Method of detecting noise in image signals

Claim 1

A method of detecting noise in image signals which are obtained by exposing a stimulable phosphor sheet carrying a radiation image stored thereon to stimulating rays, and photoelectrically detecting light emitted by the portion of the stimulable phosphor sheet exposed to the stimulating rays in proportion to the stored radiation energy by use of a photodetector, and which represent the radiation image, is detected, the method of detecting noise in image signals comprising the steps of: (i) comparing the image signal a at each remark picture element A with values (b1+T1), (b2+T2), ..., (bn+Tn) obtained by adding predetermined values T1, T2, Tn respectively to image signals b1, b2, ..., bn at a plurality of picture elements B1, B2, ..., Bn in the vicinity of said remark picture element A, and (ii) recognizing that noise is contained in said image signal a in the case where said image signal a attains a value larger than every one of said values (b1+T1), (b2+T2), ..., (bn+Tn).

Claim 2

A method of detecting noise in image signals which are obtained by exposing a stimulable phosphor sheet carrying a radiation image stored thereon to stimulating rays, and photoelectrically detecting light emitted by the portion of the stimulable phosphor sheet exposed to the stimulating rays in proportion to the stored radiation energy by use of a photodetector, and which represent the radiation image, is detected, the method of detecting noise in image signals comprising the steps of: (i) comparing the image signal a at each remark picture element A with values (b1+T1), (b2+T2), ..., (bn+Tn) obtained by adding predetermined values T1, T2, Tn respectively to image signals b1, b2, ..., bn at a plurality of picture elements B1, B2, ..., Bn in the vicinity of said remark picture element A, and (ii) recognizing that noise is contained in said image signal a in the case where said image signal a attains a value larger than every one of said values (b1+T1), (b2+T2), ..., (bn+Tn).

Claim 16

A method of detecting noise in image signals which are obtained by exposing a simtulable phosphor sheet carrying a radiation image stored thereon to stimulating rays, and photoelectrically detecting light emitted by the portion of the stimulable phosphor sheet exposed to the stimulating rays in proportion to the stored radiation energy by use of a photodetector, and which represent the radiation image, is detected, the method of detecting noise in image signals comprising the steps of: (i) calculating a representative value of a0 of image signals a1 to am at a plurality of remark picture elements A1 to Am which are adjacent to one another, (ii) comparing said representative value a0 with values (b1+T1), (b2+T2), ..., (bn+Tn) obtained by adding predetermined values T1, T2, ..., Tn respectively to image signals b1, b2, ..., bn at a plurality of picture elements A1 to Am, and (iii) recognizing that noise is contained in said image signals a1 to am in the case where said representative value a0 attains a value larger than every one of said values (b1+T1), (b2+T2), ..., (bn+Tn).

Claim 17

A method of detecting noise in image signals which are obtained by exposing a simtulable phosphor sheet carrying a radiation image stored thereon to stimulating rays, and photoelectrically detecting light emitted by the portion of the stimulable phosphor sheet exposed to the stimulating rays in proportion to the stored radiation energy by use of a photodetector, and which represent the radiation image, is detected, the method of detecting noise in image signals comprising the steps of: (i) calculating a representative value of a0 of image signals a1 to am at a plurality of remark picture elements A1 to Am which are adjacent to one another, (ii) comparing said representative value a0 with values (b1+T1), (b2+T2), ..., (bn+Tn) obtained by adding predetermined values T1, T2, ..., Tn respectively to image signals b1, b2, ..., bn at a plurality of picture elements A1 to Am, and (iii) recognizing that noise is contained in said image signals a1 to am in the case where said representative value a0 attains a value larger than every one of said values (b1+T1), (b2+T2), ..., (bn+Tn).

Claim 24

A method of detecting noise in image signals which are obtained by exposing a stimulable phosphor sheet carrying a radiation image stored thereon to stimulating rays, and photoelectrically detecting light emitted by the portion of the stimulable phosphor sheet exposed to the stimulating rays in proportion to the stored radiation energy by use of a photodetector, and which represent the radiation image, is detected, the method of detecting noise in image signals comprising the steps of: (i) calculating a value m with respect to the image signal a at each remark picture element A and image signals b1, b2, b3, ..., bn at a plurality of picture elements B1, B2, B3, ..., Bn in the vicinity of said remark picture element A, and (iii) recognizing that noise is contained in said image signal a in the case where a>m+k where k denotes a constant and the value m is the median value of said image signal a and said image signals b1, b2, b3, ..., bn.

Claim 25

A method of detecting noise in image signals which are obtained by exposing a stimulable phosphor sheet carrying a radiation image stored thereon to stimulating rays, and photoelectrically detecting light emitted by the portion of the stimulable phosphor sheet exposed to the stimulating rays in proportion to the stored radiation energy by use of a photodetector, and which represent the radiation image, is detected, the method of detecting noise in image signals comprising the steps of: (i) calculating a value m with respect to the image signal a at each remark picture element A and image signals b1, b2, b3, ..., bn at a plurality of picture elements B1, B2, B3, ..., Bn in the vicinity of said remark picture element A, and (iii) recognizing that noise is contained in said image signal a in the case where a>m+k where k denotes a constant and the value m is the median value of said image signal a and said image signals b1, b2, b3, ..., bn.

Claim 47

A method of detecting noise in image signals which are obtained by exposing a stimulable phosphor sheet carrying a radiation image stored thereon to stimulating rays, and photoelectrically detecting light emitted by the portion of the stimulable phosphor sheet exposed to the stimulating rays in proportion to the stored radiation energy by use of a photodetector, and which represent the radiation image, is detected, the method of detecting noise in image signals comprising the steps of: (i) extracting said image signals into a plurality of blocks into which said stimulable phosphor sheet is divided, each block having n picture elements, (ii) calculating a value m which depends on the extracted image signals Fi, where i=1, 2, 3, ..., n, in each of the blocks, (iii) sequentially comparing the respective image signals Fi with a value of m+k, where k denotes a constant, in each of the blocks, and (iv) recognizing that noise is contained in said image signals Fi in the case where Fi>m+k.

Claim 48

A method of detecting noise in image signals which are obtained by exposing a stimulable phosphor sheet carrying a radiation image stored thereon to stimulating rays, and photoelectrically detecting light emitted by the portion of the stimulable phosphor sheet exposed to the stimulating rays in proportion to the stored radiation energy by use of a photodetector, and which represent the radiation image, is detected, the method of detecting noise in image signals comprising the steps of: (i) extracting said image signals into a plurality of blocks into which said stimulable phosphor sheet is divided, each block having n picture elements, (ii) calculating a value m which depends on the extracted image signals Fi, where i=1, 2, 3, ..., n, in each of the blocks, (iii) sequentially comparing the respective image signals Fi with a value of m+k, where k denotes a constant, in each of the blocks, and (iv) recognizing that noise is contained in said image signals Fi in the case where Fi>m+k.

Claim 51

A method as defined in any of claims 44, 45 and 46 wherein said constant k is of a value k0 times the variance σ of said image signals Fi, where i=1, 2, 3, ..., n, and k0 denotes a constant.

Claim 57

A method of detecting noise in image signals which are obtained by exposing a stimulable phosphor sheet carrying a radiation image stored thereon to stimulating rays, and photoelectrically detecting light emitted by the portion of the stimulable phosphor sheet exposed to the stimulating rays in proportion to the stored radiation energy by use of a photodetector, and which represent the radiation image, is detected, the method of detecting noise in image signals comprising the steps of: (i) calculating the difference values Di=Fi-[Fi-1]F(i-1), where i=2, 3, ..., n, between adjacent ones among the image signals F1 , F2, F3, ..., Fn at picture elements A1, A2, A3, ..., An standing in a line in one direction, (ii) detecting the difference values Dj and Dk, where j<k, that satisfy the conditions of Dj>T1, Dk<-T2 where T1 and T2 denote positive constants, and (iii) recognizing that noise is contained in the image signals Fj to [Fk-1]F(k-1) in the case where k<j+u where u denotes a positive constant.

Claim 58

A method of detecting noise in image signals which are obtained by exposing a stimulable phosphor sheet carrying a radiation image stored thereon to stimulating rays, and photoelectrically detecting light emitted by the portion of the stimulable phosphor sheet exposed to the stimulating rays in proportion to the stored radiation energy by use of a photodetector, and which represent the radiation image, is detected, the method of detecting noise in image signals comprising the steps of: (i) calculating the difference values Di=Fi-[Fi-1]F(i-1), where i=2, 3, ..., n, between adjacent ones among the image signals F1 , F2, F3, ..., Fn at picture elements A1, A2, A3, ..., An standing in a line in one direction, (ii) detecting the difference values Dj and Dk, where j<k, that satisfy the conditions of Dj>T1, Dk<-T2 where T1 and T2 denote positive constants, and (iii) recognizing that noise is contained in the image signals Fj to [Fk-1]F(k-1) in the case where k<j+u where u denotes a positive constant.

Claim 60

A method of detecting noise in image signals which are obtained by exposing a stimulable phosphor sheet carrying a radiation image stored thereon to stimulating rays, and a photoelectrically detecting light emitted by the portion of the stimulable phosphor sheet exposed to the stimulating rays in proportion to the stored radiation energy by use of a photodetector, and which represent the radiation image, is detected, the method of detecting noise in image signals comprising the steps of: (i) calculating the difference values Di=Fi-[Fi-1]F(i-1), where i=2, 3, ..., n, between adjacent ones among the image signals F1, F2, F3, Fn at picture elements A1, A2, A3, ..., An standing in a line in one direction, (ii) detecting the difference values Dj and Dk, where j>k, what satisfy the conditions of Dj>T1, Dk<-T2 where T1 and T2 denote positive constants. (iii) calculating a two-dimensional position (s1t1) of a middle picture element A0 among such picture elements Aj to [Ak-1]A(k-1) that k<j+u, where u denotes a positive constant, on said stimulable phosphor sheet, (iv) calculating the difference values Ei=Gi-[Gi-1]G(i-1), where i=2, 3, ..., m, between adjacent ones among the image signals G1, G2, G3, ..., Gm at picture elements B1, B2, B3, ..., Bm standing in a line approximately normal to the direction in which said picture elements A1, A2, A3, ..., An stand in a line, (v) detecting the difference values Ep and Eq, where p<q, that satisfy the conditions of Ep>T3, Eq<-T4 where T3 and T4 denote positive constant, (vi) calculating a two-dimensional position (s2, t2) of a middle picture element B0 among such picture elements Bp to [Bq-1]B(q-1) that 1<p+v, where v denotes a positive constant, on said stimulable phosphor sheet, and (vii) recognizing that noise is contained in the image signals Fj to [Fk-1]F(k-1) or in the image signals Gp to [G1- 1]G(q-1) in the case where |s1-s2|<α, or |t1-t2|<β where α and β denote positive constants.

Claim 61

A method of detecting noise in image signals which are obtained by exposing a stimulable phosphor sheet carrying a radiation image stored thereon to stimulating rays, and a photoelectrically detecting light emitted by the portion of the stimulable phosphor sheet exposed to the stimulating rays in proportion to the stored radiation energy by use of a photodetector, and which represent the radiation image, is detected, the method of detecting noise in image signals comprising the steps of: (i) calculating the difference values Di=Fi-[Fi-1]F(i-1), where i=2, 3, ..., n, between adjacent ones among the image signals F1, F2, F3, Fn at picture elements A1, A2, A3, ..., An standing in a line in one direction, (ii) detecting the difference values Dj and Dk, where j>k, what satisfy the conditions of Dj>T1, Dk<-T2 where T1 and T2 denote positive constants. (iii) calculating a two-dimensional position (s1t1) of a middle picture element A0 among such picture elements Aj to [Ak-1]A(k-1) that k<j+u, where u denotes a positive constant, on said stimulable phosphor sheet, (iv) calculating the difference values Ei=Gi-[Gi-1]G(i-1), where i=2, 3, ..., m, between adjacent ones among the image signals G1, G2, G3, ..., Gm at picture elements B1, B2, B3, ..., Bm standing in a line approximately normal to the direction in which said picture elements A1, A2, A3, ..., An stand in a line, (v) detecting the difference values Ep and Eq, where p<q, that satisfy the conditions of Ep>T3, Eq<-T4 where T3 and T4 denote positive constant, (vi) calculating a two-dimensional position (s2, t2) of a middle picture element B0 among such picture elements Bp to [Bq-1]B(q-1) that 1<p+v, where v denotes a positive constant, on said stimulable phosphor sheet, and (vii) recognizing that noise is contained in the image signals Fj to [Fk-1]F(k-1) or in the image signals Gp to [G1- 1]G(q-1) in the case where |s1-s2|<α, or |t1-t2|<β where α and β denote positive constants.

