Method to allow automated image quality analysis of arbitrary test patterns

• US 6,606,395 B1
• Filed: 11/29/1999
• Issued: 08/12/2003
• Est. Priority Date: 11/29/1999
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Rasmussen, D. Rene, Dalal, Edul N.
• Primary Examiner(s): Mehta, Bhavesh M.
• Assistant Examiner(s): DESIRE, GREGORY M
• Application Number:
  US09/450,182
• Time in Patent Office: 1,352 Days
• Field of Search: 382/181, 382/278-279, 382/112, 382/287, 382/161-167, 399/8, 358/1.15, 358/406, 358/518, 358/2.1, 358/3.1, 358/3.26, 358/3.27
• US Class Current: 382/112
• CPC Class Codes: B41J 29/393 Devices for controlling or analysing the entire machine ; Controlling or analysing mechanical parameters involving printing of test patterns
• 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 1/00015 Reproducing apparatus
• CPC Class Codes: H04N 1/00023 Colour systems
• CPC Class Codes: H04N 1/00031 Testing, i.e. determining the result of a trial H04N1/00029 takes precedence; using test signals for transmission mode changing H04N2201/33371
• CPC Class Codes: H04N 1/00045 using a reference pattern designed for the purpose, e.g. a test chart
• CPC Class Codes: H04N 1/00053 out of service, i.e. outside of normal operation
• CPC Class Codes: H04N 1/00058 using a separate apparatus
• CPC Class Codes: H04N 1/00068 Calculating or estimating
• CPC Class Codes: H04N 2201/3226 of identification information or the like, e.g. ID code, index, title, part of an image, reduced-size image
• CPC Class Codes: H04N 2201/3269 of machine readable codes or marks, e.g. bar codes or glyphs
• CPC Class Codes: H04N 2201/3271 Printing or stamping
• CPC Class Codes: H04N 2201/3274 Storage or retrieval of prestored additional information

Abstract

An image quality analysis system is provided that can determine various aspects of image quality easily and with minimal user involvement and minimal user expertise. The system uses a scanner, either a stand-alone or part of a multi-function printer/scanner/copier, to scan a printed test pattern, and then perform a series of analyses on the scanned image using an image quality analysis module that may be built into the image output device being tested, or provided as a stand-alone component that can receive the output from the scanner. There are often a number of different test patterns that would be used depending on which print quality issues are being tested. By encoding each test pattern with a coded identification label, not only can the particular test pattern be identified, but the analysis to be performed can also be determined from the corresponding script when the printed test pattern is scanned and subsequently decoded. Particularly suitable decoders are OCR and barcode readers. Such identification labels and/or scripts can also be used to identify a particular machine that is being tested and other relevant information.

Claims

1. A method of performing image quality analysis on an image output device having an output station that generates a hardcopy image output from an input image, the method comprising:

providing a test pattern that may not be known in advance by an image quality analysis module, the test pattern being embedded with encoded information identifying the particular test pattern;

generating a hardcopy image output from the image output device using the test pattern as an input image;

scanning the hardcopy image to form a digital raster image;

decoding the encoded information to identify the particular test pattern and identify which of several types of image quality analysis routines is to be performed; and

performing the selected image quality analyses on appropriate regions of the digital raster image using the an image quality analysis module to evaluate image quality performance of the image output device, wherein the image quality analysis module can analyze the test pattern without knowing in advance particulars of the test pattern or which image quality analyses to perform by decoding the encoded information found on the test pattern.

2. The method of claim 1, wherein the encoded information is in the form of human readable words.

3. The method of claim 2, wherein the step of decoding includes performing optical character recognition on the encoded information.

4. The method of claim 1, wherein the encoded information is in the form of a barcode.

5. The method of claim 4, wherein the step of decoding includes reading the barcode with a bar code reader.

6. The method of claim 1, wherein scripts are stored in memory for each test pattern, and the encoded information includes identification of the relevant script, which contains information relating to an image quality analysis routine to be performed when analyzing the particular test pattern.

7. The method of claim 1, wherein the test pattern is in digital form.

8. The method of claim 1, wherein the test pattern is a hardcopy original.

9. The method of claim 1, wherein specific printer/materials data are provided in the encoded information and the image quality analyses automatically select correct calibration data based on the specific printer/materials data.

10. The method of claim 1, wherein the selected image quality analyses include at least one of color registration, motion quality, micro uniformity, macro uniformity, color correction and font quality.

11. An image quality analysis system for performing image quality analysis on an image output device that generates a hardcopy image output from an input image, the system comprising:

a arbitrary test pattern that may not be known in advance by an image quality analysis module, the test pattern being embedded with encoded information identifying the particular test pattern;

a scanner that forms a digital raster image from a hardcopy image output from an image output device to be tested that used the test pattern as an input image;

a decoder that decodes the encoded information to identify the particular test pattern and identify which of several types of image quality analysis routines is to be performed; and

the image quality analysis module that performs image quality analysis on the digital raster image based on the decoded information to evaluate image quality performance of the image output device, wherein the image quality analysis module can analyze the test pattern without knowing in advance particulars of the test pattern or which image quality analyses to perform by decoding the encoded information found on the test pattern.

12. The system of claim 11, wherein the encoded information contains human readable words.

13. The system of claim 12, wherein the decoder is an optical character recognition device.

14. The system of claim 11, wherein the encoded information is in the form of a barcode.

15. The system of claim 14, wherein the decoder is a barcode reader.

16. The system of claim 11, wherein scripts are stored in memory for each test pattern, and the encoded information includes identification of the relevant script, which contains information relating to an image quality analysis routine to be performed when analyzing the particular test pattern.

17. The system of claim 16, wherein the scripts are in the form of self-executing subroutines that automatically perform the one image quality analysis on the digital raster image.

18. The system of claim 17, wherein the test pattern includes identification of the image output device being tested.

19. The system of claim 11, wherein the encoded information indicates specific printer/materials data useful in the image quality analysis to automatically select correct calibration data.

20. The system of claim 11, wherein the image quality analysis module performs analysis of at least one of color registration, motion quality, micro uniformity, macro uniformity, color correction and font quality.