Home Made Digital Camera
Background
I use many different types of cameras, from old Polaroids, to 35mm manual focus Minoltas, to modern digital Canons. Each of these have unique strengths and weaknesses, but none of them do everything well.
None of my cameras, however, can take panoramas. Sure, you could stitch together frames, and some cameras can even help you line up shots to do so. The photographer is still stuck with a lot of post-production work, and that means one thing to me: a black hole my work goes into and never comes out of.
I realized that a scanner is really a very interesting imaging device. First, it is a respectably high resolution imager. Second, it is a line imager, meaning it really only captures a single column of pixels. Third, it is digital, so its output can be easily shared with my friends.
These strengths are also limitations. The resolution is high, but scanners actually take a great deal of light. That is, their "ISO" is fairly low. Being a line imager means that the sensor must somehow "sweep" to capture a normal 2D image. Finally, while digital, a scanner is traditionally connected to a laptop, so portability is pretty low.
Aware of these limitations and strengths, I set out to build my own digital camera using parts from a scanner.
To return to the subject of panoramas, I realized that simply spinning the imager around a point (with the proper optics) would create a cylindrical surface that represented a 360 panorama. All I needed was a steady, robust rotation table upon which to spin the camera. The very nature of the imager would take care of the stitching problem: there would be none!
Next I sought a way to free the contraption from being tethered to a laptop. If I were to take this camera out into the world to capture panoramas, I needed it to be as simple as possible. I remembered that some multi-function scanners would scan directly to flash media in addition to files on the PC. A friend pointed a simple gadget that was nothing but a small photo scanner that sent images directly to an inserted SD or CF card. This gadget would become key to my design.
Finally, I needed optics and a light proof box to actually house the imager. Digging through my collection of cameras, I found an old Tektronix oscilloscope camera for Polaroid film. This camera originally attached to the front of an oscilloscope and allowed engineers to make permanent recordings of measurements they made on an oscilloscope. I'd shot a few packs of FujiFilm Instant Film through it and found that it had a fixed focal length of about 3 or 4 inches.
Using some electrical tape and a little ingenuity, I was able to mount the guts of the photo scanner gadget in place of the film pack in the camera. I could trick the scanner into thinking it was time to start a scan using my finger to block the paper detector. The scanner would then start recording columns of pixels as soon as the image got bright enough and stop either when I took my finger off the paper detector or the image got dark.
By sweeping the camera carefully, I was able to capture "ribbons" of images of a few things around my house. I even captured some images of my face by standing directly in front of a 40W equivalent light bulb.
First Results
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Improvements
At this point, I have not reached my goal of a panoramic camera. I need to build the rotating platform to pan the camera around a scene. The optics I am using only focus at a few inches, and I need them to focus much further.
However, this camera is pretty unique. I can change the direction I manually pan the camera and the speed at which I do so. I can change the orientation of the camera as I pan as well. Suddenly, I am painting with the camera like it is a thin brush.
Conclusions
This camera is complete in its own way, but I'd like to build another camera that reaches my original goal. As such, I am ordering another scanner to take apart.
I am also considering adding a way to preview the images. I may try a digital photo frame that I can trick into reading the SD card while it is still inside the scanner electronics.
I also need to figure out a way to trick the scanner to into starting to record an image immediately, not when it likes. This may entail shining a bright LED directly onto the imager. In general, the camera as a whole is finicky and would be hard to take out into the field.