Abstract: A plurality of compression schemes are provided that achieve improved compression ratios. A first embodiment provides for compression of each pixel by one of a plurality of different entropy-based compression schemes based upon a probability cost analysis. A second embodiment provides for compression of each pixel based on a hybrid context formed using a plurality of compression schemes for improved probability determination, and thus improved entropy encoding. In embodiments of the invention, a context compression scheme similar to JBIG is applied, as well as an inverse scheme. The context scheme forms a statistical context from a concatenated sequence of previous pixel values. The inverse scheme provides a gray value estimation method based upon previous pixel values and respective threshold values. Statistics are maintained with respect to the actual current pixel value and the difference between an estimated gray value and the current pixel threshold value.

Abstract: A plurality of compression schemes are provided that achieve improved compression ratios. A first embodiment provides for compression of each pixel by one of a plurality of different entropy-based compression schemes based upon a probability cost analysis. A second embodiment provides for compression of each pixel based on a hybrid context formed using a plurality of compression schemes for improved probability determination, and thus improved entropy encoding. In embodiments of the invention, a context compression scheme similar to JBIG is applied, as well as an inverse scheme. The context scheme forms a statistical context from a concatenated sequence of previous pixel values. The inverse scheme provides a gray value estimation method based upon previous pixel values and respective threshold values. Statistics are maintained with respect to the actual current pixel value and the difference between an estimated gray value and the current pixel threshold value.

Abstract: The invention provides a plurality of compression schemes that provide improved compression ratios. An exemplary embodiment compresses each pixel by one of a plurality of different entropy-based compression schemes based upon a probability cost analysis. Another exemplary embodiment compresses each pixel based on a hybrid context formed using a plurality of compression schemes for improved probability determination, and thus improved entropy encoding.

Abstract: The invention provides for the application of a plurality of compression schemes to data such that improved compression ratios are achieved. A first embodiment provides for compression of each pixel by one of a plurality of different entropy-based compression schemes based upon a probability cost analysis. A second embodiment provides for compression of each pixel based on a hybrid context formed using a plurality of compression schemes for improved probability determination, and thus improved entropy encoding. In embodiments of the invention, a context compression scheme similar to JBIG is applied, as well as an inverse scheme. The context scheme forms a statistical context from a concatenated sequence of previous pixel values. The inverse scheme provides a gray value estimation method based upon previous pixel values and respective threshold values.

Abstract: The invention provides a plurality of compression schemes that provide improved compression ratios. An exemplary embodiment compresses each pixel by one of a plurality of different entropy-based compression schemes based upon a probability cost analysis. Another exemplary embodiment compresses each pixel based on a hybrid context formed using a plurality of compression schemes for improved probability determination, and thus improved entropy encoding.

Abstract: The invention provides for the application of a plurality of compression schemes to data such that improved compression ratios are achieved. A first embodiment provides for compression of each pixel by one of a plurality of different entropy-based compression schemes based upon a probability cost analysis. A second embodiment provides for compression of each pixel based on a hybrid context formed using a plurality of compression schemes for improved probability determination, and thus improved entropy encoding. In embodiments of the invention, a context compression scheme similar to JBIG is applied, as well as an inverse scheme. The context scheme forms a statistical context from a concatenated sequence of previous pixel values. The inverse scheme provides a gray value estimation method based upon previous pixel values and respective threshold values.

Abstract: A method and apparatus for compression of data. The invention provides for the application of a plurality of compression schemes to the data such that improved compression ratios are achieved. A first embodiment provides for compression of each pixel by one of a plurality of different entropy-based compression schemes based upon a probability cost analysis. A second embodiment provides for compression of each pixel based on a hybrid context formed using a plurality of compression schemes for improved probability determination, and thus improved entropy encoding. In embodiments of the invention, a context compression scheme similar to JBIG is applied, as well as an inverse scheme. The context scheme forms a statistical context from a concatenated sequence of previous pixel values. The inverse scheme provides a gray value estimation method based upon previous pixel values and respective threshold values.

Abstract: A method and apparatus for creating threshold arrays having a minimized gray scale variance without geometric artifacts. The invention comprises the steps of processing each candidate pixel in the threshold array using a variance minimization technique and applying a sparse image calculation on the same pixel. The preferred embodiment of the invention comprises the application of a variance minimization technique on a threshold array. The threshold array is analyzed on a pixel-by-pixel basis. Each candidate pixel that is to be turned on is examined in relation to the previous pixels that already exist. The candidate pixel is examined to determine its effect on the variance of the smoothed gray level determined by the convolution of the pixel pattern with a smoothing kernel. The candidate pixel is also examined in relation to the distribution of the angles it forms with the previously selected pixels. The preferred embodiment uses a variant of the combinatorial Hough transform.

Abstract: A method and apparatus for compression of data. The invention provides for the application of a plurality of compression schemes to the data such that improved compression ratios are achieved. A first embodiment provides for compression of each pixel by one of a plurality of different entropy-based compression schemes based upon a probability cost analysis. A second embodiment provides for compression of each pixel based on a hybrid context formed using a plurality of compression schemes for improved probability determination, and thus improved entropy encoding. In embodiments of the invention, a context compression scheme similar to JBIG is applied, as well as an inverse scheme. The context scheme forms a statistical context from a concatenated sequence of previous pixel values. The inverse scheme provides a gray value estimation method based upon previous pixel values and respective threshold values.