ERDAS Tutorial - Create a Mosaic using ERDAS IMAGINE Mosaic Pro - GIS English

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ERDAS Tutorial - Create a Mosaic using ERDAS IMAGINE Mosaic Pro

ERDAS MosaicPro is the mosaicking module for LPS and ERDAS IMAGINE® that provides a robust solution for the entire mosaicking process, from seam generation and editing through radiometric adjustment and final product generation. This add-on module offers significant improvements in functionality for IMAGINE Mosaic Tool users. ERDAS MosaicPro is particularly useful for high volume production users who require an efficient means of editing seams for
large projects that may involve large volumes of imagery.


Content and steps

Begin with two orthorectified images displayed in an IMAGINE viewer. These are the images that will be used in the mosaic.
1. Once opened, from the View group on the Home tab select the Swipe tool to easily see where the two images overlap.
Now start the mosaic workflow.
2. From the Raster tab, select Geometry group > Mosaic > Mosaic Pro.
3. From the Mosaic Pro toolbar, select Add Images.
4. If necessary, navigate to the directory that contains the first image, select it but don’t click OK.

5. Since the image has a background, select the Image Area Options tab and enable the
Compute Active Area radio button.
6. Click the Set button and make sure the Boundry Search Type is set to Corners.
7. Add a check mark in front of Crop Area and change it to 20%. This will eliminate unnecessary fiducial maks on the edges.
8. Click OK.
9. Click OK in the Add Images dialog.
Once the first image is added and the edges look correct, add the second image.
10. Repeat the previous steps to add the second image.
11. Since the second image does not have a background, deselect Crop Area.
12. Select OK, then OK in the Add Images dialog.
13. Under the Vis cell, place a checkmark by both of the images.
14. From the toolbar along the top, click Show Images to display all of the images in the workspace.

Notice that the two images have different color contrasts and it is obvious where one image ends and the other begins.
15. Next, select the Color Correction options to modify the image histograms. This will create a smoother transition from one image to the next.
16. Click Color Corrections Options.
17. Enable the Use Histogram Matching and Use Illumination Equalizing checkbox, then click OK.
18. Make sure the the Display Seam Polygons button is toggled on.
19. Select the Automatically Generate Seamlines icon.
20. Click the Weighted Seamline radio button and then click OK.

The seamlines that are automatically created display in the workspace. Notice how rigid the seamlines look. In the next step, edit the seamline to hide it in naturally occurring features within the image.
21. Click Edit Seamlines Polygon.
22. To edit, digitize a polygon around the seamline. The side of the seamline from which the polygon originated will increase in size when the polygon is completed.
Here’s a tip: Try to run the seamlines along natural barriers in the image. This will create a more crisp final product.
23. From the toolbar, select the Set Seamline Function icon. This button is used to set the function used to calculate the digital number for the pixels within the overlapped area.
24. Enable the Feathering radio button and change the Distance to 50.
25. Click OK.

Before running the mosaic you may want to preview the output.
26. Select the Mosaic Preview icon from the toolbar.
27. Draw a box over a small area where the images overlap.
28. Select Process > Preview Mosaic for Window.
29. Accept the default values and click OK.
30. If you’re unhappy with the results of the preview, make changes to the project and re- preview. You can save time by confirming the preview results before running the full mosaic project.
Now define the output options.

31. Activate the IMAGINE workspace and from the IMAGINE Ribbon, open the Drawing tab.
32. Click the Create Polygon button.
33. Create an AOI polygon around the housing development.
34. Now return to the Mosaic Pro workspace.

35. From the Mosaic Pro toolbar, click the Set Output Options icon.
36. In the Output Image Options dialog, change the Method to User-defined AOI.
37. Click Set Output AOI.
38. Select Viewer as the AOI Source and then click OK.
39. Press OK in the Output Image Options dialog.

40. From the toolbar, click on the Display Output Area Boundaries button. You can now see the outline that defines the extent of the output image.
41. In the Mosaic Tool menu, select Run Mosaic.
42. Give your file a name.
43. Click the Output Options tab and enable the Stats Ignore Value checkbox.
44. Click OK.

45. When the Mosaic Job State reads done, click Close to complete the process.
46. To view your mosaic open a new viewer.
47. Under the ERDAS IMAGINE ribbon select Home.
48. Click Add Views > Create new 2D View.
49. Right click and select Open Raster Layer.
50. Navigate to where you saved the mosaic and select Open to view the mosaic image.

Credit : Hexagon Geospatial
ERDAS Tutorial - Create a Mosaic using ERDAS IMAGINE Mosaic Pro Reviewed by Jamal CHAAOUAN on August 15, 2019 Rating: 5 ERDAS MosaicPro is the mosaicking module for LPS and ERDAS IMAGINE® that provides a robust solution for the entire mosaicking process, from...

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