[frank]

I noticed that on the computer display the left black "square" of the template image appears somewhat blacker than the right black "square". This should be caused by that the brightness/contrast of the display is not uniformly ditributed. I also found that when the template image is dispalyed with the photoshop the image is a little bit "floating" on the grey background and the grey background is a bit distracting. So I made a new test with the following changes: (1) I display the template image with another image software with a white background and the the image fits the background without floating; (2) With the lens fixed to the camera, I rotate the camera 90 degree to the left so that the camera has a portrait orientation (does this make sense?). The new test results are shown below: