Ensure that spectral distribution not starting or ending on a tenth w…

…avelength and having an interval of 10 or 20 can be integrated using practise "ASTM E308-15".
colour-science · Jun 29, 2023 · 1dbda61 · 1dbda61
1 parent b7ec8aa
commit 1dbda61
Show file tree

Hide file tree

Showing 3 changed files with 53 additions and 5 deletions.
diff --git a/colour/colorimetry/spectrum.py b/colour/colorimetry/spectrum.py
@@ -1590,6 +1590,11 @@ def trim(self, shape: SpectralShape) -> Self:
         self.wavelengths = wavelengths
         self.values = values
 
+        if self.shape.boundaries != shape.boundaries:
+            runtime_warning(
+                f'"{shape}" shape could not be honoured, using "{self.shape}"!'
+            )
+
         return self
 
     def normalise(self, factor: Real = 1) -> Self:

diff --git a/colour/colorimetry/tests/test_tristimulus_values.py b/colour/colorimetry/tests/test_tristimulus_values.py
@@ -1205,6 +1205,17 @@ def test_sd_to_XYZ_ASTME308_mi_10nm(self):
             decimal=7,
         )
 
+        np.testing.assert_array_almost_equal(
+            sd_to_XYZ_ASTME308(
+                reshape_sd(self._sd, SpectralShape(401, 701, 10)),
+                self._cmfs,
+                self._A,
+                k=1,
+            ),
+            np.array([15.6713226093, 11.7392254489, 2.2117708792]),
+            decimal=7,
+        )
+
     def test_sd_to_XYZ_ASTME308_mi_20nm(self):
         """
         Test :func:`colour.colorimetry.tristimulus_values.sd_to_XYZ_ASTME308`
@@ -1310,6 +1321,16 @@ def test_sd_to_XYZ_ASTME308_mi_20nm(self):
             decimal=7,
         )
 
+        np.testing.assert_array_almost_equal(
+            sd_to_XYZ_ASTME308(
+                reshape_sd(self._sd, SpectralShape(401, 701, 20)),
+                self._cmfs,
+                self._A,
+            ),
+            np.array([14.5220164311, 10.8790959535, 2.0490905325]),
+            decimal=7,
+        )
+
     def test_raise_exception_sd_to_XYZ_ASTME308(self):
         """
         Test :func:`colour.colorimetry.tristimulus_values.sd_to_XYZ_ASTME308`

diff --git a/colour/colorimetry/tristimulus_values.py b/colour/colorimetry/tristimulus_values.py
@@ -859,7 +859,7 @@ def sd_to_XYZ_tristimulus_weighting_factors_ASTME308(
 
     if sd.shape.boundaries != cmfs.shape.boundaries:
         runtime_warning(
-            f'Trimming "{illuminant.name}" spectral distribution shape to '
+            f'Trimming "{sd.name}" spectral distribution boundaries using '
             f'"{cmfs.name}" colour matching functions shape.'
         )
         sd = reshape_sd(sd, cmfs.shape, "Trim", copy=False)
@@ -875,6 +875,7 @@ def sd_to_XYZ_tristimulus_weighting_factors_ASTME308(
     W = adjust_tristimulus_weighting_factors_ASTME308(
         W, SpectralShape(start_w, end_w, sd.shape.interval), sd.shape
     )
+
     R = sd.values
 
     XYZ = np.sum(W * R[..., None], axis=0)
@@ -1010,6 +1011,18 @@ def sd_to_XYZ_ASTME308(
             "with measurement interval of 1, 5, 10 or 20nm!"
         )
 
+    if sd.shape.interval in (10, 20) and (
+        sd.shape.start % 10 != 0 or sd.shape.end % 10 != 0
+    ):
+        runtime_warning(
+            f'"{sd.name}" spectral distribution shape does not start at a '
+            f'tenth and will be aligned to "{cmfs.name}" colour matching '
+            'functions shape! Note that practise "ASTM E308-15" does not '
+            "define a behaviour in this case."
+        )
+
+        sd = reshape_sd(sd, cmfs.shape, copy=False)
+
     if use_practice_range:
         # pylint: disable=E1102
         cmfs = reshape_msds(cmfs, SPECTRAL_SHAPE_ASTME308, "Trim", copy=False)
@@ -1031,13 +1044,17 @@ def sd_to_XYZ_ASTME308(
         sd = sd.copy()
         if sd.shape.boundaries != cmfs.shape.boundaries:
             runtime_warning(
-                f'Trimming "{illuminant.name}" spectral distribution shape to '
+                f'Trimming "{sd.name}" spectral distribution shape to '
                 f'"{cmfs.name}" colour matching functions shape.'
             )
-            sd.trim(cmfs.shape)
+            sd = reshape_sd(sd, cmfs.shape, "Trim", copy=False)
 
         # Extrapolation of additional 20nm padding intervals.
-        sd.align(SpectralShape(sd.shape.start - 20, sd.shape.end + 20, 10))
+        sd = reshape_sd(
+            sd,
+            SpectralShape(sd.shape.start - 20, sd.shape.end + 20, 10),
+            copy=False,
+        )
         for i in range(2):
             sd[sd.wavelengths[i]] = (
                 3 * sd.values[i + 2] - 3 * sd.values[i + 4] + sd.values[i + 6]
@@ -1060,7 +1077,12 @@ def sd_to_XYZ_ASTME308(
             )
 
         # Discarding the additional 20nm padding intervals.
-        sd.trim(SpectralShape(sd.shape.start + 20, sd.shape.end - 20, 10))
+        sd = reshape_sd(
+            sd,
+            SpectralShape(sd.shape.start + 20, sd.shape.end - 20, 10),
+            "Trim",
+            copy=False,
+        )
 
     XYZ = method(sd, cmfs, illuminant, k=k)