Video See-Through HMD Exposure Control via Luminance Segmentation
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Solution Overview
Problem
Video see-through head-mounted displays (HMDs) face challenges in setting appropriate exposure for captured images, leading to visibility decreases and unnatural brightness changes due to high-luminance light sources outside the displayed image area, causing motion sickness and shadow-detail loss.
Innovation Solution
An information processing apparatus that obtains captured images, generates displayed images with a smaller angle of view by cutting out parts of the captured image, and adjusts exposure based on luminance information from both the captured and displayed image regions, using a control parameter setting unit to determine exposure settings based on the presence or absence of light sources within these regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If exposure is determined based on the captured image with a wider angle of view, then brightness of the displayed image can be appropriately set, but visibility decreases and motion sickness occurs when light sources are present outside the displayed image area
Solution Approach 1:
The patent segments the image into two distinct regions: the captured image region (wider angle of view) and the displayed image region (smaller angle of view). By separately analyzing luminance characteristics of each region, the system determines exposure based on the displayed image region only, preventing light sources outside the user's field of view from affecting brightness settings. This segmentation resolves the contradiction by allowing appropriate brightness setting while avoiding motion sickness and visibility issues.
Solution Approach 2:
The patent applies local quality analysis by focusing exposure determination on the specific region that corresponds to the displayed image area. Instead of using global luminance characteristics of the entire captured image, the system analyzes luminance locally within the displayed image region, ensuring that only relevant light sources within the user's field of view influence exposure settings, thereby maintaining both brightness appropriateness and user comfort.
2Ease of operation
If the captured image has a wider angle of view than the displayed image, then alignment between captured and displayed images is facilitated, but light sources outside the displayed area cause unnatural brightness changes and shadow-detail loss
Solution Approach 1:
The patent segments the image processing into distinct stages: capturing a wide-angle image for alignment purposes, then extracting and analyzing only the displayed image region for exposure determination. This segmentation allows the system to benefit from the wider angle of view for alignment while preventing light sources in the peripheral captured regions from causing unnatural brightness changes or shadow-detail loss in the final displayed image.
3Illumination intensity
If exposure is frequently changed with head movement to maintain brightness, then realistic sensation decreases and motion sickness increases, but maintaining fixed exposure causes visibility decreases in changing lighting conditions
Solution Approach 1:
The patent implements dynamic exposure adjustment that responds to actual lighting changes within the displayed image region while filtering out irrelevant changes. By continuously monitoring luminance characteristics of the displayed image region and adjusting exposure accordingly, the system adapts to genuine lighting condition changes without overreacting to head movements or light sources outside the field of view, thereby maintaining both brightness adaptability and user comfort.
Data Source
AI summary
A captured image obtaining unit obtains a captured image of a background camera. A luminance information deriving unit transforms a color image of the obtained captured image to a luminance image, and calculates maximum luminance values in a capture angle-of-view region and a display angle-of-view region, based on the obtained luminance image. A control parameter setting unit determines whether an absolute difference between the obtained maximum luminance values is equal to or larger than a predetermined threshold, and determines exposure of the background camera based on the luminance information of the captured angle-of-view region or the display angle-of-view region, based on the determination result. An image processing unit generates a displayed image by cutting out the display angle-of-view region from the captured image of the background camera for which an imaging parameter is set based on the determined exposure.