I was reminded (and inspired) by this
site that it is possible to perceive a stereoscopic effect without using special glasses - simply alternating between two slightly different perspectives of the same image is sufficient.
I have no fancy setup or special lens, so everything was done by hand and tweaked using GIMP.
I would take one picture then move the camera slightly to one side (very little - a cm or so was plenty - perhaps too much). Then I would slightly rotate the camera (again, very little).
I then loaded the images into GIMP and overlaid them on two separate layers.
Performed edge detection on both of them and then used the move tool to align horizontal edges (it helps to have some good horizontal edges in the image) - necessary to make the top layer transparent (I used 50% opacity). I needed to do this because shifting the camera by hand meant that the images didn't overlap perfectly. You only need to move one image, not both.
Once I knew how much to move / shift an image, I went back to the original overlayed images and moved it by the same amount.
Then I cropped, the image. Resized. Converted it to an indexed image. And, finally saved as a GIF file.
Since I had two layers, GIMP asks if I wanted to flatten them (merge then together) or export them as an animated GIF. I chose animated GIF, set the delay to 50ms and the option to loop forever.
Looking these over, I think it is important to pick a reference point that remains in the centre of both pictures. When you take the first picture, note where the centre is, then, when you shift and angle the camera, make sure the centre point is the same.
Actually worked out quite well.
(My apologies, these are quite large images - the smallest a little over 500K and the largest a little over 1M)
The images are:
- my second attempt at a 3D image. I think it is the best (marred by the fact that one image is out of focus).
- my first attempt (proof of concept).
- what happens when you move the camera too much between shots
- another pretty nice result
- fourth attempt (I aligned ages at the back of the image)
- same image (fourth attempt) with alignment done on the front edges
Hopefully, this year, I will keep doing and posting things periodically to my Posterous account.
You will have to hover over the image and click the 'Download full size' link because Posterous does something to the gifs that disables the animation on the main page.
Posterous is fiddling with the images and the GIF animation seems iffy.
You can see them at my blog over here (opens in a new window / tab). Be patient there is over 4MB of image data to download.
eclectic, avuncular dilettante 