Methods and devices for recognizing fingerprint

A non-transitory computer-readable recording medium storing instructions which, when executed by a processor, cause the processor to perform operations comprising:

• generating, by using a fingerprint sensor, an input fingerprint image that is to be used when a fingerprint verification mode is executed;
• obtaining, from a memory, a registered fingerprint image that is generated from a finger image captured by a camera and stored in the memory prior to the generating the input fingerprint image;
• determining, from among partial regions of the registered fingerprint image that is obtained, a partial region of the registered fingerprint image, which is superimposed on the input fingerprint image, as a registered superimposed image;
• converting the registered superimposed image such that a first histogram of the registered superimposed image corresponds to a second histogram of the input fingerprint image;
• and
• determining, by comparing the registered superimposed image, which is converted, with the input fingerprint image, whether the input fingerprint image is verified,
• wherein the converting comprises converting the registered superimposed image such that a first gray level average and a first gray level variance of the first histogram for first pixels in the registered superimposed image have values within a certain threshold range, based on a second gray level average and a second gray level variance, respectively, of the second histogram for second pixels in the input fingerprint image.

An electronic device comprising:

• a camera configured to capture, in a fingerprint registration mode, a finger image of a user;
• a memory configured to store, when the fingerprint registration mode is executed, a registered fingerprint image that is generated from the finger image that is captured by the camera;
• a fingerprint sensor configured to sense a fingerprint in a fingerprint verification mode;
• and
• a processor configured to:
• generate, by using the fingerprint sensor, an input fingerprint image to be used when the fingerprint verification mode is executed,
• obtain, from the memory, the registered fingerprint image that is stored in the memory, prior to the generating the input fingerprint image, in the fingerprint registration mode,
• determine, from among partial regions of the registered fingerprint image that is obtained, a partial region of the registered fingerprint image that is superimposed on the input fingerprint image as a registered superimposed image,
• convert the registered superimposed image such that a first histogram of the registered superimposed image corresponds to a second histogram of a fingerprint image, and
• determine, by comparing the registered superimposed image that is converted with the input fingerprint image, whether the input fingerprint image is verified,
• wherein the processor is further configured to convert the registered superimposed image such that a first gray level average and a first gray level variance of the first histogram for first pixels in the registered superimposed image have values within a certain threshold, based on a second gray level average and a second gray level variance, respectively, of the second histogram for second pixels in the input fingerprint image.