대표
청구항
▼
1. A system for detecting the sharpness of an image formed by an image forming optical means, comprising: (A) image sensing means for sensing the image formed by said optical means, said image sensing means having an array of a plurality of radiation sensitive elements, the individual elements producing electrical signals corresponding to the radiations incident thereon, and said image sensing means having as its output to provide the electrical signals of the respective elements in a time-seriated manner; (B) illuminance difference detecting means f...
1. A system for detecting the sharpness of an image formed by an image forming optical means, comprising: (A) image sensing means for sensing the image formed by said optical means, said image sensing means having an array of a plurality of radiation sensitive elements, the individual elements producing electrical signals corresponding to the radiations incident thereon, and said image sensing means having as its output to provide the electrical signals of the respective elements in a time-seriated manner; (B) illuminance difference detecting means for providing electrical signals representing illuminance difference in the individual minute compartments of said image based on the output of said image sensing means; (C) signal transforming means for non-linear transformation and absolute-value transformation of the electrical signals provided by said illuminance difference detecting means, said signal transforming means having at least one semi-conductor element embodying signal non-linear transformation characteristics, whereby said electrical signals are at least non-linearly transformed by utilizing said semi-conductor; and (D) image sharpness output means for providing an output representing the sharpness of said image on said image sensing means based on the non-linearly transformed and absolute-value transformed electrical signals by said signal transforming means. 2. A system according to claim 1, wherein said semiconductor element in said signal transforming means is a transistor. 3. A system according to claim 2, wherein said transistor is a field effect transistor. 4. A system according to claim 3, wherein said field effect transistor is equipped with signal square transformation characteristics, and said signal transforming means utilizes said field effect transistor in non-linear transformation and absolute-value transformation of the electrical signal provided by said illuminance difference detecting means. 5. A system according to claim 4, wherein said field effect transistor has a MOS (Metal Oxide Semi-conductor) structure. 6. A system according to any one of claims 1 to 5, further comprising: transformation control means for controlling signal transforming operation of said signal transforming means, said transformation control means controlling the signal transforming operation of said signal transforming means so as to perform different transformation between those of the electrical signals provided by said illuminance difference detecting means which correspond to a predetermined detection region of the area of said image and the other electrical signals which correspond to the outside of said prescribed detection region. 7. A system according to claim 6, wherein said transformation control means controls the signal transforming operation of said signal transforming means so that the output of said signal transforming means for the signals corresponding to the outside of said predetermined detection region becomes substantially zero. 8. A system according to claim 7, wherein said transformation control means controls the signal non-linear transforming operation of said signal transforming means so as to further differ the non-linear transformation of the signals corresponding to the said predetermined detection region with different positions of the individual minute image compartments within said prescribed detection region. 9. A system according to claim 8, wherein said transformation control means controls the signal non-linear transforming operation of said signal transforming means so as to give a higher emphasis to the signals corresponding to a central portion of said predetermined detection region than to the signals corresponding to the marginal portion of said prescribed detection region. 10. A system according to claim 7, wherein said transformation control means has means sensible to the change of ambient temperature, and controls the signal non-linear transforming operation of said signal transforming means for th signals corresponding to at least said predetermined detection region to further accord with the ambient temperature on the basis of the output of said temperature sensitive element. 11. A system according to claim 6, wherein said transformation control means controls the signal non-linear transforming operation of said signal transforming means so as to further differ the non-linear transformation of the signals corresponding to the said predetermined detection region with different positions of the individual minute image compartments within said prescribed detection region. 12. A system according to claim 11, wherein said transformation control means controls the signal non-linear transforming operation of said signal transforming means so as to give a higher emphasis to the signals corresponding to a central portion of said predetermined detection region than to the signals corresponding to the marginal portion of said prescribed detection region. 13. A system according to claim 12, wherein said transformation control means has means sensible to the change of ambient temperature, and controls the signal non-linear transforming operation of said signal transforming means for the signals corresponding to at least said predetermined detection region to further accord with the ambient temperature on the basis of the output of said temperature sensitive element. 14. A system according to claim 11, wherein said transformation control means has means sensible to the change of ambient temperature, and controls the signal non-linear transforming operation of said signal transforming means for the signals corresponding to at least said predetermined detection region to further accord with the ambient temperature on the basis of the output of said temperature sensitive element. 15. A system according to claim 11, wherein said transformation control means has means sensible to the change of ambient temperature, and controls the signal non-linear transforming operation of siad signal transforming means for the signals corresponding to at least said predetermined detection region to further accord with the ambient temperature on the basis of the output of said temperature sensitive element. 16. A system according to any one of claims 1 to 5, further comprising: transformation control means for controlling the signal transforming operation of said signal transforming means, said transformation control means controlling the signal non-linear transforming operation of said signal transforming means so as to differ non-linear transformation of those of the signals provided by said illuminance difference detecting means which correspond to a predetermined detection region for said image with respect to the different positions of the individual minute image compartments within said predetermined detection region. 17. A system according to claim 16, wherein said transformation control means controls the signal non-linear transforming operation of said signal transforming means so as to give a higher emphasis to the signals corresponding to a central portion of said predetermined detection region than to the signals corresponding to the marginal portion of said prescribed detection region. 18. A system according to claim 17, wherein said transformation control means has means sensible to the change of ambient temperature, and controls the signal non-linear transforming operation of said signal transforming means for the signals corresponding to at least said predetermined detection region to further accord with the ambient temperature on the basis of the output of said temperature sensitive element. 19. A system according to claim 16, wherein said transformation control means has means sensible to the change of ambient temperature, and control the signal non-linear transforming operation of said signal transforming means for the signals corresponding to at least said predetermined detection region to further accord with the ambient temperature on the basis of the output of said temperature sensitive element. 20. A system according to any one of claims 1 to 5, further comprising: transformation control means for controlling the signal transforming operation of said signal transforming means, said transformation control means having means sensible to the change of ambient temperature and controlling the signal non-linear transforming operation of said signal transforming means for the electrical signal provided by said iluminance difference detecting means to accord with the ambient temperature on the basis of the output of said temperature sensitive means. 21. A system according to claim 1, wherein said illuminance difference detecting means is constructed in the form of a differentiation circuit means comprising, in combination, a condenser and a resistor. 22. A system according to claim 21, further comprising: differentiating operation control means for controlling the signal differentiating operation of said differentiation circuit means, said differentiating operation control means rendering operative said differentiation circuit means in only a time when those of the outputs from said image sensing means which correspond to a predetermined detection region previously set to said image are applied to said differentiation circuit means, and rendering substantially inoperative said differentiation circuit means except in that time. 23. A system according to claim 20, wherein said differentiation circuit means is arbitrarily adjustable in its differentiation constant, and said system further including: differentiation constant adjusting means for adjusting the differentiation constant of said differentiation circuit means in accordance with the various optical factors of said image forming optical means. 24. A system according to claim 23, wherein said differentiation constant adjusting means is operatively related to said optical means so as to adjust the differentiation constant of said differentiation circuit means in accordance with the aperture ratio of said image forming optical means. 25. A system according to claim 24, wherein said image forming optical means is equipped with diaphragm means capable of arbitrarily adjusting the size of opening thereof, and said differentiation constant adjusting means is operatively related to said diaphragm means so as to adjust the differentiation constant of said differentiation circuit means in accordance with the size of opening of said diaphragm means. 26. A system according to claim 23, wherein said image forming optical means is equipped with diaphragm means capable of arbitrarily adjusting the size of opening thereof, and said differentiation constant adjusting means is operatively related to said diaphragm means so as to adjust the differentiation constant of said differentiation circuit means in accordance with the size of opening of said diaphragm means. 27. A system according to claim 1, further comprising: image signal level adjusting means provided between said image sensing means and said illuminance difference detecting means to adjust the level of the image signal to be applied to said illuminance difference detecting means, said image signal level adjusting means receptive of the output of said image sensing means for adding its electrical signals for every desired number of consecutive elements in said array of a plurality of radiation sensitive elements to produce signals which are then applied to said illuminance difference detecting means, whereby the level of the image signal to be applied to said illuminance difference detecting means is adjusted. 28. A system according to claim 27, further comprising: addition control means responsive to the level of output of said image sensing means for controlling the number of radiation sensitive elements whose electrical signals are added together in said image signal level adjusting means. 29. A system according to claim 1, wherein said radiation sensitive elements in said image sensing means are signal integration and storing type radiation sensitive elements, and said system further comprising: integration time control means for controlling the signal integration time of said radiation sensitive elements on the basis of the illuminance of said image on said image-sensing means. 30. A system according to claim 29, wherein said integration time control means is arranged to control said signal integration time on the basis of the level of output of said image-sensing means. 31. A system according to claim 30, wherein said integration time control means is arranged upon comparison of the level of output of said-image sensing means with a predetermined standard level to control said signal integration time based on said comparison result. 32. A system according to claim 31, wherein said image-sensing means further comprises signal output means for putting out the electrical signals of said respective radiation sensitive elements in a time-seriated manner, and said system further comprising: standard level setting means for obtaining said predetermined standard level through said signal output means in said image-sensing means, and wherein said integration time control means is arranged upon comparison of the level of output of said image-sensing means with said predetermined standard level obtained through said signal output means in said image sensing means by said standard level setting means to control said integration time based on said comparison result. 33. A system according to claim 31, wherein said integration time control means comprises: peak detecting means for detecting the peak level of output of said image sensing means; comparing means for comparing the peak level detected by said peak detecting means with a predetermined standard level; and integration time adjusting means for adjusting the said signal integration time based on the comparison result of said comparing means. 34. A system according to claim 33, wherein said image sensing means further comprises signal output means for putting out the electrical signals of said respective radiation sensitive elements in a time-seriated manner, and said system further comprising: standard level setting means for obtaining said predetermined standard level through said signal output means in said image sensing means, and wherein said comparing means in said integration time control means compares said peak level detected by said peak detecting means with said predetermined standard level obtained through said signal output means in said image sensing means by said standard level setting means. 35. A system according to claim 1, wherein said image sharpness output means comprises signal integrating means for integrating those of the electrical signals non-linearly transformed and absolute-value transformed by said signal transforming means which correspond to a predetermined detection region previously set to said image; said image sharpness output means provides said output representing said image sharpness on said image sensing means on the basis of the integration signal of said signal integrating means. 36. A system according to claim 35, wherein said image sharpness detecting means further comprises: integration control means for causing the integration signal of said signal integrating means to damp at a rate having a predetermined characteristic; and wherein said image sharpness output means provides said output representing the sharpness of said image on said image sensing means on the basis of the time measured from the start of damping of the integration signal of said signal integrating means and necessary for said integration signal to attain a predetermined level. 37. A system for detecting the sharpness of an image formed by an image forming optical means, comprising: (A) image-sensing means for sensing the image formed by said optical means, said image-sensing means having an array of a plurality of radiation sensitive elements, the individual elements producing electrical signals corresponding to the radiations incident thereon, and said image-sensing means having as its output to provide the electrical signals of the respective elements in a time-seriated manner; (B) illuminance difference detecting means for providing electrical signals representing illuminance differences in the individual minute compartments of said image based on the output of said image-sensing means; (C) signal transforming means for non-linear transformation and absolute-value transformation of the electrical signals provided by said illuminance difference detecting means; (D) transformation control means for controlling the signal transforming operation of said signal transforming means, said transformation control means controlling the signal non-linear transforming operation of said signal transforming means so as to differ non-linear transformation of those of the signals provided by said illuminance difference detecting means which correspond to a predetermined detection region previously set to said image with respect to the different positions of the individual minute image compartments within said predetermined detection region; and (E) image sharpness output means for providing an output representing the sharpness of said image on said image-sensing means based on the non-linearly transformed and absolute-value transformed electrical signals by said signal transforming means. 