By using the New Mask tool, you can draw a local or global exclusion mask to exclude certain parts of an image from color balancing.
Tip: You can draw two overlapping shapes to create "holes" in your mask. The area where the two shapes overlap each other will be excluded from the mask. This is useful when there are features in the exclusion mask area that you want to include in your color-balancing operation.
Figure 1. New Mask
To create an exclusion mask
- In the Mosaic Tool window, zoom, pan, or both, as necessary to an appropriate level of image detail of the area of interest.
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In the control pane, do one of the following:
- To create a global mask, under Auxiliary Images, select Global Mask.
- To create a local mask, under Source Images, right-click an image, and then on the menu that appears, click New Mask.
Notice that on the Editing toolbar, New Mask is available, and the cursor changes to reflect the drawing shape selected currently (polygon, rectangle, or ellipse).
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To select a drawing shape, click the arrow beside New Mask, and then click the shape you want; otherwise, proceed to the next step.
You can select from the following:
- Polygon
- Rectangle
- Ellipse
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In the view pane, do one or more of the following:
- With Polygon selected, click point-to-point to draw a polygon around the area you want, and then double-click to complete the shape.
- With Rectangle selected, drag to create the size of the rectangle you want.
- With Ellipse selected, drag to create the size of the ellipse you want.