Method and arrangement for ensuring quality during scanning/copying of images/documents

• US 6,345,130 B1
• Filed: 02/23/1999
• Issued: 02/05/2002
• Est. Priority Date: 08/28/1996
• Status: Expired due to Fees

• Current Assignee: ReadSoft Software Services AB (Ninestar Corporation)
• Original Assignee: Ralip International AB
• Inventors: Dahl, Magnus
• Primary Examiner(s): Boudreau, Leo
• Assistant Examiner(s): Kassa, Yosef
• Application Number:
  US09/242,688
• Time in Patent Office: 1,078 Days
• Field of Search: 382/286, 382/317, 382/318, 382/312, 382/309, 358/296, 358/403, 358/401, 358/504, 356/372, 356/374
• US Class Current: 382/286
• CPC Class Codes: G06V 10/993 Evaluation of the quality of the acquired pattern
• CPC Class Codes: H04N 1/00002 Diagnosis, testing or measuring; Detecting, analysing or monitoring not otherwise provided for error detection, error correction or monitoring in digital computers or digital computer components G06F11/00
• CPC Class Codes: H04N 1/00013 Reading apparatus
• CPC Class Codes: H04N 1/00018 Scanning arrangements
• CPC Class Codes: H04N 1/00034 Measuring, i.e. determining a quantity by comparison with a standard H04N1/00031 takes precedence
• CPC Class Codes: H04N 1/00039 Analysis, i.e. separating and studying components of a greater whole
• CPC Class Codes: H04N 1/00082 Adjusting or controlling interrupting an operation H04N1/00915; inhibiting an operation H04N1/00925
• CPC Class Codes: H04N 1/40 Picture signal circuits H04N1/387 takes precedence

Abstract

The present invention relates to an arrangement and a method for ensuring quality during scanning/copying of images/documents. The method includes the steps of feeding in the page(s) that are to be scanned/copied. Thereafter, a first measurement of outer characteristics is performed with respect to skew, double-feeding/overlapping, deviating shape, and geometric deformation for calculating a first quality measure Q₁. Thereafter, the first quality measure Q₁ is compared with a predetermined first quality limit Q+₁. If Q₁≧Q+₁, then an automatic adjustment is performed in the form of a geometric transformation in order to improve the first quality measure Q₁. Thereafter, the contents of the page are analyzed with respect to structure and objects in order to calculate a second quality measure Q₂, which is compared with a predetermined second quality limit Q+₂. If Q₂≧Q+₂, then image improvement methods are performed on each identified object. Thereafter, an information analysis of each page is performed, followed by a comparison with pre-defined form/document types for calculating a third quality measure Q₃, which is compared with a predetermined third quality limit Q+₃. If Q₃≧Q₃, then a fourth quality measure Q is calculated, which is an overall quality measure that is compared with a predetermined fourth quality limit Q+. If Q≧Q+, then pre-processing is performed in order to achieve a correct output format, depending on pre-defined information about the printer/output unit.

Claims

1. A method for ensuring quality during the scanning/copying of images/documents, the method comprising the steps:

feeding in the pages to be scanned/copied;

performing a first measurement of outer characteristics relating to skew, double-feeding/overlapping, deviating shape, and geometric deformation for calculating a first quality measure Q₁;

comparing the first quality measure Q₁ with a pre-determined first quality limit Q+₁ and sending out a warning indicating re-feeding when Q₁<

Q+₁; and

performing an automatic adjustment in the form of geometric transformation in order to improve the first quality measure Q₁ when Q₁≧

Q+₁;

analyzing the contents of the page with respect to structure and objects for calculating a second quality measure Q₂;

comparing the second quality measure Q₂ with a pre-determined second quality limit Q+₂ and sending out a warning indicating re-feeding when Q₂<

Q+₂;

performing image improvement methods on each identified object if Q₂≧

Q+₂;

performing an information analysis on each page followed by a comparison with pre-defined form/document types for calculating a third quality measure Q₃;

comparing the third quality measure Q₃ with a pre-determined third limit Q+₃ and sending out a warning indicating document error when Q₃<

Q+₃; and

calculating a fourth quality measure Q, which is a weighted combination of the quality measures Q₁-Q₃ when Q₃≧

Q+₃;

comparing the fourth quality measure Q with a pre-determined fourth quality limit Q+ and sending out a warning indicating insufficient quality when Q<

Q+; and

performing pre-processing for achieving a correct output format depending on pre-defined information concerning the printer/output unit when Q≧

Q+, wherein Q+, Q+₁-Q+₃ are entered and set by the user.

2. A method according to claim 1 wherein the step of measuring outer characteristics includes the steps of:

measuring an outer border line and curvature of the page;

measuring lengthwise running lines; and

measuring lengthwise and transverse running lines/structures.

3. A method according to claim 1, wherein the step of performing automatic adjustment in the form of geometric transformation includes the steps:

adjusting skew by means of translation and rotation; and

performing a rubber-sheet transformation.

4. A method according to claim 1, wherein the step of performing an analysis of the contents of the page with respect to structure and objects includes the steps of:

performing a legibility analysis in the form of a spatial frequency analysis of the contents of the page to measure whether sufficient resolution has been used;

segmenting the contents of the page.

5. A method according to claim 1, wherein the step of performing an information analysis includes the steps:

performing a symbol identification; and

/or

comparing with pre-defined form/document types; and

/or

comparing the contents of the page with information tables that describe sets of form/document types.

6. A method according to claim 4, wherein the result of the segmentation of the contents of the page being stored in the form of a vector IS={O₁, G₁, T₁;

O₂, G₂, T₂;

. . . ;

O_n, G_n, T_n} where O₁ is the object;

G₁ is a two-dimensional curve that defines the border line for O₁; and

T₁ is the character class of the object.

7. The arrangement for ensuring quality during scanning/copying of images/documents, comprising:

an interface/communications logical unit;

a control and monitoring unit connected to the interface/communications logic unit;

an image memory unit, connected to the interface/communications logic unit, for storing image information;

a measuring device connected to the control and monitoring unit and to the image memory unit for measuring outer characteristics relating to skew, double-feeding/overlapping, deviating shape, and geometric distortion/deformation, the measures being used by the control and monitoring unit for calculating a first quality measure Q₁;

an adjustment device connected to the control and monitoring unit, to the image memory and to the measuring device, for automatically performing an adjustment in the form of geometric transformation in order to improve the first quality measure Q₁;

an analysis device connected to the control and monitoring unit to the image memory unit and to the adjustment device, for analyzing the contents of the page with respect to structure and objects, the analysis being used by the control and monitoring unit to calculate a second quality measure Q₂;

an improvement device connected to the control and monitoring unit, to the image memory unit and to the analysis device for performing image improvement methods on each identified object;

an information analysis device connected to the control and monitoring unit, to the imagery memory unit and to the improvement device for performing an information analysis of each page, the analysis being used by the control and monitoring unit for comparison with pre-defined form/document types for calculating a third quality measure Q₃; and

a pre-processing device connected to the control and monitoring unit, to the image memory unit and to the information analysis device for performing pre-processing for achieving a correct output format depending on pre-defined information about a printer/output unit connected to the arrangement, whereby the control and monitoring unit respectively compares the quality measures Q₁-Q₃ with respective by the user entered and set quality limits Q+₁-Q+₃.

8. The arrangement according to claim 7, wherein the control and monitoring unit uses the three quality measures Q₁-Q₃, for calculating a fourth quality measure, and the control and monitoring unit sends out a warning indicating whether any of the quality measures Q, Q₁-Q₃ is less than pre-determined quality limits Q+, Q+₁-Q+₃.