[PATCH 6/6] utils: raspberrypi: ctt: Add a maximum gain parameter for LSC
David Plowman
david.plowman at raspberrypi.com
Thu Jun 6 12:15:12 CEST 2024
A max_gain parameter is added to the config file which we pass to the
lens shading calibration. This clamps the maximum luminance gain that
gets written into the tuning files so as to prevent overflows.
It is particularly useful for lenses that cut off the light completely
from the sensor corners, and allows usable tables to be generated for
them.
Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
---
utils/raspberrypi/ctt/ctt.py | 8 +++++---
utils/raspberrypi/ctt/ctt_alsc.py | 12 ++++++++----
utils/raspberrypi/ctt/ctt_config_example.json | 5 +++--
3 files changed, 16 insertions(+), 9 deletions(-)
diff --git a/utils/raspberrypi/ctt/ctt.py b/utils/raspberrypi/ctt/ctt.py
index 522933bd..96f1b5e6 100755
--- a/utils/raspberrypi/ctt/ctt.py
+++ b/utils/raspberrypi/ctt/ctt.py
@@ -269,7 +269,7 @@ class Camera:
colour channel seperately, and then partially corrects for vignetting.
The extent of the correction depends on the 'luminance_strength' parameter.
"""
- def alsc_cal(self, luminance_strength, do_alsc_colour, grid_size):
+ def alsc_cal(self, luminance_strength, do_alsc_colour, grid_size, max_gain=8.0):
if 'rpi.alsc' in self.disable:
return 1
print('\nStarting ALSC calibration')
@@ -292,7 +292,7 @@ class Camera:
call calibration function
"""
plot = "rpi.alsc" in self.plot
- alsc_out = alsc_all(self, do_alsc_colour, plot, grid_size)
+ alsc_out = alsc_all(self, do_alsc_colour, plot, grid_size, max_gain=max_gain)
cal_cr_list, cal_cb_list, luminance_lut, av_corn = alsc_out
"""
write output to json and finish if not do_alsc_colour
@@ -705,11 +705,13 @@ def run_ctt(json_output, directory, config, log_output, json_template, grid_size
alsc_d = get_config(configs, "alsc", {}, 'dict')
do_alsc_colour = get_config(alsc_d, "do_alsc_colour", 1, 'bool')
luminance_strength = get_config(alsc_d, "luminance_strength", 0.8, 'num')
+ lsc_max_gain = get_config(alsc_d, "max_gain", 8.0, 'num')
blacklevel = get_config(configs, "blacklevel", -1, 'num')
macbeth_d = get_config(configs, "macbeth", {}, 'dict')
mac_small = get_config(macbeth_d, "small", 0, 'bool')
mac_show = get_config(macbeth_d, "show", 0, 'bool')
mac_config = (mac_small, mac_show)
+ print("Read lsc_max_gain", lsc_max_gain)
if blacklevel < -1 or blacklevel >= 2**16:
print('\nInvalid blacklevel, defaulted to 64')
@@ -750,7 +752,7 @@ def run_ctt(json_output, directory, config, log_output, json_template, grid_size
Cam.json['rpi.black_level']['black_level'] = Cam.blacklevel_16
Cam.json_remove(disable)
print('\nSTARTING CALIBRATIONS')
- Cam.alsc_cal(luminance_strength, do_alsc_colour, grid_size)
+ Cam.alsc_cal(luminance_strength, do_alsc_colour, grid_size, max_gain=lsc_max_gain)
Cam.geq_cal()
Cam.lux_cal()
Cam.noise_cal()
diff --git a/utils/raspberrypi/ctt/ctt_alsc.py b/utils/raspberrypi/ctt/ctt_alsc.py
