SPOT 4.1 Basic and Advanced Software Manual for SPOT Insight ...

Ch. 8 – Viewing, Editing, and Annotating ImagesSubtract ImageUse Subtract Image to subtract an image from a selected, open image. Follow these steps:1. From the Edit menu, select Subtract Image.2. Select the Source of the image that you want tosubtract from the currently open, selected image.The image can come from one of the following threesources:−A Currently Open Document – Subtract animage from a currently open image. If the pathfor the image you are editing does not appear inthe Title box, select it from the Title drop-downlist, which lists all open images. If the file is animage sequence, specify the number of theimage in the sequence (the Sequence Index).Note: It is possible to subtract animage from itself.−−An Image File – Subtract a file from disk from the currently open, selected image. Either enterthe file path in the box, or click on the browse button to the right of the box to search for andselect the file. If the file is an image sequence, specify the number of the image in the sequence(the Sequence Index).A Database (Windows only) – Subtract a file from a SPOT database from the currently open,selected image. To subtract an image from a SPOT database you must enter the Image ID for thatimage. You can determine the eight-digit Image ID number by searching the database for theimage that you want to add. The search results display the image ID number.Note: To subtract a database file, the database must be open. For more information on usingSPOT databases, refer to Chapter 9, Using SPOT Databases.5. Enter a Scale Factor between .01 and 5. The Scale factor adjusts the brightness of the image that youare subtracting:−−Numbers between .01 and 1 darken the image.Numbers between 1 and 5 lighten the image.3. Click on OK to add or subtract the image. The combined image replaces the original.Note: Subtracting an image modifies the original file. This contrasts with the process of theMerge Images function (see below), which creates an entirely new file.158 User Guide to the SPOT Insight Camera