Image processing apparatus and method

摘要

Gradation transform considering a scene transitional direction is executed for a video signal. The statistic of the luminance distribution of the input video signal is detected. The transitional direction of brightness of a scene of the input video signal is detected. A transform characteristic in transforming the gradation characteristic of the input video signal is set based on the detection results of the statistic and transitional direction.

主权项

1. An image processing apparatus comprising:
a statistic detector that detects a statistic of a luminance distribution of an input video signal; a scene-transition detector that detects (i) a scene change of the input video signal to output scene-change information which indicates whether a scene change exists or not, detects (ii) a transitional direction of brightness of a scene of the input video signal, and detects (iii) a scene length of a scene of the input video signal; a gradation transformer that transforms a gradation characteristic of the input video signal; and a setting unit that sets a transform characteristic of the gradation transformer based on detection results of the statistic detector and the scene-transition detector, wherein the scene-transition detector compares brightness of a preceding frame with brightness of a current frame to output transitional direction information which indicates a direction of a change in the brightness as the transitional direction, wherein, if a scene change is detected and the transitional direction in the detected scene change indicates transition from a bright scene to a dark scene, and a scene length detected by the scene-transition detector is equal to or more than a predetermined scene length, the setting unit sets the transform characteristic to allocate gradation steps to a low luminance side more than the gradation steps which would have been allocated to the low luminance side when the transform characteristic is determined only from the detection results of the statistic detector based on the luminance distribution of the input video signal, and wherein, if a scene change is detected and the transitional direction in the detected scene change indicates transition from a dark scene to a bright scene, and a scene length detected by the scene-transition detector is equal or more than the predetermined scene length, the setting unit sets the transform characteristic to allocate the gradation steps to a high luminance side more than the gradation steps allocated to the high luminance side when the transform characteristic is determined only from the detection results of the statistic detector based on the luminance distribution of the input video signal.