The basic characteristics of fingerprint scanner to obtain fingerprint image

The Fingerprint Scanner obtains the fingerprint image through the fingerprint sensor. Because the fingerprint image belongs to personal privacy, the automatic fingerprint recognition system generally does not directly store the fingerprint image. The fingerprint recognition algorithm generally extracts and compares the fingerprint features from the fingerprint image. It consists of ridges and valleys. The ridges are also called lines, which correspond to the raised parts of the finger skin, and appear as lines with darker grayscale in the fingerprint image. The valleys correspond to the concave parts of the finger skin, which are sandwiched between Between the two stripes, the grayscale of the relative lines is brighter, and the fingerprint features can be divided into global features, local features and subtle features.

1. Global features include
1. Basic grain pattern: The basic grain pattern is usually divided into left skip type, right skip type, bucket type, arch type and pointed arch type.
2. Mode area
The pattern area is the area on the fingerprint image that contains the general features, and the type of the fingerprint can be distinguished from the pattern area.
3. The core point, the core point is located in the asymptotic center of the fingerprint pattern, which is often used as a reference point when discussing and comparing fingerprints.
4. Triangle point. The triangle point is the center point of the triangle pattern area in the fingerprint image. The three fingerprint lines closest to the point form an approximate equilateral triangle, and the triangle point provides the fingerprint.
5. The number of lines, as a global feature, the number of lines generally refers to the number of fingerprint lines in the pattern area, and some algorithms use the number of lines between two points as a fingerprint feature, such as the number of lines between two nodes.
2. Local features include
1. The end point of a road ends here.
2. The wide stripe road at the bifurcation point is divided into two or more stripe roads here.
3. The divergence point z6 parallel lines are separated here.
4. The isolated point is wide and the strip is very short, so that it becomes a point.
5. Short stripes and broad strips are short but not so small.
6. Ring point, a strip of road is divided into noodles and then immediately synthesized into one, a small ring formed in this way is called ring point.
7. Bridge, where two parallel lines are overlapped.
8. The speed at which the direction of the curvature of the texture changes, the endpoints and points are the fingerprint features commonly used in fingerprint identification. This book is collectively referred to as nodes. Nodes can be described by parameters such as coordinates, directions, and types.