Filter bad

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Filter bad

Filter bad

Filter bad command removes tie point pixels that do not match other tie points. It runs an iterative process where it first adjusts image rotation angles using the tie points. Then, it removes the tie point pixel with the largest mismatch distance if this pixel exceeds the given limit.

It is recommended to use this command always after the automatic placement of tie points, either by importing feature points or by searching tie points. Some of the automatically placed points are likely to be bad matches and most of them can be removed automatically with this command.

To filter out bad points:

1. Select Filter bad command from the Pixel pulldown menu.

This opens Filter bad pixels dialog:

filter_bad_pixels

2. Define a limit for removing bad pixels and click OK.

This starts the filtering process. An information dialog shows the amount of deleted tie points and pixels after finishing the process.

SETTING

EFFECT

Filter ratio

A tie point pixel is removed if it has a mismatch distance larger than the given Filter ratio. The ratio is expressed as factor of the average mismatch distance.

Keep all manual pixels

If on, manually placed tie point pixels are not effected by the filtering process.