Microscopes have allowed us to learn much about the tiny things that make up our world and our bodies. Unfortunately, the laws of physics limit the power of optical microscopes, as improvements to microscopes must involve a compromise between the resolution of a magnified image and the size of its field of view. In other words, resulting images tend to either be sharper and clearer or capture a larger area.
Over at the California Institute of Technology, engineers have have come up with a way to modify a conventional microscope to produce images that have both a wide field of view and are high-resolution. No laws of physics were violated; all the modification required was some special software and a $200 LED light array.
Here’s how the modded microscope works: The new system acquires about 150 low-resolution images of a sample. Each image corresponds to one LED element in the LED array. Therefore, in the various images, light coming from known different directions illuminates the sample. A novel computational approach, termed Fourier ptychographic microscopy (FPM), is then used to stitch together these low-resolution images to form the high-resolution intensity and phase information of the sample—a much more complete picture of the entire light field of the sample.
The final images take advantage of the wider field of view of a 2X lens and combine it with the resolution of a 20X lens, resulting in images in the gigapixel range.
Caltech researchers say the new microscopy method can have a wide variety of applications in digital pathology and could also be extended to other imaging methodologies, such as X-ray imaging and electron microscopy.
Article from Caltech: Pushing Microscopy Beyond Standard Limits
Journal article at Nature Photonics: Wide-field, high-resolution Fourier ptychographic microscopy