[libcamera-devel] [PATCH v2 02/11] utils: libtuning: modules: Add ALSC module

[Paul Elder]

Add an ALSC 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.

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>

---
Changes in v2:
- fix python errors
- fix style
- add SPDX and copyright
- don't call super().validateConfig()
- fix sector splitting
  - i forgot that we have to half the image size for each color channel
- make the base ALSC module into an abstract module, which can be easily
  used by other platforms to derive their own ALSC modules (see rkisp1's
  module later in this series; i think it's quite nice)
---
 .../tuning/libtuning/modules/alsc/__init__.py |  5 ++
 utils/tuning/libtuning/modules/alsc/alsc.py   | 78 +++++++++++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 utils/tuning/libtuning/modules/alsc/__init__.py
 create mode 100644 utils/tuning/libtuning/modules/alsc/alsc.py

diff --git a/utils/tuning/libtuning/modules/alsc/__init__.py b/utils/tuning/libtuning/modules/alsc/__init__.py
new file mode 100644
index 00000000..a8f28923
--- /dev/null
+++ b/utils/tuning/libtuning/modules/alsc/__init__.py
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Copyright (C) 2022, Paul Elder <paul.elder at ideasonboard.com>
+
+from libtuning.modules.alsc.alsc import ALSC
diff --git a/utils/tuning/libtuning/modules/alsc/alsc.py b/utils/tuning/libtuning/modules/alsc/alsc.py
new file mode 100644
index 00000000..b708b28d
--- /dev/null
+++ b/utils/tuning/libtuning/modules/alsc/alsc.py
@@ -0,0 +1,78 @@
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (C) 2019, Raspberry Pi Ltd
+# Copyright (C) 2022, Paul Elder <paul.elder at ideasonboard.com>
+
+from ..module import Module
+
+import libtuning as lt
+import libtuning.utils as utils
+
+import numpy as np
+
+
+class ALSC(Module):
+    type = 'alsc'
+    hr_name = 'ALSC (Base)'
+    out_name = 'GenericALSC'
+
+    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__()
+
+        if (sector_x_gradient is lt.gradient.Linear and sector_x_remainder is None):
+            raise ValueError('sector_x_remainder must be specified if sector_x_gradient is Linear')
+
+        if (sector_y_gradient is lt.gradient.Linear and sector_y_remainder is None):
+            raise ValueError('sector_y_remainder must be specified if sector_y_gradient is Linear')
+
+        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_alsc_images(self, images):
+        for image in images:
+            if image.alsc_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
-- 
2.30.2