METHOD AND APPARATUS FOR ENTROPY ENCODING AND DECODING
A method for encoding and decoding data includes obtaining sets of pixels from transformed data. A linear index address is obtained from an address of the pixels to obtain a memory transformed address. The memory transformed address is used to obtain a set size of the pixels. Based on the set size and a threshold value, the pixel type is identified from a list of pixel types. Based on the pixel type, a bit stream having a refinement bit is generated.
1 . A method for encoding data using a wavelet based entropy encoder, the method comprising:
partitioning the data, by a set partitioning unit, into a plurality of sets;
obtaining, by an address control and generation unit (ACGU), a set size of the plurality of sets based on a transformed memory address of one or more pixels in the plurality of sets;
scanning, by a pixel tester unit, in accordance with the set size, the plurality of sets in a single pass, wherein the single pass comprises a plurality of scanning passes;
identifying, by the pixel tester unit, a type of the one or more pixels from a list of pixel type based on a threshold value generated by the single pass; and
generating in the single pass, by a main core control unit, a bit stream, wherein the bit stream comprises encoded data, and wherein the encoded data includes at least one of a significant bit and a refinement bit.
2 . The method of claim 1 , wherein the set size is used to decode a next address for the one or more pixels.
3 . The method of claim 1 , wherein the transformed memory address is obtained by applying a linear indexing on the one or more pixels.
4 . The method of claim 1 , wherein the list of pixel type comprises at least one of a refinement pixel, a significant pixel and an insignificant pixel.
5 . The method of claim 1 , wherein the scanning passes comprise a refinement pass and a sorting pass.
6 . The method of claim 1 , wherein the threshold value includes a value of a highest significant bit in the one or more pixels in the plurality of sets.
7 . The method of claim 1 , wherein the significant bit and the refinement bit in the bit stream are arranged in one of a random order and a sequential order.
8 . An apparatus for encoding image data, the apparatus comprising:
an address control and generation unit (ACGU) for obtaining a set size based on a transformed memory address of a plurality of pixels in a plurality of sets associated with the image data, wherein the set size is used to decode a next address for the plurality of pixels;
a pixel tester unit coupled to the ACGU that (i) scans, in accordance with the set size, the plurality of sets in a single pass, wherein the single pass includes one or more scanning passes, and (ii) identifies a type of the plurality of pixels from a list of pixel types based on a threshold value; and
a main control core unit, coupled to the ACGU and the pixel tester unit, for generating a bit stream of encoded image data in the single pass, wherein the encoded image data has at least one of a significant bit and a refinement bit.
9 . The apparatus of claim 8 , wherein the ACGU comprises:
a priority encoder having one or more shift registers for obtaining a linear address of the plurality of pixels; and
a linear address to memory address converter for transforming the linear address into the transformed memory address.
10 . The apparatus of claim 8 , wherein the pixel tester unit comprises:
a check refinement block for checking for a refinement pixel from the list of pixel types based on the threshold value;
a check significant block for checking for a significant pixel from the list of pixel types based on the threshold value; and
a bit generator for generating an encoded bit stream output signal in accordance with the refinement bit, the significant bit and an insignificant bit.
11 . The apparatus of claim 8 , further comprising a bit rate control unit for controlling a rate of the generated bit stream.
12 . The apparatus of claim 8 , further comprising a stream buffer unit for starting and stopping generation of the bit stream.
13 . The apparatus of claim 8 , wherein the ACGU and the main control core unit collectively form a set partitioning unit that partitions the image data into the plurality of sets.
14 . The apparatus of claim 8 , wherein the list of pixel types comprises at least one of a refinement pixel, a significant pixel, and an insignificant pixel.
15 . The apparatus of claim 8 , wherein the one or more scanning passes in the single pass comprises a refinement pass and a sorting pass.
16 . The apparatus of claim 8 , wherein the threshold value includes a value of a highest significant bit in the plurality of pixels in the set.
17 . The apparatus of claim 8 , wherein the significant bit and the refinement bit in the bit stream are arranged in at least one of a random order and a sequential order.
18 . An apparatus for decoding encoded data provided as a bit stream comprising a plurality of bits, the apparatus comprising:
a pixel tester unit for identifying, in the plurality of bits, a pixel type from a list of pixel type based on a threshold value; and
a data generator unit for generating decoded data based on the identified pixel type.