Get Evaluating Image Filtering Based Techniques - Cc Gatech

Spatial filtering is a process by which we can alter properties of an optical image by selectively removing certain spatial frequencies that make up an object, for example, filtering video data received from satellite and space probes, or removal of raster from a television picture or scanned image.

Image filtering is changing the appearance of an image by altering the colors of the pixels. Increasing the contrast as well as adding a variety of special effects to images are some of the results of applying filters.

Filtering is a technique for modifying or enhancing an image. For example, you can filter an image to emphasize certain features or remove other features. Image processing operations implemented with filtering include smoothing, sharpening, and edge enhancement.

Image filtering involves so-called neighborhood operations, in which the value for each pixel in the scene is recalculated based on the values of surrounding pixels.

In general, spatial filters are more commonly used for edge detection while frequency filters are more often used for high frequency emphasis. Here, the filter doesn't totally block low frequencies, but magnifies high frequencies relative to low frequencies.

Mean filtering is a simple, intuitive and easy to implement method of smoothing images, i.e. reducing the amount of intensity variation between one pixel and the next. It is often used to reduce noise in images.

A filter moves systematically across a raster until each cell has been processed. Filters can be of various shapes and sizes, but are most commonly three-cell by three-cell squares. [data analysis] A desktop GIS operation used to hide (but not delete) features in a map document or attribute table.

Median Filter: Replaces each pixel's value with the median value of its neighboring pixels, effective for removing salt-and-pepper noise. Mean Filter: Replaces each pixel's value with the average value of its neighboring pixels, used for blurring and noise reduction.