38. A system according to claim 37, wherein said transformation control means controls the signal non-linear transforming operation of said signal transforming means so as to give a higher emphasis to the signals corresponding to a central portion of said prescribed detection region than to the signals corresponding to the marginal portion of said prescribed detection region. 39. A system according to claim 37 or 38, wherein said transformation control means has means sensible to the change of ambient temperature, and controls the signal non-linear transforming operation of said signal transforming means for the signals corresponding to at least said prescribed detection region to further accord with the ambient temperature on the basis of the output of said temperature sensitive element. 40. A system for detecting the sharpness of an image formed by an image forming optical means, comprising: (A) image-sensing means for sensing the image formed by said optical means, said image-sensing means having an array of a plurality of radiation sensitive elements, the individual elements producing electrical signals corresponding to the radiations incident thereon, and said image-sensing means having as its output to provide the electrical signals of the respective elements in a time-seriated manner; (B) illuminance difference detecting means for providing electrical signals representing illuminance differences in the individual minute compartments of said image based on the output of said image-sensing means; (C) signal transforming means for non-linear transformation and absolute-value transformation of the electrical signals provided by said illuminance difference detecting means; (D) transformation control means for controlling the signal transforming operation of said signal transforming means, said transformation control means having means sensible to the change of ambient temperature and controlling the signal non-linear transforming operation of said signal transforming means for the electrical signal provided by said illuminance difference detecting means to accord with the ambient temperature on the basis of the output of said temperature sensitive means; and (E) image sharpness output means for providing an output representing the sharpness of said image on said image sensing means based on the non-linearly transformed and absolute-value transformed electrical signals by said signal transforming means. 41. A system for detecting the sharpness of an image formed by an image forming optical means, comprising: (A) image sensing-means for sensing the image formed by said optical means, said image-sensing means having an array of a plurality of radiation sensitive elements, the individual elements producing electrical signals corresponding to the radiations incident thereon, and said image-sensing means having as its output to provide the electrical signals of the respective elements in a time-seriated manner; (B) differentiating circuit means for providing electrical signals representing illuminance difference in the individual minute compartments of said image based on the output of said image-sensing means; (C) differentiating operation control means for controlling the signal differentiating operation of said differentiation circuit means, said differentiating operation conrol means rendering operative said differentiation circuit means in only a time when those of the outputs from said image-sensing means which correspond to a predetermined detection region previously set to said image are applied to said differentiation circuit means and rendering substantially inoperative said differentiation circuit means except in that time. (D) signal transforming means for non-linear transformation and absolute-value transformation of the electrical signals provided by said differentiation circuit means; and (E) image sharpness output means for providing an output representing the sharpness of said image on said image-sensing means based on the non-linearly transformed and absolute-value transformed electrical signals by said signal transforming means. 42. A system according to claim 41, wherein said differentiation circuit means is arbitrarily adjustable in its differentiation constant, and said system further comprising: differentiation constant adjusting means for adjusting the differentiation constant of said differentiation circuit means in accordance with the various optical factors of said image forming optical means. 43. A system according to claim 42, wherein said differentiation constant adjusting means is operatively related to said optical means so as to adjust the differentiation constant of said differentiation circuit means in accordance with the aperture ratio of said image forming optical means. 44. A system according to claim 42 or 43, wherein said image forming optical means is equipped with diaphragm means capable of arbitrarily adjusting the size of opening thereof, and said differentiation constant adjusting means is operatively related to said diaphragm means so as to adjust the differentiation constant of said differentiation circuit means in accordance with the size of opening of said diaphragm means. 