Document cameras, also known as digital visual presenters or visualizers, are electronic imaging devices that create large-screen displays of printed material, three-dimensional objects or even people. You can display these images on large monitors or project them onto screens. Unlike traditional overhead projectors, images displayed by document cameras do not have to be transparencies. Document cameras enable you to display small visual detail at high resolution to groups in business conferences, classrooms, courtrooms and online audiences. At its most basic form, a document camera consists of an imaging device mounted on a stand focusing on objects placed on a lighted platform beneath it, and a processor to process the image digitally.
Image Sensor
Document cameras usually incorporate either a CCD or CMOS Active Pixel chip for imaging. Most cameras accommodate a motorized zoom lens and a lens with extreme close-up characteristics.
Camera Mounts
The arms that support the document camera are either rigid or the flexible "gooseneck" variety. Rigid arms may be telescoping to allow extension of the camera height. Gooseneck arms that flex allow greater maneuverability of the camera head to adapt it to imaging unusual shapes, or for specialized applications such as imaging through a microscope lens or displaying oblique views of small components.
Base Stand
Also known as the stage, a document camera's base stand serves two functions. First, it provides a flat, level area for display and illumination of the imaged objects. Second, it contains the digital imaging processing equipment, the control panel, inputs/outputs and serves as the mounting base for the camera lights. The control panel typically contains controls to zoom in and out, rotate the image, adjust brightness and contrast and capture the digital image to the unit's RAM. Input/output connections usually include 15-pin VGA, S-video, BNC and Composite Video. Many models also include a DVI connection.
Lights
Normally mounted on columns to either side of the base stand, camera lights usually have adjustments for angle of lighting and the proximity of lights to the imaged material. The light source is usually CCFL (cold cathode fluorescent light) bulbs or neutral LED lights.
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