Ultrasonic Area-Array Sensor Image Merging for Fingerprint Scanning
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Solution Overview
Problem
Current fingerprint scanning technologies, particularly those using ultrasound, are slow due to the need for mechanical scanning of each pixel individually, while swipe sensors require information about the speed of motion and direction of the digit, which complicates the process.
Innovation Solution
An ultrasonic area-array sensor method that collects and combines multiple area-images of a biological object, discarding perimeter pixels to form an extended image, allowing the object to move across the sensor, and using a processor to manage image collection and merging, eliminating the need for precise speed and direction information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single pixel sweep scanning device is used to collect acoustic images, then measurement precision is improved, but productivity deteriorates due to the need to collect each pixel individually through mechanical scanning
Solution Approach 1:
The imaging process is segmented into multiple passes, where each pass collects a portion of the fingerprint image. The system divides the complete image acquisition into sequential sweeps, allowing parallel processing of different image regions while maintaining ultrasonic imaging precision.
Solution Approach 2:
The system performs preliminary actions by collecting multiple partial images in sequential passes before final image reconstruction. Each pass prepares a portion of the complete fingerprint image, which is then synthesized into the final high-resolution image through image merging algorithms.
2Device complexity
If a line of sensing elements is used for swipe type fingerprint readers, then device complexity is reduced, but measurement precision deteriorates due to the need for speed and direction information
Solution Approach 1:
The system introduces an intermediary image merging algorithm that acts as a mediator between the simple line sensor data and the final high-precision fingerprint image. This intermediary process reconstructs the complete fingerprint image by combining multiple linear sweeps without requiring direct measurement of speed and direction.
Solution Approach 2:
The system creates multiple copies of the fingerprint image from different linear sweeps and then merges them. Each sweep produces a linear image copy that is subsequently combined with other copies to reconstruct the complete two-dimensional fingerprint image with high precision.
3Area of stationary object
If multiple area-images are collected and combined to form an extended image, then area of the image is improved, but loss of time increases due to additional image processing
Solution Approach 1:
The system performs partial image collection by acquiring multiple area-images that extend beyond the final desired image boundaries. Perimeter pixels are deliberately discarded during merging to simplify processing and eliminate the need for complex edge matching, reducing overall processing time.
Solution Approach 2:
The system extracts and discards perimeter pixels from collected area-images during the merging process. This extraction of unnecessary boundary data simplifies the image merging algorithm and reduces processing time, as the core fingerprint information is contained within the interior regions of the captured images.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances scanning speed and accuracy by creating a larger image area without requiring precise motion control, improving the efficiency and detail of fingerprint imaging compared to traditional methods.
Implementation Method 1
a piezoelectric transducer that sends an ultrasonic energy wave (often referred to as a 'pulse') through a transmitting media. The pulse partially reflects back at each media interface.
Implementation Method 2
Use of ultrasound typically employs a piezoelectric transducer that sends an ultrasonic energy wave
Data Source
AI summary
A method and device for using a small area-array sensor to produce a larger image of a biological object is disclosed. In a method according to the invention, the presence of a biological object is detected, and images of the biological object are collected using the area-array sensor. Pixels from at least some of the collected area-images are discarded to produce a set having modified area-images, and the area-images of the set are combined to form an extended image using an image merging algorithm.