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Soccer Ball Cam

This is a log of gregr's project to build a soccer ball style camera (see http://wiki.yak.net/574).

I posted a gallery of test images and QTVR files here http://wiki.yak.net/832 .

I was asked to put up some pictures of the completed project. Here they are:

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The idea is that you can shoot a picture of the whole world in one shot if you had enough cameras jammed into a ball. The soccer ball idea originally would use 32 webcams (one webcam per face). That many cameras would quickly become cumbersome, and who wants to carry around a laptop with a enough usb hubs to take pictures with such a device. Because of these issues I decided to simplify the design.

Im going to use four old point and shoot digital cameras each with a fisheye lens. I began my search for a camera that was low price, 2 or more megapixels, and readily available. I also had to find a fisheye kit specifically for the camera I chose or find a lens and mount it myself.

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Step 1. Print. Step 2. Cut out. Step 3. Fold a copy of my world! (See bottom of this page for a sample.)

I found on ebay Olympus was selling a bunch of old-stock fisheye kits. I checked all the cameras that the kit was compatible with and one of the cameras was a 2 megapixel point and shoot that was easy to find used. I bought 4 of the cameras and 4 of the fisheyes.

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I decided with 4 cameras putting each camera on the face of a tetrahedron would be the optimal configuration. Each fisheye captures 180 degrees of the world, so with a tetrahedral arrangement I will have plenty of overlap between my 4 images. So, there will be one camera pointing straight up and three pointing down at a 60 degree angle spaced 120 degrees apart. The 120 degree spacing should give me about 30% overlap on the edges of each image (10%-50% overlap is necessary to stitch images together accurately).

Update: I finally received all of my gear! Four of the above cameras ans four of the fisheye lenses.

Prototyping time... I cut out four 8 inch equilateral triangles out of foam and taped them together. To the resulting tetrahedron I attached 3 of the 4 cameras and shot some pictures with the rig...

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Straight from the camera. Straight from the camera.
Straight from the camera. Straight from the camera.
Straight from the camera.
Straight from the camera.

Update: I am having a damn hard time stitching fisheye images. My favorite stitching software is Autopano Pro and it will not stitch fisheye images until the next release version ( 1.4). I have made some attempts to undistort the fisheye images in such a way that Autopano Pro will stitch them properly. None of this worked well.

I am testing some other software to stitch images. So far every other piece of software is harder to use, and I have not gotten great results yet.

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Attempted removal of distortion. Attempted removal of distortion.
Attempted removal of distortion. Attempted removal of distortion.
Attempted removal of distortion. Test stitch.
Attempted removal of distortion. Test stitch.
Test stitch. Stitched using a different piece of software. Slightly better...
Test stitch. Stitched using a different piece of software. Slightly better...
This is projected onto a cylinder instead of a sphere. This projection makes it a bit easier to check for stitching issues.
This is projected onto a cylinder instead of a sphere. This projection makes it a bit easier to check for stitching issues.

Update: I shot this next part with all four cameras. I have gotten some very nice stitches. Check out NewProject.mov And check these beautiful stitches out:

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Update: Fold this image into a ball!

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