index 66ce8c14..1d94dfa5 100644
--- a/utils/raspberrypi/ctt/ctt_alsc.py
+++ b/utils/raspberrypi/ctt/ctt_alsc.py
@@ -13,7 +13,7 @@ from mpl_toolkits.mplot3d import Axes3D
"""
preform alsc calibration on a set of images
"""
-def alsc_all(Cam, do_alsc_colour, plot, grid_size=(16, 12)):
+def alsc_all(Cam, do_alsc_colour, plot, grid_size=(16, 12), max_gain=8.0):
imgs_alsc = Cam.imgs_alsc
grid_w, grid_h = grid_size
"""
@@ -24,7 +24,7 @@ def alsc_all(Cam, do_alsc_colour, plot, grid_size=(16, 12)):
list_cb = []
list_cg = []
for Img in imgs_alsc:
- col, cr, cb, cg, size = alsc(Cam, Img, do_alsc_colour, plot, grid_size=grid_size)
+ col, cr, cb, cg, size = alsc(Cam, Img, do_alsc_colour, plot, grid_size=grid_size, max_gain=max_gain)
list_col.append(col)
list_cr.append(cr)
list_cb.append(cb)
@@ -118,7 +118,7 @@ def alsc_all(Cam, do_alsc_colour, plot, grid_size=(16, 12)):
"""
calculate g/r and g/b for 32x32 points arranged in a grid for a single image
"""
-def alsc(Cam, Img, do_alsc_colour, plot=False, grid_size=(16, 12)):
+def alsc(Cam, Img, do_alsc_colour, plot=False, grid_size=(16, 12), max_gain=8.0):
Cam.log += '\nProcessing image: ' + Img.name
grid_w, grid_h = grid_size
"""
@@ -153,9 +153,12 @@ def alsc(Cam, Img, do_alsc_colour, plot=False, grid_size=(16, 12)):
median blur to remove peaks and save as float 64
"""
cr = cv2.medianBlur(cr, 3).astype('float64')
+ cr = cr/np.min(cr) # gain tables are easier for humans to read if the minimum is 1.0
cb = cv2.medianBlur(cb, 3).astype('float64')
+ cb = cb/np.min(cb)
cg = cv2.medianBlur(cg, 3).astype('float64')
cg = cg/np.min(cg)
+ cg = [min(v, max_gain) for v in cg.flatten()] # never exceed the max luminance gain
"""
debugging code showing 2D surface plot of vignetting. Quite useful for
@@ -179,7 +182,7 @@ def alsc(Cam, Img, do_alsc_colour, plot=False, grid_size=(16, 12)):
# print(Img.str)
plt.show()
- return Img.col, cr.flatten(), cb.flatten(), cg.flatten(), (w, h, dx, dy)
+ return Img.col, cr.flatten(), cb.flatten(), cg, (w, h, dx, dy)
else:
"""
@@ -189,6 +192,7 @@ def alsc(Cam, Img, do_alsc_colour, plot=False, grid_size=(16, 12)):
cg = np.reshape(1/g, (grid_h, grid_w)).astype('float32')
cg = cv2.medianBlur(cg, 3).astype('float64')
cg = cg/np.min(cg)
+ cg = [min(v, max_gain) for v in cg.flatten()] # never exceed the max luminance gain
if plot:
hf = plt.figure(figssize=(8, 8))
diff --git a/utils/raspberrypi/ctt/ctt_config_example.json b/utils/raspberrypi/ctt/ctt_config_example.json
index c7f90761..1105862c 100644
--- a/utils/raspberrypi/ctt/ctt_config_example.json
+++ b/utils/raspberrypi/ctt/ctt_config_example.json
@@ -3,7 +3,8 @@
"plot": [],
"alsc": {
"do_alsc_colour": 1,
- "luminance_strength": 0.5
+ "luminance_strength": 0.8,
+ "max_gain": 8.0
},
"awb": {
"greyworld": 0
@@ -13,4 +14,4 @@
"small": 0,
"show": 0
}
-}
\ No newline at end of file
+}
--
2.39.2
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