By Steve Bain
Have you ever tried to photograph a scene that’s just too large to fit in your camera’s viewfinder no matter how many steps backward you take? Unless the wide-angle lens you’re using can work miracles, this is a common challenge that many photographers face. Why not just shoot a photo panorama?
Photo panoramas incorporate multiple overlapping photos of a scene or subject into a single composite photo. Historically, building a photo panoramic using traditional non-digital tools required scissors, rubber cement, a mounting surface, and an incredible amount of patience. In the digital realm though, the task can be much faster and easier and the results much more rewarding if you have the right software tools. If you’re interested, Wikipedia showcases a collection of stunning photo panoramas that are definitely worth browsing.
Building a Basic Photo Panorama
Photo-stitching resources in recent versions of PHOTO-PAINT (X3 and X4) enable you to quickly and accurately assemble multiple overlapping images into a single image. The resizable Image Stitch dialog includes everything you need to organize multiple panoramic sections and align the overlapping portions. The available work area gives you an interactive view of the arrangement and provides access to a variety of useful tools.
You’ll find a typical Selection and Rotate tools for moving and arranging photos and Zooming and Panning tools enable you to easily navigate the work area. A Difference Tool button enables you to toggle how your currently selected image is rendered by inverting the transparency type. Other options enable you to set blending and composite methods. These tools are straightforward to use and assembling a typical multi-image scene is a relatively quick operation. For some hands-on practice, let me walk you through this basic photo-stitching tutorial:
- Download and unzip the Canyon_Vista.zip digital image set (2.5 Mb). Launch PHOTO-PAINT and open all four images at once. These images are sequentially named left to right according to their position in the panorama.
- Choose Image > Stitch and click the Add All button in the Select Images dialog that opens. With the four images listed on the Selected Files side of the dialog (as shown below), ensure the image names are in sequential order in the list using the up and down arrow buttons to the right and click the OK button.
- The Image Stitch dialog opens next with the images automatically placed in order left to right according to the stacking order in the previous dialog. If needed, resize the dialog using the bottom-right corner tab (as shown below).
- Choose the Zoom In Tool and click once at the seam between the top-left and top-center images. Then, choose the Selection Tool and click-drag the top-center image to select it. Notice the image becomes slightly transparent once it is selected.
- Move the top-center image to the left until the two images overlap and align (as shown below). You can also use your keyboard nudge keys to move the image in small increments if needed.
- The Difference Tool makes it easier to precisely align overlapping images. To explore how it works, click the Difference Tool button once to activate it. Notice the colors of your selected image become inverted and overlapping areas appear darker. This overlap will appear completely black when the images are aligned (as shown below). Click the Difference Tool button again to deactivate it.
- Using the available tools, drag the remaining two images into position. Drag the bottom image to the far right of the arrangement and use the Selection, Zoom, and/or Difference tools as needed to precisely align all four images.
- Leave all other options at their default settings and click the OK button. The Image Stitch dialog will close and a new document window will open with the four images combined in a panorama (as shown below) ready for saving.
Using Advanced Techniques
In the previous steps, we used an example that you were able to align precisely and the seams in the final result were virtually impossible to detect. Hiding the seams is the key to building a realistic-looking panorama. There are a multitude of factors I’ll cover later that can (and will) affect seam visibility. One key factor is camera or subject movement which throws overlapping areas out of alignment.
You can solve alignment problems using the Blend Image option. This feature is designed to hide non-aligned areas using transparency. In our next example, we’ll assemble a panorama adversely affected by wind and apply different Blend Image values to evaluate the results.
- Download, unzip, and open the Mountain_View.zip digital image set (3.2 Mb) in PHOTO-PAINT (X3 or X4). The images are sequentially named left to right to match their position in the panorama.
- Choose Image > Stitch to open the Select Images dialog, add the images to match the sequence shown below, and click the OK button.
- In the Image Stitch dialog, overlap and align the images in left-to-right fashion to as you did earlier in our first example. If needed, activate the Difference Tool to make alignment easier. Notice the foliage in the image is slightly out of alignment-especially on the far-right sections. In this case, align the photo elements closest to the left edge of the fifth section as closely as possible (as shown below).
