![]() There are many different false colored composites which can highlight many different features. Using bands such as near infra-red increases the spectral separation and often increases the interpretability of the data. False color composites allow us to visualize wavelengths that the human eye can not see (i.e. False Color Compositesįalse color images are a representation of a multi-spectral image produced using bands other than visible red, green and blue as the red, green and blue components of an image display. Natural color images can be low in contrast and somewhat hazy due the scattering of blue light by the atmosphere. Many people prefer true color composites, as colors appear natural to our eyes, but often subtle differences in features are difficult to recognize. The resulting composite resembles what would be observed naturally by the human eye, vegetation appears green, water dark is blue to black and bare ground and impervious surfaces appear light grey and brown. Natural or True Color CompositesĪ natural or true color composite is an image displaying a combination of visible red, green and blue bands to the corresponding red, green and blue channels on the computer. When we combine these three images we get a color composite image. ![]() Computer screens can display an image in three different bands at a time, by using a different primary color for each band. The three primary colors of light are red, green, and blue. The range of wavelengths measured by a sensor is known as a band and is commonly described by the wavelength of the energy.īands can represent any portion of the electromagnetic spectrum, including ranges not visible to the eye, such as the infrared or ultraviolet sections.Įach band of a multispectral image can be displayed one band at a time as a grey scale image, or in a combination of three bands at a time as a color composite image. These sensors, known as multispectral sensors, simultaneously measure data in multiple regions of the electromagnetic spectrum, including visible light, near and short wave infrared. ![]() The Macintosh and Windows versions and documentation on its use are available from the World Wide Web at URL: ∼biehl/MultiSpec/ MultiSpec is copyrighted (1991-2001) by Purdue Research Foundation, West Lafayette, Indiana 47907.Sensors on earth observing satellites measure the amount of electromagnetic radiation (EMR) that is reflected or emitted from the Earth’s surface. Although copyrighted, MultiSpec with its documentation is distributed without charge. Since then most (but not all) of the features in the Macintosh OS version have been ported to the Windows OS version. The GLOBE ( ) program supported the development of a subset of MultiSpec for the Windows OS in 1995. ![]() The effort was first begun on the Macintosh OS in 1988. MultiSpec has been implemented for both the Apple Macintosh ® and Microsoft Windows ® operating systems (OS). It has also found use in displaying and analyzing many other types of non-space related digital imagery, such as medical image data and in K-12 and university level educational activities. The primary purpose for the system was to make new, otherwise complex analysis tools available to the general Earth science community. It is intended to provide a fast, easy-to-use means for analysis of multispectral image data, such as that from the Landsat, SPOT, MODIS or IKONOS series of Earth observational satellites, hyperspectral data such as that from the Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) and EO-1 Hyperion satellite system or the data that will be produced by the next generation of Earth observational sensors. MultiSpec is a multispectral image data analysis software application. ![]()
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