Satellite imagery analysis
Visual analysis begins with a further improvement of visual interpretation capacity and there are a range of processors that help increase visualization before the interpretation stage:
First: Enhancing contrast:
Sensors have a wide range to accommodate varying reflection values that can be in different environments; however,
in a single environment, the situation is often just a narrow amount of values that will occur in most areas, so gray distributions tend to be very skewed.
So contrast procedures here are very necessary for most visual analyses, as in the form
Which shows a space visual and graph;
Enhancing contrast contrast increases the color contrast between image elements, especially those with similar tones,
by spreading the light grades of the scene, covering the entire color field from black to white.
Second: Cutting density:
Density Slicing is used to cut the color intensity of space images into a number of slides, so that each segment limits a specific range of color,
gives it a separate color and this method helps to process the image by coloring.
Third: Nomination (digital filtering):
One of the most interesting capabilities of digital analysis is the ability to apply digital filters;
The use of Filters filters aims to reduce this noise,
helping to better interpret the content of the image, and when selecting the appropriate candidate,
the image content of the information,
the noise ratio, the purpose of the study, and the degree of ground discrimination of the system to be used are taken into account.
The most important types of spatial filtration of the visual include:
High press: To remove low frequency components from the image while maintaining high frequency (local variations), it is based on the increased appearance of fine details in the image.
Low press: To maintain low frequency components of the image and reduce small details.
Directional: The directional filter enhances image values with multiple directions, and is often used to illustrate linear appearances in the visual.
Fourth: Mosaic Photo:
Through mosaic process, selected single images are linked in order to obtain a single image,
after different contrast enhancements and corrections
so that all images have a regular appearance and a close colour
The binding process is carried out using ground highlighters in the overlay areas between adjacent images.
Fifth: Suitable for photo channels:
The suitable image channels are intended to reduce,
or delete, topographical differences between images so that similar objects have the same ratio regardless of changes in lighting.
This process is useful for better distinguishing rock and soil types from space images, but its disadvantages are that it reduces the contrast between elements of the image,
and proportionality images can be used to obtain color images in composite colors.
The classification is divided into an observer rating and an unattended classification.