System and method for generating a preview display in a print capturing system using a non-planar prism

• US 7,321,671 B2
• Filed: 12/03/2003
• Issued: 01/22/2008
• Est. Priority Date: 12/06/2002
• Status: Expired due to Fees

• Current Assignee: Cross Match Technologies Incorporated (Assa Abloy AB)
• Original Assignee: Cross Match Technologies Incorporated (Assa Abloy AB)
• Inventors: McClurg, George W, Cannon, Greg L, Voorhees, Richard V
• Primary Examiner(s): MARIAM, DANIEL G
• Application Number:
  US10/725,541
• Publication Number:
  US 20040109589A1
• Time in Patent Office: 1,511 Days
• Field of Search: 382123-127, 382/170, 382/311
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1324 by using geometrical optics, e.g. using prisms G06V40/1312 takes precedence

Abstract

A system and method is provided for generating a preview display of a captured print image from a non-planar platen and for generating a high resolution display of a user-selected area of the preview display. The display processing system comprises a preview generation module and optionally a high resolution display processing module. After a group of captured radial scan line images is received, the preview generation module determines the representative pixel values for pixels in the group. The polar coordinate system position of the respective group is then converted to a position in the display window coordinates. The representative pixel values are plotted at the corresponding display window coordinates. The operator can request a high resolution display of an area of the preview display. When a request is received, the captured image data within that area is converted to rectangular system coordinates and displayed.

Claims

1. A method for generating a preview of a print pattern on a substantially conical platen surface, an image of the print pattern being captured in a scan made up of a series of radial scan line images along an arcuate path, comprising:

for each group of radial scan line images, the steps of;

determining a representative sensor pixel value for pixels in a group of captured radial scan line images;

converting a polar coordinate position of the respective group of captured radial scan line images to a position in rectangular display window coordinates;

plotting the representative sensor pixel values determined in said determining step at corresponding rectangular display window coordinates; and

displaying the plot of the representative sensor pixel values in a display window as a preview of the print pattern image captured on the substantially conical platen surface.

2. The method of claim 1 wherein determining a representative sensor pixel value includes determining an average sensor pixel value for pixels in the group of captured radial scan lines.

3. The method of claim 1 wherein the group of radial scan line images consists of approximately 25 radial scan lines.

4. The method of claim 1 further comprising the steps of:

receiving a request for a high resolution display of a selected area of the preview of the print pattern; and

converting the captured polar coordinate system image data contained in the portion of the preview of the print pattern to converted image data in a rectangular coordinate system.

5. The method of claim 4 wherein determining a representative sensor pixel value includes decimating the converted image data.

6. The method of claim 4, wherein said converting comprises:

for each pixel in the user selected area, the steps of;

performing a look up to obtain conversion data including the polar coordinate data and the polar offset data associated with respective pixel coordinates;

retrieving at least one sample of stored captured image data; and

interpolating each retrieved sample with weighting based on the looked up offset data to obtain a respective pixel value in rectangular coordinate system.

7. A system for generating a display of a print pattern on a substantially conical platen surface, an image of the print pattern being captured in a scan made up of a series of radial scan line images along an arcuate path, comprising:

a non planar prism;

a scanning imaging system optically coupled to the non planar prism for capturing the image data in a polar coordinate system;

an image conversion system wherein the image conversion system comprises a coordinate conversion module for converting the polar coordinate positions of the captured radial scan line images to positions in rectangular display window coordinates; and

a display processing system coupled to the scanning imaging system wherein the display processing system comprises a preview generation module for generating a preview display on the substantially conical platen surface of the captured print image preview display selected by a system user.

8. The system of claim 7 wherein the display processing system further comprises a high resolution display processing module for generating a high resolution display of an area of the preview display selected by a system user.

9. The system of claim 8 wherein the image conversion system further comprises:

a retrieval module for retrieving entries in a conversion data array and one or more samples from the captured raw polar image data;

an interpolation module for interpolating the samples using weighting based on the retrieved conversion data array entries to obtain the respective pixel values in a second coordinate system; and

a communications module for communicating the converted image data to the display processing system after all pixels in the selected area have been interpolated.

10. The system of claim 7 wherein the non planar prism is a substantially conical prism.

11. The system of claim 7 wherein the scanning and capturing system is coupled to the display processing system via a data network.