Image data compression and decompression using minimize size matrix algorithm

A data processing device comprising at least one data processor and a non-transitory computer readable medium coupled to the at least one data processor, the non-transitory computer readable medium storing instructions that when executed by the at least one data processor cause the at least one data processor to perform a process comprising:

• opening a compressed image file including arithmetically coded data, wherein a header of the compressed image file includes a location array;
• arithmetically decoding the arithmetically coded data to form a DC array and a coded AC array, and wherein elements of the DC array correspond to a set of quantised DC DCT coefficients;
• retrieving a key and a limited data array, wherein the key comprises a plurality of components and was generated using a maximum value of an original AC matrix;
• decompressing the coded AC array using the key and the limited data array to form a reduced AC array, wherein the limited data array comprises elements having values corresponding only to each unique value of the original AC matrix of quantised AC DCT coefficients prior to compression;
• rebuilding an AC matrix using the location array which stores a position in the original AC matrix of each block of data of the original AC matrix including non-zero values by forming blocks of data in the AC matrix including non-zero values and obtained from the reduced AC array and forming a rest of the AC matrix with blocks of data having only zero values, and wherein the elements of the AC matrix are a set of quantised AC DCT coefficients;
• applying an inverse quantisation to the set of quantised DC DCT coefficients and the set of quantised AC DCT coefficients to generate a plurality of sets of DCT coefficients each corresponding to a respective one of a plurality of pixel blocks, each set of DCT coefficients comprising a DC DCT coefficient and a plurality of AC DCT coefficients;
• and
• applying an inverse DCT transformation to each of the plurality of sets of DCT coefficients to form a plurality of non-overlapping pixel blocks which span a frame of image data.

A system comprising:

• a first data processing device comprising at least one first data processor and a first non-transitory computer readable medium coupled to the at least one first data processor, the first non-transitory computer readable medium storing first instructions that when executed by the at least one first data processor cause the at least one first data processor to:
• apply a discrete cosine (DCT) transformation to each of a plurality of non-overlapping pixel blocks which span a frame of image data to generate a set of DCT coefficients for each pixel block comprising a DC DCT coefficient and a plurality of AC DCT coefficients;
• quantise each set of DCT coefficients to generate a set of quantised DC DCT coefficients and a set of quantised AC DCT coefficients;
• form a DC array from the set of quantised DC DCT coefficients;
• form an AC matrix from the set of quantised AC DCT coefficients;
• form a limited data array comprising elements having values corresponding only to each unique value of the elements of the AC matrix;
• compress the AC matrix by eliminating blocks of data of the AC matrix having only zero values and forming a reduced AC array from blocks of data of the AC matrix including non-zero values;
• store a position in the AC matrix of each block of data of the AC matrix including non-zero values in a location array;
• generate a key using a maximum value of the elements of the reduced AC array, and wherein the key comprises a plurality of key components;
• compress the reduced AC array using the key to form a coded AC array, wherein a same number of elements of the reduced AC array as a number of key components are combined using the key to form a single element of the coded AC array;
• arithmetically code the DC array and the coded AC array to form arithmetically coded data;
• and
• form a compressed image file including the arithmetically coded data;
• store the location array in a header of the compressed image file and store the key and the limited data array;
• and
• a second data processing device comprising at least one second data processor, wherein the second data processing device is remote from the first data processing device, and in communication with the first data processing device, and a second non-transitory computer readable medium coupled to the at least one second data processor, the second non-transitory computer readable medium storing instructions that when executed by the at least one second data processor cause the at least one second data processor to:
• open a compressed image file including arithmetically coded data, wherein a header of the compressed image file includes a location array;
• arithmetically decode the arithmetically coded data to form a DC array and a coded AC array, and wherein elements of the DC array correspond to a set of quantised DC DCT coefficients;
• retrieving a key and a limited data array, wherein the key comprises a plurality of components and was generated using a maximum value of an original AC matrix;
• decompress the coded AC array using the key and the limited data array to form a reduced AC array, wherein the limited data array comprises elements having values corresponding only to each unique value of the original AC matrix of quantised AC DCT coefficients prior to compression;
• rebuild an AC matrix using the location array which stores a position in the original AC matrix of each block of data of the original AC matrix including non-zero values by forming blocks of data in the AC matrix including non-zero values and obtained from the reduced AC array and forming a rest of the AC matrix with blocks of data having only zero values, and wherein elements of the AC matrix are a set of quantised AC DCT coefficients;
• apply an inverse quantisation to the set of quantised DC DCT coefficients and the set of quantised AC DCT coefficients to generate a plurality of sets of DCT coefficients each corresponding to a respective one of a plurality of pixel blocks, each set of DCT coefficients comprising a DC DCT coefficient and a plurality of AC DCT coefficients;
• and
• apply an inverse DCT transformation to each of the plurality of sets of DCT coefficients to form a plurality of non-overlapping pixel blocks which span a frame of image data.