| 摘要 |
An image signal compressing circuit for compressing an input image signal non-linearly including an attenuating circuit for attenuating the input image signal to derive an attenuated image signal, a capacitance for removing a direct current component of the attenuated image signal, a direct level setting circuit for adding a variable direct current potential to the attenuated image signal having the direct component removed therefrom to produce a composite image signal, a non-additive mixing circuit for selecting a smaller image signal between the input image signal and the composite image signal as a compressed image signal, a peak detecting circuit for detecting a maximum value of the compressed image signal, and a variable direct current forming circuit for generating the variable direct current potential to be applied to the direct current level setting circuit such that the maximum value of the compressed image signal does not exceed a predetermined level, while a knee point is shifted in accordance with an excessive amplitude of the input image signal, so that a contrast of a compressed image portion is not decreased.
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