Thursday, January 18, 2007
Digital Camera Fundamentals
A useful glossary to help you decode some of digital's terminology
Compression The process of encoding files through an algorithm, which decreases the size for storage or transmission over the Internet. There are two types of compression: lossy and lossless. Lossy compression (JPEG is an example) results in a visible degradation in image quality because some image data is lost in the compression process. Lossless compression (like LZW compression) preserves all image data.
Digital Zoom A simulated zoom effect that enlarges the image on a portion of the image sensor. Because fewer pixels are used to capture the image, you end up with a significantly lower-resolution final image.
Effective Pixels Pixels on the sensor actually used to capture an image. Often, not all the pixels on a sensor can be used because: 1) some pixels on the surrounding edges of a sensor are masked off to determine a black point; or 2) some cameras, especially compact ones, have lenses that are unable to cover the entire sensor area.
Interpolation (or Resampling) Artificially increasing or decreasing the number of pixels in an image through the use of an algorithm. Some cameras increase the number of pixels automatically to compensate for digital zoom.
JPEG (Joint Pictures Expert Group) A common algorithm for the compression of image files. JPEG compression can vary from nearly lossless to highly glossy. Because JPEG is a standard, JPEG image files can be read by all image-processing software.
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