Overlap region dialog box

Overlap region dialog box

The Overlap region dialog box appears when you open the overlap between one image and the next. You use the Overlap region dialog box to adjust the alignment between the images, adjust focal length, adjust the correction for barrel distortion, control alignment fine tuning, adjust image-to-image exposure matching and adjust the correction for brightness falloff.

Common controls for all overlap tasks
Image alignment
Focal length & barrel correction
Fine tuning
Exposure & falloff correction

Common controls for all overlap tasks

The top portion of the Overlap region dialog box controls navigation and selects the task you want to perform.

<--- Prev
Closes the current overlap region and opens the one to its left. This performs the same action as the Previous image or seam command (Image menu).

Shortcuts ALT+LEFTARROW (Windows)
OPTION+LEFTARROW (Mac)
Context menu in current image pane

Next --->
Closes the current overlap region and opens the one to its right. This performs the same action as the Next image or seam command (Image menu).

Shortcuts ALT+RIGHTARROW
OPTION+RIGHTARROW (Mac)
Context menu in current image pane

Close
Closes the current overlap region and returns to the stitched image. This performs the same action as the Approve command (Image menu).

Shortcut Context menu in current image pane

Choose an Overlap task
Four different overlap tasks can be performed with the Overlap region dialog box. Selecting a task determines the set of controls that are available on the dialog box.

Image alignment — Adjust overall alignment of the overlapping images.

Focal length & barrel correction — Adjust the camera focal length setting and the correction for barrel distortion so that the images match properly.

Fine tuning — Make small-scale adjustments to correct for local mismatches in the image alignment.

Exposure & falloff correction — Adjust the image-to-image exposure matching and correct for brightness falloff in the corners of the images.

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Image alignment

The image alignment task provides the ability to adjust overall alignment between one image and the next.

Refer to “Manually aligning images” in Chapter 6, “Correcting stitching problems” for step-by-step instructions.

View overlap

Blend — Select this option to show the overlap region normally, as a blend of the two images.

Compare — Select this option to highlight differences between the images in the overlap region. A medium gray color is shown when the images match exactly. Brighter or darker colors indicate mismatches between the images.

Adjust image
Use the arrow buttons to move the right hand image relative to the left hand image. Individual clicks on the buttons move the image by single pixels. Holding a button down causes the image to move continuously. If you hold the button for a long time, the motion accelerates.

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Focal length & barrel correction

The focal length and barrel correction task provides the ability to interactively adjust the focal length and barrel correction settings.

Refer to “Adjusting focal length and barrel correction” in Chapter 6, “Correcting stitching problems” for step-by-step instructions.

View overlap

Blend — Select this option to show the overlap region normally, as a blend of the two images.

Focal length
Enter the focal length of the lens in millimeters. This may be the actual focal length of the lens or the 35mm equivalent focal length, depending upon the options you selected on Wizard step 3/9 – Describe your camera or the Camera properties dialog box.

You can click the up and down arrows to adjust the focal length value by small steps. Holding a button down continuously adjusts the value. If you hold the button for a long time, the adjustment accelerates.

NOTE: The focal length setting applies to all overlap regions in your panorama and may slightly affect the image-to-image alignment. You should check the alignment in each overlap region after changing this setting.

Refine ±50%
Select this button to refine the focal length setting based upon the current pair of images at their current relative alignment. You may get erratic results if the overall image alignment is incorrect, so adjust overall alignment before refining focal length.

Correct barrel distortion
If your camera and lens combination exhibit barrel (or pincushion) distortion, you can use this value to correct it. Use small negative numbers (-0.05 is a large correction) to correct barrel distortion. Use small positive numbers (0.05 is a large correction) to correct pincushion distortion. To disable the correction, enter zero.

NOTE: The correction for barrel distortion applies to all overlap regions in your panorama and may slightly affect the image-to-image alignment. You should check the alignment in each overlap region after changing this setting.

NOTE: Correcting barrel distortion will increase the time required to compute your panorama.

Refine with focal length
If you select this checkbox, the barrel correction will be refined with the focal length when you select the Refine ±50% button.

Enter the focal length of the lens in millimeters. This may be the actual focal length of the lens or the 35mm equivalent focal length, depending upon the options you selected on Wizard step 3/9 – Describe your camera or the Camera properties dialog box.

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Fine tuning

The fine tuning task provides the ability to make small-scale adjustments to correct for local mismatches in the image alignment.

Refer to “Fine tuning the image alignment” in Chapter 6, “Correcting stitching problems” for step-by-step instructions.

View overlap

Blend — Select this option to show the overlap region normally, as a blend of the two images.

Adjust tile
Use the arrow buttons to move the right hand image relative to the left hand image within the selected fine tuning tile.

Individual clicks on the buttons move the image by single pixels. Holding a button down causes the image to move continuously. If you hold the button for a long time, the motion accelerates.

Auto fine tune
Use this button to discard the fine tuning of the current overlap region and then automatically fine tune the region.

Clear fine tuning
Use this button to discard the fine tuning of the current overlap region.

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Exposure & falloff correction

The exposure and falloff correction task provides the ability to adjust exposure matching between one image and the next and the brightness falloff correction.

Refer to “Fine tuning the image alignment” in Chapter 6, “Correcting stitching problems” for step-by-step instructions.

<--- Brightness --->
Use this slider to adjust the exposure matching between adjacent images. Moving the slider to the left increases the brightness of the lefthand image (or decreases the brightness of the righthand image). Moving the slider to the right increases the brightness of the righthand image (or decreases the brightness of the lefthand image).

Correct brightness falloff
If your camera and lens combination exhibit brightness falloff in the corners you can use these values to correct it.

Amount — The brightness falloff factor in the extreme corners of the image. The value represents the brightness in the corner of the image relative to the center of the image. For example, a value of 0.1 means that the brightness has fallen off by one tenth (i.e. to 90% brightness) in the corner.

Size — The spread of the falloff outward from the corners of the image. The value represents the distance from the corner at which the falloff reaches approximately 50% of its maximum. For example, a value of 0.1 means that the brightness falloff is at 50% of the maximum falloff at about one tenth the distance from the corners to the center.

NOTE: Correcting brightness falloff will increase the time required to compute your panorama.

NOTE: The brightness falloff correction applies to all overlap regions in your panorama. You should check each overlap region after changing this setting.

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