Building Panoramic Images in The GIMP
Panoramic landscapes make for some amazing photos. There's nothing like the feeling of relaxation and tranquility gained by gazing over the vivid images of sweeping wilderness, minus the hassle of actually getting there. Using a digital camera, it's possible to stitch photos together to simulate the expensive effects of a landscape filter. After I'd bought my digital camera (a Nikon Coolpix 4300) and set it up to work under Linux, getting software to stitch photos together was my next task.
The Nikon Coolpix 4300, like most digital cameras, comes with software on CD to perform rudimentary photo-stitching. Unfortunately, the software is not for Linux. Using Google, it was hard to find anything that would do the job under Linux, until I remembered The GIMP. There are two ways to use The GIMP to create a panoramic photo, easy and hard. The hard way is to set up layers out of the different photos, edit filter and layer masks, mess about with transparency and layer them together, manually.
The easy way is to use Pandora. Pandora is a plugin for The GIMP that takes photos and tries to match the edges of the photos together, using a best guess at where one photo ends and the next begins.
Because Pandora is a GIMP plugin, to install it, you need The GIMP version 1.2 or 1.3, as well as Gimptool, which is provided in The GIMP development package. Untar Pandora to a working directory, cd into it, and run make. Pandora detects which version of The GIMP is available and installs it automatically.
Fire up The GIMP. Pandora should now be available under the Extensions (Xtns) menu as Make Panorama. Select the photos you want to stitch together and click the Add File button; under The GIMP 1.2, you need to add the photos individually, as they should appear from left to right. It's possible to create vertical panoramas, but you need to make use of the rotate feature, as Pandora works horizontally.
Pandora can be set with some options before it does its work. The option to feather the layers creates a fade toward the edge of the photos, where the photo becomes slightly translucent. Keep it toggled to create a semi-transparent fade at the sides of each photo, making them easier to line up.
Related to feathering is overlap. Often, photos have minor differences in sky colour; overlap helps to blend the difference so it isn't noticeable. The higher the overlap, the further in from the edge of the photo the feathering takes effect.
Once you're happy with your choices, click OK and Pandora starts to perform its magic.
When the processing has finished, you are presented with a set of layers, one for each original photo. The layers, represented with a dotted line at the edge, should be lined up roughly to what Pandora thinks are the common portions of each picture. Because Pandora is mostly a means of automating the layer creation and feathering, your panorama likely may require a bit more work before you can start impressing your friends.
Using the Move layers and selections tool (represented by the four-directional arrow), you can select a layer and move it, by holding the left mouse button down while moving the mouse. The easiest way to line the images up is to find a common landmark at the edge of each photo—mountains or trees are ideal—and use these as the anchor around which the images are aligned.
Once the layers are lined up to your satisfaction, you may notice that the pictures have moved out of their perfect vertical alignment, resulting in a jagged top and bottom edge.
Right-click in the image window, and choose Layers→Flatten Image. This merges the layers into one. If you haven't finished lining up the edges, you can undo this last action. Now, using the Select rectangular regions tool, select a region from the bottom left corner to the top right, ignoring all white space caused by the jagged edges mentioned earlier. Copy into a new image, save and you're done.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
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With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide