Fingerprint signal processing system and fingerprint signal processing method
AssigneeImage Match Design Inc.
InventorsZheng-Xiong Chen, Sun-How Jiang
Life of this patent
Estimating the term…
Abstract
A fingerprint signal processing system for a fingerprint sensor includes a calibration control circuit, a register circuit, a decode circuit and a normalization circuit. The calibration control circuit is configured to receive a background calibration control signal and an image signal from the fingerprint sensor, and convert the image signal into a plurality of digital signals according to a plurality of offsets. When the background calibration control signal is at a high level, the calibration control circuit is configured to read a plurality of calibration parameters from the register circuit.
Claims22
A fingerprint signal processing system for a fingerprint sensor, comprising:
- a calibration control circuit, receiving a background calibration control signal, receiving an encoded analog signal from the fingerprint sensor, and converting the encoded analog signal into a plurality of digital signals, wherein the encoded analog signal is a piece of primitive image data read by the fingerprint sensor;
- a register circuit, electrically connected with the calibration control circuit and storing the digital signals, wherein the digital signals are stored in form of a 2-dimensional matrix;
- a first row of the 2-dimensional matrix includes a plurality of calibration parameters;
- while the background calibration control signal is at a high level, the calibration control circuit reads the plurality of calibration parameters from the register circuit to update a plurality of offsets of the plurality of digital signals;
- and
- a decode circuit electrically connected with the register circuit and used to convert the plurality of digital signals into a plurality of pixel signals.
A fingerprint signal processing method for a fingerprint sensor, comprising steps:
- receiving an analog signal from the fingerprint sensor, and converting the analog signal into a plurality of digital signals;
- converting the plurality of digital signals into a plurality of pixel signals;
- and
- normalizing the plurality of pixel signals to generate a plurality of normalized pixel signals, wherein the pixel signals are in form of an N×M matrix;
- both N and M are natural numbers;
- each column of pixel signals includes N pieces of pixel signals;
- the step of normalizing the plurality of pixel signals includes steps:
- calculating an average pixel value of each column, wherein the average pixel value is calculated according to less than N pieces of the pixel signals;
- and
- subtracting the average pixel value from N pieces of the pixel signals to generate N pieces of normalized pixel signals.
A fingerprint signal processing method for a fingerprint sensor, comprising steps:
- using a calibration control circuit to receive a background calibration control signal, and receive an analog signal from the fingerprint sensor, and convert the analog signal into a plurality of digital signals;
- using a register circuit to store the plurality of digital signals;
- and
- using a decode circuit to convert the plurality of digital signals into a plurality of pixel signals,
- wherein while the background calibration control signal is at a high level, the calibration control circuit reads a plurality of calibration parameters from the register circuit to update a plurality of offsets of the digital signals.
Dependencies are inferred from the claim text.