Smartphone Perspective Correction for Digital Watermark Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Smartphones struggle to decode digital watermarks due to perspective distortion and scale issues when capturing images of objects at off-axis angles or from inappropriate distances, leading to consumer confusion about the presence of watermarks.

Innovation Solution

The smartphone determines its perspective and distance relative to an object by capturing images from different positions and applying geometrical corrections to mitigate distortion, guiding the user to a suitable viewing pose for accurate watermark detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the smartphone captures imagery of a watermarked object at a large off-axis angle or from too-great/too-close distance, then the device can capture the object, but the perspective distortion causes the decoding algorithm to fail to recognize the watermark

Engineering Contradiction:

Improveability to capture objects at various positions and distancesVSAvoidwatermark detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary actions by determining the smartphone's geometric pose relative to the object before capturing the final image. It calculates perspective distortion parameters and provides guidance to reposition the smartphone, or pre-processes the captured image by determining the geometric relationship between the smartphone and object to enable subsequent perspective correction and accurate watermark detection.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by determining the smartphone's pose and perspective distortion characteristics, then using this information to guide the user in repositioning the device or to correct the captured imagery. This feedback loop ensures that the final image has minimal perspective distortion and optimal scale for reliable watermark detection.

Inventive Principle:

Principle #23Feedback

2Loss of time

If the smartphone uses quick wave motion to determine geometrical relationship, then it can rapidly assess perspective distortion, but the process adds complexity to the capture operation

Engineering Contradiction:

Improvetime for perspective assessmentVSAvoidgeometrical relationship determination process

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The system employs periodic action by having the user perform a quick wave motion—a repeated or rhythmic movement— to capture multiple images during the motion. These sequential images are then processed to determine the geometric relationship between the smartphone and object, enabling rapid perspective assessment through the periodic sampling of the wave motion.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The quick wave motion serves as a preliminary action that quickly establishes the geometric relationship before the final capture. By performing the wave motion first, the system determines perspective distortion parameters in advance, allowing for rapid assessment and subsequent correction without adding significant complexity to the overall capture process.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the system provides guidance to reposition the smartphone for optimal viewing pose, then watermark detection accuracy improves, but the ease of operation decreases

Engineering Contradiction:

Improvewatermark detection accuracyVSAvoiduser guidance requirements

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The system implements self-service by automatically determining the smartphone's pose and perspective distortion characteristics, then providing automated guidance to reposition the device. The system serves itself by analyzing the captured images, calculating the geometric relationship, and generating repositioning instructions without requiring manual measurement or complex user intervention, thereby maintaining ease of operation while improving detection accuracy.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The feedback mechanism automatically analyzes the captured imagery, determines the geometric relationship between the smartphone and object, and provides guidance to reposition the device for optimal viewing pose. This automated feedback loop improves watermark detection accuracy while minimizing the burden on the user, as the system handles the complex analysis and guidance generation automatically.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9398210B2Methods and systems for dealing with perspective distortion in connection with smartphone cameras

Publication Date: 2016.07.19 DIGIMARC LLC

AI summary

Arrangements are detailed to aid a user in positioning a camera-equipped device (e.g., a smartphone) at a particular viewing position relative to an object being imaged. Other embodiments discern the device's viewing position, and then undertake image or other processing that is dependent on such viewpoint. A great number of other features and arrangements are also detailed.