Fingerprint image detecting device and method

Abstract

Provided is a fingerprint image detecting device and a method. By use of the characteristics that an analog-to-digital converter sends out data sequentially when it converts data of a two-dimensionalanalog image into pixel data, a fingerprint image detecting device and method generate digital output data having a plurality of rows of data, generate a plurality of one-dimensional datum segments linearly from the digital output data, and determine whether the two-dimensional analog image is a real fingerprint image according to the plurality of one-dimensional datum segments. Thus, the detection of a fingerprint image is implemented by means of one-dimensional calculation instead of two-dimensional calculation, thereby effectively reducing computational load and computational time.

Description

technical field [0001] The present invention relates to an image detection device, in particular to a fingerprint image detection device and its method which use one-dimensional calculation instead of two-dimensional calculation. Background technique [0002] Using fingerprints for identity identification is to press the finger on the sensing unit to obtain a two-dimensional analog image, and then convert the two-dimensional analog image into two-dimensional digital data, such as two-dimensional pixel data, and then read the entire two-dimensional pixel data, and identify the identity based on the read two-dimensional pixel data. However, in the above identification process, after the finger leaves the sensing unit, sometimes there will be residual fingerprints on the sensing unit, for example, wet fingers will leave fingerprints on the sensing unit, At this time, the two-dimensional simulated image obtained from the sensing unit is a residual fingerprint trace, not a real ...

AI Technical Summary

Problems solved by technology

However, in the above identification process, after the finger leaves the sensing unit, sometimes there will be residual fingerprints on the sensing unit, for example, wet fingers will leave fingerprints on the sensing unit, At this time, the two-dimensional simulated image obtained from the sensing unit is a residual fingerprint trace, not a real fingerprint image. If the two-dimensional simulated image is directly identified, it will lead to a wrong operation of fingerprint identification, and there is a Therefore, after the sensing unit obtains the two-dimensional simulation image, it will detect whether the obtained two-dimensional simulation image is a real fingerprint image through the fingerprint image detection device. After confirming the obtained two-dimensional simulation image Identity recognition is performed only after the image is a real fingerprint image to avoid misuse

[0003] The known fingerprint image detection device reads several two-dimensional regions from the two-dimensional pixel data, and according to the average gray scale value of each pixel in each two-dimensional region and the maximum representative value and minimum value in the two-dimensional region The difference between the representative values ​​is used to determine whether the two-dimensional simulated image is a real fingerprint image. Taking the reading of several two-dimensional areas of 8×8 pixels as an example, two-dimensional calculations must be performed on the two-dimensional areas of 8×8 pixels, namely To average the grayscale values ​​of 64 two-dimensional pixels, and then sort the grayscale values ​​of the 64 two-dimensional pixels to obtain the maximum representative value (for example, the 11th largest grayscale value among the 64 two-dimensional pixels ) and the minimum representative value (such as the 11th smallest grayscale value among the 64 two-dimensional pixels) and calculate the difference. In the process of this two-dimensional operation, 64 two-dimensional data must be calculated, so the number of calculations In addition, the reading of the two-dimensional pixel data is continuous in time. Due to the large number of calculations, when the reading of the next area is completed, the calculation of the current area cannot be completed, let alone the entire two-dimensional pixel data. When the data reading is completed, the judgment of whether the two-dimensional simulated image is a real fingerprint image is completed, so an additional storage unit is required to store the data for judging whether the two-dimensional simulated image is a real fingerprint image, resulting in increased costs and delays Or delay the time of identification, moreover, the several two-dimensional areas correspond to different positions of the two-dimensional simulation image, so the parameters of the several two-dimensional areas are not the same with each other, resulting in too many analysis parameters, increasing The difficulty of adjusting the fingerprint image detection device

[0004] Another known fingerprint image detection device is to calculate the sum of the grayscale values ​​of each pixel in a set area in the two-dimensional pixel data, and when the sum of the grayscale values ​​is greater than a threshold value, it is determined that the two-dimensional The simulated image is a real fingerprint image. Although this method has a small number of calculations, it only judges whether the two-dimensional simulated image is a real fingerprint image based on the local area of ​​the two-dimensional pixel data (that is, the set area), rather than based on The entire two-dimensional pixel data is used to determine whether the two-dimensional simulated image is the real fingerprint image, so it is easy to misjudgment, resulting in a poor recognition rate of the fingerprint image

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