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Glossary
CCD
A charge-coupled device (CCD) is a light-sensitive integrated circuit that stores and displays the data
for an image in such a way that each pixel in the image is converted into an electrical charge with
intensity relative to a gray level in the grayscale. The MiniLumi system has a black and white sensor
with 65,536 gray levels, so there will be a separate value for each gray level that can be stored and
recovered. CCD is one of two main types of image sensors used in digital cameras to create high-
quality, low-noise images.
Dynamic Range
Dynamic range is the range that a sensor is capable of differentiating. If the sensor can differentiate
between two points in an image, then each point is translated into a pixel of the image; if the sensor
is unable to differentiate, then the two points will be pixels of noise. Dynamic range is also referred
to as Signal to Noise Ratio (SNR).
Exposure Time
The length of time light passes through the lens to form an image.
Fluorescence
A process by which a fluorescent molecule is excited at one wavelength and triggers the emission of a
photon with longer (less energetic) wavelength; making it possible to detect, image, and measure the
amount of fluorescence in samples as small as individual cells, and with multiple fluorescent colors.
Gain
A camera feature that increases or decreases the strength of an electrical signal. When the gain is
increased brightness also increases, and so does any electronic “noise”. This results in a brighter
image with less clarity.
Iris
A mechanical diaphragm that adjusts the lens aperture; with high levels of illumination, the iris
should be minimized; with low levels of illumination, the iris should be maximized.
Pixel
A pixel, or picture element, is the basic unit that the camera uses to build an image. Image size is also
measured in pixels.
Pseudo-colors
Using pseudo-colors to color an image artificially can reveal textures and qualities within the image
that may not have been apparent with the original coloring. Essentially, the pseudo-color module
populates the image based on its grayscale value, which maps to the full RGB color range. Therefore,
red and yellow (warm colors) indicate oversaturated areas, and blue (cold color) indicates under-
saturated areas in the image. Green indicates midrange levels.
