Assessing print quality using intensity histograms and perimeter lengths

Patent metadata

Field	Value
Publication number	US-2021203790-A1
Application number	US-201716077055-A
Country	US
Kind code	A1
Filing date	Jan 17, 2017
Priority date	Jan 17, 2017
Publication date	Jul 1, 2021
Grant date	—

Abstract

In one example in accordance with the present disclosure, a method for assessing print quality is described. According to the method, a printed mark is converted into a digital binary mark. A number of values are calculated for the digital binary mark. The number of values include at least a perimeter length value and a value describing a characteristic of an intensity histogram for the digital binary mark. A combined representation of the number of values for the digital binary mark are compared against a combined representation of a number of values for a model printed mark. When the combined representation for the digital binary mark is greater than a predefined distance away from the combined representation for the model printed mark, an operation of a printing device that generated the printed mark is adjusted.

First claim

What is claimed is:

1 . A method for assessing print quality comprising:
converting a printed mark into a digital binary mark; calculating a number of values for the digital binary mark including at least a perimeter length value and a value describing a characteristic of an intensity histogram for the digital binary mark; comparing a combined representation of the number of values for the digital binary mark against a combined representation of a number of values for a model printed mark; and adjusting operation of a printing device that generated the printed image when the combined representation for the digital binary mark is greater than a predetermined distance away from the combined representation for the model printed mark.

2 . The method of claim 1 , wherein the number of values further comprise:
a perimeter roughness value; an intensity histogram mean value; an intensity histogram variance value; and an intensity histogram-to-variance ratio value.

3 . The method of claim 1 , wherein the model printed mark has a target print quality.

4 . The method of claim 1 ; wherein the combined representation of the number of values for the digital binary mark is a linear combination of the number of values.

5 . The method of claim 1 , wherein the combined representation of the number of values for the digital binary mark is a weighted combination of the number of value based on their relative correlation to print quality.

6 . The method of claim 1 , further comprising:
determining a centroid of the digital binary mark; and dividing the digital binary mark into radially-defined segments; wherein calculating a number of values for the digital binary mark is performed on a per-segment basis.

7 . The method of claim 1 , further comprising processing a print job to which the printed mark corresponds while converting the printed mark, calculating the number of values, and comparing a combined representation of the number of values.

8 . The method of claim 1 , wherein print quality is assessed against a sample mark without a test pattern.

9 . A print system comprising:
a printing device to form a printed mark on media by depositing fluid on the media; a print quality assessment device, comprising:
a capture engine to:
capture a digital representation of the printed mark; and
convert the digital representation into a digital binary mark;

an analysis engine to calculate a number of values for the digital binary mark;
a compare engine to compare a combined representation of the number of values for the digital binary mark against a combined representation of a number of values for a model printed mark; and
a controller to adjust an operation of at least one component of the printing device when the combined representation for the digital binary mark is greater than a threshold distance away from the combined representation for the model printed mark.

10 . The system of claim 9 , wherein the controller reduces the speed of the printing device.

11 . The system of claim 9 , wherein the capture device is a scanner.

12 . The system of claim 9 , wherein the model printed mark is specific to the printing device in the print system.

13 . A computer system comprising:
a processor; a machine-readable storage medium coupled to the processor; and an instruction set to assess print quality, the instruction set being stored in the machine-readable storage medium to be executed by the processor, wherein the instruction set comprises:
instructions to convert a printed mark into a digital binary mark;
instructions to calculate a number of values for the digital binary mark, wherein the number of values comprise:
a perimeter roughness value;
a perimeter length value;
an intensity histogram mean value;
an intensity histogram variance value; and
an intensity histogram mean-to-variance ratio value;

instructions to compare the combined representation of the number of values for the digital binary mark against a combined representation for a number of values of a model printed mark; and
instructions to adjust operation of a printing device that generated the printed mark when the combined representation for the digital binary mark is greater than a threshold distance away from the combined representation for the model printed mark.

14 . The system of claim 13 , wherein the instructions to assess print quality are executed without reference to a test pattern.

15 . The system of claim 13 , wherein the instruction set to assess print quality further comprises instructions to select, from a set of model printed marks, the model printed mark as it reflects a desired target print quality.

Assignees

• Hewlett Packard Development Co

Inventors

• Simske Steven J
• Walters Karl
• Sexton Douglas A

Classifications

• H04N1/6036 Primary

  involving periodic tests or tests during use of the machine · CPC title

• H04N1/50

  Picture reproducers (for halftone screening H04N1/52) · CPC title

• H04N1/00082

  Adjusting or controlling (interrupting an operation H04N1/00915; inhibiting an operation H04N1/00925) · CPC title

• H04N1/00045

  using a reference pattern designed for the purpose, e.g. a test chart · CPC title

• H04N1/00031 Primary

  Testing, i.e. determining the result of a trial (H04N1/00029 takes precedence; using test signals for transmission mode changing H04N2201/33371) · CPC title