Adjusting Perceived Head Roundness in Stereoscopic Video
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Solution Overview
Problem
Current stereoscopic video calling systems distort the perceived roundness of a head image due to camera separation issues, leading to unnatural appearances such as the 'Pinocchio effect' and 'Pancake effect', where features like the nose appear elongated or the sides appear wider than expected, disrupting natural gaze interaction.
Innovation Solution
A method that adjusts the perceived local depth in stereoscopic images by identifying and transforming specific regions like the nose and side of the head, using techniques like translation and re-sampling to align the disparity with expected depths, thereby improving the natural scaling of facial features and reducing distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If camera separation is increased to provide stereoscopic images, then stereoscopic depth perception is improved, but perceived roundness of head features deteriorates causing distortion effects
Solution Approach 1:
The patent applies parameter changes by adjusting the disparity values of specific facial regions (nose, cheeks, jaw) to compensate for the distortion caused by increased camera separation. The system modifies the depth parameters locally in different facial zones to restore natural perceived roundness while preserving overall stereoscopic depth perception.
Solution Approach 2:
The patent implements local quality by applying region-specific disparity adjustments to different parts of the face. The nose region, cheek regions, and jaw regions each receive customized disparity modifications tailored to their specific geometric characteristics and expected depth profiles, rather than applying a uniform correction across the entire image.
2Measurement precision
If camera separation is increased beyond nominal eye separation, then stereoscopic disparity range is improved, but head roundness reproduction deteriorates
Solution Approach 1:
The system changes disparity parameters selectively in different facial regions to compensate for the effects of increased camera separation. By adjusting the disparity magnitude and sign in specific zones (e.g., reducing nose tip disparity, adjusting cheek disparity), the patent restores accurate head roundness reproduction despite the larger baseline separation.
Solution Approach 2:
The patent applies local quality by treating different facial regions with customized disparity correction strategies. Each region (nose, cheeks, jaw) has its own expected depth profile and receives targeted adjustments, allowing the system to maintain high head roundness reproduction accuracy even with extended disparity ranges from increased camera separation.
3Device complexity
If cameras are positioned outside display active area, then device complexity is reduced, but gaze correction deteriorates
Solution Approach 1:
The patent replaces the mechanical solution of co-locating cameras with eye images (which would require complex beam combiners and optical systems) with a digital image processing approach. By computing and applying disparity corrections to the captured images, the system achieves gaze correction without the mechanical complexity of optical beam combining hardware.
Solution Approach 2:
The patent introduces an intermediary digital processing step that mediates between the simple camera positioning and the desired gaze correction effect. The image processing algorithm acts as an intermediary that compensates for the suboptimal camera placement, achieving the appearance of correct gaze without requiring the cameras to be physically co-located with the eye images.
Data Source
AI summary
In telecommunication video calling and videoconferencing systems, it is strongly desirable for remote observers to interact with natural gaze cues. In natural gaze interaction, the camera for a source observer appears to be co-located in the eye region of a destination observer image and vice versa. The appearance of camera co-location is achieved for stereoscopic camera pair that are placed either side of an autostereoscopic 3D display. Such cameras typically provide stereoscopic images that have disparity distributions that provide unnatural perceived head roundness. The present embodiments achieve perceived head roundness that is closer to that expected in natural face to face interaction by modification of perceived local depth in detected regions of the head.