45. A system for detecting the sharpness of an image formed by an image forming optical means, comprising: (A) image sensing-means for sensing the image formed by said optical means, said image-sensing means having an array of a plurality of radiation sensitive elements, the individual elements producing electrical signals corresponding to the radiation incident thereon, and said image-sensing means having as its output to provide the electrical signals of the respective elements in a time-seriated manner; (B) differentiating circuit means for providing electrical signals representing illuminance difference in the individual minute compartments of said image based on the output of said image-sensing means, said differentiation circuit means having its differentiation constant arbitrarily adjustable; (C) differentiation constant adjusting means for adjusting the differentiation constant of said differentiation circuit means in accordance with the aperture ratio of said image forming optical means; (D) signal transforming means for non-linear transformation and absolute-value transformation of the electrical signals provided by said differentiation circuit means; and (E) image sharpness output means for providing an output representing the sharpness of said image on said image-sensing means based on the non-linearly transformed and absolute-value transformed electrical signals by said signal transforming means. 46. A system according to claim 45, wherein said differentiation constant adjusting means is operatively related to said optical means so as to adjust the differentiation constant of said differentiation circuit means in accordance with the aperture ratio of said image forming optical means. 47. A system according to claim 45 or 46, wherein said image forming optical means is equipped with diaphragm means capable of arbitrarily adjusting the size of opening thereof, and said differentiation constant adjusting means is operatively related to said diaphragm means so as to adjust the differentiation constant of said differentiation circuit means in accordance with the size of opening of said diaphragm means. 48. A system for detecting the sharpness of an image formed by an image forming optical means, comprising: (A) image sensing means for sensing the image formed by said optical means, said image-sensing means having an array of a plurality of radiation sensitive elements, the individual elements producing electrical signals corresponding to the radiation incident thereon, and said image-sensing means having as its output to provide the electrical signals of the respective elements in a time-seriated manner; (B) illuminance difference detecting means for providing electrical signal representing illuminance difference in the individual minute compartments of said image based on the output of said image-sensing means; (C) signal transforming means for non-linear transformation and absolute-value transformation of the electrical signals provided by said illuminance difference detecting means; and (D) image sharpness output means for providing an output representing the sharpness of said image on said image-sensing means based on the non-linearly transformed and absolute-value transformed electrical signals by said signal transforming means, said image sharpness output means comprising signal integrating means for integrating those of the electrical signals non-linearly transformed and absolute-value transformed by said signal transforming means which correspond to a predetermined detection region previously set to said image; and integration control means for causing the integration signal of said signal integrating means to damp at a rate having a predetermined characteristic whereby said image sharpness output means provides said output representing the sharpness of said image on said image-sensing means on the basis of the time measured from the start of damping of the integration signal of said signal integrating means and necessary for said integration signal to attain a predetermined level. 49. A system for scanning an image formed by an image forming optical means, comprising: (A) image scanning means for scanning the image formed by said optical means, said image scanning means having an array of a plurality of radiation sensitive elements, the individual elements producing electrical signals corresponding to the radiations incident thereon, and said image scanning means having as its output to provide the electrical signals of the respective elements in a time-seriated manner; and (B) image signal level adjusting means for adjusting the level of the image signal obtained by the output of said image scanning means, said image signal level adjusting means receptive of the output of said image scanning means for adding its electrical signals for every arbitrary number of consecutive elements in said array of the plurality of radiation sensitive elements in said image scanning means to produce output signals, whereby said added signals are produced as said image signal to adjust the level of said image signal given on the basis of the output of said image scanning means. 50. A system according to claim 49, further comprising: addition control means responsive to the level of output of said image scanning means for controlling the number of radiation sensitive elements whose electrical signals are added together in said image signal level adjusting means. 51. A system according to claim 49 or 50, wherein said radiation sensitive elements in said image scanning means are signal integration and storing type radiation sensitive elements, and said system further comprising: integration time control means for controlling the signal integration time of said radiation sensitive elements on the basis of the illuminance of said image on said image scanning means. 52. A system according to claim 51, wherein said integration time control means is arranged to control said signal integration time on the basis of the level of output of said image scanning means. 53. A system according to claim 52, wherein said integration time control means is arranged upon comparison of the level of output of said image scanning means with a predetermined standard level to control said signal integration time based on said comparison result. 