Automated Pano Stitching with Photomerge


If you've taken the time to get your pano set up right during the shoot (in other words, you used a tripod and overlapped the shots by about 20% to 30% each), you can have Photoshop's Photomerge feature automatically stitch your panoramic images together. If you handheld your camera for the pano shoot, you can still use Photomergeyou'll just have to do most of the work manually.

Step One

Open the photos that you want Photomerge to stitch together as one panoramic image. In the example shown here, I opened three shots in Photoshop. Note: Be sure to open your images consecutively in the order you want to stitch them together.

Step Two

There are two ways to access Photomerge: (1) Go under Photoshop's File menu, under Automate, and choose Photomerge (as shown here), or (2) in the Adobe Bridge you can Command-click (PC: Control-click) on the photos you want to stitch, then go under the Bridge's Tools menu, under Photoshop, and choose Photomerge.

Step Three

If you choose Photomerge from Photoshop's Automate menu (rather than the Bridge), a dialog appears asking which files you want to combine into a panorama. Any files you have open will appear in the window, or you can change the Use pop-up menu to Files, and then choose individual photos to open. When your file names appear in the window, Shift-click the top and bottom images to select them in the window. Make sure the Attempt to Automatically Arrange Source Images checkbox is on if you want Photomerge to try to build your pano for you, and then click OK.

Step Four

If your pano images were shot correctly (as I mentioned in the introduction of this technique), the Photomerge dialog will appear and stitch your images together seamlessly (if not, skip to Step 12). Note: By default, Photomerge creates a flattened image, but if you want a layered file instead (great for creating panoramic video effects), turn on the Keep as Layers checkbox in the bottom right-hand corner of the dialog.

Step Five

You might also try the Perspective Stitching to see if you like the results better. To turn this on, and see an instant preview of the results, go to the Settings section on the right side of the Photomerge dialog and click on the Perspective radio button. You can see how it adjusts the perspective, but it also creates a cropping issue (which you'll deal with a little later). So, click OK in the dialog, and Photomerge will create the pano.

Step Six

In the pano shown here, the horizon line is a bit tilted to the left. Although you can rotate individual sections from right within Photomerge, it's easier if you correct an overall problem like this after you've created the pano, so start by choosing the Measure tool from the Toolbox (it's nested under the Eyedropper tool). Click-and-drag the Measure tool along the horizon (which is at the base of the Manhattan skyline, in this example), starting at the left and dragging to the right.

Step Seven

Now, go under the Image menu, under Rotate Canvas, and choose Arbitrary. This brings up the Rotate Canvas dialog, and the amount of angle (as provided by the Measure tool) is already calculated. You just have to click OK to straighten your pano.

Step Eight

Here's the straightened panonow you just have to crop it down to size (this is a fairly common routine when using Photomerge to stitch your photos, so don't think you're doing it wrong, especially if you use the Perspective effect, as we have herecropping is just part of the job).

Step Nine

Now it's time to crop away the excess area. Press the letter C to get the Crop tool, then drag out your cropping border so the extra areas at the top, bottom, and sides will be cropped away, leaving a nice, clean, wide rectangular panorama.

Step Ten

Press Return (PC: Enter) to apply your crop, and your panorama will appear as one image. Now it only needs one more thingsharpening. Go under the Filter menu, under Sharpen, and choose Smart Sharpen. Try an Amount of 60% and a Radius setting of 1 pixel.

Step Eleven

When you click OK, the sharpening is applied to the photo, and in this case it helps bring out the twinkling lights of the city, adding more contrast. Now, this pano stitcheven with having to rotate it after we were doneis what we call a "best-case scenario," where you shot the panos on a tripod and overlapped enough so Photomerge had no problems; it just did its thing, making it perfect the first time. But you know, and I know, life just isn't like that...

Step Twelve

More likely what you'll get (especially if you handheld your camera or didn't allow enough overlap) is a warning dialog letting you know that Photomerge "ain't gonna do it for you" (that's a technical phrase coined by Adobe's Alabama tech office). In other wordsit's up to you. So if you've had problems since Step 3, read on.

Step Thirteen

Once you click OK in that warning dialog, Photomerge will try to merge as many segments together as possible. The segments it can't merge will be placed in the Lightbox (the horizontal row across the top of the dialog). Although Photomerge didn't do all the work for you, it can still helpjust make sure the Snap to Image checkbox (in the bottom right-hand corner) is turned on.

Step Fourteen

Using the Select Image tool (the hollow arrow at the top of the Toolbox on the left), drag a segment from the Lightbox into your work area near the first image. When you get close to the main image, release your mouse button. If Photomerge sees a common overlapping area, it will snap them together and blend any visible edges (thanks to Snap to Image). If you need to rotate a segment, click on it with the Select Image tool first, then switch to the Rotate Image tool (R), and click-and-drag within the segment to rotate it. When the images are stitched together, click OK. You'll have a little cropping to do, but outside of that, Photomerge does most of the work.



    The Photoshop CS2 Book(c) for Digital Photographers
    The Photoshop CS2 Book for Digital Photographers (Voices That Matter)
    ISBN: B002DMJUBS
    EAN: N/A
    Year: 2006
    Pages: 187
    Authors: Scott Kelby

    flylib.com © 2008-2017.
    If you may any questions please contact us: flylib@qtcs.net