**2.1. Benefits of soft biometrics**

• Can be used to improve the recognition accuracy and speed of a primary biometric system [12].

• Can be used when there is a difficulty to collect a primary biometric trait or the collected data is not clear due to the sensor error or data collected from a distance with no cooperation with the user.

Some problems associated with the unimodal biometric systems can be overcome by the use of the multi-biometric systems that combine the information obtained from multiple sources [15]. Still, such a system has two major limitations: first, the overall cost to construct the system can be prohibitive due to the need for more high-quality sensors, large storage capacity, and computational requirements. Second, the system requires a longer time for verification, hence causing inconvenience to the users [10]. However, soft biometrics are the solution to decrease the cost by using the same sensor [10]. The main steps for a biometric system are as follow [7, 16] as shown in **Figure 3**:

A Survey on Soft Biometrics for Human Identification http://dx.doi.org/10.5772/intechopen.76021 41

• Enrollment is the first step where biometric traits of the person are collected by the sensor and saved to the dataset as a template for verification purpose and later on used for identi-

• Enhancing the stored data to get high recognition rate by doing preprocessing as histogram

• Extracting features vector from the individual for identification and match it with the

• Template dataset: enrolling data means storing biometric data to the dataset as a template to be compared with the stored one. In the case of authentication, biometric data are

• Classification and matching: biometric feature data are validated against the template data

• Decision can be rejected or accepted according to the matching similarity score or the

fication. Successful biometric enrollment is necessary for the next steps.

equalization, clipping the area of interest dealing with the illumination.

matched against a reference template from the template database.

**Figure 3.** Biometric system enrollment and identification diagram.

stored template data.

in the dataset

threshold value.

