We can’t all afford four-figure priced twelve megapixel digital cameras with wide angle lenses. We can, however, all use free software to embellish the photographs taken by our modest equipment and belie their resolution and viewing angle. Set the GIMP aside for a moment and launch Hugin, a powerful cross-platform GTK frontend that will help you quickly and easily stitch individual photographs into one, large, seamless panorama.

Panoramas from start to finish

Panoramas are created by stitching multiple images together. To do this, you must find spots where your images overlap and designate them as control points. Then you will optimize your collection by selecting the best way to rotate, distort, and align these images so that they come together seamlessly. Finally, you will stitch and blend them all together and do some postprocessing.

Taking good panoramic photographs

When composing photographs with the intention of combining them into panoramas, it is best to adhere as closely as possible to the following rules:

• Take all photographs from the same location, using a tripod if possible
• Aim for a 33% overlap between each frame
• Keep the camera’s metering equal between shots
• Keep the white balance equal between shots

You can take vertical panoramas as well as horizontal ones, or even multi-rowed ones

Remember, you can take vertical panoramas as well as horizontal ones, or even multi-rowed ones. Use as many images as you like, but bear in mind that larger and more complex panoramas will take longer to process. Erring in any of these guidelines will not prevent you from composing a brilliant panorama, however it will make it more difficult and may aggravate seams between the individual photographs. Such issues may be fixed with the GIMP or another image manipulation tool after the panorama is stitched, though white balance and color deviation issues should be fixed beforehand.

Introducing Hugin and associated tools

To combine your photographs you can use Hugin, a GPL-licensed frontend to Panorama Tools available for GNU/Linux, Mac OSX, and Windows in several languages. Hugin will let you design your panorama, but you’ll need additional tools to find control points and do the actual image processing. Try Autopano-SIFT for automatically finding control points, though you may also do this manually, and Enblend for blending the images together. Both these tools are also GPL and cross-platform.

Figure 1: Unfortunately, Hugin does not greet you with an intuitive or simple interface

Larger and more complex panoramas will take longer to process

You must first configure Hugin to work with the tools you have installed. Access the configuration dialog in File → Preferences. Ignore the first three tabs (“Panotools”, “Finetune”, and “Misc.”), they will most likely have the correct options predefined. In the fourth tab, “Autopano”, make sure Autopano-SIFT is selected, that it is pointing to the correct binary location, and that the Arguments are set to -o %0 %i. In the final tab, “Enblend”, make sure Hugin has found the proper executable and set its arguments to -v -m XYZ, where XYZ is equal to about half your physical RAM (this is how much image cache Enblend will use). You may want to enable the checkboxes in the “Enblend” tab to cut down on temporary file space usage. Make sure these settings are correct each time you launch Hugin.

Finding control points

I have selected six four-megapixel JPEGs that I want to stitch into a horizontal panorama. The images were taken handheld and not well composed. However, Hugin and its tools should have no problems combining them seamlessly.

Figure 2: Use the “Images” tab to choose which photographs you wish to combine

To begin composing your panorama, drag and drop your images into the “Images” tab or select them using the “Add Individual Images” button. Once your images are listed in the “Images” tab, select whichever photograph will represent the middle of your panorama and click “Anchor this image for position”. The “Camera and Lens” tab is used to correct images for camera error, ignore this since Hugin should have already filled in these variables based on your camera’s EXIF data.

There is a choice to be made now: do you want to trust Autopano-SIFT to choose control points, or would you rather do it yourself? Autopano-SIFT will generally do a good job, but having these complicated decisions made by complex algorithms can be be a very lengthy process, often taking several hours, regardless of your Desktop computer’s processing power. Manually selecting the control points may prove to be far quicker, but will take some experience and perhaps some frustration. Either way, you will probably need to do some manual adjustment to the selected control points based on the preview of your final panorama.

Autopano-SIFT will generally do a good job, but having these complicated decisions made by complex algorithms can be be a very lengthy process

If you choose to let Autopano-SIFT select your control points, click “Create Ctrl Points” on the “Images” tab and go out for some coffee. Read on to learn how to adjust Autopano-SIFT’s selections.