[Automatic contrast limiting circuit and method thereof with spatial domain infinite impulse response filter]
First Claim
1. An automatic contrast limiting circuit with a spatial domain infinite impulse response filter, for evaluating a contrast value, comprising:
- a spatial domain infinite impulse response filter, for receiving an input signal for generating a spatial domain infinite impulse response filtering value;
a peak value detector, coupled to the spatial domain infinite impulse response filter, for generating a peak value during a predetermined recording interval corresponding to the spatial domain infinite impulse response filtering value; and
a contrast evaluator, coupled to the peak value detector, for evaluating the contrast value according to the peak value and a predetermined threshold,wherein when the contrast evaluator determines the peak value higher than the predetermined threshold, the contrast value is 1;
otherwise, the contrast value is a value of the predetermined threshold divided by the peak value.
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Abstract
An automatic contrast limiting circuit and method thereof with spatial domain infinite impulse response filter are disclosed. A spatial domain infinite impulse response filter is adapted to generate an output value of the spatial domain infinite impulse response filter related to an input signal. A peak value detector is adapted to detect the peak output value of the spatial domain infinite impulse response filter during a predetermined recording interval. A contrast evaluator is used to evaluate the required contrast value referring to a predetermined threshold value and the output value of the spatial domain infinite impulse response filter.
46 Citations
4 Claims
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1. An automatic contrast limiting circuit with a spatial domain infinite impulse response filter, for evaluating a contrast value, comprising:
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a spatial domain infinite impulse response filter, for receiving an input signal for generating a spatial domain infinite impulse response filtering value; a peak value detector, coupled to the spatial domain infinite impulse response filter, for generating a peak value during a predetermined recording interval corresponding to the spatial domain infinite impulse response filtering value; and a contrast evaluator, coupled to the peak value detector, for evaluating the contrast value according to the peak value and a predetermined threshold, wherein when the contrast evaluator determines the peak value higher than the predetermined threshold, the contrast value is 1;
otherwise, the contrast value is a value of the predetermined threshold divided by the peak value.
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2. An automatic contrast limiting circuit with a spatial domain infinite impulse response filter, for evaluating a contrast value, comprising:
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a spatial domain infinite impulse response filter, for receiving an input signal for generating a spatial domain infinite impulse response filtering value; a peak value detector, coupled to the spatial domain infinite impulse response fitter, for generating a peak value during a predetermined recording interval corresponding to the spatial domain infinite impulse response filtering value; a contrast evaluator, coupled to the peak value detector, for evaluating the contrast value according to the peak value and a predetermined threshold, a front-end spatial domain infinite impulse response filter, for receiving a front-end input signal for generating a front-end spatial domain infinite impulse response filtering value; and a front-end peak value detector, coupled to the front-end spatial domain infinite impulse response filter for generating a front-end peak value during a front-end predetermined recording interval to be the input signal of the spatial domain infinite impulse response filter according to the spatial domain infinite impulse response filtering value.
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3. An automatic contrast limiting circuit with a spatial domain infinite impulse response filter, for evaluating a contrast value, comprising:
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a spatial domain infinite impulse response filter, for receiving an input signal for generating a spatial domain infinite impulse response filtering value; a peak value detector, coupled to the spatial domain infinite impulse response filter, for generating a peak value during a predetermined recording interval corresponding to the spatial domain infinite impulse response filtering value; a contrast evaluator, coupled to the peak value detector, for evaluating the contrast value according to the peak value and a predetermined threshold, a front-end spatial domain infinite impulse response filter, for receiving a front-end input signal for generating a front-end spatial domain infinite impulse response filtering value; and a front-end peak value detector, coupled to the front-end spatial domain infinite impulse response filter for generating a front-end peak value during a front-end predetermined recording interval to be the input signal of the spatial domain infinite impulse response filter according to the spatial domain infinite impulse response filtering value, wherein the front-end spatial domain infinite impulse response filter comprises; a first multiplier, for multiplying the front-end input signal with a first factor value for generating a first output value; an adder, coupled to the first multiplier for generating a sum of the first output value and a second output value to be the front-end spatial domain infinite impulse response filtering value; and a second multiplier, for multiplying the front-end spatial domain infinite impulse response filtering value with a second factor value for generating the second output value, wherein a sum of the first factor value and the second factor value is 1.
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4. An automatic contrast controlling method of a spatial domain infinite impulse response filter, adapted to evaluate a contrast value, comprising:
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receiving an input signal for generating a spatial domain infinite impulse response filtering value; generating a peak value during a recoding interval according to the spatial domain infinite impulse response filtering value; and evaluating the contrast value according to the peak value and a predetermined threshold, wherein when the peak value is higher than the predetermined threshold, the contrast value is 1;
otherwise, the contrast value is a value of the predetermined threshold divided by the peak value.
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Specification