- Leave the Blend Image value set to the default of 5 and click the OK button. The dialog closes and a new document window of the combined images is created. Notice the edges of each photo section remain visible (as shown below).
- Reassemble the same images a second time using the Image Stitch dialog and be sure to align the overlapping images in the same way you did the first time. However, this time set the Blend Image value to 100 and click the OK button to close the dialog. Another new document is created with the assembled images, but in this instance the seams are virtually invisible (as shown below).
The Blend Image unit measure is pixel-based and combines the overlapping photo sections using transparency. The value you use should not exceed the distance of the smallest overlap or some of the seams may be visible in the final assembled image. It may also help to know that if you choose Create Objects From Images, no blend value will be applied to the photo objects that will result from using this option.
Another alignment technique you may need to use is rotation. You can rotate a selected image interactively using the Rotate Tool or in precise increments using the spinner controls or by entering values. For hands-on practice applying rotation to an image, follow these steps:
- Download, unzip, and open Fruit_Bowl.zip digital image set (8.6 Mb) in PHOTO-PAINT. Choose Image > Stitch to open the Select Images dialog and add both images in the order shown below (with the Fruit bowl right image at the top of the Selected Files list).
- Click the OK button. Adding the images in reverse order will enable you to control the stacking order of the images so that the left image is stacked on top of the right image in the final assembly. Notice that in the Image Stitch dialog (shown below) the images are also loaded out of order.
- In the Image Stitch work area, transpose the position of the images using the Selection Tool as shown below. Drag the two images to align them as closely as you can and notice that no matter what you do, the images will not precisely align. In this case, the solution is to rotate one of the images slightly.
- Click to select the image of the left half of the bowl and enter a rotation value of 358.5 degrees in the Rotate Image box (as shown below).
- Use the Selection Tool to drag the image of the right side of the bowl so that the two overlapping images of the pear stem are nearly aligned (as shown below). To fine-tune the alignment, use your nudge keys and use the edges of the bowl for visual reference.
- With the two images aligned in the work area, enter 100 in the Blend Image option and click the OK button to assemble the two images in a new document window (shown below). Notice the seam is hidden and the two images are precisely aligned.
- If you closely examine the rotated half of the assembled image, you’ll notice there are slight serrations caused by the rotation we applied. If needed, you can apply single-clicks using the Touch-Up Brush set to a Size of 10 pixels and a Strength setting of High to reduce this anomaly (see below).
Panorama Best Practices
Producing a successful panorama scene is not only the result of having the right tool to reassemble the parts, it involves a little advance planning and carefully deciding whether your actual photo situation is a good candidate. Consider these suggestions to increase your chances of success:
- Avoid Movement Any movement between photo sections will make image alignment difficult (if not impossible). Ocean waves, blowing trees, clouds, and moving objects such as vehicles and people are some obvious examples. Likewise, camera movement can also be a factor. If possible, use a tripod or similar stabilizing method.
- Use Consistent Exposure Be certain your panorama photo sections are taken using the same exposure. Most non-digital cameras offer exposure lock settings you can use, while many digital cameras include panorama-specific modes which will (among other things) lock the exposure setting.
- Avoid Distortions Wide-angle or macro lens settings can cause inconsistent distortions between photos, so avoid using these if possible. Using zoom lens settings have the opposite effect and tend to reduce distortion.
- Scan Carefully When digitizing photographic prints with a scanner, be sure to disable any built-in or automated scanner color-correction features since these features often apply different correction scans. Be sure to crop out any borders or white edges during or after scanning.
- Correct After Assembling If you plan to correct your panorama for color, lighting, or other anomalies, do this after using assembling the sections. This will save you time and avoid any filter inconsistencies.
- Higher Resolution is Better Scan your photos at as high a resolution as possible to maximize the blending opportunities and/or minimize rotation effects.
Steve Bain is an award-winning illustrator and designer, and an author of nearly a dozen books, including CorelDRAW®: The Official Guide.