P.133: 3D Multi‐Touch System by Using Coded Optical Barrier on Embedded Photo‐Sensors

Abstract

Limited by construction complexity, bare finger touch systems are not ready to be used on mobile devices. Hence, we proposed a system using coded optical barrier with less hardware and software complexity; based on the construction, touch algorithm is programed to obtained 3D location (x,y,z) of input(s). Finally, our concept was implemented on a 4-inch panel. The system was able to sense up to 3 touch inputs simultaneously within 35 mm working range. Author Keywords3D touch; multi-touch; near-distance touch; in-cell photo sensor; depth sensing; bare finger. Background3D touch is a platform that user performs natural gestures to manipulate virtual 3D images. In general, 3D touch systems can be separated into two classes by their working range. The first class, which is based on machine [1] and camera constructions [2], works in far-distance environment; it is already well-applied on TV game consoles. However, their construction limitations, such as additional device and blind range issues, restrict the feasibility to be implemented on mobile devices. Therefore, the second class, 3D touch in near-distance should be established. A promising candidate is in-cell photo sensor touchscreen [3]. However, it is not ready for 3D touch yet owing to low sensitivity. To conquer the issue, extra optical designs should be constructed. They can be diversified into two types. First, light pen [4] system, where user holds patterned light pen to interact, which are considered inconvenient. Second, bare finger system, where ideally light source can be integrated with display so that user can perform nature gestures; it's hence more user-friendly. Prior Approaches and ObjectivesIn a bare finger system, ideally, user can naturally manipulate computer with bare hand. Listed below are three prior systems but still needed to be improved. The limitation and comparison is described in Figure 1. First, 3D finger touch with sequential illuminator [5] was proposed by M.C. Ma et al. It used sequential light at different tilt angles to spot the touch point. However, in the construction, slow frame rate was induced due to capturing sequence. In addition, complex lateral light source made it difficult to be realized on products. Second, a system LCD with integrated 3-dimensional input device [6] was proposed by C. Brown et al. Their key contribution is to propose a construction of directional sensor. It analyzed disparity in the sensor to obtain depth value. However, owing to the sensor design, working range was too restricted for practical use. In addition, constrained by the architecture, the aforementioned two systems were unable to support multi-touch. Third, an LCD display system with depth-sensing capability based on coded aperture imaging [7] was proposed by S. Suh et al. The system uses dynamic lens-less imaging system to enlarge working range. Nevertheless, switches between display mode and touch mode of LC would reduce frame rate and cause image flickering. Moreover, processing numbers of images accounts for huge computation.Br...

Compact and high resolution virtual mouse using lens array and light sensor

“…Generally, camera-based technology is better in high resolution and anti-interference [9][10][11] while source-sensor-based technology is better in response time and compact volume [12][13][14][15] . However, as mentioned above, high resolution, anti-interference, fast response time, compact volume, along with acceptable cost are all considerably concerned for practical virtual mouse.…”

High‐resolution and compact virtual mouse using lens arrays to capture finger images on light sensors

“…Current technologies that are potential to realize such a virtual mouse mainly include dual‐camera positioning, structured light, time of flight, and integral imaging . These technologies have achieved great success in different application fields; however, they have respective shortcomings in consideration of the particular requirements of a virtual mouse.…”

“…Current technologies that are potential to realize such a virtual mouse mainly include dual-camera positioning, structured light, time of flight, and integral imaging. [6][7][8][9][10][11][12][13][14] These technologies have achieved great success in different application fields; however, they have respective shortcomings in consideration of the particular requirements of a virtual mouse. For instance, the structured light technology introduced by Andrews and Litchinitser 7 and integral imaging technology introduced by Traver et al 8 call for powerful computing capacity; the time of flight technology introduced by Breuer et al 9 has a relatively high cost; and the dualcamera positioning technology introduced by Morrison 10 leads to a considerable volume.…”