Patent EP0750272A2 successfully refreshed from Google Patents.
EP0750272A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Image binarization apparatus and method
Assignee: Toshiba Corp
•
Filing: 1996-06-21
•
Granted: —
•
Expires: 2016-06-21
Abstract
Abstract A binarization circuit comprises the function (S21 to S31) of comparing the density value of the target pixel with the density value of surrounding pixels in the vicinity, the function (S21 to S31) of judging whether or not the target pixel is isolated from the surrounding pixels, and the function (S32 to S36) of detecting the density values of the target pixels which makes the target pixels isolated by binarization process, the function (S32 to S36) of calculating out accumulated isolated pixels frequencies of each density value detected by the detecting function when the judging means and the detecting means finished each process of all the original image, and the function of determining a threshold value on the basis of the accumulated isolated pixels frequencies.
Inventors
- 👤 Toru c/o Int. Prop. Div. Homma
- 👤 c/o Int. Prop. Div. Yura Koji
- 👤 Yoshikatu c/o Int. Prop. Div. Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 12:39
CPC Classifications
G; G06; G06V; G06V30/00; G06V30/10; G06V30/16; G06V30/162
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
99 words
An apparatus for binarizing images, characterized by comprising: (FIG. 4A) means (S1 to S6) for computing a difference between densities of adjacent pixels of an original image (A) and comparing the difference with a predetermined value (a); means (S7, S9) for detecting an edge area of the original image on the basis of the comparison result of the computing means; means (S8, S10 to S16) for determining a threshold value (θ) on the basis of a density distribution of pixels (G(K)) in the edge area; and means for binarizing the original image on the basis of the threshold value.
Claim 2
Dependent Claim
66 words
An apparatus according to claim 1, characterized in that the comparing means includes: an X-direction differential filter (C2) for comparing pixels adjacent to each other in the horizontal direction of a target pixel to compute the difference between them; and a Y-direction differential filter (C3) for comparing pixels adjacent to each other in the vertical direction of the target pixel to compute the difference between them.
Claim 3
Dependent Claim
77 words
An apparatus according to claim 1, characterized in that the threshold determining means includes: means (S8, S10) for performing a differentiating process on each density value in the edge area for each pixels, the differentiating process counts "+1" on a lower density adjacent pixel, and counts "-1" on a higher density adjacent pixel; and means (S11 to S15) for performing an integrating process on the result of the differentiating process so as to determine the density distribution.
Claim 4
Dependent Claim
68 words
An apparatus according to claim 1, characterized in that the threshold determining means includes: processing means (S8, S10) for performing a frequency adding process on the lower density values and a frequency subtracting process on the higher density values in comparing the densities in the edge area; and means (S11 to S15) for performing an accumulating process on the results of the processing means for each density value.
Claim 5
Dependent Claim
32 words
An apparatus according to claim 4, characterized in that the threshold determining means includes means (S16) for determining a threshold value on the basis of a density value having a largest frequency.
Claim 6
Dependent Claim
34 words
An apparatus according to claim 1, characterized in that the threshold determining means includes means (S16) for determining a density value having the maximum frequency plus a constant (α) value as the threshold value.
Claim 7
Independent Claim
197 words
An apparatus for binarizing images, characterized by comprising: (FIG. 8) means (S21 to S31) for comparing density values of target pixels composed of n × m pixels (n and m are each an integer of 1 or more) of an original image (A) with density values of a plurality of surrounding pixels in vicinities of the target pixels and outputting a comparison result; means (S21 to S31) for judging on the basis of the comparison result whether or not the target pixels are isolated from the surrounding pixels; means (S21 to S31) for detecting the density values of the target pixels which makes the target pixels isolated by binarization process, when the judging means has judged that the target pixels are isolated; means (S21 to S31) for calculating out accumulated isolated pixels frequencies of each density value detected by the detecting means when the judging means and the detecting means finished each process of all the original image; means (S32 to S36) for determining a threshold value on the basis of the accumulated isolated pixels frequencies (G(K)) calculated by the calculating means; and means (5) for binarizing the original image on the basis of the threshold value.
Claim 8
Dependent Claim
56 words
An apparatus according to claim 7, characterized in that the judging means includes: means (S28) for judging that the density of the target pixels is the largest of the densities of the surrounding pixels; and means (S30) for judging that the density of the target pixels is the smallest of the densities of the surrounding pixels.
Claim 9
Dependent Claim
73 words
An apparatus according to claim 7, characterized in that the threshold determining means includes: means (S29, S31) for performing a differentiating process on each density value of the target pixels which makes the target pixels isolated by the binarization process, when the judging means has judged that the target pixels are isolated; and means (S32 to S35) for performing an integrating process on a result of the differentiating process with respect to density.
