31 results about "Color image coding" patented technology

A lossless image encoding / decoding method and apparatus. The lossless color image encoding apparatus includes a motion prediction image generator estimating a motion between a previous image and a current image and outputting a corresponding prediction image, a residue generator generating a temporal residue corresponding to a difference between a prediction image generated by the motion prediction image generator and the corresponding block of the current image with respect to different components of the color image, a prediction residue generator generating prediction residues by defining a linear-transformed value of one residue among the different components of the color image output from the residue generator as a predictor and using differences between each of the residues of the other components and the predictor, and an entropy encoder receiving the residue forming the predictor from the residue generator and the prediction residues from the prediction residue generator and generating a bitstream. Encoding methods, decoding apparatuses, and decoding methods can be implemented similarly.

The invention discloses an image encryption method and device based on cascade transformation, and the method comprises the steps: S1, generating a phase mask according to a chaotic sequence; s2, randomly generating a real integer matrix, and encoding the real integer matrix and the first color image to generate a full quaternion matrix; s3, performing modulation and quaternion Gyrator transformation on the full quaternion matrix according to the phase mask to obtain a first amplitude and a first phase; s4, encoding the first amplitude and the second color image to generate a quaternion matrix, and performing amplitude truncation to obtain a second amplitude and a second phase; s5, multiplying the first phase by the second phase, and performing modulation and quaternion Gyrator transformation on the quaternion matrix according to a phase mask to obtain a third amplitude and a third phase; s6, repeatedly executing S4 and S5 until the Nth amplitude and the Nth phase of the last color image are obtained. The method has relatively high transmission efficiency and security.

A color image residue transform and / or inverse transform method and apparatus, and a color image encoding and / or decoding method and apparatus using the same are provided. The residue transform method includes: obtaining a residue corresponding to the difference of an original image and a predicted image; and transforming the residue by using a relation between residues of color image components. The residue inverse transform method includes: generating a residue for each component by performing residue inverse transform of the residue transformed original image; and restoring the original image by adding a predicted image to the residue of each component. Also, the color image lossless encoding method using the residue transform includes: obtaining a residue corresponding to the difference of an original image and a predicted image; and performing encoding by transforming the residue by using the relation between residues of predetermined components. The decoding method includes: extracting residue transformed image data from the coded data of the original image; generating a residue for each component by performing residue inverse transform of the residue transformed image data; and restoring the original image by adding a predicted image to the residue of each component. According to the methods and apparatuses, by performing transform between residues of each color component, the redundancy of the residue of each color component is removed such that when a color image is encoded, a higher compression efficiency can be achieved.