Video Decoder Noise Removal for Chrominance Signal Separation
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Solution Overview
Problem
Conventional video decoders fail to effectively remove luminance noise from chrominance signals during demodulation, leading to degraded color representation in SECAM composite video baseband signals.
Innovation Solution
A video decoder is designed with signal generators that multiply and low-pass-filter composite video baseband signals using cosine and sine components, followed by differentiation and operations to generate signals for noise removal, utilizing control values to correct chrominance signals and remove luminance noise components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional video decoder processes composite video baseband signal, then chrominance signal can be separated, but luminance noise remains in chrominance signal causing color noise
Solution Approach 1:
The patent segments the chrominance signal processing into multiple stages: initial separation of C signal from Y signal, demodulation to extract chrominance components, and subsequent noise removal stage. This segmentation allows targeted treatment of luminance noise without affecting the overall chrominance signal quality.
Solution Approach 2:
The patent extracts the luminance noise component from the chrominance signal using a noise removal unit that specifically targets and removes Y signal components embedded in the C signal, while preserving the actual chrominance information for accurate color representation.
2Productivity
If Y signal component is included in C signal, then chrominance signal can be demodulated, but color noise is generated
Solution Approach 1:
The patent performs preliminary separation of the C signal from the composite video baseband signal before demodulation. This preliminary action isolates the chrominance carrier component, allowing subsequent demodulation to proceed efficiently while the noise removal unit subsequently eliminates any Y signal contamination that may have been carried through.
3Device complexity
If conventional decoder uses simple separation method, then device complexity is low, but color representation characteristic is degraded
Solution Approach 1:
The patent introduces a noise removal unit as an intermediary component between the demodulation stage and the color signal output. This intermediary specifically targets and removes luminance noise from the chrominance signal, significantly improving color representation accuracy without requiring a complete redesign of the decoder architecture.
Data Source
AI summary
A video decoder removes noise caused by a luminance signal component when separating a chrominance signal from a composite video baseband signal. The video decoder includes a first signal generator generating a first signal, a second signal generator generating a second signal, a third signal generator differentiating the first and second signals and performing a predetermined operation on the differentiated signals to generate a third signal, an operating unit performing a predetermined operation on the third signal to output the chrominance signal, a fourth signal generator performing a predetermined operation on the first and second signals to generate a fourth signal having a value corresponding to the amplitude of the chrominance signal, and a noise removal unit correcting the chrominance signal in response to the third and fourth signals to remove luminance component noise included in the chrominance signal.