Introduction to digital image processing

Basic concept Functions f (x, y)

Function f (x, y) can be used to represent an image. X and Y are plane coordinates. The result of f (x, y) is called an amplitude, indicating the intensity or gray scale of the point.

Digital Image)

When x, y, and F are finite discrete values, this image is called a digital image. What is a discrete value? discrete variable is a non-continuous value. X and Y are actually two-dimensional array indexes. F is a discrete value, also known as pixels. But this definition is a bit confusing, or here better understand: http://baike.baidu.com/view/286845.htm

Electromagnetic spectrum)

Electromagnetic waves spread at the speed of light in the air, including visible light and radio. Divided by frequency, wavelength, and wave source:

Radio waves

Microwave

Infrared

Visible Light

UV

Lunqin Ray

Gamma Ray)

Reference: http://baike.baidu.com/view/49801.htm

From image processing to Computer Vision

The order from left to right, that is, the order from low to advanced. Note that there is no clear demarcation point between the three.

Image processing, image analysis, and computer vision (part of AI)

Image processing definition: both input and output are image processing, as well as processing for Extracting Features and recognizing targets from images. Including low-level, intermediate, and advanced processing.

Low-level processing: Noise Reduction, contrast enhancement, and image regionalization.

Intermediate processing: segmentation, reducing the description of the target object (not clear ?), Make it more suitable for computer processing and classification of different targets.

Advanced processing: Understanding goals, visual cognition, and other functions.

Digital Image Origin

In 1921, the image was encoded and decoded using a special font on a telegraph printer, resulting in black and white images and remote transmission.

In 1922, the photographic Restoration Technology With Punched tape improved the color tone and resolution.

In December 1929, 15 levels of gray scale were supported.

Later, the emergence and development of modern computers have promoted the development of digital images. The rapid development of large-capacity storage and display systems is mainly used for medical imaging, Earth remote sensing, astronomy, and archaeology. The use of X-ray computer tomography is an important application. So far, Google's program has been able to recognize images of cats.

A large number of examples of practical use, such as remote sensing using visible and infrared spectroscopy, UV band imaging, vascular photography, cat, and imaging radar in the microwave band.

Apart from electromagnetic waves and sound waves, other technologies can also be used for digital image processing.

Basic Steps for Digital Image Processing

There is nothing to say.

Composition of general image processing systems

See the figure below: