METHOD FOR MEASURING IMAGE NOISE OF IMAGE READER, RESOLUTION MEASURING APPARATUS AND RESOLUTION MEASURING METHOD, AND RECORDING MEDIUM THEREFOR

Title:

METHOD FOR MEASURING IMAGE NOISE OF IMAGE READER, RESOLUTION MEASURING APPARATUS AND RESOLUTION MEASURING METHOD, AND RECORDING MEDIUM THEREFOR

Document Type and Number:

WIPO Patent Application WO/1999/056458

Kind Code:

A1

Abstract:

According to a method for measuring image noise of an image reader of the invention, image data collected by reading a measurement area having a uniform density of a test chart is analyzed by an image analyzing program of a computer, an abnormal part of the image data is extracted, and it is judged whether or not the abnormal part is noise based on predetermined criteria. According to a method for measuring the resolution of an image reader of the invention, a test chart prepared by slightly shifting the pitch of a black-and-white line pair pattern from the pixel pitch of the image reader is read in such a way that there is always a portion where the pattern coincides with a pixel, only a necessary portion of the read image data is segmented, the gradation difference is calculated for each pixel of the whole segmented image data, the maximum gradation difference is found, and if the maximum gradation difference exceeds an acceptance/rejection judging value, a resolution test acceptance is given.

Inventors:

HONDA KEIJI (JP)
NITTA SYUU (JP)
HASHIMOTO MASAHIDE (JP)

Application Number:

PCT/JP1999/002241

Publication Date:

November 04, 1999

Filing Date:

April 27, 1999

Export Citation:

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Assignee:

PFU LTD (JP)
HONDA KEIJI (JP)
NITTA SYUU (JP)
HASHIMOTO MASAHIDE (JP)

International Classes:

G06T1/00; H04N1/00; H04N1/04; (IPC1-7): H04N1/00; G06T1/00; H04N1/04

Foreign References:

JPS61238169A	1986-10-23
JPH05268417A	1993-10-15
JPH0998264A	1997-04-08
JPH07111565A	1995-04-25
JPH066589A	1994-01-14

Other References: