Threshold: use the slider for coarse adjustment, and the spin control for fine adjustment to control edge detection sensitivity. This value should be set so that edges and details are clearly visible and noise is smoothed out. Adjustment must be made carefully, because the gap between "noisy", "smooth", and "blur" is very small. Adjust it as carefully as you would adjust the focus of a camera.
Distancia de procura cara diante por límites: