Abnormnal pattern detecting or judging apparatus, circular pattern judging apparatus, and image finding apparatus

• US 5,850,465 A
• Filed: 08/28/1991
• Issued: 12/15/1998
• Est. Priority Date: 06/26/1989
• Status: Expired due to Fees

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Adachi, Yuuma, Hara, Shoji, Nakajima, Nobuyoshi, Ito, Wataru, Shimura, Kazuo
• Primary Examiner(s): McElheny, Jr., Donald E.
• Application Number:
  US07/751,449
• Time in Patent Office: 2,666 Days
• Field of Search: 364/413.01, 364/413.02, 364/413.03, 382/6, 382/130, 382/132, 395/21, 395/23, 395/924, 128/922
• US Class Current: 382/132
• CPC Class Codes: G06T 2207/10116 X-ray image
• CPC Class Codes: G06T 2207/20068 Projection on vertical or horizontal image axis
• CPC Class Codes: G06T 2207/20084 Artificial neural networks [ANN]
• CPC Class Codes: G06T 2207/20224 Image subtraction
• CPC Class Codes: G06T 2207/30061 Lung
• CPC Class Codes: G06T 2207/30096 Tumor; Lesion
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06T 7/174 involving the use of two or more images
• CPC Class Codes: G06V 10/44 Local feature extraction by analysis of parts of the pattern, e.g. by detecting edges, contours, loops, corners, strokes or intersections; Connectivity analysis, e.g. of connected components
• CPC Class Codes: Y10S 128/92 Computer assisted medical diagnostics

Abstract

An abnormal pattern detecting apparatus comprises a device for finding prospective abnormal patterns in a radiation image of an object from an image signal representing the radiation image, and a device for finding anatomical information about the object from the image signal. From the image signal components of the image signal, which represent the image information at positions in the vicinity of each prospective abnormal pattern, a characteristic measure calculating device calculates a plurality of characteristic measures for each prospective abnormal pattern. An abnormal pattern finding device utilizes the characteristic measures and the anatomical information in order to find a true abnormal pattern from the prospective abnormal patterns.

Claims

1. An abnormal pattern detecting apparatus wherein an abnormal pattern in a radiation image of an object is detected from an image signal made up of a series of image signal components representing the radiation image,

the abnormal pattern detecting apparatus comprising:

i) prospective abnormal pattern finding means for receiving said image signal and finding prospective abnormal patterns from said image signal,

ii) information operating means for receiving said image signal and finding anatomical information concerning said object from said image signal,

iii) characteristic measure calculating means for receiving said image signal and said prospective abnormal patterns and calculating a plurality of characteristic measures for each of said prospective abnormal patterns, the calculations being made from the image signal components of said image signal, which represent image information at positions in the vicinity of each of said prospective abnormal patterns, and

iv) true abnormal pattern finding means which utilizes the plurality of said characteristic measures and said anatomical information to find a true abnormal pattern from said prospective abnormal patterns.

2. An abnormal pattern detecting apparatus as defined in claim 1 wherein said true abnormal pattern finding means is provided with a neural network, which receives information concerning the plurality of said characteristic measures and which outputs a measure representing the level of the probability that each of said prospective abnormal patterns will be a true abnormal pattern.

3. An abnormal pattern detecting apparatus as defined in claim 1 wherein said prospective abnormal pattern finding means includes means for findings said prospective abnormal patterns by processing said image signal with a spatial-domain filter.

4. An abnormal pattern detecting apparatus as defined in claim 1 wherein the plurality of said characteristic measures include at least one of the area, the shape, and the contrast of each of said prospective abnormal patterns.

5. An abnormal pattern detecting apparatus as defined in claim 1 wherein said radiation image of the object has been stored on a stimulable phosphor sheet.

6. An abnormal pattern detecting apparatus as defined in claim 5 further including read-out means for obtaining said image signal from a read-out operation wherein said stimulable phosphor sheet is exposed to stimulating rays, which cause said stimulable phosphor sheet to emit light in proportion to the amount of energy stored thereon during its exposure to radiation, and the emitted light is detected photoelectrically.