54. A system according to claim 53, wherein said image scanning means further comprises signal output means for putting out the electrical signals of said respective radiation sensitive elements in a time-seriated manner, and said system further comprising: standard level setting means for obtaining said predetermined standard level through said signal output means in said image scanning means, and wherein said integration time control means is arranged upon comparison of the level of output of said image-sensing means with said predetermined standard level obtained through said signal output means in said image scanning means by said standard level setting means to control said integration time based on said comparison result. 55. A system according to claim 53, wherein said integration time control means comprises: peak detecting means for detecting the peak level of output of said image scanning means; comparing means for comparing the peak level detecting by said peak detecting means with a predetermined standard level; and integration time adjusting means for adjusting the said signal integration time based on the comparison result of said comparing means. 56. A system according to claim 55, wherein said image scanning means further comprises signal output means for putting out the electrical signals of said respective radiation sensitive elements in a time-seriated manner, and said system further comprising: standard level setting means for obtaining said predetermined standard level through said signal output means in said image scanning means, and wherein said comparing means in said integration time control means compared said peak level detected by said peak detecting means with said predetermined standard level obtained through said signal output means in said image scanning means by said standard level setting means. 57. A system for scanning an image formed by an image forming optical means, comprising: (A) image scanning means for scanning the image formed by said image forming optical means, said image scanning means comprising: a plurality of signal integrating and storing type radiation sensitive elements, each element providing an electrical signal corresponding to the amount of incident radiation integrated; and signal output means for putting out the electrical signals of the respective elements in a time-seriated manner; (B) standard level setting means for obtaining a standard level through said signal output means in said image scanning means; and (C) integration time control means for controlling the signal integration time of said radiation sensitive elements in said image scanning means, said integration time control means comparing the level of output of said image scanning means with said standard level obtained by said standard level setting means through said signal output means in said image scanning means and controlling said signal integration time based on said comparison result. 58. A system according to claim 57, wherein said integration time control means comprises: peak detecting means for detecting the peak level of output of said image scanning means; comparing means for comparing the peak level detected by said peak detecting means with a predetermined standard level; and integration time adjusting means for adjusting said signal integration time based on the comparison result of said comparing means. 59. A system according to claim 36, wherein said damping rate has a characteristic such that the rate is constant with respect to the change in time. 60. A system according to claim 36, wherein said damping rate has a characteristic such that the rate varies in dependence upon the change in time. 61. A system according to claim 48, wherein said damping rate has a characteristic such that the rate is constant with respect to the change in time. 62. A system according to claim 48, wherein said damping rate has a characteristic such that the rate varies in dependence upon the change in time. 63. A system according to claim 60, wherein said integration control means is arranged to exponentially damp said integration signal of said signal integrating means. 64. A system according to claim 36 or 37 or 59 or 60, wherein said image sharpness output means further comprises: digitalizing means for converting said time measured from the start of damping of the integration signal of said signal integrating means and necessary for said integration signal to attain a predetermined level to a corresponding number of pulses; and said image sharpness output means provides said output representing the sharpness of said image on said image-sensing means on the basis of the output of said digitalizing means in the form of a digital word. 65. A system according to claim 64, wherein said signal integrating means is a dual-slope integrating means, said dual-slope integrating means having first and second slope modes, whereby when in said first slope mode, the signal corresponding to said predetermined detection region is integrated, and when in said second slope mode, said integration signal is reverse-integrated as is damping at said damping rate. 66. A system according to claim 36 or 63 or 59 or 60, wherein said signal integrating means is a dual-slope integrating means, said dual-slope integrating means having first and second slope modes, whereby when in said first slope mode, the signal corresponding to said predetermined direction region is integrated, and when in said second slope mode, said integration signal is reverse-integrated as is damping at said damping rate. 67. A system according to claim 62, wherein said integration control means is arranged to exponentially damp said integration signal of said signal integrating means. 