices=[np.s_[5:10, 0], np.s_[7:12, 3],
-                                        np.s_[2, 7]])
+                             nan_slices=[np.s_[5:10, 0], np.s_[7:12, 3],
+                                         np.s_[2, 7]])
 
         # also make an image that doesn't have nonf data values, but has
         # masked values at the same locations, to make sure they give the same
@@ -240,13 +246,13 @@ def test_mask_treatment_bkg_img_spectrum(self, method, expected):
         for image in [image1, image2]:
 
             # construct a flat trace in center of image
-            trace = FlatTrace(image, img_size/2)
+            trace = FlatTrace(image, img_size / 2)
 
             # create 'Background' object with `mask_treatment` set
             # 'width' should be > size of image to use all pix (but warning will
             # be raised, which we ignore.)
             background = Background(image, mask_treatment=method,
-                                    traces=trace, width=img_size+1)
+                                    traces=trace, width=img_size + 1)
 
             # test background image matches 'expected'
             bk_img = background.bkg_image()
@@ -265,7 +271,7 @@ def test_sub_bkg_image(self):
         """
         Test that masked and nonfinite data is handled correctly when subtracting
         background from image, for all currently implemented masking
-        options ('filter', 'omit', and 'zero-fill'). 
+        options ('filter', 'omit', and 'zero-fill').
         """
 
         # make image, set some value to nan, which will be masked in the function
@@ -288,7 +294,7 @@ def test_sub_bkg_image(self):
         # 2d mask is reduced to a 1d mask to mask out full columns in the
         # presence of any nans - this means that (as tested above in
         # `test_mask_treatment_bkg_img_spectrum`) those columns will have 0.0
-        # background. In this case, image.mask is expanded to mask full 
+        # background. In this case, image.mask is expanded to mask full
         # columns - the image itself will not have full columns set to np.nan,
         # so there are still valid background subtracted data values in this
         # case, but the corresponding mask for that entire column will be masked.
@@ -314,4 +320,3 @@ def test_sub_bkg_image(self):
 
         assert np.all(np.isfinite(subtracted_img_zero_fill.data))
         assert np.all(subtracted_img_zero_fill.mask == 0)
-

specreduce/tests/test_extract.py

@@ -81,6 +81,7 @@ def test_boxcar_extraction(mk_test_img):
     assert np.allclose(spectrum.flux.value, np.full_like(spectrum.flux.value, 67.15))
 
 
+
 def test_boxcar_outside_image_condition(mk_test_img):
     #
     # Trace is such that extraction aperture lays partially outside the image
@@ -326,3 +327,62 @@ def test_horne_interpolated_nbins_fails(mk_test_img):
                           spatial_profile={'name': 'interpolated_profile',
                                            'n_bins_interpolated_profile': 100})
         ex.spectrum
+
+class TestMasksExtract():
+
+    def mk_flat_gauss_img(nrows=200, ncols=160, nan_slices=None, add_noise=True):
+
+        """
+        Makes a flat gaussian image for testing, with optional added gaussian
+        nosie and optional data values set to NaN. Variance is included, which
+        is required by HorneExtract. Returns a Spectrum1D with flux, spectral
+        axis, and uncertainty.
+        """
+
+        sigma_pix = 4
+        col_model = models.Gaussian1D(amplitude=1, mean=nrows/2,
+                                      stddev=sigma_pix)
+        spec2dvar = np.ones((nrows, ncols))
+        noise = 0
+        if add_noise:
+            np.random.seed(7)
+            sigma_noise = 1
+            noise = np.random.normal(scale=sigma_noise, size=(nrows, ncols))
+
+        index_arr = np.tile(np.arange(nrows), (ncols, 1))
+        img = col_model(index_arr.T) + noise
+
+        if nan_slices:  # add nans in data
+            for s in nan_slices:
+                img[s] = np.nan
+
+        wave = np.arange(0, img.shape[1], 1)
+        objectspec = Spectrum1D(spectral_axis=wave*u.m, flux=img*u.Jy,
+            uncertainty=VarianceUncertainty(spec2dvar*u.Jy*u.Jy))
+
+        return objectspec
+
+    def test_boxcar_fully_masked():
+        """
+        Test that the appropriate error is raised by `BoxcarExtract` when image
+        is fully masked/NaN.
+        """
+
+        img = mk_img()
+
+        with pytest.raises(ValueError, match='Image is fully masked.'):
+            # fully NaN image
+            img = np.zeros((4, 5)) * np.nan
+            Background(img, traces=FlatTrace(self.mk_img(), 2))
+
+        with pytest.raises(ValueError, match='Image is fully masked.'):
+            # fully masked image (should be equivalent)
+            img = NDData(np.ones((4, 5)), mask=np.ones((4, 5)))
+            Background(img, traces=FlatTrace(self.mk_img(), 2))
+
+        # Now test that an image that isn't fully masked, but is fully masked
+        # within the window determined by `width`, produces the correct result
+        msg = 'Image is fully masked within background window determined by `width`.'
+        with pytest.raises(ValueError, match=msg):
+            img = self.mk_img(nrows=12, ncols=12, nan_slices=[np.s_[3:10, :]])
+            Background(img, traces=FlatTrace(img, 6), width=7)