Fingerprint scanner, the larger the collection area, the more accurate the recognition?

In our daily life, fingerprint recognition has long been one of the most common methods of identity verification, from mobile phone unlocking to security access control, fingerprint recognition has gradually become mainstream due to its convenient and fast characteristics. However, has it ever occurred to you why some devices have fast recognition speeds while others are always verified over and over again? The size of the fingerprint scanner's capture area may be the key. With 20 years of fingerprint algorithm research experience, IDWorld is committed to providing a full range of fingerprint scanner products. This article will bring you an in-depth understanding of the working principle of fingerprint scanner, the relationship between capture area and recognition accuracy, and help you find the best balance when purchasing a fingerprint scanner.

Fingerprint scanner working principle and recognition accuracy relationship

Basic principle of Fingerprint scanner

The basic working principle of Fingerprint scanner is to scan the surface texture of a fingerprint and extract its unique details, which include ridges, bifurcation points and subtle texture changes. Modern fingerprint scanning technology usually uses optical, capacitive or ultrasonic scanning techniques. Optical fingerprint scanners capture the fingerprint image through optical sensors, while capacitive fingerprint scanners use capacitive sensors to sense the ridges and valleys of the fingerprint. Regardless of the technology, their core objective is to enable authentication by comparing the user-supplied fingerprint image against a template stored in a database.

Although there are different types of fingerprint scanner, the basic principle revolves around ‘uniqueness’, as each person's fingerprint is unique. The accuracy of recognition is not only related to the scanning technology, but also to the quality of the captured fingerprint image.

Key factors affecting recognition accuracy

The accuracy of fingerprint recognition is affected by many factors, the most important of which include the clarity of the fingerprint image, the resolution of the fingerprint sensor, the cleanliness of the fingerprint, and the quality of the fingerprint itself. Fingerprint clarity is directly related to whether the module can extract enough details, if the fingerprint image is blurred or partially obscured, then it is difficult for the recognition system to accurately compare. The resolution of the sensor, on the other hand, determines how much detail the system is able to capture. The higher the resolution, the better it is able to capture small differences in the fingerprint, and the recognition accuracy will increase accordingly. In addition, the cleanliness of the fingerprint will also affect the recognition result. Dust, oil or water stains will obscure part of the fingerprint's features, leading to a decrease in recognition accuracy.

Impact of capture area on recognition results

The larger the capture area of a Fingerprint scanner, the higher the recognition accuracy. This is because fingerprint features are not limited to a small area, but all parts of the fingerprint (e.g., the belly and tip of the finger) contain important information. A larger capture area captures more details and thus provides a more comprehensive image of the fingerprint. This enables the system to extract fingerprint features more accurately, reducing the probability of misidentification or missed identification. Especially in the case of poor quality fingerprints or partially damaged fingerprints, a larger capture area provides the system with more usable information, which helps to improve the fault tolerance of identification.

Why is it that a larger fingerprint area is more accurate?

Larger area provides more details

With a larger capture area, the sensor is able to capture more details of the fingerprint surface. These details include ridges, bifurcations, endpoints, and many more tiny features that make a fingerprint unique. In fingerprint recognition, the comparison of these details is key to ensuring the accuracy of the recognition. If the captured area is too small, it may not be able to capture the complete features of the fingerprint, leading to bias in the comparison and thus affecting the identification result. Especially for the elderly or people with worn fingerprints, a larger scanning area avoids missing information and ensures that the recognition system can extract more features from the complete fingerprint data.

Relationship between resolution and capture area of a Fingerprint scanner

The resolution of a Fingerprint scanner is usually measured in dots per inch (DPI), which determines the amount of detail that can be captured by the scanner. The higher the resolution, the finer the grain and detail the scanner is able to capture, while the acquisition area affects the amount of that detail. If the module captures a small area, even with a high resolution, only a portion of the fingerprint features can be captured, which may limit the effectiveness of the recognition. On the contrary, a larger acquisition area combined with a high-resolution module can provide richer fingerprint data, thus improving recognition accuracy.

Improved accuracy in real-world applications

In practical applications, the capture area of a fingerprint scanner is usually closely related to the recognition accuracy. For example, in security systems, mobile devices or time and attendance systems, the accuracy of fingerprint recognition is critical. Especially in multi-user applications, the capture area of the fingerprint scanner and the accuracy of the module are particularly important. By increasing the capture area, recognition errors due to missing or worn fingerprint parts can be reduced, thus improving user experience and system reliability. For example, the fingerprint recognition module of a smartphone usually adopts a larger area of the sensor to ensure that the user can unlock the device easily and avoid recognition failure due to inaccurate finger position or too small touch area.

How to choose the right fingerprint scanner to improve the recognition effect?

Consider the scanning technology of the fingerprint scanner

When choosing the right fingerprint scanner, the first thing to consider is the scanning technology. Common fingerprint scanning technologies include optical scanning, capacitive scanning, ultrasonic scanning, etc. Optical scanning technology is usually less expensive. Optical scanning technology is usually less costly and suitable for general use, but it is more sensitive to the presence of stains or moisture on the finger; capacitive scanning has higher anti-interference ability and is suitable for more complex environments; while ultrasonic technology can provide higher accuracy and can work effectively in more complex environments. Choosing the right technology based on actual needs and budget can help improve recognition stability and accuracy.

Optimising the balance between capture area and accuracy

Although increasing the fingerprint capture area can improve recognition accuracy, not all situations require a very large area to be scanned. In some application scenarios, especially on mobile devices, too large a capture area may cause the module design to become inconvenient or costly. Therefore, it is especially important to choose a suitable balance. In general, when choosing a suitable fingerprint scanner for your application scenario, you should consider factors such as capture area, scanning speed, module size and user experience, and strive to find the optimal balance between performance and convenience.

Fingerprint scanner performance evaluation criteria

When evaluating the performance of a fingerprint scanner, there are several key metrics to focus on: including capture speed, recognition accuracy, durability, anti-interference capability, and supported working environment conditions. A high-performance fingerprint scanner should maintain stable recognition accuracy under different environments (e.g. changing light, different finger dryness and humidity). In addition, durability is an important evaluation criterion. fingerprint scanners need to be able to withstand long-term use without performance degradation, especially in frequently used locations (e.g. corporate time and attendance, access control systems, etc.). Choosing a fingerprint scanner that meets these criteria can significantly improve the reliability and accuracy of the entire system.

In conclusion, choosing the right fingerprint scanner requires comprehensive consideration of various factors, including capture area, resolution, durability and working environment. Although increasing the fingerprint capture area can significantly improve recognition accuracy, maximisation is not necessary in all cases. By reasonably analysing the technical characteristics and application scenarios of fingerprint scanner, we can achieve an efficient user experience while satisfying recognition accuracy. We hope this article can inspire you to understand the influencing factors of fingerprint recognition, and also help you to be more comfortable when shopping for a fingerprint scanner in the future.