Repair or editing of damaged (torn) scanned halftone prints

摘要

When restoring a scanned halftone image of a damaged document, parameters of the halftone structure (geometry) are estimated, as is an intended contone gray level for damaged portions of the image. Locations of halftone cell tiles in the scanned image are determined based on the halftone structure, and a halftone profile model is generated using the estimated halftone parameters and contone information. Image segments are aligned using global features for coarse alignment and halftone structure for fine alignment, such as in cases where the scanned halftone image contains unconnected fragments. Missing parts of the damaged document image are filled in using the halftone profile model and estimated contone values.

主权项

1. A computer-implemented method for repairing an electronic version of a damaged document, comprising:
receiving a scanned halftone image of the damaged document; determining that the scanned halftone image comprises unconnected fragments; aligning the unconnected fragments using global features for coarse alignment and halftone structure for fine alignment; determining one or more halftone structure parameters; estimating contone gray levels for portions of the damaged document; identifying locations of halftone cell tiles in the damaged document and positions of pixels within the identified tiles; building a halftone profile model that describes halftone dot growth patterns using the determined halftone parameters and the estimated contone gray levels; filling in a damaged region of the document using the halftone profile model and the estimated contone gray levels to generate a restored digital halftone image; and outputting the restored digital halftone image.