utils: libtuning: modules: alsc: Add raspberrypi ALSC module

Add an ALSC module for Raspberry Pi.

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

2 files changed, 247 insertions, 0 deletions

diff --git a/utils/tuning/libtuning/modules/lsc/__init__.py b/utils/tuning/libtuning/modules/lsc/__init__.py
index 47d9b846..7cdecdb8 100644
--- a/utils/tuning/libtuning/modules/lsc/__init__.py
+++ b/utils/tuning/libtuning/modules/lsc/__init__.py
@@ -3,3 +3,4 @@
 # Copyright (C) 2022, Paul Elder <paul.elder@ideasonboard.com>
 
 from libtuning.modules.lsc.lsc import LSC
+from libtuning.modules.lsc.raspberrypi import ALSCRaspberryPi
diff --git a/utils/tuning/libtuning/modules/lsc/raspberrypi.py b/utils/tuning/libtuning/modules/lsc/raspberrypi.py
new file mode 100644
index 00000000..58f5000d
--- /dev/null
+++ b/utils/tuning/libtuning/modules/lsc/raspberrypi.py
@@ -0,0 +1,246 @@
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (C) 2019, Raspberry Pi Ltd
+# Copyright (C) 2022, Paul Elder <paul.elder@ideasonboard.com>
+#
+# raspberrypi.py - ALSC module for tuning Raspberry Pi
+
+from .lsc import LSC
+
+import libtuning as lt
+import libtuning.utils as utils
+
+from numbers import Number
+import numpy as np
+
+
+class ALSCRaspberryPi(LSC):
+    # Override the type name so that the parser can match the entry in the
+    # config file.
+    type = 'alsc'
+    hr_name = 'ALSC (Raspberry Pi)'
+    out_name = 'rpi.alsc'
+    compatible = ['raspberrypi']
+
+    def __init__(self, *,
+                 do_color: lt.Param,
+                 luminance_strength: lt.Param,
+                 **kwargs):
+        super().__init__(**kwargs)
+
+        self.do_color = do_color
+        self.luminance_strength = luminance_strength
+
+        self.output_range = (0, 3.999)
+
+    def validate_config(self, config: dict) -> bool:
+        if self not in config:
+            utils.eprint(f'{self.type} not in config')
+            return False
+
+        valid = True
+
+        conf = config[self]
+
+        lum_key = self.luminance_strength.name
+        color_key = self.do_color.name
+
+        if lum_key not in conf and self.luminance_strength.required:
+            utils.eprint(f'{lum_key} is not in config')
+            valid = False
+
+        if lum_key in conf and (conf[lum_key] < 0 or conf[lum_key] > 1):
+            utils.eprint(f'Warning: {lum_key} is not in range [0, 1]; defaulting to 0.5')
+
+        if color_key not in conf and self.do_color.required:
+            utils.eprint(f'{color_key} is not in config')
+            valid = False
+
+        return valid
+
+    # @return Image color temperature, flattened array of red calibration table
+    #         (containing {sector size} elements), flattened array of blue
+    #         calibration table, flattened array of green calibration
+    #         table
+
+    def _do_single_alsc(self, image: lt.Image, do_alsc_colour: bool):
+        average_green = np.mean((image.channels[lt.Color.GR:lt.Color.GB + 1]), axis=0)
+
+        cg, g = self._lsc_single_channel(average_green, image)
+
+        if not do_alsc_colour:
+            return image.color, None, None, cg.flatten()
+
+        cr, _ = self._lsc_single_channel(image.channels[lt.Color.R], image, g)
+        cb, _ = self._lsc_single_channel(image.channels[lt.Color.B], image, g)
+
+        # \todo implement debug
+
+        return image.color, cr.flatten(), cb.flatten(), cg.flatten()
+
+    # @return Red shading table, Blue shading table, Green shading table,
+    #         number of images processed
+
+    def _do_all_alsc(self, images: list, do_alsc_colour: bool, general_conf: dict) -> (list, list, list, Number, int):
+        # List of colour temperatures
+        list_col = []
+        # Associated calibration tables
+        list_cr = []
+        list_cb = []
+        list_cg = []
+        count = 0
+        for image in self._enumerate_lsc_images(images):
+            col, cr, cb, cg = self._do_single_alsc(image, do_alsc_colour)
+            list_col.append(col)
+            list_cr.append(cr)
+            list_cb.append(cb)
+            list_cg.append(cg)
+            count += 1
+
+        # Convert to numpy array for data manipulation
+        list_col = np.array(list_col)
+        list_cr = np.array(list_cr)
+        list_cb = np.array(list_cb)
+        list_cg = np.array(list_cg)
+
+        cal_cr_list = []
+        cal_cb_list = []
+
+        # Note: Calculation of average corners and center of the shading tables
+        # has been removed (which ctt had, as it was unused)
+
+        # Average all values for luminance shading and return one table for all temperatures
+        lum_lut = list(np.round(np.mean(list_cg, axis=0), 3))
+
+        if not do_alsc_colour:
+            return None, None, lum_lut, count
+
+        for ct in sorted(set(list_col)):
+            # Average tables for the same colour temperature
+            indices = np.where(list_col == ct)
+            ct = int(ct)
+            t_r = np.round(np.mean(list_cr[indices], axis=0), 3)
