What kind of camera are you acquiring your images with? The image format could be automatically converted to the format generated by the camera. You could check the image format just before it goes into the Learn Pattern to verify it is the same format that you originally selected.
If the image format is getting changed, you need to change it back to an image format the Learn Pattern will accept. You can use Cast Image or Extract Color Plane to get a valid image.
Bruce
Bruce Ammons
Ammons Engineering
