You will find many posts stressing the importance of color depth for Image Recognition. The color depth captured for your needle files must match the color depth on your target machine. When both image capture and target machines are both physical desktops, that is straightforward enough.
Things get a little more complicated if you are using mstsc.exe or similar method to access a remote or virtual (vmware) desktop.
The color depth on the remote cannot be greater than on the physical desktop viewing the remote. That color depth can change during a script run if you walk down the hall and connect to the remote from a different physical machine.
Here are some observations true at my site:
Physical Machine display set to 32 bit.
Mstsc display requested to be 32 bit.
Remote display is set to 24 bit.
Macro Scheduler images are 24 bit per Windows Explorer.
Physical Machine display reduced to 16 bit.
Mstsc display requested to be 16 bit.
Remote display is set to 16 bit.
Macro Scheduler images are 32 bit per Windows Explorer.
Physical Machine display reduced to 32 bit.
Macro Scheduler images are 32 bit per Windows Explorer.
Note from looking at the captured image attributes, you cannot tell if the display was 16 or 32 bit.
In some cases 24 bit images are recognized on 16bit playback, but not always. My theory is the 24 bit images are recognized if they contain only 16bits of information.
The obvious conclusion is to make sure all of your physical and remote machines are set to standard color depths. Don't forget that increasing the screen resolution can reduce color depth. Also use standard display effects (preferably none).
If your application displays 24bit or 32bit images and you standardized on 16bit for the reasons stated above, the display may contain dithered colors (random mixture of 2 colors to approximate an unavailable color). Increasing the color tolerance should reduce the impact of dithering and allow images to be recognized.
Please add any more observations or tips you may have on color depth.
Thanks,
Gale
