On the other hand, hyperspectral imaging technology is facilitated by the high informational content hence continuous development. It is therefore positioned to become a primary remote sensing technology used on a global scale.

Multispectralcamera

In multispectral data, reflected energy in the spectrum spans a wider range. It makes it difficult to get a lot of detail on an object or surface area captured. It is because the wavelength bands are much broader.

On the other hand, hyperspectral imaging can detect thousands of different bands within the light spectrum. Sich imagery is extremely helpful to detect certain objects and minerals if an analyst is familiar with their spectral properties. Just like multispectral, their satellites also follow the sun-synchronization, Low Earth Orbit.

Meanwhile, one of the downfalls of hyperspectral remote sensing is its complexity. It has many bands one has to work with; hence, it may be difficult to reduce redundancies or hard work.

In the article below, we give a more detailed overview of multispectral and hyperspectral remote sensing. Let’s get started.

While when it comes to hyperspectral data, images present hundreds of points of each band hence much more detail to observe. The wavelength is split into numerous narrow bands that capture a unique spectral fingerprint or signature of an object. Therefore, the images captured contain much more data, thus preventing any analyst from the potential to detect differences among land and water features.

Hyperspectralcamera

In this image a deep depth of field allows the viewer to take in many subjects, including an artillery shell mid-flight. Photo by Staff Sgt. Steven Schneider In this image a deep depth of field allows the viewer to take in many subjects, including an artillery shell mid-flight. Download Image  Share Image: X Facebook Email Photo by: Staff Sgt. Steven Schneider VIRIN: 170918-O-N0132-7230C

In this image a medium depth of field allows the viewer to focus on multiple subjects without creating confusion for your eyes Photo by Sebastian J. Sciotti Jr. In this image a medium depth of field allows the viewer to focus on multiple subjects without creating confusion for your eyes Download Image  Share Image: X Facebook Email Photo by: Sebastian J. Sciotti Jr. VIRIN: 170525-D-SS007-019C

Spectral resolution refers to the number and width of the electromagnetic spectrum portions measured by a sensor. Multispectral remote sensing has a poor spectral resolution. Thus, it makes it harder to discern the Earth’s features as easily as hyperspectral sensors. The reason is that multispectral sensors are captured in small numbers due to the wide bands.

Multispectralandhyperspectralremote sensing PDF

On the other hand, hyperspectral remote sensing has a high spectral resolution that makes it possible to detect the spectral properties of objects and minerals. It gives the better capability to see the unseen.

Spectral imaging was first introduced in the early 1970s and was mainly for military applications. It was originally referred to as multispectral. Due to the increase of spectral bands and advancements through successive generations of imaging, hyperspectral was introduced.

The focal length of the lens determines the image magnification. The wider the lens, the shorter the focal length. This allows you to capture a wider depth of field. The longer or more zoomed in the camera lens, the less depth of field you capture.

Multispectral remote sensing images have lower informational content hence continued use of the same technology over time. Due to the lack of information richness in this imaging technology, it faces a disability of continual development.

Multispectral remote sensing systems use parallel sensor arrays that detect radiation in a small number of broader wavebands.

Hyperspectral imaging

Infographic illustrates how changing the aperture, the focal length and the distance from the subject affect the depth of field. Download Image  Share Image: X Facebook Email Photo by: DINFOS PAVILION Team VIRIN: 200907-D-PA656-0002

Multispectral imaging follows a Low Earth Orbit and sun-synchronous. The multispectral satellites capture data along 5 to 10 bands of the spectrum. Most often, it also captures all three primary colors and a few blocks in the infrared portion.

RGBvs multispectral vs hyperspectral

Difference betweenmultispectralandhyperspectralremote sensing

Meanwhile, hyperspectral imaging makes it possible to collect several hundred spectral bands in a single acquisition. Such a feature has made it expensive as it demands more technological advancement to produce more detailed spectral data. With this comes issues related to increased sensor and image costs, data volumes and data-processing costs, and high demand to maintain operations.

Depth of field (DoF) is the area between the nearest and farthest points from the camera that are acceptably sharp in an image. A deep DoF means all or most of your photo will be in focus, including the foreground, subject and background. Use a deep DoF in group photos, landscape shots and when elements in the background or foreground add to the message the photo is attempting to communicate. A shallow DoF means more narrow range will be acceptably sharp in the image. Shallow DoF is good to use when you want to isolate your subject from their surroundings, such as in a portrait or when elements in the background or foreground may be distracting.

Hyperspectral cameras as on the other hand, can detect many different wavelengths separately. They can also see across a wider spectrum than a human can by covering parts of the infrared and ultraviolet regions. Therefore, in this imaging technique, analysts will acquire a 2-dimensional image whereby every pixel in the image contains a continuous spectrum.

You can affect the depth of field by changing the following factors: aperture, the focal length and the distance from the subject.

Distance to subject refers to the length between the camera and the focus of the image. The closer the camera is to the subject it is focusing on, the narrower the depth of field will be. Inversely, the farther away the subject is from the camera, the wider the depth of field will be.

In this image you can see how a shallow depth of field keeps the focus on the action. Photo by Samuel King In this image you can see how a shallow depth of field keeps the focus on the action. Download Image  Share Image: X Facebook Email Photo by: Samuel King VIRIN: 170908-F-OC707-0517C

hyperspectralvs.multispectralremote sensing ppt

The aperture is the opening created by a set of overlapping metal blades, known as the diaphragm, inside a photographic lens. This opening controls the amount of light coming through the lens. The wider the aperture, the less depth of field you capture. The smaller the aperture, the deeper the depth of field.

Multispectral and hyperspectral are types of spectral imaging with similar technologies. They are distinct imaging methods in that they each have their own application spaces. Such application spaces have evolved to include; remote sensings like map species, mineral exploration, food engineering, agriculture, atmospheric studies, ecology, health care, and agriculture.

In multispectral remote sensing, each pixel has a discrete sample spectrum. For example, some wavebands may have 4 to 20 data points per pixel.

Multispectral remote sensing involves the acquisition of visible, near-infrared, and short-wave infrared images. These images are acquired in several broad wavelength bands. Therefore, a multispectral image captures the image data within a specific wavelength range across the electromagnetic spectrum. The different materials captured reflect and absorb differently at these different wavelengths. In this imaging method, it is possible to differentiate among materials by their spectral reflection signatures as observed in these remotely sensed images. It makes direct identification not possible.

Multispectral images are captured with special cameras that separate wavelengths using filters or with instruments that are sensitive to particular wavelengths. These can include light from frequencies that are invisible to the human eye.

Multispectralandhyperspectral imaging

Meanwhile, in hyperspectral remote sensing, the bands are much narrower. These numerous narrow bands in hyperspectral sensors provide a continuous spectral measurement across the entire electromagnetic spectrum. Therefore, this makes them more sensitive to subtle variations in reflected energy.

Multispectral sensors commonly collect data from three to six spectral bands in a single observation. Such features make them cost-effective. They are cheap to buy and maintain as the image captures are not complex.

On the other hand, hyperspectral remote sensing is a technique that analyzes a wide spectrum of light instead of just assigning primary colors to each pixel. Its primary goal is to obtain a spectrum from each pixel in the image of a scene to find objects, detect processes, or identifying materials. Hyperspectral remote sensing samples a wide variety of bandwidths in the light spectrum. This aims to provide a rich dataset and detect objects of interest not visible to single-bandwidth imaging sensors.

Due to the limited number of bands in multispectral remote sensing, data analysis and interpretation are straightforward. It is also easier to understand.

The following graphic illustrates how changing these factors: aperture, focal length and the distance from the subject affect the depth of field.