Definition of data redundancy and several major classifications

Meaning and purpose of data redundancy

After digitizing video and audio signals, the volume of data is staggering, so storing large amounts of image and audio information needs to greatly improve the storage capacity of the system, usually by using a large disk or disc, but this is just one way to solve mass storage, and the role of data redundancy is to save additional data or data on a separate hard disk, to prevent data loss, the following explanation of what is data redundancy? What are the types?

Data and information, although often used together, but the concept is not the same, the data is used to record and transmit information, data is the carrier of information. The real useful is not the data itself, but the information carried by the data, the relationship between the amount and the volume of data can be given by: I=d-du (I,d,du, respectively, the amount of information, the amount of data and redundancy.) redundant du refers to data redundancy in D. ）

Redundancy, refers to the repeated configuration of some parts of the system, when the system fails, the redundant configuration of the components involved and assume the work of the faulty parts, thereby reducing the system failure time. The technology of redundant network card is the technology of mainframe and medium-sized machine, and now it is owned by PC Server gradually. Redundant, automatic redundancy, that is, when a device is damaged, it can automatically replace the device as a back-up device.

Data redundancy refers to the duplication between data, it can be said that the same data stored in different data files phenomenon, can be said to increase the independence of data and reduce data redundancy is the enterprise-wide information resources management and large-scale information systems to obtain the success of the premise, the so-called data redundancy refers to the data in the database has duplicate information exists, This naturally wastes a lot of storage space, especially when storing large amounts of data, data redundancy refers to the same data is repeatedly stored. This will change the value of the other property as well. Data redundancy not only increases the cost of updating, but also the potential inconsistency of data and the waste of storage space.

Storing such exported data items in a database requires more storage space, also known as data redundancy. The storage of redundant data is not only a high cost but also the source of inconsistent data, data redundancy or information redundancy is the inevitable behavior of production and life, there is no good or bad general tendency.

What are the types of data redundancy

Generally, the types of data redundancy in image, video, and audio data are as follows:

(1) Structural redundancy: Some images generally have very strong texture structure, such as Mat image, we call it redundant structure.

(2) Information entropy redundancy: Also known as coding redundancy, refers to a group of data carrying the average amount of information. Because of the various redundancy in the multimedia data, the multimedia data can be compressed. For different redundancy, people have proposed a variety of methods to implement the compression of multimedia data.

(3) Time redundancy: This is the redundancy that is often contained in sequence images (TV images, motion images) and voice data. In TV and animated images, the same background is often included between adjacent frames, but the position of moving objects changes slightly. Therefore, for the two adjacent frames in the sequence image, only the differences between them are recorded, and the part of the information which is duplicated, called time redundancy, is removed. Similarly, because the audio produced by people while talking is continuous and gradual, there is also time redundancy in the sound information.

(4) Space redundancy: a kind of redundancy which often occurs in image data. In the same image, the regular object and the rule background (the so-called rule refers to the surface is ordered rather than completely disorganized arrangement) of the surface of the physical characteristics of the correlation, digital image representation of data redundancy. For example, in a static image of a large blue sky, grassland, where the data of each pixel is exactly the same, if the point of storage, it will produce so-called space redundancy. Exactly the same data can be compressed, very close to the data can also be compressed, because the compressed data recovery of the eyes of the future is not distinguishable from the original picture, this compression is the space redundancy compression.

(5) Knowledge Redundancy: There are many images of the understanding and some basic knowledge has a considerable correlation. For example, the image of a human face has a fixed structure. For example, there is a nose above the mouth, eyes on the top of the nose, and nose in the midline of the face. This kind of regularity structure can be obtained by prior knowledge and background knowledge, which is called knowledge redundancy. ⑤ Visual Redundancy: It is caused by the insensitivity of human organs. For example, in high brightness, the human visual sensitivity decreases, the gray value of the expression can be rough. For too strong and too weak sounds, if the "threshold" is exceeded, people's auditory feelings will be masked. Using these sensory features, you can also compress part of the data without being perceived by people.

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Definition of data redundancy and several major classifications