Video Frame Pen Stroke Masking for Physical Whiteboard Legibility
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Solution Overview
Problem
Conventional videoconferencing systems struggle to effectively share content written on physical writing surfaces like whiteboards during virtual meetings, as capturing this content often requires focusing on the writing surface, which means participants are no longer visible, and specialized digital whiteboards are expensive and less intuitive.
Innovation Solution
A videoconferencing method that processes video frames from a camera to enhance the legibility of pen strokes on physical writing surfaces by applying adaptive thresholding and generating a pen stroke mask, allowing the system to share the content clearly while still capturing participants, using a separate, portable camera and computing apparatus connected to the videoconferencing endpoint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the camera focuses on the writing surface to capture content, then the legibility of written content is improved, but participants become invisible
Solution Approach 1:
The video feed is segmented into multiple regions: a first region displaying the writing surface content with enhanced legibility, and a second region displaying participants. This segmentation allows both objectives to be achieved simultaneously by dividing the display area rather than choosing one over the other.
Solution Approach 2:
The solution transitions from a single-dimension focus (either content or participants) to a two-dimension layout where content occupies a first region and participants occupy a second region. This dimensional change allows both elements to be visible simultaneously without compromising legibility or participant visibility.
2Measurement precision
If specialized digital whiteboards are used to improve content sharing, then legibility is improved, but equipment cost increases
Solution Approach 1:
Instead of requiring expensive specialized digital whiteboards, the system captures images of the physical writing surface using a standard camera and processes these images through image processing algorithms. This copying approach uses inexpensive equipment to achieve digital whiteboard functionality.
Solution Approach 2:
The patent replaces the mechanical/electronic system of specialized digital whiteboards with a software-based image processing system. By substituting hardware complexity with computational processing, the solution achieves similar legibility improvements at lower equipment cost.
3Measurement precision
If adaptive thresholding is applied to enhance pen stroke visibility, then legibility is improved, but processing time increases
Solution Approach 1:
The adaptive thresholding is applied selectively to specific regions of interest in the video frames, particularly to areas containing writing content. By limiting the processing scope to local regions rather than entire frames, processing time is reduced while maintaining legibility enhancement where needed.
Data Source
AI summary
A method of processing of a sequence of video frames from a camera capturing a writing surface for subsequent transmission to at least one of a remote videoconferencing client and a remote videoconferencing server. The method comprises receiving the sequence of video frames from the camera; and selecting an image area of interest in the video frames, comprising selecting one of a sub-area of the video frames and an entire area of the video frames. The method also comprises, for each current video frame of the sequence of video frames, generating a pen stroke mask by applying adaptive thresholding to the image area of interest. The method also comprises generating an output video frame using the pen stroke mask. Corresponding systems and computer readable media are disclosed.