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Image analysis is a methodology used to extract data from images rather than counting
or measuring directly. The advantages are that the captured images are permanent, allowing
more time for study, and they can be subjected to enhancement and automated analysis
techniques to improve data quality.
Image analysis begins with a digitized image, which means that the image is composed of
a rectangular array of individual points of color, called pixels. Typical images are 768
pixels by 512 pixels, with each pixel being a value between 0 and 255. The pixel value
represents a color that can be displayed on a computer monitor or some other display
device. Using computers, the image pixels can be manipulated mathematically to change the
appearance of the image or to determine some quality of the image.
FIDUCIAL MARKERS Selected
points on an image that are used as a frame of reference in locating objects or in
positioning (registering) images containing the same fiducial markers.
FRAME GRABBER A device
that converts a video signal to a digitized image. Frame grabbers are usually located in a computer and are connected to a video camera.
IMAGE ACQUISITION The
digitization and storage of an image.
IMAGE ENHANCEMENT Modification
of the pixels of an image to improve its appearance. Common enhancement methods are
smoothing, sharpening, histogram modification, and filtering.
IMAGE PROCESSING A
general term for the acquisition and manipulation of digital images.
PIXEL A single point of color
in a digitized image.
REGISTRATION The process
of finding common points between images of the same area collected by different
instruments or under different conditions. This is necessary to guarantee that points in
one image can be accurately mapped to another image for analysis.
TIFF FILE Tagged Image File
Format is a common type of image file format that contains a variety of descriptive
information as well as the image data itself.
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