Time-of-flight 3-D Sensor Sampling for Smartphone Facial ID

　　Time-of-flight technology directly measures the depth and amplitude information in every pixel by using only one infrared flash light source.The modulated IR light is emitted to focus on the entire scene or subject,and the ToF imager captures the reflected light from the subject.The measured phase difference between the emitted and received light,as well as the amplitude values,yields highly reliable distance information and a grayscale image of the complete scene simultaneously.

　　ToF minimizes power consumption and provides fast data acquisition for real-time operation.In addition,the required depth-data processing for ToF is less demanding than for other algorithm-intensive depth-sensing technologies,including structured light and stereovision,saving additional power within the application processor,according to ToF proponents.

　　An inherent benefit of time-of-flight technology is the simplicity of the ToF camera module:It consists of only two key components—the imager and one flash illumination component—without the need for any mechanical baseline.The low component count enabled the small size of the module developed by Infineon and pmdtechnologies,as well a lean and fast calibration procedure for easy and robust mass production,according to the companies.The modules do not have to be recalibrated during use.

　　Infineon and pmdtechnologies claim that theirs are the only ToF-based depth-sensing camera modules integrated in commercially available smartphones.

　　The image sensor chip is produced in Dresden,Germany,and was developed in Munich and in Graz,Austria.Samples are available now,with volume production scheduled to start in the fourth quarter.Software partners including Sensible Vision Inc.and Idemia offer application software for facial detection and authentication.