Gradient correction for color negative film picking up image and its device

Abstract

Abstract PURPOSE:To obtain an appropriate color signal even in a state irrespective of under- and over-exposure, by detecting average, maximum and minimum values in one screen with respect to respective three chrominance signals as characteristic values and by processing gamma correction to the chrominance signals on the basis of the above characteristic values. CONSTITUTION:Characteristic value detecting circuit 21 detects the average, maximum and minimum values in one screen with regard to the chrominance signal prior to gamma correction and respective detecting signals 21a, 21b and 21c are delivered to an arithmetic circuit 22. The arithmetic circuit 22 obtains a relation between the exposure degrees of a negative film and the gamma values of gamma correction circuit by the combination of average value with the difference between the maximum and minimum values through an experiment or the like in advance and allows said data to be tabulated. The tabulated data judges the exposure degrees and gamma values corresponding to characteristic values which are inputted and then outputs gamma value variation signals 22 a to a gamma correction circuit 36 so as to be the judged gamma value and at the same time, outputs signals 22b which make the judged exposure degrees indicate to a displayer 23. Operator outputs gamma value variation signals 25a from a key board 25 to a gamma correction circuit 36 so as to be the gamma values corresponding to the exposure degrees displayed in the displayer 23 by looking at these exposure degrees.

Inventors

• 👤 Isao Takahashi
• 👤 功 高橋

Bibliographic Details