7. An abnormal pattern detecting apparatus as defined in claim 6 wherein said stimulating rays are a laser beam.

8. An abnormal pattern detecting apparatus as defined in claim 1 wherein said radiation image of the object has been recorded on photographic film.

9. An abnormal pattern detecting apparatus wherein an abnormal pattern in a radiation image of an object is detected from an image signal made up of a series of image signal components representing the radiation image,

the abnormal pattern detecting apparatus comprising:

i) first prospective abnormal pattern finding means for finding prospective abnormal patterns from said image signal,

ii) characteristic measure calculating means for calculating a plurality of characteristic measures for each of said prospective abnormal patterns, which have been found by said first prospective abnormal pattern finding means, the calculations being made from the image signal components of said image signal, which represent image information at positions in the vicinity of each of said prospective abnormal patterns,

iii) second prospective abnormal pattern finding means which utilizes the plurality of said characteristic measures, which have been calculated by said characteristic measure calculating means, in order to find a prospective abnormal pattern having a high probability of being a true abnormal pattern, from said prospective abnormal patterns,

iv) display means which utilizes said image signal and information representing said prospective abnormal pattern, which has a high probability of being a true abnormal pattern, in order to display a visible image in which said prospective abnormal pattern is shown clearly, and

v) input means with which information about whether said prospective abnormal pattern shown in said visible image is or is not a true abnormal patter is entered,

wherein said second prospective abnormal pattern finding means is provided with a learning function means for changing the operations for finding a prospective abnormal pattern having a high probability of being a true abnormal pattern from said prospective abnormal patterns found by said first prospective abnormal pattern finding means in accordance with said information entered with said input means.

10. An abnormal pattern detecting apparatus as defined in claim 9 wherein said second prospective abnormal pattern finding means is provided with a neural network means for performing a learning function by a back propagation method, in which said information entered with said input means is utilized as an instructor signal.

11. An abnormal pattern detecting apparatus as defined in claim 9 wherein said first prospective abnormal pattern finding means finds said prospective abnormal patterns by processing said image signal with a spatial-domain filter.

12. An abnormal pattern detecting apparatus as defined in claim 9 wherein the plurality of said characteristic measures include at least one of the area, the shape, and the contrast of each of said prospective abnormal patterns.

13. An abnormal pattern detecting apparatus as defined in claim 9 wherein said radiation image of the object has been stored on a stimulable phosphor sheet.

14. An abnormal pattern detecting apparatus as defined in claim 13 further including read-out means for obtaining said image signal from a read-out operation wherein said stimulable phosphor sheet is exposed to stimulating rays, which cause said stimulable phosphor sheet to emit light in proportion to the amount of energy stored thereon during its exposure to radiation, and the emitted light is detected photoelectrically.

15. An abnormal pattern detecting apparatus as defined in claim 14 wherein said stimulating rays are a laser beam.

16. An abnormal pattern detecting apparatus as defined in claim 9 wherein said radiation image of the object has been recorded on photographic film.

17. An abnormal pattern detecting apparatus wherein an abnormal pattern in a radiation image of an object is detected from an image signal made up of a series of image signal components representing the radiation image,

the abnormal pattern detecting apparatus comprising:

i) operation means for finding anatomical regions in the radiation image from said image signal,

ii) storage means for storing filtering characteristic information concerning a plurality of abnormal pattern detecting filters, which correspond to the anatomical regions, and

iii) detecting means for detecting an abnormal pattern by reading the characterizing information regarding said abnormal pattern detecting filters, which correspond to the anatomical regions found by said operation means, from said storage means, and processing the image signal components, which represent image information at the anatomical regions in the radiation image, with the corresponding abnormal pattern detecting filters.

18. An abnormal pattern detecting apparatus as defined in claim 17 wherein said radiation image of the object has been stored on a stimulable phosphor sheet.

19. An abnormal pattern detecting apparatus as defined in claim 18 further including read-out means for obtaining said image signal from a read-out operation wherein said stimulable phosphor sheet is exposed to stimulating rays, which cause said stimulable phosphor sheet to emit light in proportion to the amount of energy stored thereon during its exposure to radiation, and the emitted light is detected photoelectrically.

