3D Point Cloud Edge Pixel Filtering for ToF Depth Accuracy

The patent segments the depth map processing into distinct stages: obtaining a first depth map, generating a second depth map through shifting operations, comparing the two maps to identify edge pixels, and finally filtering based on edge pixel distribution. This segmentation allows efficient processing by breaking down the complex edge detection task into manageable steps that can be executed sequentially with optimized computational resources.

The patent performs preliminary actions by creating multiple shifted versions of the depth map before the actual edge detection occurs. By pre-generating these shifted depth maps and identifying potential edge regions in advance, the system reduces the computational burden during the final edge detection and filtering stage, thereby decreasing overall processing time while maintaining detection accuracy.

The patent extracts only the essential information needed for edge pixel identification by comparing shifted depth maps and focusing specifically on regions where depth differences exceed a threshold. This extraction approach avoids unnecessary computational operations on non-edge regions, reducing power consumption while maintaining accurate edge pixel identification. The system takes out only the relevant edge pixel data from the entire depth map for further processing.

The patent applies partial action by performing depth map shifting and comparison operations only on regions where edges are likely to occur, rather than processing the entire depth map uniformly. By using adaptive thresholds that focus computational effort on critical regions, the system achieves accurate edge detection with reduced overall computational burden and lower power consumption compared to exhaustive conventional methods.

The patent introduces an intermediary filtering mechanism that processes depth information between acquisition and final object detection. The edge pixel identification and filtering system acts as a mediator that separates mixed reflections from foreground and background objects by identifying and excluding edge pixels that contain contaminated depth data. This intermediary step maintains processing simplicity while significantly improving depth information accuracy through targeted filtering.

The patent converts the harmful effect of mixed reflections into a beneficial filtering opportunity. By detecting edge pixels where mixed reflections occur (through depth map comparison and thresholding), the system identifies precisely which data points need filtering. The presence of mixed reflections actually helps locate edge regions, which then become the focus of the filtering operation, ultimately improving overall depth map quality by removing contaminated data.