What Is Remote Sensing?

Remote sensing refers to non-contact, long-range detection technology. Generally refers to the use of sensors / remote sensors to detect the electromagnetic wave radiation and reflection characteristics of objects. Remote sensing is the use of remote-sensing-type instruments that are sensitive to electromagnetic waves to detect target features while away from the target and non-contact target objects.

Remote sensing, literally, can be simply understood as distant perception, which refers to all contactless long-range detection; from the perspective of modern technology, "remote sensing" is an applied detection instrument. The technology to detect and identify long-range research objects using space vehicles and modern electronic and optical instruments.

Remote sensing Remote sensing instruments on platforms such as artificial earth satellites and aviation can be used to perform inductive telemetry and resource management monitoring on the earth's surface (such as resource management of trees, grassland, soil, water, minerals, farm crops, fish and wildlife, etc.) A combination of new technologies.

Remote sensing is an emerging technology developed in the early 1960s based on aerial photography technology. Start as

The propagation of vibrations is called waves. The propagation of electromagnetic vibrations is electromagnetic waves. The electromagnetic wave band can be divided into:

Remote sensing is a comprehensive technology for ground observation. Its implementation requires both a complete set of technical equipment and the participation and cooperation of multiple disciplines. Therefore, implementing remote sensing is a complex systematic project. According to the definition of remote sensing,

As a comprehensive science of ground observation, remote sensing is not only an objective need for people to understand and explore the natural world, but also has features unmatched by other technical means.

At present, remote sensing has formed a multi-level, multi-perspective, and multi-domain observation system from the ground to the air to the space, from the collection and processing of information and data to interpretation analysis and application. An important means of information.

In order to improve the processing speed of such huge data,

The remote sensing spectral domain is expanding

With the increasing maturity of thermal infrared imaging, airborne multi-polarization synthetic aperture radar, high-resolution surface penetration radar, and spaceborne synthetic aperture radar technology, the remote sensing spectrum has changed from the earliest visible light to near-infrared, short-wave infrared, thermal infrared, The development of the microwave direction and the expansion of the spectral domain will further adapt to the wide-range distribution of the characteristic peak wavelengths of various material reflections and radiation spectrums.

Improved remote sensing time resolution

The large, medium, and small satellites cooperate with each other, and the combination of high, medium, and low orbits ranges from several hours to 18 days in time resolution, forming a series of complementary time resolutions. ^[1]

Remote sensing spatial resolution

With the application of new sensors with high spatial resolution, the spatial resolution of remote sensing images has grown from 1km, 500m, 250m, 80m, 30m, 20m, 10m, and 5m to 1m. Military reconnaissance satellite sensors can reach resolutions of 15cm or higher. The improvement of spatial resolution is conducive to the improvement of classification accuracy, but it also increases the difficulty of computer classification.

Remote sensing spectral resolution

The development of hyperspectral remote sensing has made the width of remote sensing bands from 0.4 m (black and white photography), 0.1 m (multispectral scanning) to 5 nm (imaging spectrometer) in the early days. , Can highlight the slight differences in the peak wavelengths of reflections of specific features; at the same time, the application of imaging spectrometers, etc., improves the spectral resolution of features, which is beneficial to distinguish the spectral response characteristics of various substances in different bands.

2D 3D Remote sensing 2D to 3D measurement

The development and application of airborne three-dimensional imagers and interferometric synthetic aperture radars have developed ground targets from two-dimensional measurements to three-dimensional measurements.

Remote sensing image processing technology

Various new and efficient remote sensing image processing methods and algorithms will be used to solve the processing, correction, fusion and remote sensing information visualization of massive remote sensing data.

Development of remote sensing and remote sensing analysis

Remote sensing analysis technology has changed from "qualitative" to "quantitative". Quantitative remote sensing has become a hotspot in the development of remote sensing applications.

Remote sensing remote sensing extraction technology

Establish an expert system suitable for automatic interpretation of remote sensing images, and gradually realize the automatic extraction of thematic information of remote sensing images.