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April 8, 2007
Microscope design: Rudolf Oldenbourg and Marc Levoy
Software and web page: Zhengyun Zhang
At left below is a prototype light field microscope (LFM) assembly that is portable, inexpensive (about $2,000, not including the base microscope), and can be installed on a compatible microscope in less than a minute. In this example the base microscope is a Nikon Eclipse 80i. We have also built a version for Zeiss microscopes. Attached to the Nikon's camera port (above the eyepieces) is a custom-machined housing for our microlens array (circled in red). The array contains 288 x 192 microlenses, with each microlens measuring 125 microns on a side. We image the microlenses through a relay lens system consisting of two Nikon f/1.4 50mm lenses. The camera (at top) is a Retiga 4000R 2048x2048 cooled CCD camera.
At right below, PhD student Zhengyun Zhang uses both hands to manipulate light field micrographs using his software viewer. With his left hand, he is translating the microscope stage in the usual way. With his right hand, he is digitally tilting the specimen around the X or Y axes using a mouse. Since light fields are being continuously streamed to his software from the Retiga camera, and his software can compute oblique or refocused views from these light fields at roughly 30 Hz, the view he sees on the screen is both interactive and live. This software runs on any PC with a reasonably fast graphics accelerator card.
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Light Field Microscope
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Real-time Viewer
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| The microlens array is inside a custom housing, circled in red. | The specimen is a speck of fluorescent crayon wax, the objective is 40x/0.95 (dry), and the camera is a Retiga 4000R (2K x 2K pixels). |
April 30, 2007
Specimen and photography: Elizabeth Doyle, Todd Anderson, William Gilly
Processing and web page: Marc Levoy
We have installed one of our new light field microscopes in Stanford's Hopkins Marine Station, which means simply that we have loaned them one of the microlens arrays in its housing that is shown in the red circle above. Under the direction of PhD student Todd Anderson, and advised by Professors Stuart Thompson and William Gilly, several of the undergraduates have been collecting local organisms and examining them under the light field microscope. Here are a few of the light fields they have captured.
Fern spore
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Venom duct of cone snail (Conus magus)
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| 60x/1.1NA (water), rhodamine auto-fluorescence. | Radular sac, 20x/0.5NA (water), red image is transmitted light, green is rhodamine auto-fluorescence in the rhodamine band. |