A crucial instrument for Earth observation, climate monitoring, and navigation comes from cameras on satellites. For instance, wind speeds can be calculated using UV lasers through satellites worldwide, or the sizes of farmed areas of particular plants can be estimated using special filters. A satellite camera also plays a significant role in disaster management, transportation infrastructure development, environmental protection, and nature conservation.
Satellite imagery aids in keeping up with technological advancements, delivering diversified solutions, and providing the most up-to-date, high-quality data to various enterprises throughout the world. So, let’s find out more about satellite cameras in this article.
What is Satellite Camera?
A satellite imager is a detecting device equipped with a sensor constantly monitoring from space over the Earth’s surface, capturing the signal generated or reflected by the subject or the surrounding region. Satellite cameras capture massive electromagnetic waves. Corporations and governments across the world primarily utilize imaging satellites.
Now that we know what satellite camera does, let’s learn about how satellite camera works. Satellite cameras are more than simply a webcam in orbit; every 10 minutes, their imagers capture one whole side of the Earth. However, unlike a typical camera, a satellite camera does not capture the image in a single snap.
Instead, it sweeps back and forth across the Earth, constructing the image in 10 lengthy segments before beaming it down to a ground station. The image captured by a satellite camera is cut into strips and divided into its component colors. The resulting image we perceive is made up of pixels in red, green, and blue colors.
A unique image is acquired in the satellite for each visible ‘channel’ and additional unseen specters, such as infrared. When the satellite image arrives at the ground station, it is not the typical square image. Instead, a series of colorful stripes form a psychedelic jigsaw puzzle that must be completed. All this may sound confusing so let’s break it down.
To put it simply, Earth observation satellites have a camera or sensor aboard that captures all reflected light from the region of interest on Earth. It’s then transformed into binary data, subsequently turned into short wave radio waves, and relayed back to Earth. The ground station intercepts these radio signals, converts them to binary data, and then reconstructs them into a picture.
Considering all conversion and processing, it can take anywhere from a few hours to a few days, depending on what is captured. This entire phenomenon is also called remote sensing. Technological advancements in remote sensors allow us to collect data worldwide while significantly enhancing humanity’s awareness of its own living environment from both geographical and temporal perspectives and providing a growing amount of data resources for digital Earth.
Types of Sensors
There are currently several satellites observing the Earth, each with its own particular purpose. Satellite cameras capture electromagnetic radiation reflected from the Earth using several types of sensors. Remotely sensed satellite imagery is becoming more widespread as governmental and commercial entities worldwide continue to launch satellites equipped with technologically superior sensors into orbit.
A passive sensor on a satellite camera is an electromagnetic detector capable of receiving and monitoring natural emissions generated by the Earth’s surface and atmospheric elements. An active sensor is a radar that measures signals that are reflected, refracted, or dispersed by the surface of the Earth or its atmosphere. The power detected by passive sensors is affected by the Earth’s surface composition, physiological temperatures, surface roughness, and other physicochemical parameters.
Active sensors are analogous to a handheld camera with a flash switched on. When you snap a photo with the flash on, the camera sends its light source. The camera records the reflected light back to the camera lens after it lights the object. Active sensors are more helpful than passive sensors since they can be utilized in any season and at any time of the day (passive sensors fail to capture the regions of the Earth with low lighting).
Different Kinds of Imaging
A satellite camera can capture panchromatic, multispectral, and hyperspectral pictures.
Panchromatic Images
The first satellite images were captured using a black-and-white camera placed on a spacecraft. A panchromatic image is a high-resolution single-band grayscale image that merges data from the observable R, G, and B bands. As a result, a panchromatic image can be viewed in the same way as a black-and-white aerial shot of the region.
Multispectral Images
A multispectral image comprises many monochrome photos of the same subject, each captured with a different sensor. Each picture is known as a band. A well-known multispectral is an RGB color image consisting of red, green, and blue colors, each captured using a sensor sensitive to a distinct wavelength.
Hyperspectral Images
Hyperspectral sensors measure energy in smaller and more numerous bands than multispectral sensors. A hyperspectral image can include up to 200 (or more) contiguous spectral bands. Hyper-spectral sensors’ multiple small bands give a continuous spectral measurement over the whole electromagnetic spectrum, making them more sensitive to minor fluctuations in reflected energy.
Final Thoughts
The potential of satellites will undoubtedly increase as technology progresses. New markets will develop, as will new possibilities to test the limits of what space technology now provides. Satellite cameras have greatly helped humanity by being excellent tools in space exploration and will continue to be so in the coming years.