How does the CytoCam-IDF camera work?

The CytoCam is a novel lightweight handheld video microscope.
The optical system has been designed for the purpose of microcirculation imaging. It is based on a a set of high resolution lenses with a magnification factor x4 and provides an optical resolution of more than 300 lines/mm which is a 50 % improvement over earlier devices and provides a significant improvement on image quality 

The probe incorporates Incident Dark Field (IDF) illumination, based on the work of Sherman and Cook [1].

It uses 12 Green LEDS with high brightness. The LED’s are controlled by a control unit which generates a pulse with a duration of 2 ms. The control unit synchronizes the pulse with the clock signal of the sensor exposure. This short light pulse and the short exposure result in sharper contours of fast moving RBCs.

The camera is fully digital and contains a high-resolution sensor with a pixel size of 1,4 micron. As it is used in binning mode the effective pixel size is 2,8 micron, resulting in a 3.5 megapixel frame size. The combination of a 4x optical magnification with the sensor image area provides a 1,55 x 1,16 mm field of view, which is almost twice as large as the field of view of earlier devices.

Additionally, a completely new feature is the quantitative focusing mechanism. This feature uses a linear motor drive, which positions the sensor within 2 microns. Furthermore, it significantly eases the focusing problem. Once the focus depth for a specific patient has been established repeated measurements can be made without the need for subsequent focus adjustments, which significantly reduces the measurement time allowing serial measurements to be easily made.

The CytoCam is a pen like device and is held as such. The low weight of the device (120 gram) minimizes pressure artifact problems that were present in the earlier heavy devices.

The camera is connected to a device controller based on a medical grade computer or a suitable portable device such as laptop or tablet, which is used for image storage. The device controller connects to the camera with a USB3 based camera adapter with a dedicated microprocessor for controlling the camera.

[1] Sherman H, Klausner S, Cook WA (1971)Incident dark-field illumination: a new method for microcirculatory study. Angiology;22(5):295-303.