False color composite
Sensors on earth observing satellites measure the amount of electromagnetic radiation (EMR) that is
reflected or emitted from the Earth’s surface. 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 range of wavelengths measured by a sensor is known as a
band and is commonly described by the wavelength of the energy. Bands can represent any portion
of the electromagnetic spectrum, including ranges not visible to the eye, such as the infrared or
ultraviolet sections.
Each 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. The three primary colors of light are
red, green, and blue. Computer screens can display an image in three different bands at a time, by
using a different primary color for each band. When we combine these three images, we get a color
composite image.
False Color Composites
False 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. False color
composites allow us to visualize wavelengths that the human eye cannot see (i.e. near-infrared). Using
bands such as near infra-red increases the spectral separation and often increases the interpretability
of the data. There are many different false colored composites which can highlight many different
features. See the heading below for more information about common band combinations for false
color composites.
False colour composite true colour composite
A false colour image is one in which the R, G, and B values do not correspond to the true colours of
red, green and blue. The most commonly seen false-colour images display the very-near infrared as
red, red as green, and green as blue. An artificially generated colour image in which blue, green and
red colours are assigned to the wavelength regions to which they do not belong in nature. For
example, in standard a False Colour Composite blue is assigned to green radiations (0.5 to 0.6 µm),
green is assigned to red radiations (0.6 to 0.7 µm and red is assigned to Near Infrared radiation (0.7 to
0.8 µm). This false colour composite scheme allows vegetation to be detected readily in the image.
vegetation appears in different shades of red depending on the types and conditions of the vegetation,
since it has a high reflectance in the NIR band.
Standard False Colour Composite (FCC)
• NIR band – Red; Red band – Green; Green band – Blue
• In IRS: Band 4 – Red; Band 3 – Green; Band 2 – Blue
Other False Colour Composite
Any other combinaton of colours
• E.g., Blue band – Red; Red band – Green; Green band – Blue
• E.g., Blue band – Red; Red band – Green; NIR band – Blue
Preparing of FCC from IRS-LISS 3:
Under the Indian remote sensing programme, under the IRS system various satellites has been sent
out to data capture and research purposes. The LISS 3 or Linear Imaging Self Scanning Sensor is being
used by the RESOURCESAT-I and RESOURCESAT-II. Under LISS 3 of these two satellites various bands
have been used for FCC and interpretation.
Band Colour Wavelength Spatial resolution
2 Green .52-.59 23
3 Red .62-.68 23
4 Nir .77-.86 23
5 swir 1.55-1.70 70
Now based on the rules of standard FCC, the LISS 3 data makes out-
Green – blue
Red – green
Near infrared- red
By standard fcc under LISS, band 2, 3 and 4 are replaced or exchanged by band 1, 2 and 3.
4-3-2 to 3-2-1
From landsat data:
Landsat 4 and 5 under the US space programme uses the following bands –
Band Colour Wavelength (cm) Spatial resolution
1 Blue .45-.52 30
2 Green .52-.60 30
3 Red .63-.69 30
4 NIR .76-.90 30
5 SWIR I 1.55-1.75 30
6 Thermal 10.41-12.5 120
7 SWIR II 2.08-2.35 30
Under the standard FCC rule, The TM of landsat band 2, 3 and 4 are converted or exchanged into band
1, 2 and 3 respectively.
4-3-2 to 3-2-1
From OLI:
Under the us space programme, NASA has send landsat 8 which uses Operational Land Imager (OLI)
which uses the bands –
Band Colour Wavelength (cm) Spatial resolution
1 Coastal aerosol .43-.45 30
2 Blue .45-.49 30
3 Green .53-.59 30
4 Red .64-.67 30
5 NIR .85-.88 30
6 SWIR I 1.57-1.65 30
7 SWIR II 2.11-2.29 30
8 Panchromatic 0.50-0.68 15
9 Cirrus 1.36-1.38 30
10 Thermal iR I 10.60-11.99 100
11 Thermal IR II 11.50-12.51 100
Under standard FCC, from OLI the band 3,4 and 5 are passed through or converted in band 2, 3 and 4.
5-4-3 to 4-3-2
