Method and system for measuring text-rendering quality
First Claim
1. A method that assesses character-rendering quality, the method comprising:
- transmitting a test-character set of test characters to a character-rendering device for rendering;
intercepting digital pixel-based character maps for the test characters of the test-character set, used by the character-rendering device for rendering the test characters, to serve as an input-character set of input characters;
capturing, with a computing system, the test characters rendered by the character-rendering device to serve as an output-character set of output characters;
for each input character, generating with the computing system, from the intercepted input characters, one or more first metrics that reflect differences between the input character and at least two of the input characters;
for each output character, generating with the computing system, from the intercepted input characters and the captured output characters, one or more second metrics that reflect differences between the output character and at least two of the input characters; and
outputting one or more indications of character-rendering quality based on the first and second metrics.
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Accused Products
Abstract
Method embodiments of the present invention provide for semi-automated or fully automated assessment of the quality of device-rendered text, including graphical symbols, characters, and other printable or displayable patterns. Method embodiments of the present invention employ one or more metrics that involve the comparison of input characters, including text characters, symbols, and character-like graphics, with corresponding digital output characters obtained by capturing images of characters rendered by a character-rendering device. The one or more metrics include individual computed relative entropy APQi metrics, reflective of differences in character-to-character distance distributions between one input character c, and the set of input characters c*, a cumulative computed relative entropy APQ, stroke irregularity, contrast measure, sharpness, and background uniformity. These individual metrics can be computed and stored separately as well as output to a user of a character-rendering-quality measurement system, or may be combined together in various ways to produce one or more comprehensive, cumulative metrics for storage and output.
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Citations
14 Claims
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1. A method that assesses character-rendering quality, the method comprising:
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transmitting a test-character set of test characters to a character-rendering device for rendering; intercepting digital pixel-based character maps for the test characters of the test-character set, used by the character-rendering device for rendering the test characters, to serve as an input-character set of input characters; capturing, with a computing system, the test characters rendered by the character-rendering device to serve as an output-character set of output characters; for each input character, generating with the computing system, from the intercepted input characters, one or more first metrics that reflect differences between the input character and at least two of the input characters; for each output character, generating with the computing system, from the intercepted input characters and the captured output characters, one or more second metrics that reflect differences between the output character and at least two of the input characters; and outputting one or more indications of character-rendering quality based on the first and second metrics. - View Dependent Claims (2, 4, 5, 6, 7, 8)
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3. A method that assesses character-rendering quality, the method comprising:
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transmitting a test-character set of test characters to a character-rendering device for rendering; intercepting digital pixel-based character maps for the test characters of the test-character set, used by the character-rendering device for rendering the test characters, to serve as an input-character set of input characters; capturing, with a computing system, the test characters rendered by the character-rendering device to serve as an output-character set of output characters; for each input character ci, generating with the computing system, from the intercepted input characters and the captured output characters, one or more metrics that reflect differences between the input characters and the output characters; and outputting one or more indications of character-rendering quality based on the one or more metrics, wherein capturing test characters rendered by the character-rendering device to serve as an output-character set of output characters further includes; capturing images of test characters rendered by the character-rendering device by an image-capturing device; generating digitally-encoded, pixel-based representations of the test characters rendered by the character-rendering device from the captured images; tone mapping the digitally-encoded representations of the rendered test characters; and registering the digitally-encoded representations of the rendered test characters with the input characters in order to generate a set of digitally encoded output characters corresponding to the input characters to serve as the output-character set of output characters.
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9. A method that assesses character-rendering quality, the method comprising:
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transmitting a test-character set of test characters to a character-rendering device for rendering; intercepting digital pixel-based character maps for the test characters of the test-character set, used by the character-rendering device for rendering the test characters, to serve as an input-character set of input characters; capturing, with a computing system, the test characters rendered by the character-rendering device to serve as an output-character set of output characters; for each input character ci, generating with the computing system, from the intercepted input characters and the captured output characters, metrics that reflect differences between the input characters and the output characters, including a cumulative metric metric for each set of metrics metrici which is generated as
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10. A method that assesses character-rendering quality, the method comprising:
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transmitting a test-character set of test characters to a character-rendering device for rendering; intercepting digital pixel-based character maps for the test characters of the test-character set, used by the character-rendering device for rendering the test characters, to serve as an input-character set of input characters; capturing, with a computing system, the test characters rendered by the character-rendering device to serve as an output-character set of output characters; for each input character ci, generating with the computing system, from at least one of eroded or dilated transformations of the intercepted input characters superimposed over the captured output characters, one or more outline metrics that reflect differences between the input characters and the output characters; and outputting one or more indications of character-rendering quality based on the one or more metrics. - View Dependent Claims (11, 12, 13, 14)
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Specification