68. A system according to claim 48 or 67 or 61 or 62, wherein said image sharpness output means further comprises: digitalizing means for converting said time measured from the start of damping of the integration signal of said signal integrating means, and necessary for said integration signal to attain a predetermined level to a corresponding number of pulses; and said image sharpness output means provides said output representing the sharpness of said image on said image-sensing means on the basis of the output of said digitalizing means in the form of a digital word. 69. A system according to claim 68, wherein said signal integrating means is a dual-slope integrating means, said dual-slope integrating means having first and second slope modes, whereby when in said first slope mode, the signal corresponding to said predetermined detection region is integrated, and when in said second slope mode, said integration signal is reverse-integrated as is damping at said damping rate. 70. A system according to claim 48 or 67 or 61 or 62, wherein said signal integrating means is dual-slope integrating means, said dual-slope integrating means having first and second slope modes, whereby when in said first slope mode, the signal corresponding to said predetermined detection region is integrated, and when in said second slope mode, said integration signal is reverse-integrated as is damping at said damping rate. 71. A system according to claim 48 or 61 or 62 or 67, wherein said image sharpness output means further comprises: comparing means for comparing the integration signal of said signal integration means with said predetermined level to detect whether the integration signal attains the predetermined level at the time of damping of the integration signal. 72. A system according to claim 71, wherein said image sharpness output means further comprises: compensating means for compensating for the offset voltage of said signal integration means and said comparing means. 73. A system according to claim 72, wherein said compensating means includes: a memory element for memorizing, as an offset compensation signal, the output of the comparing means at the time of resetting the signal integration means. 74. A system according to claim 72, wherein said signal integration means includes a memory element for memorizing the integration signal; and said compensating means includes a feed-back circuit for providing said memory element in the signal integration means with the output of the comparing means at the time of resetting the signal integrating means. 75. A system according to claim 69, wherein said image sharpness output means further comprises: comparing means for comparing the integration signal of said signal integration means with said predetermined level to detect whether the integration signal attains the predetermined level at the time of damping of the integration signal. 76. A system according to claim 75, wherein said image sharpness output means further comprises: compensating means for compensating for the offset voltage of said signal integrating means and said comparing means. 77. A system according to claim 76, wherein said compensating means includes: a memory element for memorizing, as an offset compensation signal, the output of the comparing means at the time of resetting the signal integration means. 78. A system according to claim 76, wherein said signal integration means includes a memory element for memorizing the integration signal; and said compensating means includes a feed-back circuit for providing said memory element in the signal integration means with the output of the comparing means at the time of resetting the signal integrating means. 79. A system according to claim 70, wherein said image sharpness output means further comprises: comparing means for comparing the integration signal of said signal integration means with said predetermined level to detect whether the integration signal attains the predetermined level at the time of damping of the integration signal. 80. A system according to claim 79, wherein said image sharpness output means further comprises: compensating means for compensating for the offset voltage of said signal integration means and said comparing means. 81. A system according to claim 80, wherein said compensating means includes: a memory element for memorizing, as an offset compensation signal, the output of the comparing means at the time of resetting the signal integration means. 82. A system according to claim 81, wherein said signal integration means includes a memory element for memorizing the integration signal; and said compensating means includes a feed-back circuit for providing said memory element in the signal integration means with the output of the comparing means at the time of resetting the signal integrating means. 83. A system according to claim 21, wherein said differentiation circuit means is arbitrarily adjustable in its differentiation constant, and said system further including: differentiation constant adjusting means for adjusting the differentiation constant of said differentiation circuit means in accordance with the various optical factors of said image forming optical means. 84. A system as in claim 83, wherein said differentiation constant adjusting means is operatively related to said optical means so as to adjust the differentiation constant of said differentiation circuit means in accordance with the aperture ratio of said image forming optical means. 85. A system as in claim 84, wherein said image forming optical means is equipped with diaphragm means capable of arbitrarily adjusting the size of the opening thereof, and said differentiation constant adjusting means is operatively related to said diaphragm means so as to adjust the differentiation constant of said differentiation circuit means in accordance with the size of the opening of said diaphragm means. 86. A system as in claim 83, wherein said image forming optical means is equipped with diaphragm means capable of arbitrarily adjusting the size of the opening thereof, and said differentiation constant adjustment means is operatively related to said diaphragm means so as to adjust the differentiation constant of said differentiation circuit means in accordance with the size of the opening of said diaphragm means.
