Mach band
An optical illusion of dark and light fringes within adjacent areas of contrasted tone. It is a psychophysiological phenomenon which aids human detection of boundaries or edges.

Median filter
A spatial filter, which substitutes the median value of DN from surrounding pixels for that recorded at an individual pixel. It is useful for removing random noise.

Microwave
Region of the elctromagnetic spectrum in the wavelength range of 0.1 to 30 cm.

Mid-infrared (MIR)
The range of EM wavelengths from 8 to 14 µm dominated by emission of thermally generated radiation from materials; also known as thermal infrared.

Mie scattering
The scattering of EM energy by particles in the atmosphere with comparable dimensions to the wavelength involved.

Minimum ground separation
Minimum distance on the ground between two targets at which they can be resolved on an image.

Minus
blue photographs-Black-and-white photographs acquired using a filter that removes blue wavelengths to produce higher spatial resolution.

Mixed pixel
A pixel whose DN represents the average energy reflected or emitted by several types of surface present within the area that it represents on the ground; sometimes called a mixel.

Modulate
To vary the frequency, phase, or amplitude of electromagnetic waves.

Modulation transfer function (MTF)
A method of describing spatial resolution.

Mosaic
Composite image or photograph made by piecing together individual images or photographs
covering adjacent areas.

MSS
Multispectral scanner system of Landsat that acquires images of four wavelength bands
in the visible and reflected IR regions.

Multiband Camera
System that simultaneously acquires photographs of the same scene at different wavelengths.

Multispectral classification
Identification of terrain categories by digital processing of data acquired by multispectral scanners.

Multispectral scanner
Scanner system that simultaneously acquires images of the same scene at different wavelengths.