20. An abnormal pattern detecting apparatus as defined in claim 19 wherein said stimulating rays are a laser beam.

21. An abnormal pattern detecting apparatus as defined in claim 17 wherein said radiation image of the object has been recorded on photographic film.

22. An abnormal pattern detecting apparatus wherein, from an image signal made up of a series of image signal components representing a radiation image of an object which is constituted of soft tissues and bones, an abnormal pattern appearing as an approximately circular pattern in the radiation image is detected,

the abnormal pattern detecting apparatus comprising:

i) image operation means for obtaining a soft tissue image signal, which is made up of a series of soft tissue image signal components primarily representing an image of the soft tissues in said object, from a plurality of image signals representing a plurality of radiation images of said object, which radiation images have been formed with at least two kinds of radiation having different energy distributions, and

ii) abnormal pattern finding means for finding an abnormal pattern, which appears in a soft tissue image, by processing said soft tissue image signal with an abnormal pattern finding filter,

wherein said abnormal pattern finding filter comprises;

a) first means for calculating the differences, Δ

ij=fij-f0, between the value of a soft tissue image signal component f0 representing a predetermined picture element P0 in said soft tissue image and the values of soft tissue image signal components fij representing the picture elements Pij, which are located on each of a plurality of lines Li, where i=1, 2, . . . , n, extending from said predetermined picture element P0 to peripheral parts of said soft tissue image, said picture elements Pij being spaced a plurality of predetermined distances rij, where j=1, 2, . . . , m, from said predetermined picture element P0,

b) second means for finding a representative value, which is representative of said differences Δ

ij, for each of said lines Li,

c) third means for calculating a mean-level value of two said representative values for each set of two said lines which extend from said predetermined picture element P0 in approximately opposite directions, and

d) fourth means for judging, from mean-level values, which have been calculated for a plurality of said sets of lines, whether said predetermined picture element P0 falls or does not fall within a region corresponding to said abnormal pattern.

23. An abnormal pattern detecting apparatus as defined in claim 22 further comprising a judgment means for calculating a plurality of differences between the values of the soft tissue image signal components representing adjacent picture elements in the abnormal pattern, which has been found by said abnormal pattern finding means, said picture elements being located along each of two different directions in said soft tissue image,

means for calculating a mean-level value of the absolute values of the plurality of said differences for each of two said different directions, or a mean-level value of the square values of the plurality of said differences for each of two said different directions, and

means for making, from mean-level values, which have been calculated for two said different directions, a judgment as to the level of the probability that said abnormal pattern, which has been found by said abnormal pattern finding means, will be a true abnormal pattern.

24. An abnormal pattern detecting apparatus as defined in claim 22 wherein said representative value is the maximum value of said differences Δ

ij, which have been found for each of said lines Li.

25. An abnormal pattern detecting apparatus as defined in claim 22 wherein said representative value is the minimum value of said differences Δ

ij, which have been found for each of said lines Li.

26. An abnormal pattern detecting apparatus as defined in claim 22 wherein said radiation image of the object has been stored on a stimulable phosphor sheet.

27. An abnormal pattern detecting apparatus as defined in claim 26 further including read-out means for obtaining said image signal from a read-out operation wherein said stimulable phosphor sheet is exposed to stimulating rays, which cause said stimulable phosphor sheet to emit light in proportion to the amount of energy stored thereon during its exposure to radiation, and the emitted light is detected photoelectrically.

28. An abnormal pattern detecting apparatus as defined in claim 27 wherein said stimulating rays are a laser beam.

29. An abnormal pattern detecting apparatus as defined in claim 22 wherein said radiation image of the object has been recorded on photographic film.

30. An abnormal pattern detecting apparatus wherein, from an image signal made up of a series of image signal components representing a radiation image of an object which is constituted of soft tissues and bones, an abnormal pattern appearing as an approximately circular pattern in the radiation image is detected,

the abnormal pattern detecting apparatus comprising:

i) image operation means for obtaining a soft tissue image signal, which is made up of a series of soft tissue image signal components primarily representing an image of the soft tissues in said object, from a plurality of image signals representing a plurality of radiation images of said object, which radiation images have been formed with at least two kinds of radiation having different energy distributions, and

ii) abnormal pattern finding means for finding an abnormal pattern, which appears in a soft tissue image, by processing said soft tissue image signal with an abnormal pattern finding filter,

wherein said abnormal pattern finding filter comprises;

a) first means for calculating the gradients ∇

fi of soft tissue image signal components fi representing the picture elements Pi, which are located on a plurality of lines Li, wherein i=1, 2, . . . , n, extending from a predetermined picture element P0 in said soft tissue image to peripheral parts of said soft tissue image, said picture elements Pi being spaced a predetermined distance ri from said predetermined picture element P0,

b) second means for calculating the normalized gradients ∇

fi/|∇

fi| by dividing said gradients ∇

fi by their magnitudes |∇

fi|,

c) third means for calculating the projections of said normalized gradients ∇

fi/|∇

fi| on vectors directed from said picture elements Pi to said predetermined picture element P0, the projections being expressed as ∇

fi/|∇

fi|*ei, where ei denotes the unit vectors directed from said picture elements Pi to said predetermined picture element P0, and * denotes the inner product,

d) fourth means for calculating a mean-level value from the values of said projections ∇

fi/|∇

fi|*ei, and

e) fifth means for judging, from said mean-level value, whether said predetermined picture element P0 falls or does not fall within the region corresponding to said abnormal pattern.

31. An abnormal pattern detecting apparatus as defined in claim 30 further comprising a judgment means for calculating a plurality of differences between the values of the soft tissue image signal components representing adjacent picture elements in the abnormal pattern, which has been found by said abnormal pattern finding means, said picture elements being located along each of two different directions in said soft tissue image,

means for calculating a mean-level value of the absolute values of the plurality of said differences for each of two said different directions, or a mean-level value of the square values of the plurality of said differences for each of two said different directions, and

means for making, from mean-level values, which have been calculated for two said different directions, a judgment as to the level of the probability that said abnormal pattern, which has been found by said abnormal pattern finding means, will be a true abnormal pattern.

32. An abnormal pattern detecting apparatus as defined in claim 30 wherein said radiation image of the object has been stored on a stimulable phosphor sheet.

33. An abnormal pattern detecting apparatus as claimed in claim 32 further including read-out means for obtaining said image signal from a read-out operation wherein said stimulable phosphor sheet is exposed to stimulating rays, which cause said stimulable phosphor sheet to emit light in proportion to the amount of energy stored thereon during its exposure to radiation, and the emitted light is detected photoelectrically.

34. An abnormal pattern detecting apparatus as defined in claim 33 wherein said stimulating rays are a laser beam.

35. An abnormal pattern detecting apparatus as defined in claim 30 wherein said radiation image of the object has been recorded on photographic film.

36. An abnormal pattern detecting apparatus wherein, from an image signal made up of a series of image signal components representing a radiation image of an object which is constituted of soft tissues and bones, an abnormal pattern appearing as an approximately circular pattern in the radiation image is detected,

the abnormal pattern detecting apparatus comprising:

i) image operation means for obtaining a soft tissue image signal, which is made up of a series of soft tissue image signal components primarily representing an image of the soft tissues in said object, from a plurality of image signals representing a plurality of radiation images of said object, which radiation images have been formed with at least two kinds of radiation having different energy distributions, and

ii) abnormal pattern finding means for finding an abnormal pattern, which appears in a soft tissue image, by processing said soft tissue image signal with an abnormal pattern finding filter,

wherein said abnormal pattern finding filter comprises;

a) first means for calculating the gradients ∇

fij of soft tissue image signal components fij representing the picture elements Pij, which are located on each of a plurality of lines Li, where i=1, 2, . . . , n, extending from a predetermined picture element P0 in said soft tissue image to peripheral parts of said soft tissue image, and which are spaced a plurality of predetermined distances rij, where j=1, 2, . . . , m, from said predetermined picture element P0,

b) second means for calculating the normalized gradients ∇

fij/|∇

fij| by dividing said gradients ∇

fij by their magnitudes |∇

fij|,

c) third means for calculating the projections of said normalized gradients ∇

fij/|∇

fij| on vectors which are directed from said picture elements Pij to said predetermined picture element P0, the projections being expressed as ∇

fij/|∇

fij|*ei, where ei denotes the unit vectors directed from said picture elements Pij to said predetermined picture element P0, and * denotes the inner product,

d) fourth means for finding a representative value {∇

fij/|∇

fij|*ei}r, which is representative of said projections ∇

fij/|∇

fij|*ei, for each of said lines Li,

e) fifth means for calculating a mean-level value of said representative values {∇

fij/|∇

fij|*ei}r, which have been found for the plurality of said lines Li, and

f) sixth means for judging from said mean-level value, whether said predetermined picture element P0 falls or does not fall within the region corresponding to said abnormal pattern.

37. An abnormal pattern detecting apparatus as defined in claim 36 further comprising a judgment means for calculating a plurality of differences between the values of the soft tissue image signal components representing adjacent picture elements in the abnormal pattern, which has been found by said abnormal pattern finding means, said picture elements being located along each of two different directions in said soft tissue image,

means for calculating a mean-level value of the absolute values of the plurality of said differences for each of two said different directions, or a mean-level value of the square values of the plurality of said differences for each of two said different directions, and

means for making, from mean-level values, which have been calculated for two said different directions, a judgment as to the level of the probability that said abnormal pattern, which has been found by said abnormal pattern finding means, will be a true abnormal pattern.

38. An abnormal pattern detecting apparatus as defined in claim 36 wherein said representative value is the maximum value of said projections ∇

fij/|∇

fij|*ei, which have been found for each of said lines Li.

39. An abnormal pattern detecting apparatus as defined in claim 36 wherein said representative value is the minimum value of said projections ∇

fij/|∇

fij|*i, which have been found for each of said lines Li.

40. An abnormal pattern detecting apparatus as defined in claim 36 wherein said radiation image of the object has been stored on a stimulable phosphor sheet.

41. An abnormal pattern detecting apparatus as defined in claim 40 further including read-out means for obtaining said image signal from a read-out operation wherein said stimulable phosphor sheet is exposed to stimulating rays, which cause said stimulable phosphor sheet to emit light in proportion to the amount of energy stored thereon during its exposure to radiation, and the emitted light is detected photoelectrically.

42. An abnormal pattern detecting apparatus as defined in claim 41 wherein said stimulating rays are a laser beam.

43. An abnormal pattern detecting apparatus as defined in claim 36 wherein said radiation image of the object has been recorded on photographic film.

44. An abnormal pattern detecting apparatus wherein, from an image signal made up of a series of image signal components representing a radiation image of an object which is constituted of soft tissues and bones, an abnormal pattern appearing as an approximately circular pattern in the radiation image is detected,

the abnormal pattern detecting apparatus comprising:

i) image operation means for obtaining a soft tissue image signal, which is made up of a series of soft tissue image signal components primarily representing an image of the soft tissues in said object, from a plurality of image signals representing a plurality of radiation images of said object, which radiation images have been formed with at least two kinds of radiation having different energy distributions, and

ii) abnormal pattern finding means for finding an abnormal pattern, which appears in a soft tissue image, by processing said soft tissue image signal with an abnormal pattern finding filter,

wherein said abnormal pattern finding filter comprises;

a) first means for calculating;

(1) a mean-level value Q0 from the values of soft tissue image signal components representing a plurality of picture elements, which are located in a center region including a predetermined picture element P0 in said soft tissue image, and

(2) mean-level values Qi, wherein i=1, 2, . . . , n, each representing the mean level of the values of soft tissue image signal components representing a plurality of picture elements, which are located in each of a plurality of peripheral regions surrounding said center region,

b) second means for calculating the differences Δ

i, where i=1, 2, . . . , n, between said mean-level value Q0 corresponding to said center region and the respective mean-level values Qi, wherein i=1, 2, . . . , n, corresponding to said peripheral regions,

c) third means for finding a first characteristic value, which is representative of said differences Δ

i, and a second characteristic value, which represents the amount of dispersion in said differences Δ

i,

d) fourth means for calculating the ratio of said first characteristic value to said second characteristic value,

e) fifth means for comparing said ratio with a predetermined threshold value, and

f) sixth means for judging, from the results of the comparison, whether said predetermined picture element P0 falls or does not fall within the region corresponding to said abnormal pattern.

45. An abnormal pattern detecting apparatus as defined in claim 44 further comprising a judgment means for calculating a plurality of differences between the values of the soft tissue image signal components representing adjacent picture elements in the abnormal pattern, which has been found by said abnormal pattern finding means, said picture elements being located along each of two different directions in said soft tissue image,

means calculating a mean-level value of the absolute values of the plurality of said differences for each of two said different directions, or a mean-level value of the square values of the plurality of said differences for each of two said different directions, and

means for making, from mean-level values, which have been calculated for two said different directions, a judgment as to the level of the probability that said abnormal pattern, which has been found by said abnormal pattern finding means, will be a true abnormal pattern.

46. An abnormal pattern detecting apparatus as defined in claim 44 wherein said first characteristic value is the mean-level value of said differences Δ

i.

47. An abnormal pattern detecting apparatus as defined in claim 44 wherein said radiation image of the object has been stored on a stimulable phosphor sheet.

48. An abnormal pattern detecting apparatus as defined in claim 47 further including read-out means for obtaining said image signal from a read-out operation wherein said stimulable phosphor sheet is exposed to stimulating rays, which cause said stimulable phosphor sheet to emit light in proportion to the amount of energy stored thereon during its exposure to radiation, and the emitted light is detected photoelectrically.

49. An abnormal pattern detecting apparatus as defined in claim 48 wherein said stimulating rays are a laser beam.

50. An abnormal pattern detecting apparatus as defined in claim 44 wherein said radiation image of the object has been recorded on photographic film.

51. An abnormal pattern detecting apparatus wherein, from an image signal made up of a series of image signal components representing a radiation image of an object which is constituted of soft tissues and bones, an abnormal pattern appearing as an approximately circular pattern in the radiation image is detected,

the abnormal pattern detecting apparatus comprising:

i) image operation means for obtaining a soft tissue image signal, which is made up of a series of soft tissue image signal components primarily representing an image of the soft tissues in said object, from a plurality of image signals representing a plurality of radiation images of said object, which radiation images have been formed with at least two kinds of radiation having different energy distributions, and

ii) abnormal pattern finding means for finding an abnormal pattern, which appears in a soft tissue image, by processing said soft tissue image signal with an abnormal pattern finding filter,

wherein said abnormal pattern finding filter comprises;

a) first means for calculating;

(1) a mean-level value Q0 of the values of soft tissue image signal components representing a plurality of picture elements, which are located in a center region including a predetermined picture element P0 in said soft tissue image, and

(2) mean-level values Qij, each representing the mean level of the values of soft tissue image signal components representing a plurality of picture elements located in each of a plurality of peripheral regions, each said peripheral region including each of picture elements Pij, which are located on each of a plurality of lines Li, where i=1, 2, . . . , n, extending from said predetermined picture element P0 to peripheral parts of said soft tissue image, said picture elements Pij being spaced a plurality of predetermined distances rij, where j=1, 2, . . . , m, from said predetermined picture element P0,

b) second means for finding a representative value Qi, which is representative of said mean-level values, for each said lines Li,

c) third means for calculating the differences Δ

i, where i=1, 2, . . . , n, between said mean-level value Q0 corresponding to said center region and the respective representative values Qi, which have been found for the plurality of said lines Li,

d) fourth means for finding a first characteristic value, which is representative of said differences Δ

i, and a second characteristic value, which represents the amount of dispersion in said differences Δ

i,

e) fifth means for calculating the ratio of said first characteristic value to said second characteristic value,

f) sixth means for comparing said ratio with a predetermined threshold value, and

g) seventh means for judging, from the results of the comparison, whether said predetermined picture element P0 falls or does not fall within the region corresponding to said abnormal pattern.

52. An abnormal pattern detecting apparatus as defined in claim 51 further comprising a judgment means for calculating a plurality of differences between the values of the soft tissue image signal components representing adjacent picture elements in the abnormal pattern, which has been found by said abnormal pattern finding means, said picture elements being located along each of two different directions in said soft tissue image,

means for calculating a mean-level value of the absolute values of the plurality of said differences for each of two said different directions, or a mean-level value of the square values of the plurality of said differences for each of two said different directions, and

means for making, from mean-level values, which have been calculated for two said different directions, a judgment as to the level of the probability that said abnormal pattern, which has been found by said abnormal pattern finding means, will be a true abnormal pattern.

53. An abnormal pattern detecting apparatus as defined in claim 51 wherein said representative value Qi is the maximum value of said mean-level values Qij corresponding to the peripheral regions located along each of said lines Li.

54. An abnormal pattern detecting apparatus as defined in claim 51 wherein said representative value Qi is the minimum value of said mean-level values Qij corresponding to the peripheral regions located along each of said lines Li.

55. An abnormal pattern detecting apparatus as defined in claim 51 wherein said radiation image of the object has been stored on a stimulable phosphor sheet.

56. An abnormal pattern detecting apparatus as defined in claim 55 further including read-out means for obtaining said image signal from a read-out operation wherein said stimulable phosphor sheet is exposed to stimulating rays, which cause said stimulable phosphor sheet to emit light in proportion to the amount of energy stored thereon during its exposure to radiation, and the emitted light is detected photoelectrically.

57. An abnormal pattern detecting apparatus as defined in claim 56 wherein said stimulating rays are a laser beam.

58. An abnormal pattern detecting apparatus as defined in claim 51 wherein said radiation image of the object has been recorded on photographic film.

59. An image finding apparatus wherein, from an image signal made up of a series of image signal components representing a radiation image of a human body, a tumor image in the radiation image is found,

the image finding apparatus comprising:

i) characteristic measure calculating means for calculating characteristic measures for a plurality of picture elements in said radiation image by processing said image signal with a spatial-domain filter, which yields the characteristic measures whose values vary in accordance with whether a predetermined picture element in said radiation image falls or does not fall within the region corresponding to said tumor image,

ii) prospective tumor image finding means for finding prospective tumor images from said characteristic measures, and

iii) tumor image finding means for finding a tumor image from said prospective tumor images;

wherein said tumor image finding means is provided with;

a) difference calculating means for calculating a plurality of differences between the values of the image signal components representing adjacent picture elements in a region corresponding to each said prospective tumor image, said picture elements being located along each of two different directions in said radiation image,

b) mean calculating means for calculating a mean-level value of the absolute values of the plurality of said differences for each of two said different directions, or a mean-level value of the square values of the plurality of said differences for each of two said different directions, and

c) judgment means for judging, from mean-level values, which have been calculated for two said different directions, whether said prospective tumor image is or is not a true tumor image.

60. An image display apparatus comprising:

i) a first image display section which is provided with;

a) means for entering an image control signal,

b) first image processing means for processing an original image signal in accordance with said image control signal,

c) first display means for displaying an image represented by an image signal, which has been processed by said first image processing means, and

d) transmission means for transmitting both said original image signal and said image control signal independently of each other, and

ii) a second image display section which is provided with;

e) reception means for independently receiving both said original image signal and said image control signal, which are transmitted by said transmission means,

f) second image processing means for processing said original image signal in accordance with the received image control signal, and

g) second display means for displaying an image represented by an image signal, which has been processed by said second image processing means.

61. An image display apparatus as defined in claim 60 wherein said image control signal represents the information about the positions of an abnormal pattern in an image represented by said original image signal.

62. An image display apparatus as defined in claim 60 wherein said original image signal is obtained by reading out a radiation image which has been stored on a stimulable phosphor sheet.

63. An image display apparatus as defined in claim 62 wherein said original image signal is obtained from a read-out operation wherein said stimulable phosphor sheet is exposed to stimulating rays, which cause said stimulable phosphor sheet to emit light in proportion to the amount of energy stored thereon during its exposure to radiation, and the emitted light is detected photoelectrically.

64. An image display apparatus as defined in claim 63 wherein said stimulating rays are a laser beam.

65. An image display apparatus as defined in claim 60 wherein said original image signal is obtained by reading out a radiation image which has been recorded on photographic film.