摘要:
A coding system comprises the comparing circuit which compares a magnitude of the range on the number line which is allocated to the most probability symbol with a magnitude of the fixed range on the number line which is allocated to the Less Probability Symbol. If the range allocated to the MPS is smaller than that to the LPS, and when the symbol is the MPS, the range allocated to the LPS is generated. If the range allocated to the MPS is smaller than that to the LPS, and when the symbol is the LPS, the range allocated to the MPS is generated. By the system, a coding efficiency is improved especially when a probability of occurrence of LPS (Less Probability Symbol) is approximate to 1/2.
摘要:
A coding method of a binary Markov information source comprises the steps of providing a range on a number line from 0 to 1 which corresponds to an output symbol sequence from the information source, and performing data compression by binary expressing the position information on the number line corresponding to the output symbol sequence. The present method further includes the steps of providing a normalization number line to keep a desired calculation accuracy by expanding a range of the number line which includes a mapping range, by means of a multiple of a power of 2, when the mapping range becomes below 0.5 of the range of the number line; allocating a predetermined mapping range on the normalization number line for less probable symbols LPS proportional to its normal occurrence probability; allocating the remaining mapping range on the normalization number line for more probable symbols MPS; and reassigning the predetermined mapping range to the remaining mapping range the half of a portion where the allocated remaining range is less than 0.5, when the allocated remaining range becomes below 0.5.
摘要:
Although data is transmitted with efficiency by an arithmetic encoding system, the number of carry control signals increases in proportion to the number of consecutive bits "1" s or bytes X`FF` s in a conventional system. In the present invention, an arithmetic encoder 302 `detects the possibility of a carry generated during arithmetic coding operation being propagated beyond at least a predetermined number of consecutive bytes X`FF` s in a supplied arithmetic code 315. When the propagation of the carry is impossible, a carry control signal is inserted into the first 2 bits of the byte other than X`FF` which occurs immediately after the consecutive bytes X`FF` s so as to transmit the presence or absence of a carry. An arithmetic decoder 303 detects the continuation of at least a predetermined number of bytes X`FF` s in the arithmetic code 315, and arithmetically decodes an output value YN316 on the basis of the predicted value MPS317 of the occurrence probability of the output value YN316 to be encoded and the region width Qe of the complementary predicted value LPS. Since the number of total bits of the inserted carry control signals is reduced by this "one-time 2-bits insertion system", the total number of transmitted code bits is also reduced.
摘要:
A coding method of a binary Markov information source comprises the steps of providing a range on a number line from 0 to 1 which corresponds to an output symbol sequence from the information source, and performing data compression by binary expressing the position information on the number line corresponding to the output symbol sequence. The present method further includes the steps of providing a normalization number line to keep a desired calculation accuracy by expanding a range of the number line which includes a mapping range, by means of a multiple of a power of 2, when the mapping range becomes below 0.5 of the range of the number line; allocating a predetermined mapping range on the normalization number line for less probable symbols LPS proportional to its normal occurrence probability; allocating the remaining mapping range on the normalization number line for more probable symbols MPS; and reassigning the predetermined mapping range to the remaining mapping range the half of a portion where the allocated remaining range is less than 0.5, when the allocated remaining range becomes below 0.5.
摘要:
This invention relates to a coding system and the coding method in encoding information source symbols of an image. When the total number of original information source symbols cannot be known at the decoding site just from the encoded symbols, it is an object to finish the decoding process correctly and decode the symbols equal to the number of original information source symbols.At an encoding site, the total number of information source unit composed of a finite number of information source symbols is placed at the tail of code at the completion of encoding process. For example, at the encoding site, the number of horizontal pels of an image are transmitted in advance as an information source unit and the total number of lines are placed at the tail of code at the completion of encoding process. At the decoding site, the number of decoded lines is counted and decoded up to the number of lines placed at the tail of code. As a result, it is possible to judge the end of information source symbols without missing the total number.
摘要:
A coding system comprises the comparing circuit which compares a magnitude of the range on the number line which is allocated to the most probability symbol with a magnitude of the fixed range on the number line which is allocated to the Less Probability Symbol. If the range allocated to the MPS is smaller than that to the LPS, and when the symbol is the MPS, the range allocated to the LPS is generated. If the range allocated to the MPS is smaller than that to the LPS, and when the symbol is the LPS, the range allocated to the MPS is generated. By the system, a coding efficiency is improved especially when a probability of occurrence of LPS (Less Probability Symbol) is approximate to 1/2.
摘要:
A prediction value is previously set in an MPS table corresponding to a state number, a state number for an encoding pixel is obtained from a STATE table, the prediction value is determined based on the MPS table using the state number, a pixel-to-symbol converter compares the prediction value and the encoding pixel to obtain a symbol, and an arithmetic encoder obtains an LPS interval from an LSZ table using the state number for the encoding pixel, and the arithmetic encoder implements encoding based on the symbol and the LPS interval.
摘要:
In an adaptive probability estimation method, an index referring to coding parameters is determined according to occurrence probabilities of symbols from estimated occurrence counts of symbols, thresholds for probability values that determine the probability intervals corresponding to the indexes are set to values that are examined with small operational load, and an index referring to the corresponding occurrence probability is selected without division, using the probability intervals determined by the thresholds for probability values.
摘要:
An image memory outputs a target encoding pixel and a plurality of reference pixels in the vicinity thereof. A boundary mode determining unit determines a maximum value and a minimum value of the reference pixels, determines an average value of the maximum value and the minimum value, compares the respective reference pixel values with the average value, detects a boundary in the target encoding pixel and the reference pixels based on comparison results, and detects a pixel distribution state of the reference pixels based on the detected boundary. An adaptive predictor calculates a prediction value by performing a calculation based on a function corresponding to the pixel distribution state and the reference pixels. A prediction difference calculating unit determines a difference value between the prediction value and a value of the target encoding pixel. A prediction coincidence determining unit compares the prediction value and the target encoding pixel value, and outputs a comparison result as a binary signal. A context generator generates a context based on the pixel distribution state and the difference value of the prediction difference calculating unit. An arithmetic encoder encodes the binary signal based on the context thus generated.
摘要:
Plural decoded results are obtained from one code data based on with/without change information attached to encoding information shared by the receiver. An encoder having a modeling unit 502A′ for modeling input data sequence 501 to obtain a data value 503 and a parameter 504, an encoding unit 505′ for encoding output from the modeling unit, and a code sending unit 506′ for sending output from the encoding unit, the encoder includes: a) a setting changing unit 523A for instructing to change one of the data value and the parameter based on change information 521; and at least one of following b-1) and b-2): b-1) a data manipulating unit 530A for manipulating either of the data value 503 or the parameter 504 output from the modeling unit to output to the encoding unit based on the change information instructed by the setting changing unit; and b-2) a code manipulating unit 531A for obtaining encoded result by instructing the encoding unit to perform predetermined change or manipulating sending code output sent by the code sending unit based on the change information instructed by the change setting unit. Further, a decoder having corresponding function is provided.