Claim 63

A method of detecting noise in image signals comprising the steps of: (i) comparing the image signal a at each remark picture element A with values (b1+T1), (b2+T2), ..., (bn+Tn) obtained by adding predetermined values T1, T2, ..., Tn respectively to image signals b1, b2, ..., bn at a plurality of picture elements B1, B2, ..., Bn in the vicinity of said remark picture element A, and (ii) recognizing that noise is contained in said image signal a in the case where said image signal a attains a value larger than every one of said values (b1+T1), (b2+T2), ..., (bn+Tn).

Claim 64

A method of detecting noise in image signals comprising the steps of: (i) comparing the image signal a at each remark picture element A with values (b1+T1), (b2+T2), ..., (bn+Tn) obtained by adding predetermined values T1, T2, ..., Tn respectively to image signals b1, b2, ..., bn at a plurality of picture elements B1, B2, ..., Bn in the vicinity of said remark picture element A, and (ii) recognizing that noise is contained in said image signal a in the case where said image signal a attains a value larger than every one of said values (b1+T1), (b2+T2), ..., (bn+Tn).

Claim 65

A method of detecting noise in image signals comprising the steps of: (i) calculating a representative value a0 of image signals a1 to am at a plurality of remark picture elements A1 to Am which are adjacent to one another, (ii) comparing said representative value a0 with values (b1+T1), (b2+T2), ..., (bn+Tn) obtained by adding predetermined values T1, T2, ..., Tn respectively to image signals b1, b2, ..., bn at a plurality of picture elements B1, B2, ..., Bn in the vicinity of said remark picture elements A1 to Am, and (iii) recognizing that noise is contained in said image signals a1 to am in the case where said representative value a0 attains a value larger than every one of said values (b1+T1), (b2+T2), ..., (bn+Tn).

Claim 66

A method of detecting noise in image signals comprising the steps of: (i) calculating a representative value a0 of image signals a1 to am at a plurality of remark picture elements A1 to Am which are adjacent to one another, (ii) comparing said representative value a0 with values (b1+T1), (b2+T2), ..., (bn+Tn) obtained by adding predetermined values T1, T2, ..., Tn respectively to image signals b1, b2, ..., bn at a plurality of picture elements B1, B2, ..., Bn in the vicinity of said remark picture elements A1 to Am, and (iii) recognizing that noise is contained in said image signals a1 to am in the case where said representative value a0 attains a value larger than every one of said values (b1+T1), (b2+T2), ..., (bn+Tn).

Claim 67

A method of detecting noise in image signals comprising the steps of: (i) calculating a value m with respect to the image signal a at each remark picture element A and image signals b1, b2, b3, ..., bn at a plurality of picture elements B1, B2, B3, ..., Bn in the vicinity of said remark picture element A, and (iii) recognizing that noise is contained in said image signal a in the case where a>m+k where k denotes a constant and the value m is the median value of said image signal a and said image signals b1, b2, b3, ..., bn.

Claim 68

A method of detecting noise in image signals comprising the steps of: (i) calculating a value m with respect to the image signal a at each remark picture element A and image signals b1, b2, b3, ..., bn at a plurality of picture elements B1, B2, B3, ..., Bn in the vicinity of said remark picture element A, and (iii) recognizing that noise is contained in said image signal a in the case where a>m+k where k denotes a constant and the value m is the median value of said image signal a and said image signals b1, b2, b3, ..., bn.

Claim 69

A method of detecting noise in image signals comprising the steps of: (i) extracting said image signals into a plurality of blocks each having n picture elements, (ii) calculating a value m which depends on the extracted image signals Fi, where i=1, 2, 3, ..., n, in each of the blocks, (iii) sequentially comparing the respective image signals Fi with a value of m+k, where k denotes a constant, in each of the blocks, and (iv) recognizing that noise is contained in said image signals Fi in the case where Fi>m+k.

Claim 70

A method of detecting noise in image signals comprising the steps of: (i) extracting said image signals into a plurality of blocks each having n picture elements, (ii) calculating a value m which depends on the extracted image signals Fi, where i=1, 2, 3, ..., n, in each of the blocks, (iii) sequentially comparing the respective image signals Fi with a value of m+k, where k denotes a constant, in each of the blocks, and (iv) recognizing that noise is contained in said image signals Fi in the case where Fi>m+k.

