utils: libtuning: modules: Add base LSC module

Add a base LSC module to libtuning's collection of modules. It is based
on raspberrypi's ctt's ALSC, but customizable for different lens shading
table sizes, among other things. It alone is insufficient as a module,
but it provides utilities that are useful for and which will simplify
implementing LSC modules.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

utils/tuning/libtuning/modules/lsc/__init__.py

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Copyright (C) 2022, Paul Elder <paul.elder@ideasonboard.com>
+
+from libtuning.modules.lsc.lsc import LSC

utils/tuning/libtuning/modules/lsc/lsc.py

@@ -0,0 +1,72 @@
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (C) 2019, Raspberry Pi Ltd
+# Copyright (C) 2022, Paul Elder <paul.elder@ideasonboard.com>
+
+from ..module import Module
+
+import libtuning as lt
+import libtuning.utils as utils
+
+import numpy as np
+
+
+class LSC(Module):
+    type = 'lsc'
+    hr_name = 'LSC (Base)'
+    out_name = 'GenericLSC'
+
+    def __init__(self, *,
+                 debug: list,
+                 sector_shape: tuple,
+                 sector_x_gradient: lt.Gradient,
+                 sector_y_gradient: lt.Gradient,
+                 sector_average_function: lt.Average,
+                 smoothing_function: lt.Smoothing):
+        super().__init__()
+
+        self.debug = debug
+
+        self.sector_shape = sector_shape
+        self.sector_x_gradient = sector_x_gradient
+        self.sector_y_gradient = sector_y_gradient
+        self.sector_average_function = sector_average_function
+
+        self.smoothing_function = smoothing_function
+
+    def _enumerate_lsc_images(self, images):
+        for image in images:
+            if image.lsc_only:
+                yield image
+
+    def _get_grid(self, channel, img_w, img_h):
+        # List of number of pixels in each sector
+        sectors_x = self.sector_x_gradient.distribute(img_w / 2, self.sector_shape[0])
+        sectors_y = self.sector_y_gradient.distribute(img_h / 2, self.sector_shape[1])
+
+        grid = []
+
+        r = 0
+        for y in sectors_y:
+            c = 0
+            for x in sectors_x:
+                grid.append(self.sector_average_function.average(channel[r:r + y, c:c + x]))
+                c += x
+            r += y
+
+        return np.array(grid)
+
+    def _lsc_single_channel(self, channel: np.array,
+                            image: lt.Image, green_grid: np.array = None):
+        grid = self._get_grid(channel, image.w, image.h)
+        grid -= image.blacklevel_16
+        if green_grid is None:
+            table = np.reshape(1 / grid, self.sector_shape[::-1])
+        else:
+            table = np.reshape(green_grid / grid, self.sector_shape[::-1])
+        table = self.smoothing_function.smoothing(table)
+
+        if green_grid is None:
+            table = table / np.min(table)
+
+        return table, grid