Difference between SAR Image and Optical Image | SAR vs. Optical Sensors

 In remote sensing, the electromagnetic imaging sensor is known as Synthetic Aperture Radar, or SAR, is often used. In order to get a clear picture of the Earth's surface, the SAR sensor is attached to an airplane or satellite. This technology is sometimes used in more distant applications, such as taking images of Venus's surface.

SAR Image/ SAR Sensors

Optical Image/ Optical Sensors

The image captured from synthetic aperture radar is called SAR image.

The Image captured from optical sensor like a film camera or a TV camera is called optical image.

SAR uses a wavelength of 1 cm to 1 m.

Optical sensors use wavelengths near that of visible light, or 1 micron.

Optical sensors cannot see through clouds or storms because of the difference in wavelengths. Because electromagnetic waves scatter or reflect at various frequencies and wavelengths, the Earth's surface appears substantially different in the two sensors. The intensity of the received signal is typically determined by the surface roughness of objects that seem smooth at one wavelength but relatively rough at a shorter one.

SAR sensor carries its own illumination source, in the form of radio waves transmitted by an antenna

optical sensors rely upon the sun's illumination or thermal radiation to create the brightness that is observed by the sensor

The picture captured by an optical sensor change with the time of day due to variations in the sun's angle, while SAR can be utilised effectively at any time of day or night.

SAR is a side-looking sensor.

Optical sensors mainly look straight down.

Both the images contain different information, and for some applications SAR images are better, while for other applications, optical images are better. For example, SAR is better for imaging the ice in the Canadian Arctic. In an optical image, snow and ice appear bright white, and relatively featureless. But in a SAR image, the surface roughness patterns are clearly portrayed, and trained observers can deduce the age and thickness of the ice.

Satellite data may be used in a variety of ways, each with advantages and disadvantages. radar imaging is better than optical imagery when it's foggy and you're looking to emphasize the roughness of the surfaces.

Read more

Roughness and Brightness of SAR Image

Different Types of SAR | Strip mapping Mode SAR | Spotlight Mode SAR | Inverse SAR (ISAR)

Problems in Synthetic Aperture Radar (SAR) Image

Radar Categorization Based on Antenna Size | RAR (Real Aperture Radar) | SAR (Synthetic Aperture Radar)

Radar | Types of Radar | Active Radar | Passive Radar

Applications for Synthetic Aperture Radar (SAR)

How Synthetic Aperture Radar (SAR) Images are Created?

Note: If you are taking help from the above work and  also incorporating the above content in your research work, Kindly make sure you are citing the below papers.

  1. https://www.sciencedirect.com/science/article/pii/S2215098617314003
  2. https://www.sciencedirect.com/science/article/pii/S1319157817301106
  3. https://www.sciencedirect.com/science/article/pii/S1319157817303865
  4. https://link.springer.com/article/10.1007/s11831-021-09548-z

                For more image processing topics refer: https://www.gofastresearch.com/

Difference between SAR Image and Optical Image | SAR vs. Optical Sensors Difference between SAR Image and Optical Image | SAR vs. Optical Sensors Reviewed by IPR on February 24, 2022 Rating: 5

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