Claim 71

A method of detecting noise in image signals comprising the steps of: (i) calculating the difference values Di=Fi-F(i-1), where i=2, 3, ..., n, between adjacent ones among the image signals F1, F2, F3, Fn at picture elements A1, A2, A3, ..., An standing in a line in one direction, (ii) detecting the difference values Dj and Dk, where j<k, that satisfy the conditions of Dj>T1, Dk<-T2 where T1 and T2 denote positive constants, and (iii) recognizing that noise is contained in the image signals Fj to F(k-1) in the case where k<j+u where u denotes a positive constant.

Claim 72

A method of detecting noise in image signals comprising the steps of: (i) calculating the difference values Di=Fi-F(i-1), where i=2, 3, ..., n, between adjacent ones among the image signals F1, F2, F3, Fn at picture elements A1, A2, A3, ..., An standing in a line in one direction, (ii) detecting the difference values Dj and Dk, where j<k, that satisfy the conditions of Dj>T1, Dk<-T2 where T1 and T2 denote positive constants, and (iii) recognizing that noise is contained in the image signals Fj to F(k-1) in the case where k<j+u where u denotes a positive constant.

Claim 73

A method of detecting noise in image signals comprising the steps of: (i) calculating the difference values Di=Fi-F(i-1), where i=2, 3, ..., n, between adjacent ones among the image signals F1, F2, F3, ..., Fn at picture elements A1, A2, A3, ..., An standing in a line in one direction, (ii) detecting the difference values Dj and Dk, where j<k, what satisfy the conditions of Dj>T1, Dk<-T2 where T1 and T2 denote positive constants, (iii) calculating a two-dimensional position (s1, t1) of a middle picture element A0 among such picture elements Aj to A(k-1) that k<j+u, where u denotes a positive constant, (iv) calculating the difference values Ei=Gi-G(i-1), where i=2, 3, ..., m, between adjacent ones among the image signals G1, G2, G3, ..., Gm at picture elements B1, B2, B3, ..., Bm standing in a line approximately normal to the direction in which said picture elements A1, A2, A3, ..., An stand in a line, (v) detecting the difference values Ep and Eq, where p<q, that satisfy the conditions of Ep>T3, Eq<-T4 where T3 and T4 denote positive constant, (vi) calculating a two-dimensional position (s2, t2) of a middle picture element B0 among such picture elements Bp to B(q-1) that q<p+v, where v denotes a positive constant, on said stimulable phosphor sheet, and (vii) recognizing that noise is contained in the image signals Fj to F(k-1) or in the image signals Gp to G(q-1) in the case where |s1-s2|<α, or |t1-t2|<β where α and β denote positive constants.

Claim 74

A method of detecting noise in image signals comprising the steps of: (i) calculating the difference values Di=Fi-F(i-1), where i=2, 3, ..., n, between adjacent ones among the image signals F1, F2, F3, ..., Fn at picture elements A1, A2, A3, ..., An standing in a line in one direction, (ii) detecting the difference values Dj and Dk, where j<k, what satisfy the conditions of Dj>T1, Dk<-T2 where T1 and T2 denote positive constants, (iii) calculating a two-dimensional position (s1, t1) of a middle picture element A0 among such picture elements Aj to A(k-1) that k<j+u, where u denotes a positive constant, (iv) calculating the difference values Ei=Gi-G(i-1), where i=2, 3, ..., m, between adjacent ones among the image signals G1, G2, G3, ..., Gm at picture elements B1, B2, B3, ..., Bm standing in a line approximately normal to the direction in which said picture elements A1, A2, A3, ..., An stand in a line, (v) detecting the difference values Ep and Eq, where p<q, that satisfy the conditions of Ep>T3, Eq<-T4 where T3 and T4 denote positive constant, (vi) calculating a two-dimensional position (s2, t2) of a middle picture element B0 among such picture elements Bp to B(q-1) that q<p+v, where v denotes a positive constant, on said stimulable phosphor sheet, and (vii) recognizing that noise is contained in the image signals Fj to F(k-1) or in the image signals Gp to G(q-1) in the case where |s1-s2|<α, or |t1-t2|<β where α and β denote positive constants.