Chameleon: Increase the margins for VGA screen check
The VGA signal is analog. The color is degraded. It also has some
anti-alias effect. The exact-match check is not feasible. So increase
the margins to accept some kind of differences.
BUG=chromium:429931
TEST=Tested on Peppy by running Chameleon tests. Tests passed.
TEST=Tested on Parrot by running Chameleon tests. Tests passed.
Change-Id: Ia35bbecdedb873d89f9d51af2204cb7810b86c28
Reviewed-on: https://chromium-review.googlesource.com/229667
Tested-by: Wai-Hong Tam <waihong@chromium.org>
Reviewed-by: Hung-ying Tyan <tyanh@chromium.org>
Commit-Queue: Wai-Hong Tam <waihong@chromium.org>
diff --git a/server/cros/chameleon/chameleon_test.py b/server/cros/chameleon/chameleon_test.py
index 48227bc..8a2a8e0 100644
--- a/server/cros/chameleon/chameleon_test.py
+++ b/server/cros/chameleon/chameleon_test.py
@@ -28,9 +28,12 @@
_TIMEOUT_VIDEO_STABLE_PROBE = 10
- _PIXEL_DIFF_VALUE_MARGIN_FOR_ANALOG_SIGNAL = 5
+ _PIXEL_DIFF_VALUE_MARGIN_FOR_ANALOG_SIGNAL = 30
_PIXEL_DIFF_VALUE_MARGIN_FOR_DIGITAL_SIGNAL = 1
+ _TOTAL_WRONG_PIXELS_MARGIN_FOR_ANALOG_SIGNAL = 0.04 # 4%
+ _TOTAL_WRONG_PIXELS_MARGIN_FOR_DIGITAL_SIGNAL = 0
+
_FLAKY_CALL_RETRY_TIME_OUT_SEC = 20
_FLAKY_CALL_RETRY_DELAY_SEC = 1
@@ -427,9 +430,10 @@
if a pixel difference exceeds this margin, will treat as a wrong
pixel. Sets None means using default value by detecting
connector type.
- @param total_wrong_pixels_margin: The margin for the number of wrong
- pixels. If the total number of wrong pixels exceeds this margin,
- the check fails.
+ @param total_wrong_pixels_margin: The percentage of margin for wrong
+ pixels. The value is in a closed interval [0.0, 1.0]. If the
+ total number of wrong pixels exceeds this margin, the check
+ fails.
@return: None if the check passes; otherwise, a string of error message.
"""
@@ -441,6 +445,10 @@
logging.error(message)
return message
+ assert 0.0 <= total_wrong_pixels_margin <= 1.0
+ size = image_a.size[0] * image_a.size[1]
+ max_acceptable_wrong_pixels = int(total_wrong_pixels_margin * size)
+
diff_image = ImageChops.difference(image_a, image_b)
histogram = diff_image.convert('L').histogram()
@@ -451,12 +459,12 @@
logging.debug('Histogram of difference: %r', histogram)
message = ('Result of %s: total %d wrong pixels (diff up to %d)'
% (tag, total_wrong_pixels, max_diff_value))
- if total_wrong_pixels > total_wrong_pixels_margin:
+ if total_wrong_pixels > max_acceptable_wrong_pixels:
logging.error(message)
return message
message += (', within the acceptable range %d' %
- total_wrong_pixels_margin)
+ max_acceptable_wrong_pixels)
logging.warning(message)
else:
logging.info('Result of %s: all pixels match (within +/- %d)',
@@ -466,7 +474,7 @@
def check_screen_with_chameleon(
self, tag, pixel_diff_value_margin=None,
- total_wrong_pixels_margin=0, verify_mirrored=True):
+ total_wrong_pixels_margin=None, verify_mirrored=True):
"""Checks the DUT external screen with Chameleon.
1. Capture the whole screen from the display buffer of Chameleon.
@@ -478,23 +486,34 @@
if a pixel difference exceeds this margin, will treat as a wrong
pixel. Sets None means using default value by detecting
connector type.
- @param total_wrong_pixels_margin: The margin for the number of wrong
- pixels. If the total number of wrong pixels exceeds this margin,
- the check fails.
+ @param total_wrong_pixels_margin: The percentage of margin for wrong
+ pixels. The value is in a closed interval [0.0, 1.0]. If the
+ total number of wrong pixels exceeds this margin, the check
+ fails.
@param verify_mirrored: True if compare the internal screen and
the external screen when the resolution matches.
@return: None if the check passes; otherwise, a string of error message.
"""
+ # Tolerate pixel errors differently for VGA.
+ is_vga = self.display_facade.get_external_connector_name().startswith(
+ 'VGA')
if pixel_diff_value_margin is None:
- # Tolerate pixel errors differently for VGA.
- if self.display_facade.get_external_connector_name() == 'VGA':
+ if is_vga:
pixel_diff_value_margin = (
self._PIXEL_DIFF_VALUE_MARGIN_FOR_ANALOG_SIGNAL)
else:
pixel_diff_value_margin = (
self._PIXEL_DIFF_VALUE_MARGIN_FOR_DIGITAL_SIGNAL)
+ if total_wrong_pixels_margin is None:
+ if is_vga:
+ total_wrong_pixels_margin = (
+ self._TOTAL_WRONG_PIXELS_MARGIN_FOR_ANALOG_SIGNAL)
+ else:
+ total_wrong_pixels_margin = (
+ self._TOTAL_WRONG_PIXELS_MARGIN_FOR_DIGITAL_SIGNAL)
+
chameleon_image = self.chameleon_capturer.capture()
dut_image_external = self.external_capturer.capture()
@@ -559,7 +578,7 @@
def load_test_image_and_check(self, tag, expected_resolution,
- pixel_diff_value_margin=None, total_wrong_pixels_margin=0,
+ pixel_diff_value_margin=None, total_wrong_pixels_margin=None,
under_mirrored_mode=True, error_list = None):
"""Loads the test image and checks the image on Chameleon.
@@ -573,9 +592,10 @@
if a pixel difference exceeds this margin, will treat as a wrong
pixel. Sets None means using default value by detecting
connector type.
- @param total_wrong_pixels_margin: The margin for the number of wrong
- pixels. If the total number of wrong pixels exceeds this margin,
- the check fails.
+ @param total_wrong_pixels_margin: The percentage of margin for wrong
+ pixels. The value is in a closed interval [0.0, 1.0]. If the
+ total number of wrong pixels exceeds this margin, the check
+ fails.
@param under_mirrored_mode: True if don't make fails error on check the
resolution between dut and expected. It will also compare the
internal screen and the external screen.
