Histogram Smoothing via Fixed Distribution Amount for Image Brightness Stability
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Solution Overview
Problem
Existing image processing technologies face instability in histogram smoothing results, particularly during exposure changes, leading to uneven image brightness due to rapid histogram changes when the number of gradations is reduced, especially with flat subjects.
Innovation Solution
An image processing apparatus and method that generates a cumulative histogram by distributing count values to adjacent gradations with a fixed distribution amount, stabilizing histogram smoothing through contrast correction using a cumulative histogram.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of gradations is reduced to facilitate processing, then processing complexity is reduced, but histogram stability deteriorates during exposure changes
Solution Approach 1:
The patent applies preliminary action by pre-distributing frequency values to adjacent gradations before exposure changes occur. The distribution processing section continuously updates the histogram by distributing count values to neighboring gradations based on pixel value positions, ensuring the histogram is already smoothed and stable when exposure changes happen, preventing rapid fluctuations.
Solution Approach 2:
The patent changes the parameter of histogram representation by distributing frequency counts across multiple gradations rather than concentrating them in single gradation bins. This parameter change from discrete to distributed counting stabilizes the histogram during exposure changes while maintaining reduced gradation numbers for efficient processing.
2Productivity
If the number of gradations is reduced, then processing speed is improved, but image brightness uniformity deteriorates during exposure changes
Solution Approach 1:
The distribution processing section performs preliminary smoothing by distributing frequency values to adjacent gradations before exposure changes affect the image. This ensures that when exposure changes occur, the histogram already reflects a smoothed distribution, preventing sudden brightness shifts and maintaining uniformity in the processed image.
Solution Approach 2:
The patent transforms the histogram data structure by distributing count values across multiple gradation bins based on pixel value positions. This parameter transformation from concentrated to distributed counting maintains brightness uniformity during exposure changes while enabling fast processing with reduced gradation numbers.
3Productivity
If histogram smoothing is performed with reduced gradations, then processing efficiency is improved, but histogram response sensitivity to exposure changes worsens
Solution Approach 1:
The patent changes the measurement approach by distributing frequency counts to adjacent gradations based on relative pixel value positions. This parameter change from direct counting to distributed counting maintains histogram sensitivity to exposure changes while enabling efficient processing with reduced gradation numbers, as the distribution captures subtle shifts in pixel value distributions.
Solution Approach 2:
The distribution processing section acts as an intermediary between raw histogram data and the cumulative histogram generation. By distributing frequency values to adjacent gradations as an intermediate step, it preserves sensitivity to exposure changes while maintaining processing efficiency with reduced gradations, bridging the gap between simplified data and accurate representation.
Data Source
AI summary
An image processing apparatus according to the present invention comprises a histogram generating section for generating a histogram by counting a frequency value for each gradation of a predetermined number of gradations as brightness distribution of input image data, a distribution processing section for distributing a count value of the histogram to adjacent gradations, a cumulative histogram generating section for generating a cumulative histogram by accumulating the histograms obtained by the histogram generating section from a low gradation side, and a gradation correction processing section for performing contrast correction by using the cumulative histogram, wherein the distribution processing section fixes a distribution amount to the predetermined number of gradations when distributing the count value to the adjacent gradations.