[PATCH v4 21/23] libtuning: lsc: rkisp1: Do not calculate ratios to green

[Stefan Klug]

The current LSC algorithm for the rkisp1 just forwards the LSC tables to
the hardware, so absolute factors are needed and not ratios compared to
green. Therefore every channel needs to be calculated independently.

Signed-off-by: Stefan Klug <stefan.klug at ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
---
 utils/tuning/libtuning/modules/lsc/rkisp1.py | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/utils/tuning/libtuning/modules/lsc/rkisp1.py b/utils/tuning/libtuning/modules/lsc/rkisp1.py
index 512233aeae9d..c02b2306b37b 100644
--- a/utils/tuning/libtuning/modules/lsc/rkisp1.py
+++ b/utils/tuning/libtuning/modules/lsc/rkisp1.py
@@ -33,13 +33,13 @@ class LSCRkISP1(LSC):
     #         table, flattened array of (blue's) green calibration table
 
     def _do_single_lsc(self, image: lt.Image):
-        cgr, gr = self._lsc_single_channel(image.channels[lt.Color.GR], image)
-        cgb, gb = self._lsc_single_channel(image.channels[lt.Color.GB], image)
-
-        # \todo Should these ratio against the average of both greens or just
-        # each green like we've done here?
-        cr, _ = self._lsc_single_channel(image.channels[lt.Color.R], image, gr)
-        cb, _ = self._lsc_single_channel(image.channels[lt.Color.B], image, gb)
+        # Perform LSC on each colour channel independently. A future enhancement
+        # worth investigating would be splitting the luminance and chrominance
+        # LSC as done by Raspberry Pi.
+        cgr, _ = self._lsc_single_channel(image.channels[lt.Color.GR], image)
+        cgb, _ = self._lsc_single_channel(image.channels[lt.Color.GB], image)
+        cr, _ = self._lsc_single_channel(image.channels[lt.Color.R], image)
+        cb, _ = self._lsc_single_channel(image.channels[lt.Color.B], image)
 
         return image.color, cr.flatten(), cb.flatten(), cgr.flatten(), cgb.flatten()
 
-- 
2.43.0