[request] need different match scores for different brightness of same (nearly gray scale) image (enabled / disabled)

A button in a toolbar might be enabled or disabled. It seems, that if the button image is nearly gray scale (nearly no colored pixels), the image is found with score 1.0 in all cases (enabled/disabled button on enabled/disabled toolbar).

The testcase (available at https://files.me.com/rhocke/s4wkeh) wil run on a Mac out of the box.

This bug is based on the related question, where more information can be found.

Here the script and the results from the above mentioned testcase:

[code]
fillButtonEnabled = "fillButtonEnabled.png"
fillButtonDisabled = "fillButtonDisabled.png"

def myFind(btn, tb):
 m = toolbars[tb].find(Pattern(btn))
 m.highlight(1)
 print "Found %s on %s as %s"%(btn, tb, str(m))

toolbarEnabled = "toolbarEnabled.png"
toolbarDisabled = "toolbarDisabled.png"

dir = getBundlePath()
import os

toolbars = {}
# find both buttons on both toolbars
for tb in (toolbarEnabled, toolbarDisabled):
 os.popen('open "'+os.path.join(dir, tb)+'"') # opens the toolbar image in Preview.app
 wait(2)
 toolbars[tb] = selectRegion("select " + tb)
 for btn in (fillButtonEnabled, fillButtonDisabled):
  myFind(btn, tb)
[end code]

My results:

[log] highlight Match[114,197 32x13] score=1,00, target=center for 1.0 secs
Found fillButtonEnabled.png on toolbarEnabled.png as Match[114,197 32x13] score=1,00, target=center

[log] highlight Match[115,197 32x13] score=1,00, target=center for 1.0 secs
Found fillButtonDisabled.png on toolbarEnabled.png as Match[115,197 32x13] score=1,00, target=center

[log] highlight Match[105,223 32x13] score=1,00, target=center for 1.0 secs
Found fillButtonEnabled.png on toolbarDisabled.png as Match[105,223 32x13] score=1,00, target=center

[log] highlight Match[106,223 32x13] score=1,00, target=center for 1.0 secs
Found fillButtonDisabled.png on toolbarDisabled.png as Match[106,223 32x13] score=1,00, target=center