Systems and methods for scanning signatures in a string field. In one implementation, the invention provides a method for signature scanning. The method includes receiving a particular string field, scanning the particular string field for a plurality of signatures using a larger scan step size, scanning the particular string field for the remaining signatures that are shorter than what can be scanned by the larger scan step size separately either using the same scanning method but a smaller scan step size or using a different scan method and the same or a smaller scan step size, and outputting any identified signatures in the particular string field.

A method of a fingerprint sensing system arranged in a smartcard configured to acquire fingerprint data of a user with a fingerprint sensor for biometric authentication, and a fingerprint sensing system performing the method. The method comprises detecting a finger of the user contacting a sensing area of the fingerprint sensor, initializing the fingerprint sensor with a predetermined sensor setting, acquiring a calibration sub-image which is confined in size to a subarea of the sensing area, determining whether or not a quality criterion is met for the acquired calibration sub-image, and if so acquiring one or more further sub-images confined in size to a subarea of the sensing area during a time period when the smartcard is not engaged in waiting time extension request signalling with a card reader, and combining a plurality of the acquired further sub-images into a representation of a fingerprint of the user.

A fingerprint entry prompting method, includes: obtaining an i.sup.th entered fingerprint image, during a process of collecting and combining N fingerprint images entered in sequence to generate a fingerprint template of a user, wherein N≧i≧2, and N and i are integers; obtaining an overlap region between the i.sup.th entered fingerprint image and a determined template image, wherein the determined template image is generated by combining i-1 previously entered fingerprint images; and presenting a prompting message when the overlap region satisfies a prompting condition, wherein the prompting message is configured to instruct the user to move a finger towards a specified direction and re-enter the i.sup.th fingerprint image.

A method, a user terminal are provided for fingerprint unlocking. The method includes receiving a partial fingerprint image during a process of pressing a fingerprint recognition sensor of a user terminal where the partial fingerprint image corresponds to part of fingerprints of a finger, matching the partial fingerprint image during the process of receiving the partial fingerprint image, and unlocking a user terminal when the partial fingerprint image is matched.

A method for controlling unlocking and a terminal includes the follows. Feature points of class i of a finger of a user is acquired by scanning the finger with the i.sup.th scanning partition of a fingerprint recognition sensor of a terminal, the fingerprint recognition sensor has M scanning partitions, M is a positive integer not less than 2 and i is a positive integer not greater than M. The acquired feature points of class i is added into a current feature point set. A matching process is performed between the current feature point set and a pre-stored fingerprint template. The terminal is unlocked when the current feature point set is matched.

A method for controlling unlocking is provided. The method includes the following operations. A touch operation of a finger of user on a fingerprint recognition sensor of a terminal is detected. A first fingerprint image is received according to a preset capacity auto control (CAC) parameter corresponding to a default finger, the finger of the user is in the steady state. N second fingerprint images are received according to N sets of CAC parameters; N is an integer greater than 1. A target fingerprint image is determined and matched. The terminal is unlocked when the target fingerprint image is matched.

A method and a terminal are provided for launching an application. The method includes acquiring a sliding trace of a sliding operation performed on a fingerprint recognition sensor of a terminal, acquiring a fingerprint image and matching the fingerprint image during the acquisition of the sliding trace, determining a target application corresponding to the sliding trace, and launching the target application when the fingerprint image is successfully matched.

A fingerprint unlocking method may include receiving a first fingerprint image. The number of target feature points of the first fingerprint image is determined. A target adjustment parameter corresponding to the number of target feature points is acquired according to a preset mapping relation between the number of feature points and adjustment parameters. A second fingerprint image is received according to the target adjustment parameter. A terminal is unlocked when the second fingerprint image matches with a preset fingerprint template. A terminal is also provided.

A method for controlling unlocking may include the following. The number of feature points in a current feature point set of a user finger is acquired. When the number of the feature points in the current feature point set is greater than or equal to a first preset threshold and when the current feature point set matches with a pre-saved fingerprint template, a mobile terminal is unlocked. A related mobile terminal is also provided.

Systems and methods determine a swipe direction of an object on an electronic device to enable the performance of actions in response to the determined swipe direction. The swipe direction may be determined with respect to a biometric authentication sensor of the electronic device. According to certain aspects, signals that indicate the presence of an object may be received from proximity sensor(s) and/or a biometric authentication sensor. The swipe direction of the object may be determined based on the signals. An action may be performed on the electronic device in response to determining the swipe direction. An improved user experience of the electronic device may result through the use of these systems and methods.