Computing cutlines

You can compute cutlines by using any of the following methods:

Minimum squared difference: Suitable for most mosaicking projects and, in most cases, produces the cleanest cutlines. A cutline is determined in each overlapped area between two adjacent images with minimum-squared differences of gray values at the same locations of the region in all image channels.
Minimum difference: Suitable for most mosaicking projects. A cutline is determined in each overlapped area between two adjacent images, with minimum differences of gray values at the same locations of the region.
Minimum relative difference: Similar to Minimum Difference, but provides better output when similar sections of data appear dissimilar among various images.
Edge: Well suited for use with intense-urban-area imagery or imagery containing many linear features.
The benefit of using Edge is that it tends to avoid placing cutlines across linear features.
Maximum data: Places the cutlines on the boundary of the real-image pixels, meaning that No Data pixels are ignored when determining the image boundary.
Import: Use polygons in a vector file you specify.
The cutlines are computed exactly as per the vector file.
File extents: Computes the cutlines as the extents of the input imagery.
NoData pixels are included in computing the cutlines.

Note: At this time, computation of cutlines applies to all source images. If you want to create or modify cutlines for an individual image, or a group or range of images, you can do so in the Mosaic Tool window after you generate the mosaic preview. For more information, see Working with cutlines.

To compute cutlines

Select the Compute cutlines check box.
In the Method list, select from the following the method to use to compute cutlines:
- Minimum squared difference
- Minimum difference
- Minimum relative difference
- Edge
- Maximum data
- Import
- File extents
If in the Method list you selected Minimum squared difference, Minimum difference, Minimum relative difference, Edge, or Maximum data, and you want to use a global or a local mask, do the following, as applicable:
- To use a global mask, beside the Global mask box, click Select, and then select the file containing the global-mask layer you want.
- To use a local mask, in the Local mask list, select from the following according to the type of mask you want:
  - None: All pixels through which a cutline can pass are valid candidates.
  - Last vector: Sets the last-created vector segment in the source image as the mask layer.
    When no vector segment exists, all pixels through which a cutline can pass are valid candidates.
  - Last bitmap: Sets the last-created bitmap segment in the source image as the mask layer.
    When no bitmap segment exists, all pixels through which a cutline can pass are valid candidates.
  - Specific segment: Defines a specific segment in the source image as the mask layer.
    When you select this type of local mask, enter the segment number in the Segment number box.
If in the Method list you selected Import, beside Existing cutlines, click Select, and then select the file, layer, and segment you want; otherwise, proceed to the next step.
To continue setting up mosaic preparation, proceed to Setting up color balancing; otherwise, click Run.