HDR Cinema Signal Normalization for Backward Compatibility
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Solution Overview
Problem
Current digital cinema systems face challenges in delivering higher dynamic range (HDR) content while maintaining backward compatibility with legacy standard dynamic range (SDR) systems, often resulting in image quality loss due to differences in signal processing at the transmitting and receiving ends.
Innovation Solution
A method and device for processing digital images or video signals that involve converting HDR content to SDR at the transmitting end, encoding and decoding both signals, and using normalization parameters to reconstruct HDR content at the receiving end, ensuring the same input is used for processing at both ends to maintain image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If HDR content is delivered to legacy SDR systems, then dynamic range is improved, but image quality deteriorates due to processing differences
Solution Approach 1:
The patent applies preliminary action by pre-calculating and embedding normalization parameters at the transmitting end before content delivery. These parameters are derived from the HDR content characteristics and are used to guide the SDR conversion process, ensuring optimal image quality is maintained even when delivering HDR content to SDR systems.
Solution Approach 2:
The patent implements feedback by using the same decompressed SDR signal as input for both normalization at the transmitting end and mapping at the receiving end. This closed-loop approach ensures consistency between the normalization parameters generated and the actual signal being processed, eliminating quality loss that would occur from using different input signals at each end.
2Adaptability or versatility
If different signals are used for normalization at transmitting end and mapping at receiving end, then processing flexibility is improved, but image quality deteriorates
Solution Approach 1:
The patent merges the input signals by using the same decompressed SDR signal for both normalization at the transmitting end and mapping at the receiving end. This unification ensures that the normalization parameters are derived from the exact same signal that is being mapped, guaranteeing consistency and eliminating quality degradation that would result from signal mismatches.
3Adaptability or versatility
If HDR content is converted to SDR at transmitting end, then backward compatibility is improved, but dynamic range information is lost
Solution Approach 1:
The patent introduces normalization parameters as an intermediary that carries dynamic range information from the HDR content to the SDR conversion process. These parameters are embedded in the bitstream and used at the receiving end to guide the mapping process, effectively preserving dynamic range information guidance even though the content is converted to SDR for backward compatibility.
Data Source
AI summary
Methods and systems for image processing and delivery of higher dynamic range cinema content are disclosed. A digital cinema signal with a lower dynamic range is obtained from a digital cinema signal with a higher dynamic range, for example through mapping. The lower dynamic range digital cinema signal is encoded and decoded at the transmitting end. The decoded lower dynamic range digital cinema signal is normalized to produce a set of normalization parameters which enable the mapping process at the receiving end to produce a final image with higher dynamic range that is of a higher quality. Alternatively, the higher dynamic range digital cinema signal is also encoded and decoded at the transmitting end, to produce a set of normalization parameters which enable the mapping process at the receiving end to produce a final image with higher dynamic range that is of a higher quality.