Archive for the 'Apollo' Category

Major update to CleVR Stitcher

Wednesday, September 5th, 2007

CleVR StitcherI’ve just pushed out an update to the CleVR Stitcher which is probably the biggest improvement yet. Loads more features, loads of bugs fixed and a much nicer interface. You will find all the details here: CleVR panoramic photo Stitcher. As always, it’s totally free. Let me know what you think.

I decided to enter it into the Adobe AIR Developer Derby. It’s hard to judge its chances, but I’d love to win that squishy stress ball. If they’re going on innovation, I’d say they’d be hard-pressed to find an AIR app that is pushing the boundaries more than this. In terms of using AIR technologies, we’re using almost all of them! We’ll wait and see…

Image enhancement with histogram stretching in Actionscript

Friday, July 27th, 2007

Yesterday’s update to the CleVR Stitcher has a number of new features. One of these is image enhancement for the finished panorama. This corrects under- or over-exposed images, and works in a similar way to “Auto levels” in Photoshop, or Enhance in iPhoto. See below for more details and a demo.
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Bicubic and bilinear interpolation in Actionscript 3

Monday, July 2nd, 2007

For the second release of utility code from CleVR Stitcher, the Adobe AIR panoramic photo stitcher, I’m offering our InterpolatedBitmapData class.
The class adds support for bicubic and bilinear interpolation to the Actionscript BitmapData class. It adds two public methods - getPixelBilinear and getPixelBicubic. You can call these with sub-pixel coordinates and it will interpolate the RGB value for that point. This should be useful for anyone doing more complex transformations than those offered by the Matrix class. I hope it will be useful to someone. Do let me know if you’re using it. As ever, a link back to clevr.com is appreciated but not required.

Download it as part of the CleVR Actionscript Library

Linear algebra and matrix manipulation library for Actionscript 3

Saturday, June 30th, 2007

While developing the CleVR Stitcher, I needed to do quite a bit of linear algebra. I was disappointed to find that there was no Actionscript library out there for doing this, so I had to write my own. Rather than doing it from scratch, I decided to start with NIST’s Java Matrix library: JAMA, which is in the public domain.

For the benefit of anyone else needing to do stuff like this, I’m releasing the library. It’s not a full port, as I only implemented the stuff that I need. It does however support most regular operations for manipulating real matrices. As well as the normal algebra stuff, it includes classes for singular value decomposition and QR decomposition. I hope others find it useful. Let me know if you’re using it. A link back to clevr.com from your site would be appreciated but is not required.

Download it as part of the CleVR Actionscript Library

Adobe AIR panoramic photo stitcher

Monday, June 25th, 2007

Update: The CleVR Stitcher can now be found at http://www.clevr.com/stitcher


The Stitcher is the oldest part of CleVR, originally developed nearly four years ago, so it’s needing an upgrade. It was developed in Java, delivered by Web Start, a system that I’ve never been happy with. I decided that the best plan for the new version was to rewrite it from scratch. It’s a Flex-based Adobe AIR app. AIR, formerly called Apollo, is a new cross-platform runtime under development by Adobe. The first beta was released earlier this month, and it’s a joy to develop for. I’m pleased to announce the first alpha version of the new AIR-based CleVR Stitcher. You’ll need a CleVR account to use it. It’s free, and only takes a couple of minutes to sign up.

The choice for the development platform will be surprising to many people. The idea of doing computer vision and image processing in Flash sounds like madness, but the advances in Flash Player 9 make it possible. While developing the CleVR panorama viewer, it became apparent to me quite how powerful some of the new features were, and the performance improvements in the new Player have made it feasible. The current version is slower than the Java stitcher, but there’s a lot more optimisation that I can do, and it’s certainly usable.

Currently it’s missing a number of features from the Java version, most importantly the ability to repair failed stitches. However, I’ve made several improvements to the algorithms, so there should be fewer failed stitches. The repair facility will be added in a future release, as will several other useful features.

Give it a try, and let me know of any bugs that you find, and any other comments that you have.

Web apps on the desktop

Friday, November 3rd, 2006

While CleVR is mostly web-based, the Stitcher has always needed to be a desktop app. This is for a number of reasons. Primarily it’s because it needs access to the local filesystem so that you can import your photos. Also, it is processor intensive, so runs best as a native app.

However, it also needs to be tightly-integrated with the server, so that it can handle the uploading, authentication and similar. It also needs to be cross-platform, as we don;t have the resources to develop separate apps for Mac, Windows (and possibly Linux). The current system is pretty good - we use Java Webstart which allows us to launch from the browser, while giving us the access we need to the filesystem and native libraries. However, I’ve never been totally happy with it, and am always looking for a better solution. Luckily, there seem to be some on the way.

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