+            t_b = np.round(np.mean(list_cb[indices], axis=0), 3)
+
+            cr_dict = {
+                'ct': ct,
+                'table': list(t_r)
+            }
+            cb_dict = {
+                'ct': ct,
+                'table': list(t_b)
+            }
+            cal_cr_list.append(cr_dict)
+            cal_cb_list.append(cb_dict)
+
+        return cal_cr_list, cal_cb_list, lum_lut, count
+
+    # @brief Calculate sigma from two adjacent gain tables
+    def _calcSigma(self, g1, g2):
+        g1 = np.reshape(g1, self.sector_shape[::-1])
+        g2 = np.reshape(g2, self.sector_shape[::-1])
+
+        # Apply gains to gain table
+        gg = g1 / g2
+        if np.mean(gg) < 1:
+            gg = 1 / gg
+
+        # For each internal patch, compute average difference between it and
+        # its 4 neighbours, then append to list
+        diffs = []
+        for i in range(self.sector_shape[1] - 2):
+            for j in range(self.sector_shape[0] - 2):
+                # Indexing is incremented by 1 since all patches on borders are
+                # not counted
+                diff = np.abs(gg[i + 1][j + 1] - gg[i][j + 1])
+                diff += np.abs(gg[i + 1][j + 1] - gg[i + 2][j + 1])
+                diff += np.abs(gg[i + 1][j + 1] - gg[i + 1][j])
+                diff += np.abs(gg[i + 1][j + 1] - gg[i + 1][j + 2])
+                diffs.append(diff / 4)
+
+        mean_diff = np.mean(diffs)
+        return np.round(mean_diff, 5)
+
+    # @brief Obtains sigmas for red and blue, effectively a measure of the
+    # 'error'
+    def _get_sigma(self, cal_cr_list, cal_cb_list):
+        # Provided colour alsc tables were generated for two different colour
+        # temperatures sigma is calculated by comparing two calibration temperatures
+        # adjacent in colour space
+
+        color_temps = [cal['ct'] for cal in cal_cr_list]
+
+        # Calculate sigmas for each adjacent color_temps and return worst one
+        sigma_rs = []
+        sigma_bs = []
+        for i in range(len(color_temps) - 1):
+            sigma_rs.append(self._calcSigma(cal_cr_list[i]['table'], cal_cr_list[i + 1]['table']))
+            sigma_bs.append(self._calcSigma(cal_cb_list[i]['table'], cal_cb_list[i + 1]['table']))
+
+        # Return maximum sigmas, not necessarily from the same colour
+        # temperature interval
+        sigma_r = max(sigma_rs) if sigma_rs else 0.005
+        sigma_b = max(sigma_bs) if sigma_bs else 0.005
+
+        return sigma_r, sigma_b
+
+    def process(self, config: dict, images: list, outputs: dict) -> dict:
+        output = {
+            'omega': 1.3,
+            'n_iter': 100,
+            'luminance_strength': 0.7
+        }
+
+        conf = config[self]
+        general_conf = config['general']
+
+        do_alsc_colour = self.do_color.get_value(conf)
+
+        # \todo I have no idea where this input parameter is used
+        luminance_strength = self.luminance_strength.get_value(conf)
+        if luminance_strength < 0 or luminance_strength > 1:
+            luminance_strength = 0.5
+
+        output['luminance_strength'] = luminance_strength
+
+        # \todo Validate images from greyscale camera and force grescale mode
+        # \todo Debug functionality
+
+        alsc_out = self._do_all_alsc(images, do_alsc_colour, general_conf)
+        # \todo Handle the second green lut
+        cal_cr_list, cal_cb_list, luminance_lut, count = alsc_out
+
+        if not do_alsc_colour:
+            output['luminance_lut'] = luminance_lut
+            output['n_iter'] = 0
+            return output
+
+        output['calibrations_Cr'] = cal_cr_list
+        output['calibrations_Cb'] = cal_cb_list
+        output['luminance_lut'] = luminance_lut
+
+        # The sigmas determine the strength of the adaptive algorithm, that
+        # cleans up any lens shading that has slipped through the alsc. These
+        # are determined by measuring a 'worst-case' difference between two
+        # alsc tables that are adjacent in colour space. If, however, only one
+        # colour temperature has been provided, then this difference can not be
+        # computed as only one table is available.
+        # To determine the sigmas you would have to estimate the error of an
+        # alsc table with only the image it was taken on as a check. To avoid
+        # circularity, dfault exaggerated sigmas are used, which can result in
+        # too much alsc and is therefore not advised.
+        # In general, just take another alsc picture at another colour
+        # temperature!
+
+        if count == 1:
+            output['sigma'] = 0.005
+            output['sigma_Cb'] = 0.005
+            utils.eprint('Warning: Only one alsc calibration found; standard sigmas used for adaptive algorithm.')
+            return output
+
+        # Obtain worst-case scenario residual sigmas
+        sigma_r, sigma_b = self._get_sigma(cal_cr_list, cal_cb_list)
+        output['sigma'] = np.round(sigma_r, 5)
+        output['sigma_Cb'] = np.round(sigma_b, 5)
+
+        return output