Depth Capture Modulating Illumination Levels
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Solution Overview
Problem
Depth camera systems face limitations in capturing accurate depth maps due to the dynamic range of the scene, where bright areas become saturated and dark areas lack sufficient illumination, leading to incomplete feature detection and reconstruction.
Innovation Solution
The system employs multiple cameras with overlapping fields of view and an active projection source that modulates illumination levels by varying the emission interval and power, capturing images at different exposure settings to combine into a high dynamic range depth map, ensuring detailed reconstruction of both bright and dark areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single illumination level is used in active depth camera systems, then the system structure remains simple, but the depth dynamic range is limited causing saturation in bright areas and insufficient illumination in dark areas
Solution Approach 1:
The system dynamically adjusts the illumination level of the active projection system across multiple exposure intervals. The processor controls the projection source to emit light at different illumination levels (first illumination level during first exposure interval, second illumination level during second exposure interval) to capture depth information across a wider dynamic range, resolving the contradiction between simple structure and extended depth range.
Solution Approach 2:
The system changes the illumination parameter by capturing images at multiple different illumination levels. The processor modulates the illumination level of the active projection system between exposure intervals, varying the light intensity parameter to optimize depth capture for both bright and dark areas of the scene, thereby expanding the depth dynamic range.
2Illumination intensity
If multiple images at different illumination levels are captured, then the depth dynamic range increases, but the capture time increases
Solution Approach 1:
The system employs periodic action by capturing multiple sets of images at different illumination levels across sequential exposure intervals. The processor alternates between first exposure interval with first illumination level and second exposure interval with second illumination level, systematically collecting depth data at varying light conditions to build a comprehensive high dynamic range depth map.
3Illumination intensity
If the projection source emits light continuously at high power, then the illumination is sufficient for dark areas, but bright areas become saturated
Solution Approach 1:
The system applies partial action by using different illumination levels for different exposure intervals rather than continuous high-power emission. The processor controls the projection source to emit at first illumination level during first exposure interval and second illumination level during second exposure interval, providing sufficient illumination for dark areas while preventing saturation in bright areas through selective illumination application.
Data Source
AI summary
A method for capturing a depth map includes: controlling a plurality of cameras to capture, concurrently, a plurality of first images during a first exposure interval, each of the cameras concurrently capturing a corresponding one of the first images, the cameras having overlapping fields of view; controlling a projection source to emit light at a first illumination level during the first exposure interval; controlling the cameras to capture, concurrently, a plurality of second images during a second exposure interval, each of the cameras concurrently capturing a corresponding one of the second images; controlling the projection source to emit light at a second illumination level during the second exposure interval, the second illumination level being different from the first illumination level; combining the first images with the second images to generate a depth map; and outputting the depth map.