Stash current work.

colour_hdri/examples/examples_adobe_dng_sdk_colour_processing.ipynb

@@ -81,12 +81,12 @@
     "from colour_hdri import (\n",
     "    ROOT_RESOURCES_EXAMPLES,\n",
     "    camera_neutral_to_xy,\n",
-    "    camera_space_to_XYZ_matrix,\n",
     "    convert_dng_files_to_intermediate_files,\n",
     "    convert_raw_files_to_dng_files,\n",
     "    filter_files,\n",
     "    read_dng_files_exif_tags,\n",
     "    highlights_recovery_LCHab,\n",
+    "    matrix_camera_space_to_XYZ,\n",
     "    update_exif_tags,\n",
     ")\n",
     "from colour_hdri.models import (\n",
@@ -193,7 +193,7 @@
     "        analog_balance,\n",
     "    )\n",
     "\n",
-    "    M_camera_space_to_XYZ = camera_space_to_XYZ_matrix(\n",
+    "    M_camera_space_to_XYZ = matrix_camera_space_to_XYZ(\n",
     "        xy,\n",
     "        CCT_calibration_illuminant_1,\n",
     "        CCT_calibration_illuminant_2,\n",
@@ -215,7 +215,7 @@
     "    read_dng_files_exif_tags((DNG_FILES[0],))[0]\n",
     ")\n",
     "\n",
-    "# In order to avoid artefacts, white balancing should be peformed before\n",
+    "# In order to avoid artefacts, white balancing should be performed before\n",
     "# demosaicing thus we need to pass appropriate gains to *dcraw*.\n",
     "WHITE_BALANCE_MULTIPLIERS = colour.algebra.vector_dot(M_CAMERA_SPACE_TO_XYZ, np.ones(3))\n",
     "\n",

colour_hdri/examples/examples_merge_from_ldr_files.ipynb

@@ -73,7 +73,6 @@
     "    camera_response_functions_Debevec1997,\n",
     "    filter_files,\n",
     "    image_stack_to_HDRI,\n",
-    "    weighting_function_Debevec1997,\n",
     ")\n",
     "from colour_hdri.plotting import plot_HDRI_strip\n",
     "\n",

colour_hdri/generation/hdri.py

@@ -23,6 +23,7 @@
 from __future__ import annotations
 
 import numpy as np
+from colour.constants import EPSILON
 from colour.hints import ArrayLike, Callable, NDArrayFloat
 from colour.utilities import as_float_array, tsplit, tstack, warning
 
@@ -53,7 +54,7 @@ def image_stack_to_HDRI(
     Parameters
     ----------
     image_stack
-        Stack of single channel or multi-channel floating point images. The
+        Stack of single channel or multichannel floating point images. The
         stack is assumed to be representing linear values except if
         ``camera_response_functions`` argument is provided.
     weighting_function
@@ -71,8 +72,13 @@ def image_stack_to_HDRI(
     --------
     If the image stack contains images with negative or equal to zero values,
     unpredictable results may occur and NaNs might be generated. It is
-    thus recommended encoding the images in a wider RGB colourspace or clamp
-    negative values.
+    thus recommended encoding the images in a wider RGB colourspace. This
+    definition avoids NaNs creation by ensuring that all values are greater or
+    equal to current floating point format epsilon. In practical applications
+    such as HDRI merging with photographic material there should never be a
+    pixel with a value exactly equal to zero. Ideally, the process should not
+    be presented by any negative photometric quantity  even though RGB
+    colourspace encodings allows to do so.
 
     References
     ----------
@@ -98,14 +104,16 @@ def image_stack_to_HDRI(
                     f'"{image.path}" image channels contain negative or equal '
                     f"to zero values, unpredictable results may occur! Please "
                     f"consider encoding your images in a wider gamut RGB "
-                    f"colourspace or clamp negative values."
+                    f"colourspace."
                 )
 
-            image_data = np.clip(image.data, 0, 1)
+            image_data = np.clip(image.data, EPSILON, 1)
+
+            weights = np.clip(weighting_function(image_data), EPSILON, 1)
 
-            weights = weighting_function(image_data)
             if i == 0:
                 weights[image_data >= 0.5] = 1
+
             if i == len(image_stack) - 1:
                 weights[image_data <= 0.5] = 1