Grid Sample Fixture
Below is a photograph of the Plexiglass fixture that holds 36 Petri plates and provides white LED illumination to each unit cell. It is approximately 1 m x 1 m and is mounted on a tubular aluminum frame. The three-axis robot that positions the camera with micron-level resolution at programmable time intervals is also visible at left. Not visible behind the fixture is an array of infrared LEDs that provides the imaging illumination. The camera is equipped with a long-pass filter so that the image is made from the infrared backlight not the ambient visible light.