Adobe Photoshop CS4 - Manual (Page 299)

292 USING PHOTOSHOP CS4
Layers
Last updated 1/10/2010
Using the Auto-Align Layers command, you can combine images in several ways:
• Replace or delete parts of images that have the same background. After aligning the images, use masking or
blending effects to combine parts of each image into one image.
• Stitch images together that share overlapping content.
• For video frames shot against a static background, you can convert frames into layers, then add or delete content
across multiple frames.
1 Copy or place the images you want to align into the same document.
Each image will be in a separate layer. See “ Duplicate layers ” on page 286.
You can load multiple images into layers using a script. Choose File > Scripts > Load Files into Stack.
2 (Optional) In the Layers panel, create a reference layer by locking it. See “ Lock layers ” on page 294. If you do not
set a reference layer, Photoshop will analyze all the layers and select the one at the center of the final composition
as the reference.
3 Select the remaining layers you want to align.
To select multiple adjacent layers from the panel, Shift-click; To select noncontiguous layers, Ctrl-Click (Windows) or
Command-click (Mac
OS).
Note: Do not select adjustment layers, vector layers, or Smart Objects which do not contain information needed for
alignment.
4 Choose Edit > Auto-Align Layers, and choose an alignment option. For stitching together multiple images that
share overlapping areas—for example, to create a panorama—use the Auto, Perspective, or Cylindrical options. To
align scanned images with offset content, use the Reposition Only option.
Auto Photoshop analyzes the source images and applies either a Perspective or Cylindrical layout, depending on
which produces a better composite.
Perspective Creates a consistent composition by designating one of the source images (by default, the middle image)
as the reference image. The other images are then transformed (repositioned, stretched, or skewed, as necessary) so
that overlapping content across layers is matched.
Cylindrical Reduces the “bow-tie” distortion that can occur with the Perspective layout by displaying individual
images as on an unfolded cylinder. Overlapping content across layers is still matched. The reference image is placed at
the center. Best suited for creating wide panoramas.
Spherical Aligns images with wide fields of view (vertical and horizontal). Designates one of the sources images (the
middle image, by default) as the reference image and spherically transforms the other images so that overlapping
content is matched.
Scene Collage Aligns layers and matches overlapping content, without changing the shape of the objects in the image
(for example, a circle will still be a circle).
Reposition Only Aligns the layers and matches overlapping content, but does not transform (stretch or skew) any of
the source layers.
Lens Correction Automatically corrects for lens defects:
• Vignette Removal Compensates for a lens defect that causes the edges, especially the corners, of an image to be
darker than the center.
• Geometric Distortion Compensates for barrel, pincushion, or fisheye distortion.