发明授权
US4145709A Automatic localized micro-contrast control for photographic printing systems 失效
用于照相印刷系统的自动局部微对比度控制

  • 专利标题: Automatic localized micro-contrast control for photographic printing systems
  • 专利标题(中): 用于照相印刷系统的自动局部微对比度控制
  • 申请号: US834197
    申请日: 1977-09-19
  • 公开(公告)号: US4145709A
    公开(公告)日: 1979-03-20
  • 发明人: Michael J. Kelly
  • 申请人: Michael J. Kelly
  • 专利权人: Kelly Michael J
  • 当前专利权人: Kelly Michael J
  • 主分类号: G03B27/72
  • IPC分类号: G03B27/72 H04N5/84
Automatic localized micro-contrast control for photographic printing
systems
摘要:
A method and apparatus for adjusting an exposure of a negative image having incremental areas to enhance the contrast of a print resulting from the negative image. The incremental areas of the negative image to be printed are initially scanned providing corresponding sensor signals which are directed to a processing circuit which separates the sensor signals into amplitude ranges according to the amplitude of the sensor signal and according to the amplitude range of the sensor signal as compared to an average sensor signal. Each range is inputted to a signal generator which provides a corresponding signal having an adjusted wavelength determining contrast and an adjusted amplitude determining intensity of exposure, each dependant upon the corresponding amplitude range and amplitude of the sensor signals, respectively. If the sensor signals are at an amplitude which is less than the average sensor signal, the corresponding signal has a proportionally increased intensity. If the sensor signals are at an amplitude which is greater than the average sensor signal the corresponding signal has a proportionally decreased intensity. The corresponding signals are directed to a color gun of a CRT which is used to provide the light necessary to illuminate the corresponding incremental area of the negative image for printing on a raw photographic stock. The wavelength of the corresponding signal generator is pre-set dependant upon the amplitude range to result in a CRT output which provides color light corresponding to a desired level of contrast created by the photographic raw stock.
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