Single Image HDR Generation via Gradient-Based Gray-Scale Compensation
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Solution Overview
Problem
Current digital image capture devices struggle with generating high dynamic range (HDR) images due to limitations in photo-sensitivity adjustment, leading to images with insufficient dynamic range, requiring multiple captures with different exposure settings and resulting in storage inefficiencies and time-consuming synthesis processes, which can also cause image bloom.
Innovation Solution
A method involving gray-scale processing and image compensation is applied to a single digital image, converting it into a high dynamic gray-scale pattern using calculated gradients and compensation values to generate an HDR image, reducing the need for multiple captures and synthesizing time, while avoiding image bloom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple images with different exposure settings are captured and synthesized to generate HDR image, then the dynamic range of the image is improved, but the storage space requirement increases and the synthesis time is extended
Solution Approach 1:
The patent applies parameter changes by modifying the gray-scale values of pixels through mathematical transformations. It calculates compensation values based on gradient information and applies these to adjust the brightness distribution, thereby expanding the dynamic range of a single image without requiring multiple captures or synthesis operations.
2Illumination intensity
If multiple images with different exposure settings are captured and synthesized to generate HDR image, then the dynamic range of the image is improved, but the storage space requirement increases
Solution Approach 1:
The patent transforms a single image into an HDR image by changing the parameter space of pixel values. Through gradient calculation and compensation value application, it expands the brightness range within the same image data structure, avoiding the need to store multiple full-resolution images while achieving HDR效果.
3Illumination intensity
If image processing is performed to simulate HDR image by raising brightness of too-dark areas, then the visibility of dark areas is improved, but image bloom is generated at the borders
Solution Approach 1:
The patent applies local quality by calculating gradient information for each pixel and applying compensation values that are locally adapted to the specific region. This ensures that brightness adjustment is performed differently in different areas - dark areas are brightened while preserving texture, and border areas are handled specially to avoid bloom effects.
Solution Approach 2:
The patent uses parameter changes by calculating compensation values based on gradient magnitude and direction. These compensation values are added to the original gray-scale values in a controlled manner, adjusting brightness locally while maintaining the relationship between adjacent pixels to prevent bloom artifacts at borders.
Data Source
AI summary
A method of generating a high dynamic range (HDR) image and a digital image pickup device using the same are described. The digital image pickup device is employed to generate an HDR image according to a single digital image. The method includes the steps of obtaining an original image; performing a gray-scale processing to convert the original image into an original gray-scale pattern, in which each pixel in the original gray-scale pattern is assigned with a gray-scale value; performing a conversion procedure according to a gradient and a compensation value of the gray-scale value of each pixel in the original gray-scale pattern, and generating a high dynamic gray-scale pattern by using the gradients and the compensation values; and compensating the original image with the high dynamic gray-scale pattern, so as to generate the HDR image.