Method and electronic device for noise mitigation

A portable electronic device, comprising:

• a fingerprint sensor having an array of pixels, and
• a control unit electrically connected to the fingerprint sensor,
• wherein the control unit is configured for:
• selecting a sampling matrix, wherein the sampling matrix represents a sampling pattern for acquiring a fingerprint image using the fingerprint sensor;
• applying a linear filter to the acquired fingerprint image, wherein setup of the linear filter depends on the sampling matrix and the linear filter is provided for noise reduction within the acquired fingerprint image;
• and
• determining a representation of a fingerprint pattern based on said filtered fingerprint image;
• determining a log-likelihood ratio for noise being present within the fingerprint image,
• comparing the log-likelihood ratio with a predetermined threshold;
• and
• performing filtering of the fingerprint image only if the log-likelihood ratio is above the predetermined threshold,
• wherein the fingerprint sensor is a two-dimensional fingerprint sensor and the sampling matrix corresponds to a selected portion of the plurality of sensing elements.

A computer program product comprising a non-transitory computer readable medium having stored thereon a computer program for a control unit adapted for controlling a portable electronic device, the portable electronic device comprising a fingerprint sensor and a control unit, wherein the fingerprint sensor is a two-dimensional fingerprint sensor, and

• wherein the computer program product comprises:
• code for selecting a sampling matrix, wherein the sampling matrix represents a sampling pattern for acquiring a fingerprint image using the fingerprint sensor;
• code for acquiring the fingerprint image using the fingerprint sensor and according to the sampling matrix;
• code for applying a linear filter to the acquired fingerprint image, wherein setup of the linear filter depends on the sampling matrix and the linear filter is provided for noise reduction within the acquired fingerprint image;
• code for determining a representation of a fingerprint pattern based on said filtered fingerprint image;
• code for determining a log-likelihood ratio for noise being present within the fingerprint image,
• code for comparing the log-likelihood ratio with a predetermined threshold;
• and
• code for performing filtering of the fingerprint image only if the log-likelihood ratio is above the predetermined threshold,
• wherein the sampling matrix corresponds to a selected portion of the plurality of sensing elements.