Backlight Spread Approximation in Local Dimming Systems
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Solution Overview
Problem
Current backlight local dimming systems require complex operations and large storage space for light spread function calculations, leading to high hardware costs and increased operation time, especially in large LCD devices with high brightness demands.
Innovation Solution
A method and apparatus that approximate backlight spread in a local dimming system by using backlight pulse width modulation signals for equalization, generating a backlight seed image, calculating positions and coordinates, and performing a bilinear transformation to estimate a backlight spread image, reducing computational load and hardware requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light spread function is established and convolution operation is performed to obtain backlight spreading, then the backlight spread image can be accurately generated, but the storage space requirement increases and hardware cost increases
Solution Approach 1:
The patent extracts only the essential information needed for backlight spread approximation by using a simplified mapping relationship between backlight source positions and pixel positions, rather than storing and processing complete light spread functions. This extraction approach maintains sufficient accuracy while dramatically reducing storage requirements.
Solution Approach 2:
The patent creates a simplified copy of the light spread function through coordinate transformation and mapping relationships, which captures the essential spreading characteristics without requiring the full original function. This copied representation enables accurate backlight spread calculation with minimal storage overhead.
2Measurement precision
If convolution operation is performed to emulate actual backlight intensity spreading, then the backlight spread image can be generated, but the operation time increases
Solution Approach 1:
The patent replaces the complex mechanical convolution operation with a more efficient coordinate transformation and mapping approach. By substituting the heavy computational convolution process with simpler mathematical transformations based on position relationships, the system achieves the same backlight spread emulation with significantly reduced operation time.
Solution Approach 2:
The patent changes the computational parameters from convolution operations to coordinate mapping and transformation operations. This parameter change fundamentally alters the computational complexity, reducing the operation time while maintaining the accuracy of backlight spread image generation through position-based mapping relationships.
3Measurement precision
If light spread function is established for the entire display panel, then the backlight spreading can be accurately modeled, but the hardware cost increases
Solution Approach 1:
The patent segments the display panel into multiple regions with different backlight source configurations, and applies simplified mapping relationships to each segment. This segmentation approach allows accurate backlight spread modeling for each region while avoiding the need for a single complex light spread function for the entire panel, thereby reducing hardware requirements.
Solution Approach 2:
The patent creates simplified copies of the light spread characteristics for each display region through coordinate mapping, rather than maintaining a single comprehensive light spread function. This regional copying approach preserves the essential spreading characteristics needed for accurate modeling while significantly reducing the hardware complexity and cost.
4Device complexity
If blurring process with low pass filter is used to obtain light spread function, then the computation can be simplified, but the operation complexity remains high
Solution Approach 1:
The patent extracts the essential spreading characteristics directly from the geometric relationships between backlight sources and pixels, bypassing the need for complex blurring processes and low pass filters. This extraction approach simplifies the computation by focusing only on the critical position-based mapping rather than performing elaborate signal processing operations.
Data Source
AI summary
An apparatus of approximating backlight spread is used in a display to estimate a backlight spread image corresponding to an image after backlight spreading of a plurality of backlight sources arranged in a matrix form. An equalizer receives backlight pulse width modulation signals of the backlight sources for performing an equalization operation and generating corresponding equalization signals. A backlight seed image constructor receives the equalization signals to establish a backlight seed image. A first calculation unit calculates positions corresponding to the backlight seed image based on a backlight spread image. A second calculation unit calculates coordinates of the backlight seed image corresponding to the positions. A distance calculator calculates distance differences between the positions and coordinates of the backlight seed image. A bilinear transformation unit performs a bilinear transformation on pixels of the backlight seed image and the distance differences so as to generate the backlight spread image.