Luminance Cumulative Distribution for Real-Time Image Visibility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Digital image photographing apparatuses face limitations in dynamic range, leading to poor image visibility in conditions like backlight, where bright and dark regions have wide variance, and existing methods for enhancing visibility are time-consuming, require additional hardware, and cannot process pixels in real time.
Innovation Solution
An apparatus and method that perform image processing on each pixel of continuously input color images by calculating luminance cumulative distribution, determining baseband signals, generating luminance compensation values, and applying luminance gain to enhance visibility without additional hardware resources, using a luminance value cumulative distribution calculator, baseband signal determining unit, luminance compensation value generator, and luminance gain generator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multi exposure synthesizing algorithm or histogram spreading method is used to enhance visibility, then image visibility is improved, but processing time increases and real-time processing becomes impossible
Solution Approach 1:
The image processing is segmented into distinct functional modules: histogram calculation unit, cumulative distribution function calculation unit, threshold determination unit, and pixel value adjustment unit. Each module performs a specific operation that can be executed efficiently and independently, enabling real-time processing while maintaining visibility enhancement quality.
Solution Approach 2:
The patent transforms the complex multi-exposure synthesis problem into a parameter transformation problem by using cumulative distribution function calculations. Instead of processing multiple exposure images separately and combining them, the method adjusts pixel values based on cumulative distribution parameters, significantly reducing computational complexity and processing time.
2Productivity
If separate microprocessor and external memory are used for visibility enhancement, then processing capability is improved, but device complexity and cost increase
Solution Approach 1:
The image processing unit is designed to perform multiple functions: it can execute the visibility enhancement algorithm, manage memory operations, and process image data without requiring separate dedicated hardware components. This multi-functional design reduces device complexity while maintaining processing capability.
Solution Approach 2:
The system uses its existing internal resources (processor, memory, and image processing unit) to perform visibility enhancement without needing external assistance. The image processing unit leverages the cumulative distribution function calculations to self-adjust pixel values, eliminating the need for separate microprocessors or external memory.
3Measurement precision
If histogram spreading or gamma curve method is used, then visibility enhancement is achieved, but bright and dark portions cannot be corrected simultaneously causing deterioration
Solution Approach 1:
The patent applies different processing strategies to different regions of the image based on their luminance characteristics. By determining thresholds from the cumulative distribution function, the method identifies and processes dark regions specifically, adjusting only those pixels that fall below the threshold while leaving brighter regions unchanged. This localized approach prevents deterioration in bright portions while enhancing dark regions.
Solution Approach 2:
The cumulative distribution function is calculated in advance from the histogram data before actual pixel value adjustment occurs. This preliminary calculation establishes the threshold values that guide subsequent processing, ensuring that both bright and dark portions are accounted for in the enhancement strategy, preventing unexpected deterioration during processing.
Data Source
AI summary
An apparatus for enhancing the visibility of color images includes: a luminance value cumulative distribution calculator that calculates a cumulative distribution function of the number of pixels from a minimum value of luminance values; a baseband signal determining unit that determines baseband signal pixels having luminance values smaller than a threshold level; a luminance compensation value generator that generates luminance compensation values to apply the lower-level luminance compensation values as the pixels have higher-level luminance values, for the pixels having the luminance values larger than the threshold level; a luminance gain generator that determines a luminance gain applied to the luminance compensation values according to a mean luminance values of the input images and the level of the luminance values of the pixels to which the luminance compensation values are applied; and a luminance value enhancing unit that summing the luminance compensation values including the gain with the luminance values.