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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However, if the dog did not bark during a burglary, this is a low-probability event and contains a lot of information. Sem perdas Lossless e com perdas pequenas Lossy. The fact that one sound can drown out another seems reasonable.

Curso de Sistemas de Informação |

One way to improve what you see in low light is to viskalg to one side of the object. 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. The outer ear consists of the structure appostila directs the sound waves, or pressure waves, to the tympanic membrane, or eardrum.

The middle ear is an air-filled cavity containing three small bones that provide coupling between the tympanic membrane and the oval window, which leads into the inner ear. Suppose we send the first value, then in place of subsequent values we send the difference between it and the previous value. Vusualg the number of bytes required to represent multimedia data can be huge.

download do VisualG

The range decreases with age; older people are usually unable to hear the higher frequencies. Putting all of this information together, we can develop visualh model for monochromatic vision, shown in Figure 8. We can take advantage of this form of redundancy by constructing a list of these words and then represent them by their position in the vishalg.


Text compression is an important area for lossless compression. Download do Visualg 3. The muscles of the eye move the eyeball, positioning the image of the object on the fovea.

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. However, each value is close to the previous value.


However, at a given instant we cannot perceive the entire range of brightness. The sequence of transmitted values would be Example 1. Thus, we can model the eye as a receptor whose output goes to a logarithmic nonlinearity.

There are a number of other, more complicated masking phenomena that also lend support to this theory see [97, 98] for more information. The barking of a dog during a burglary is a high-probability event and, therefore, does not contain too much information.

A Tutorial for Beginners ; -Tutorial no slideshare: The range of brightness levels that the eye can perceive at any given instant is much smaller than the total range it is capable of perceiving.

Thus, video is generally compressed using lossy compression. Although the rods are more numerous than the cones, the cones provide better resolution because they are more closely packed in the fovea.

As in vision, auditory perception has several nonlinear components. We create these compact representations by identifying and using structures that exist in the data.

For example, a totally random string of letters will contain more information in the mathematical sense than a well-thought-out treatise on information theory.

The limitations of auditory perception play a major role in the design of audio compression algorithms.

A Tutorial for Beginners. For example, in order wpostila digitally represent 1 second of video without compression using the CCIR formatwe need more than 20 megabytes, or megabits. There are three kinds of cones, each of which are most sensitive at different wavelengths of the visible spectrum.


The human ear can hear sounds from approximately 20 Hz to 20 kHz, a This is vieualg the just noticeable difference jnd. This means we have obtained a compression ratio of 1. Lossless compression is generally used for applications that cannot tolerate any difference between the original and reconstructed data.

The ratio y is known as the Weber fraction or Weber ratio.

Fonte – Infocacto

To represent 2 minutes of uncompressed CD-quality music 44, samples per second, 16 bits per sample requires more than 84 million bits. We also know that the eye acts as a spatial lowpass filter [94, 95].

The eye is a globe-shaped object with a lens in the front that focuses objects onto the retina in the back of the eye. In brief, data compression is the art or science of representing information in a compact form.

If something is represented in the data that cannot be perceived by the user, is there any point in preserving that information? Suppose we have an event A, which is a set of outcomes aposyila some random experiment. If we consider the number of seconds in a movie, we can easily see why we would need compression. 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 occur less often.

This way the object is imaged visyalg the rods, which are more sensitive to light. A;ostila cones are mostly concentrated in a very small area of the retina called the fovea.