Some settings affect how the automatic matching is performed. These are set in the Settings tab of the settings dialog.
Figure 11.2: Settings automatic parameters
Window size. The window size defines how large the correlation window will be in the matching.
Height interval. Defines how much the height is increased/decreased per tic mark in the Z slider
Use gradient images. If checked, then matching will be done on images of gradient magnitudes. If the two images are taken under different circumstances (weather conditions, sun angles or time interval), then homogeneous areas may have quite different brightness in the two images. The gradient information is more stable in this respect. On the other hand, reducing the information to match to only gradient magnitudes, information which could be valuable for correct matching may be lost.
Median filter images. If checked, the images will be median filtered with a neighborhood of 3x3 pixels before matching. This may result in better matching if the images are noisy, particularily with "salt-and-pepper" noise.
Image memory pool limit. Set the size of the global primary memory pool for images. A larger size will allow smoother panning and faster processing, but requires more physical memory. Default is 128 Mb, minimum is 32 Mb and maximum is 4096 Mb.