Interactive input systems that allow users to input ink into an application program using an active pointer (eg. a pointer that emits light, sound or other signal), a passive pointer (eg. a finger, cylinder or other object) or other suitable input device such as for example, a mouse or trackball, are well known. These interactive input systems include but are not limited to: touch systems comprising touch panels employing analog resistive or machine vision technology to register pointer input such as those disclosed in U.S. Pat. Nos. 5,448,263; 6,141,000; 6,337,681; 6,747,636; 6,803,906; 7,232,986; 7,236,162; and 7,274,356 and in U.S. Patent Application Publication No. 2004/0179001 assigned to SMART Technologies ULC of Calgary, Alberta, Canada, assignee of the subject application, the contents of which are incorporated by reference; touch systems comprising touch panels employing electromagnetic, capacitive, acoustic or other technologies to register pointer input; tablet personal computers (PCs); laptop PCs; personal digital assistants (PDAs); and other similar devices.
Above-incorporated U.S. Pat. No. 6,803,906 to Morrison et al. discloses a touch system that employs machine vision to detect pointer interaction with a touch surface on which a computer-generated image is presented. A rectangular bezel or frame surrounds the touch surface and supports digital cameras at its corners. The digital cameras have overlapping fields of view that encompass and look generally across the touch surface. The digital cameras acquire images looking across the touch surface from different vantages and generate image data. Image data acquired by the digital cameras is processed by on-board digital signal processors to determine if a pointer exists in the captured image data. When it is determined that a pointer exists in the captured image data, the digital signal processors convey pointer characteristic data to a master controller, which in turn processes the pointer characteristic data to determine the location of the pointer in (x,y) coordinates relative to the touch surface using triangulation. The pointer coordinates are conveyed to a computer executing one or more application programs. The computer uses the pointer coordinates to update the computer-generated image that is presented on the touch surface. Pointer contacts on the touch surface can therefore be recorded as writing or drawing or used to control execution of application programs executed by the computer.
U.S. Patent Application Publication No. 2004/0179001 to Morrison et al. discloses a touch system and method that differentiates between passive pointers used to contact a touch surface so that pointer position data generated in response to a pointer contact with the touch surface can be processed in accordance with the type of pointer used to contact the touch surface. The touch system comprises a touch surface to be contacted by a passive pointer and at least one imaging device having a field of view looking generally along the touch surface. At least one processor communicates with the at least one imaging device and analyzes images acquired by the at least one imaging device to determine the type of pointer used to contact the touch surface and the location on the touch surface where pointer contact is made. The determined type of pointer and the location on the touch surface where the pointer contact is made are used by a computer to control execution of an application program executed by the computer.
In order to determine the type of pointer used to contact the touch surface, in one embodiment a curve of growth method is employed to differentiate between different pointers. During this method, a horizontal intensity profile (HIP) is formed by calculating a sum along each row of pixels in each acquired image thereby to produce a one-dimensional profile having a number of points equal to the row dimension of the acquired image. A curve of growth is then generated from the HIP by forming the cumulative sum from the HIP.
Although passive touch systems provide some advantages over active touch systems and work extremely well, using both active and passive pointers in conjunction with a touch system provides more intuitive input modalities with a reduced number of processors and/or processor load.
Camera-based touch systems having multiple input modalities have been considered. For example, U.S. Pat. No. 7,202,860 to Ogawa discloses a camera-based coordinate input device allowing coordinate input using a pointer or finger. The coordinate input device comprises a pair of cameras positioned in the upper left and upper right corners of a display screen. The field of view of each camera extends to a diagonally opposite corner of the display screen in parallel with the display screen. Infrared emitting diodes are arranged close to the imaging lens of each camera and illuminate the surrounding area of the display screen. An outline frame is provided on three sides of the display screen. A narrow-width retro-reflection tape is arranged near the display screen on the outline frame. A non-reflective reflective black tape is attached to the outline frame along and in contact with the retro-reflection tape. The retro-reflection tape reflects the light from the infrared emitting diodes allowing the reflected light to be picked up as a strong white signal. When a user's finger is placed proximate to the display screen, the finger appears as a shadow over the image of the retro-reflection tape.
The video signals from the two cameras are fed to a control circuit, which detects the border between the white image of the retro-reflection tape and the outline frame. A horizontal line of pixels from the white image close to the border is selected. The horizontal line of pixels contains information related to a location where the user's finger is in contact with the display screen. The control circuit determines the coordinates of the touch position, and the coordinate value is then sent to a computer.
When a pen having a retro-reflective tip touches the display screen, the light reflected therefrom is strong enough to be registered as a white signal. The resulting image is not discriminated from the image of the retro-reflection tape. However, the resulting image is easily discriminated from the image of the black tape. In this case, a line of pixels from the black image close to the border of the outline frame is selected. Since the signal of the line of pixels contains information relating to the location where the pen is in contact with the display screen. The control circuit determines the coordinate value of the touch position of the pen and the coordinate value is then sent to the computer.
Although Ogawa is able to determine the difference between two passive pointers, the number of input modalities is limited to relatively few types of pointers such as pen and finger inputs. More pointers are capable using polarization techniques; however, these techniques require proper orientation when the pointer contacts the display screen in order to avoid confusion with other pointer modalities.
It is therefore an object of the present invention at least to provide a novel interactive input system and a novel bezel therefor.