Tuesday, October 30, 2012

How To See It All - Taking The Wide View

Back in the day when I used real film and paper pictures, I used to make panorama pictures by a laborious processing of cutting the pictures and taping them together to (almost) make a panorama picture. I have seen that there are iPhone apps that will take a continuous photo that allows you just pan your phone and capture a single panorama picture. However, the iPhone is still limited to a 5MP camera. If you really want to get a deep depth picture, you have to go to larger capacity camera. Just for fun, I recently picked up a 14MP Vivitar camera on Craigslist for $35. On my first foray using the camera, at various locations I took multiple pictures meaning to manually stitch these together to make a  single panorama. This would allow me to capture the scenes as I saw them, rather than resorting to manual wide angle pictures that would distort the scene.

Not relishing the difficulty of manually doing the stitching, I looked for a tool that was free and would automatically stitch the pictures together. What I found was a tool called Hugin. It is a little terse, but with practice, I was able to stitch panoramas with ease.

A note of caution here. While the tool can work wonders, it does has it's limits for common point recognition. When taking a series of pictures for a panorama, it is important to have a great deal of overlap from one picture to another. If the tool can't find the points, it will prompt you to find common points. This is an awkward process, but sometimes it works out fine. I'll leave those advanced topics for you to explore on your own.

When hugin starts, you see this:
hugin start display

It really is as simple as 1-2-3. First you select your pictures by pressing the 1. Load Images button. This opens a file selection box where you select all the pictures you want to make the panorama from. Once that is done, you will be prompted to enter the the data for your camera.

I did not fool with looking up the specs for the lens of my point and shoot. Instead, I opted to enter in the HFOV and let it calculate the other data. Assuming a normal point & shoot digital camera, with no setting modifications, this value is normally 50 degrees. Once you hit OK there, you press 2. Align on the main page, and the program does it stuff. If all goes well, the processing completes and you are presented with the preview screen.

From this window, you can choose the Projection screen to select equi-rectangular to flatten out the picture if desired, and select crop to remove unwanted edge effects. Once those edits are done, close this window, and select 3 Create Panorama, you will be prompted for a few more file names, and tada! you have a panoramic picture in a TIFF format.

It is worth noting that these TIFF files can get enormous, especially if you are merging 14MP images. Once the TIFF is created, the file can be shrunk by using a conversion program like JPEGView to convert it to a JPEG, which will typically shrink the file to less that a few megs. It is worth noting that in panorama stitching of large files with few alignment points, the tool will occasionally exhaust system resources and hang. The work around is to align fewer files, then align those composites in a separate step.

Once you use the tool a few times, the process becomes amazingly fast. For example, I noted the pictures in this example on a friend's album, downloaded them, ran them through the tool, shrunk the results, and had the resulting panorama in an e-mail in a couple of minutes. I invite you to look at the trail guides for some examples of what these tools can do. It is worth noting that the banner panorama at the top of the blog was done manually several years ago from scans of film pictures taken with a 35mm SLR. We've come a long way baby!

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