Current digital door lock systems are mainly designed for users' convenience, so they have weakness in security. Thus, this paper suggests a video digital doorlock system grouped with a relay device, a server, and a digital doorlock with a camera, sensors, and communication modules, which is detecting or recognizing objects approaching to the front of the door lock system and sending images and door-opening information to users' smart devices. Experiments showed that the suggested system has 96∼98% recognition rate of approaching objects and requires 17.1∼23.9 seconds for transmission on average, depending on network systems. Therefore, the system is thought to have enough capability for real time security response by monitoring the front area of the doorlock system.

Video digital door lock(VDDL) system detects people who access to the door and acquires the human image. Design considerations is that current consumption must be minimized by applying fast human detection algorithm because of battery-based operation. Since the digital door lock takes an image through a fixed camera, detection of a person based on background image leads to high degree of reliability. This paper deals with a single human detection algorithm suitable for VDDL with fulfilling these requirements such that it detects a moving object in an image, then identifies whether the object is a person or not using image processing. The proposed image processing algorithm consists of two steps: Firstly, it detects the human image region using both background image and skin color information. Secondly, it identifies the person using polar histogram based on proportional information of human body. Proposed algorithm is implemented in VDDL and is verified the performance through experiments.

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