On-Chip Digital Watermarking in CMOS Image Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current digital watermarking techniques face challenges in efficiently embedding and detecting watermarks in images captured by CMOS image sensors, particularly in integrating watermarking processes on-chip and effectively incorporating location information for image management and travel logs.
Innovation Solution
The method involves embedding digital watermarks on-chip within CMOS image sensors, using techniques such as slight variations in pixel characteristics and color filters to introduce a watermark component during image capture, and incorporating GPS or location data to enable location-based image management and travel log creation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital watermarking is applied to image signals captured by CMOS sensors, then image authentication and location tracking are enabled, but the device complexity and manufacturing precision requirements increase
Solution Approach 1:
The patent combines the watermarking encoder with the CMOS image sensor chip, integrating the watermark embedding function directly into the image capture device. This merging eliminates the need for separate watermarking hardware, reducing overall system complexity while enabling reliable image authentication and location tracking through the embedded watermarks containing GPS coordinates and timestamps
2Ease of manufacture
If watermark embedding is integrated on-chip with CMOS sensor, then manufacturing quality control is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent introduces deliberate local variations in pixel characteristics (such as slight differences in photodetector sensitivity or color filter properties) to embed watermark information. These controlled local quality differences allow the watermark to be encoded in the image signal itself during capture, enabling manufacturing quality control through standard processes while the systematic variations carry the authentication data
Solution Approach 2:
The watermark embedding is achieved by making systematic changes to pixel parameters during the manufacturing process, such as varying the doping concentration or physical dimensions of select photodetectors. These parameter changes create detectable patterns in the captured images that encode location and authentication information without requiring ultra-precise manufacturing beyond standard CMOS capabilities
3Loss of information
If slight variations in pixel characteristics are used to embed watermark, then imperceptible watermarking is achieved, but the measurement precision requirements increase
Solution Approach 1:
The patent uses the natural variations in pixel characteristics as a template or copying mechanism for embedding the watermark. Instead of adding external watermark patterns that might be visible, the system copies and encodes location information into the existing statistical properties of the pixel array, making the watermark imperceptible while maintainable through correlation-based detection that accounts for the known pixel variation patterns
Data Source
AI summary
The disclosure describes methods and apparatus for providing digital watermarks or steganographic indicia in image or video data. One implementation embeds digital watermarks on-chip with respect to a CMOS or CCD image array. Some implementations introduce a watermark component during image capture, the watermark being introduced through variations in physical characteristics of a set of pixels. Other implementations are provided and claimed as well.