User guide

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Glossary
Glossary
• Artifact: In imaging, a flaw caused either by the imaging process or by the hardware itself. For
example, dust on the camera lens could cause small bright or dark spots in an image.
• Aspect Ratio: The ratio between an image's width and its height. If the aspect ratio is not
preserved, the image will appear stretched or squashed.
• Bits: The smallest units of computer measurement. A bit is a single binary value (i.e. it can be
"on" or "off" only). Bits typically are combined into units of eight, called "bytes." Modern computer
processors work with groups of 4 ("32-bit processor") or 8 ("64-bit processor") bytes at a time.
• BMP: Microsoft Bitmap image file format. BMP is a lossless format which provides some
compression to reduce file size. BMP files generally have a BMP extension.
• Control Handle: A small square at the corner (or similar point) of a graphical object that marks its
extent and indicates that the object is selected. Usually the object can be resized by dragging the
control handle; in some cases, different behavior results.
• Electrophoresis: The movement of suspended particles through a fluid or gel through the
application of electrical current to the suspension medium.
• Fidelity: The degree to which an image is true (i.e. accurate and uncorrupted) to the original
scene it represents. Also used in audio technology with the same meaning.
• GIF: Graphic Interchange Format, a proprietary Xerox image compression format. GIF is a lossy
compression format that results in very small files. Files stored in GIF usually have a GIF
extension.
• Image Depth: The size (and thus range) of intensity numbers supported per pixel in an image.
• Intensity: The measure of brightness of a pixel. In a monochrome image, each pixel has a single
intensity. In a colored image, each pixel has three intensities: one for red; one for green; and one
for blue. The actual intensity values depend on an image's depth.
• JPEG: A common lossy compression image format used to store images on disk. JPEG files
generally have JPG or JPEG extensions.
• Lossless Compression: Compression schemes that preserve the image's integrity in full.
Generally, lossless compression results in much larger files than lossy compression on the same
image.
• Lossy Compression: Compression schemes that tolerate some pixel value changes to make the
image compress to a smaller size. Because the changes are irreversible, the image has "lost"
some of its original detail after such an operation.
• Macro Mode: Close-up mode for a digital camera or web-camera. Macro mode is usually
appropriate for imaging microbiology slides.
• Microbiology: The branch of biology dealing with microscopic forms of life.
• Microscopy: The use of or investigation with a microscope.
• Monochrome: Black-and-white, with shades of gray.
• Pixel: Short for "picture element." A pixel is a single dot in a computer image. The dot has a
certain color (for a color image) or an intensity (for a monochrome image). For a more detailed
explanation, see Inside a Pixel.