摘要:
A method and a system for dynamically thresholding an image signal. The system comprises a computing block. The computing block receives the image signal and a minimum and a maximum within each of a set of windows centered on the current pixel in the image signal, and computes, for each of the windows, based on the current pixel and the respective minimum and maximum, a respective indicator representing the distance and direction of the current pixel relative to a respective threshold plane, and outputs a control signal based on the indicators.
摘要:
The image data is analyzed to identify blobs having similar characteristics. Various blobs are gathered together and placed into a foreground plane based on one or more color characteristics and/or spatial characteristics. Each blob gathered onto a foreground plane has a color that is similar to a color associated with that foreground plane. One or more portions of the image data that is not mapped into any foreground plane may be mapped into a background plane.
摘要:
A highly efficient method and system for eliminating halftone screens from scanned documents while preserving the quality and sharpness of text and line-art is disclosed. The method and system utilizes a single channel screen frequency estimator module, which generates a screen frequency estimate for image data. The module generates a signal based on the highly filtered image signal at low contrast levels, and based on a reliable estimate to the halftone frequency at higher contrast levels. The single channel screen estimate module has adequate performance in resolution ranges from 300 to 600 dpi.
摘要:
A method and a system for separating an image signal into a set of image planes in accordance with a control signal. The system comprises a selector module, an edge processing module and a foreground/background separation module. The selector module receives the control signal and produces a selector signal. The edge processing module receives the selector signal and produces a decision signal. The foreground/background separation module receives the image signal and the decision signal, and outputs a foreground signal and a background signal, a representation of the current pixel of the image signal being included in at least one of the foreground signal and the background.
摘要:
A Statistics Module (STS) is disclosed for collecting essential statistics about an image content for the purpose of applying various image enhancement operations such as page background removal and automatic neutral detection to determine if the page is gray or colored. The Statistics Module uses the blurred signal BLR from a De-Screen Module in order to eliminate some of the scanner noise. The output is a special 3D color histogram array.
摘要:
Pixel blocks of an input image are type classified based on an analysis of the secord differences between the values of neighboring pixels in the rows and columns of each pixel block. A histogram of these second order differences may be employed to refine this analysis
摘要:
Apparatus and methods for de-screening an image signal utilizing a bank of filters to provide several increasingly blurred versions of the original image signal is disclosed. At any given time, one or more of the blurred versions are created, on a pixel-by-pixel basis. The outputs from a selected pair of blurred signals are then blended together to create a variable blending output that can vary smoothly from no blurring to maximum blurring in a smooth and continuous manner. In addition, the apparatus and methods provide enhanced text and line art by using a variable un-sharp masking mechanism with independent post-blur sharpening control, and detect and enhance neutral (no-color) output pixels.
摘要:
Image data is analyzed line by line to identify pixels having similar color and edge characteristics. The pixels on one line are linked to pixels on another line, if they share similar characteristics. The linked pixels are then grouped together in regions and the average color of the region is calculated. An image map is generated that identifies the regions to which the pixels belong, along with a final table of the regions appearing in the image.
摘要:
The image data is processed into a background plane and a plurality of foreground planes. Holes are inserted onto the background plane, in regions which are assigned to a foreground plane. The background plane is sub-sampled, and holes remaining in the sub-sampled image are filled with the average color of the non-zero sub-sampled pixels over pre-determined blocks such as JPEG blocks. If a block is entirely made of holes, the block is filled with a constant color that is propagated from the average color of a previous block. The resulting background plane is far smoother than the original image data and thus can be effectively sub-sampled and highly compressed without adverse deterioration in reconstructed image quality.
摘要:
The image data is initially processed in a manner that is similar to that used to convert the image data into 3-layer mixed raster content format. After the image data is initially processed through a first stage of the three-layer segmentation process, rather than completing the segmentation into foreground and background planes, the image data is analyzed to identify regions having similar image characteristics. These regions are grouped together in cluster if they share color characteristics and are spatially close. The clusters are then sorted according to their size, and placed into a binary foreground plane based on one or more color characteristics. Each cluster gathered into a binary foreground plane having the same color as the color of the cluster.