Veja grátis o arquivo Apostila VisualG completa enviado para a disciplina de Programação I Categoria: Outros – 8 – O visualg é uma das melhores ferramentas que existem para aprender a programar. Aprenda agora a programar no visualg com o melhor material da web. O Visualg é um programa que permite criar, editar, interpretar e que também executa os algoritmos em português estruturado (portugol) como se fosse um.

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As in vision, auditory perception has several nonlinear components. A Tutorial for Beginners.

If the quality of the reconstructed speech is to be similar to that heard on the telephone, a significant loss of information can be tolerated. Visuxlg, if the background illumination is changed, the range over which the Weber ratio remains constant becomes relatively small. Ele indicou este curso como um ponto de partida. Notice that the mind does not perceive everything the eye sees.

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This is called the just noticeable difference jnd. The retina contains two kinds of receptors, called rods and cones. Instead, the eye adapts to an average brightness level. The ratio y is known as the Weber fraction or Weber ratio.

A Tutorial for Beginners ; -Tutorial no slideshare: Suppose we have the following sequence: Visuualg perdas Lossless e com perdas pequenas Lossy. Download do Visualg 2.

download do VisualG – Exercícios e Material de Informática

The ear is divided into three parts, creatively named the outer ear, the middle ear, and the inner ear. Although this equivalence of the mathematical and semantic definitions of information holds true most of the time, it does not hold all of the time. The library is exhaustively documented, written in a simple and friendly style, and thoroughly tested.

The rods are more sensitive to light than cones, and in low light most of our vision is due to the operation of rods. It is very important that the reconstruction is identical to the text original, as very small differences can result in statements with very different meanings.


In brief, data compression is the art or science of representing information in a compact form.

To represent 2 minutes of uncompressed CD-quality music 44, samples per second, 16 bits per sample requires more than 84 million bits. What is not so intuitive about masking is that if we were to try to mask a pure tone with noise, only the noise in a small frequency range around the tone being masked contributes to the masking.

Notice that we have assigned a codeword with only a single bit to the symbol that occurs most often, and correspondingly longer codewords to symbols that visyalg less often. Although the idea of a quantitative measure of information has been around for a while, the person who pulled everything together into what is now called information a;ostila was Claude Elwood Shannon, an electrical engineer at Bell Labs.

In order to represent eight symbols, we need to use 3 bits per symbol. Thus, we can model the eye as a receptor whose output goes to a logarithmic nonlinearity.

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This way the object is imaged on the rods, which are more sensitive to light. As there are 41 symbols in the sequence, this works out to approximately 2. We create these compact representations by identifying and using structures that exist in the data.

If we consider the number of seconds in a movie, we can easily see why we would need compression. However, visyalg a given instant we cannot perceive the entire range of brightness. This type of compression scheme is called a dictionary compression scheme. The sequence of transmitted values would apoztila. Similarly, when viewing a reconstruction of a video sequence, the fact that the reconstruction is different from the original is generally not important as long as the differences do not result in annoying artifacts.

Lossy compression techniques involve some loss of information, and data that have been compressed using lossy techniques generally cannot be recovered or reconstructed exactly. The limitations of auditory perception aostila a major role in the design of audio compression algorithms. In many applications, this lack of exact reconstruction is not a problem. Obviously, Sherlock Holmes understood information theory! Many times, for example, when transmitting or storing speech and images, the data are intended to be perceived by a human, and humans viskalg limited perceptual abilities.


This ratio is known to be constant at about 0. For example, we cannot hear the very high frequency sounds that dogs can hear. Suppose we have an event A, which is a set of outcomes of some random experiment.

This means we have obtained a compression ratio visuslg 1. Even if we ignore the mathematical definition of information and simply use the definition we use in everyday language, this makes some intuitive sense. The cones are mostly concentrated in a very small area of the retina called the fovea. The outer ear consists of the structure that directs the sound waves, or pressure waves, to the apowtila membrane, or eardrum. This range of frequencies is called the critical band.

Shannon defined a quantity called self-information. For example, in order to digitally represent 1 second of video without compression using the CCIR formatwe need more than 20 megabytes, or megabits. And the number of bytes required to represent multimedia data can be huge.

Therefore, if the probability of an event is low, the amount of self-information associated with it is high; if the probability of an event is high, the information associated with it is low.

Another very interesting audio phenomenon is that of masking, where one sound blocks out or masks the perception of another sound.

Listen to music on your mp3 player or watch a DVD and you are being entertained courtesy of compression. When dealing with text, along with statistical redundancy, we also see redundancy in the form of words that repeat often.