 Hi-speed deterministic approach in detecting defective pixels within an image sensor |
| OF THE INVENTION Referring to the figures, exemplary embodiments of the invention will now be ... |
|
| Mathematical model for gray scale and contrast enhancement of a digital image |
| What is disclosed is a method that specifies identifying a category to which a pixel belongs and ... |
|
| Optical device, optical device driving unit, and camera system |
| It is an object of the present invention to change and set preset velocity information and change ... |
|
| System and method for providing call-handling services on a data network telephone system |
| These and other features and advantages of the present invention will become more apparent from the ... |
|
| Method for the manufacture of a pn junction with high breakdown voltage |
| The present invention provides a method which guarantees the manufacture of an area-saving pn ... |
|
| Composite channel field effect transistor and method of fabrication |
| Accordingly, it is an object of the present invention to provide an improved composite channel ... |
|
| Metal-composite bonding |
| I claim: 1. A method of bonding a high strength, thermally stable, graphite fiber reinforced glass ... |
|
| Electrolyzer and process |
| What I claim is: 1. The method for electrically connecting valve metal anode ribs and cathodically ... |
|
|
Method, apparatus and system for compressing data
| Details |
Inventors: Zador, Andrew Michael;
Assignee: Zador; Andrew Michael (Kitchener, CA)
Primary Examiner: Tadayon; Bijan
Assistant Examiner: Alavi; Amir
Attorney, Agent or Firm: Gowling Lafleur Henderson LLP
An apparatus and method for image data compression performs a modified zero-tree coding on a range of absolute image values from the largest to a determined smaller absolute value, based upon file size or quality. If it is desired to maintain more detail in the image, then a vector quantizer codes the remaining values below this determined smaller value to zero, and lossless entropy coding is performed on the results of the two coding steps. The determined smaller value can be adjusted by examination of the histogram of the tree, or iteratively to meet a preselected compressed image size criterion or to meet a predefined level of image quality, as determined by any suitable metric. If the image to be compressed is in RGB color space, the apparatus converts the RGB image to a less redundant color space before commencing further processing. |
|
DETAILED DESCRIPTION It is an object of the present invention to provide a novel data compression method, apparatus and system which obviates or mitigates some of the disadvantages of prior art.
According to a first aspect of the present invention, there is provided a method of compressing a digital image to obtain a compressed image data set for subsequent reconstruction, comprising the steps of: (i) determining if the digital image is a color image in RGB color space and converting any determined RGB color images to a less redundant color space; (ii) performing a wavelet decomposition upon each of the color planes of the image in said less redundant color space to obtain a transform of DC and non-DC terms for each color plane; (iii) lossless delta coding of the DC terms; (iv) converting the transform to sign and magnitude format and selecting a division point comprising an adjacent pair of bit-planes (or adjacent pair of magnitudes), which separate the non-DC terms (i.
e.
--the differential or AC terms) into first and second ranges based upon absolute magnitudes, the first range comprising the values of the transform which are greater in magnitude than those values in the second range of the transform; (v) employing a scalar quantizer to encode the values in the first range; (vi) employing a vector quantizer to encode the values in the second range; and (vii) coding the resulting data set with a lossless entropy coder to obtain a compressed image data set.
Preferably, the method also allows error detection and correction codes to be applied in the lossless coding of DC terms, modified zero-tree and/or vector quantizers, as desired, based upon importance of the coded information to the final reconstructed quality, and compression requirements.
The method will permit the coding of the most visually significant data into the smallest (and soonest sent) blocks, thus permitting less rigorous error control on the last (and statistically largest) blocks which carry little visual data, and progressively less error control on each successive (larger, visually less significant) block
|
|
Image Analysis 