Claim 10
Dependent Claim
70 words
An apparatus according to claim 7, characterized in that the threshold determining means includes first means (S29, S31) for performing a frequency adding process on the lower density values and a frequency subtracting process on the higher density values, when the judging means has judged that the target pixels are isolated; and second means (S27) for performing an integrating process on a result of the processes of the first means.
Claim 11
Dependent Claim
33 words
An apparatus according to claim 9, characterized in that the threshold determining means includes means (S37) for determining a minimal value of the results (G(K)) of the integrating process as the threshold value.
Claim 12
Independent Claim
103 words
A method of binarizing images, characterized by comprising: (FIG. 4A) a step (S1 to S6) of computing a difference between densities of adjacent pixels of an original image (A) and comparing the difference with a predetermined value (a); a step (S7, S9) of detecting an edge area of the original image on the basis of the comparison result of the computing step; a step (S8, S10 to S16) of determining a threshold value (θ) on the basis of a density distribution (G(K)) of pixels in the edge area; and a step of binarizing the original image on the basis of the threshold value.
Claim 13
Dependent Claim
73 words
A method according to claim 12, characterized in that the comparing step includes: a step of making a comparison using an X-direction differential filter (C2) that compares pixels adjacent to each other in the horizontal direction of a target pixel to compute the difference between them and a Y-direction differential filter (C3) that compares pixels adjacent to each other in the vertical direction of the target pixel to compute the difference between them.
Claim 14
Dependent Claim
79 words
A method according to claim 12, characterized in that the threshold determining step includes: a step (S8, S10) of performing a differentiating process on each density value in the edge area for each pixels, the differentiating process counts "+1" on a lower density adjacent pixel, and counts "-1" on a higher density adjacent pixel; and a step (S11 to S15) of performing an integrating process on the result of the differentiating process so as to determine the density distribution.
Claim 15
Dependent Claim
70 words
A method according to claim 12, characterized in that the threshold determining step includes: a processing step (S8, S10) of performing a frequency adding process on the lower density values and a frequency subtracting process on the higher density values in comparing the densities in the edge area; and a step (S11 to S15) of performing an accumulating process on the results of the processing step for each density value.
Claim 16
Dependent Claim
33 words
A method according to claim 15, characterized in that the threshold determining step includes a step (S16) of determining a threshold value on the basis of a density value having a largest frequency.
Claim 17
Dependent Claim
35 words
A method according to claim 12, characterized in that the threshold determining step includes a step (S16) of determining a density value having the maximum frequency plus a constant (α) value as the threshold value.
Claim 18
Independent Claim
203 words
A method of binarizing images, characterized by comprising: (FIG. 8) a step (S21 to S31) of comparing density values of target pixels composed of n × m pixels (n and m are each an integer of 1 or more) of an original image (A) with density values of a plurality of surrounding pixels in vicinities of the target pixels and outputting a comparison result; a step (S21 to S31) of judging on the basis of the comparison result whether or not the target pixels are isolated from the surrounding pixels; a step (S21 to S31) of detecting the density values of the target pixels which makes the target pixels isolated by binarization process, when the judging step has judged that the target pixels are isolated; a step (S21 to S31) of calculating out accumulated isolated pixels frequencies of each density value detected by the detecting step when the judging step and the detecting step finished each process of all the original image; a step (S32 to S36) of determining a threshold value on the basis of the accumulated isolated pixels frequencies (G(K)) calculated by the calculating step; and a step (5) of binarizing the original image on the basis of the threshold value.
Claim 19
Dependent Claim
58 words
A method according to claim 18, characterized in that the judging step includes: a step (S28) of judging that the density of the target pixels is the largest of the densities of the surrounding pixels; and a step (S30) of judging that the density of the target pixels is the smallest of the densities of the surrounding pixels.
Claim 20
Dependent Claim
75 words
A method according to claim 18, characterized in that the threshold determining step includes: a step (S29, S31) of performing a differentiating process on each density value of the target pixels which makes the target pixels isolated by the binarization process, when the judging step has judged that the target pixels are isolated; and a step (S32 to S35) of performing an integrating process on a result of the differentiating process with respect to density.
Claim 21
Dependent Claim
72 words
A method according to claim 18, characterized in that the threshold determining step includes a first step (S29, S31) of performing a frequency adding process on the lower density values and a frequency subtracting process on the higher density values, when the judging step has judged that the target pixels are isolated; and a second step (S27) of performing an integrating process on a result of the processes of the first step.
Claim 22
Dependent Claim
34 words
A method according to claim 20, characterized in that the threshold determining step includes the step (S37) of determining a minimal value of the results (G(K)) of the integrating process as the threshold value.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.