Gigapixel Microscope Reveals Tiny Parts Of The Big Picture
[JBumstead] didn’t want an ordinary microscope. He wanted one that would show the big picture, and not just in a euphemistic sense, either. The problem though is one of resolution. The higher the resolution in an image — typically — the narrower the field of view given the same optics, which makes sense, right? The more you zoom in, the less area you can see. His solution was to create a microscope using a conventional camera and building a motion stage that would capture multiple high-resolution photographs. Then the multiple photos are stitched together into a single image. This allows his microscope to take a picture of a 90x60mm area with a resolution of about 15 μm. In theory, the resolution might be as good as 2 μm, but it is hard to measure the resolution accurately at that scale.
As an Arduino project, this isn’t that difficult. It’s akin to a plotter or an XY table for a 3D printer — just some stepper motors and linear motion hardware. However, the base needs to be very stable. We learned a lot about the optics side, though.
Two Nikon lenses and an aperture stop made from black posterboard formed a credible 3X magnification element. We also learned about numerical aperture and its relationship to depth of field.
One place the project could improve is in the software department. Once you’ve taken a slew of images, they need to blend together. It can be done manually, of course, but that’s no fun. There’s also a MATLAB script that attempts to automatically stitch the images together, blending the edges together. According to the author, the code needs some work to be totally reliable. There are also off-the-shelf stitching solutions, which might work better.
We’ve seen similar setups for imaging different things. We’ve even seen it applied to a vintage microscope.