Patent Publication Number: US-2011050729-A1

Title: System and method for adjusting display orientation

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to video display and, more particularly, to adjusting video display orientation for viewing comfort or convenience. 
     BACKGROUND OF THE INVENTION 
     As digital media gain popularity, people spend more and more time surfing internet, watching digital media programs, reading articles, playing video games, etc., on personal computers, digital media devices, or other electronic devices with video displays. It is generally more comfortable to view a display when the display panel is parallel to the face of the viewer and an reference line corresponding to horizontal is parallel to a line connecting two pupils of the viewer. When viewing a display, two pupils of a viewer in generally on the same level, i.e., the line connecting the two pupils are generally horizontal. To accommodate this normal and most common posture of the viewer, the display panel of a personal computer placed on a leveled desk surface generally has its top and bottom sides substantially horizontal. The display of a document is generally in an upright orientation so that the lines of the text in the document is parallel to the top side of the display panel. 
     A viewer sometimes departs from the normal posture when using a personal computer. For example, the viewer may tilt his head to a side in order to reach an object or take a more comfortable or restful posture. When the viewer tilts his head, he would view the display panel at an angle. There are computers on the market that enable the viewer to use keys or a user interface to rotate the document on display to an orientation parallel to the viewer&#39;s eyelevel. Rotating the document requires the viewer to consciously adjust the document on display, which is inconvenient because the viewer may often tilt his head in a subconscious move and stay in the tilted posture for an indefinite time before readjusting this head to another position. Furthermore, it would be difficult to rotate the document precisely. The viewer may rotate the document on display too much or too little for his viewing comfort. 
     Accordingly, it would be advantageous to have an electronic device with video display and a method for adjusting the display for viewing comfort. It is desirable for the method to be able to adjust the display automatically following viewer&#39;s movement. It is also desirable to be able to adjust the display with high precision. It would be of further advantage if the video display adjustment can be implemented easily and cost efficiently. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a functional block diagram illustrating an electronic device having a video display adjustment mechanism implemented thereon in accordance with an embodiment of the present invention; 
         FIG. 2  is a functional block diagram illustrating a display adjustment system in accordance with an embodiment of the present invention; 
         FIG. 3  is a schematic diagram illustrating a display panel having an eyelevel detection unit in accordance with an embodiment of the present invention; and 
         FIG. 4  is a flowchart illustrating a display adjustment process in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS 
     Various embodiments of the present invention are described herein below with reference to the figures, in which elements of similar structures or functions are represented by like reference numerals throughout the figures. It should be noted that the figures are only intended to facilitate the description of various embodiments of the present invention. They are not intended as an exhaustive description of the present invention or as a limitation on the scope of the present invention. Furthermore, the figures are not necessarily drawn to scales. 
       FIG. 1  is a functional block diagram illustrating an electronic device  10  having a video display mechanism implemented thereon in accordance with an embodiment of the present invention. It should be noted that  FIG. 1  shows only those elements in device  10  necessary for the description of the structure and operation of device  10  in accordance with a preferred embodiment of the present invention. By way of example, electronic device  10  may be a desktop personal computer, a laptop personal computer, a personal digital assistant (PDA), a mobile telephone, a digital media device, etc. 
     Device  10  includes a digital signal processing unit (DSP)  12 , a data storage unit  14 , a memory unit  16 , and a display element or unit  18 . Data storage unit  14 , memory unit  16 , and display unit  18  are coupled to DSP  12  via signal transmission buses. In accordance with the present invention, DSP  12  may include a microprocessor (μP), a microcontroller (μC), a central processing unit (CPU), or the likes. Data storage unit  14  may include one or more nonvolatile memory units such as, for example, a magnetic hard disc, an optical memory disk, read only memory (ROM), flash memory, ferroelectric random access memory (FeRAM), magentoresistive random access memory (MRAM), etc. Memory unit  16  may include a cache memory unit or a volatile memory unit such as, for example, dynamic random access memory (DRAM), static random access memory (SRAM), zero capacitor random access memory (Z-RAM) twin-transistor random access memory (TTRAM), etc. Display unit  18  may include a video display of various kinds, such as, for example, liquid crystal display (LCD), cathode ray tube display (CRT), electroluminescent display (ELD), light emitting diode display (LED), etc. In accordance with the present invention, device  10  may include additional elements not shown in  FIG. 1 . For example, device  10  may also include a data input system, a user interface, an audio system, a radio, a global positioning system (GPS), etc. 
     Electronic device  10  also includes an imaging module  11 . In accordance with a preferred embodiment, imaging module  11  includes an image sensor  15  and a signal encoder  17  coupled thereto. Image sensor  15  includes an array of photoelectric light sensors, e.g., charge-coupled device (CCD) sensors, complementary metal-oxide-semiconductor (CMOS) sensors, etc., for generating electric signals in response to light images. Digital signal encoder  17  is also coupled to DSP  12 . Digital signal encoder  17  encodes the electric signal from image sensor  15  into data packets and, transmits the data packets to DSP  12 . 
     In operation, DSP  12  processes user commands and data inputs and generates operation codes to data storage unit  14 , memory unit  16 , and display unit  18 . For example, when a user wants to view a file, the user may use a keyboard or keypad (not shown in  FIG. 1 ) to input the filename or click on a file icon. In response to the user input, DSP  12  searches data storage unit  14  for the corresponding file. After locating the file, DSP  12  stores at least a portion of the file in memory unit  16 . In response to user instructions, DSP  12  selects sections of data in memory unit  16  and displays the data on display unit  18 . 
       FIG. 2  is a functional block diagram illustrating a display adjustment system  20  in accordance with an embodiment of the present invention. By way of example, display adjustment system  20  is implemented on electronic device  10  described herein above with reference to  FIG. 1 . In addition to imaging module  11 , display adjustment system  20  includes an eyelevel tracking module  22  and a display adjustment or rotation module  24 . In accordance with an embodiment of the present invention, eyelevel tracking module  22  and display rotation module  24  are implemented in one or more integrated circuit chips. In this embodiment, imaging module  11  is coupled to DSP  12  (shown in  FIG. 1 ) through eyelevel tracking module  22  and display adjustment module  24 . In accordance with an alternative embodiment, eyelevel tracking module  22  and display rotation module  24  are implemented through firmware in a ROM. In accordance with another alternative embodiment, eyelevel tracking module  22  and display rotation module  24  are implemented through software stored in data storage unit  14  shown in  FIG. 1 . 
       FIG. 3  is a schematic diagram illustrating a front view of a display panel  30  in accordance with an embodiment of the present invention. By way of example, display panel  30  is an LCD panel in display unit  18  of electronic device  10  shown in  FIG. 1 . In accordance with an embodiment of the present invention, image sensor  15  in imaging module  11  is installed on display panel  30 .  FIG. 3  shows image sensor  15  being installed in the middle of the topside of display panel  30 . However, this is not intended as a limitation on the scope of the present invention. In accordance to the present invention, image sensor  15  may be disposed on the bottom, on the side, or at a corner of display panel  30 . Furthermore, image sensor  15  is not limited to being installed on display panel  30 . Image sensor may be disposed separately from display panel  30 . For example, image sensor  15  may be placed on a desk and coupled to device  10  through either a wired connection, e.g., a universal serial bus (USB), or a wireless connection, e.g., a wireless connection following the Bluetooth protocol. 
     In a normal mode, a file  32  is displayed in an upright orientation on display panel  30 , so that the a reference line, e.g., a line of text, in file  32 , is substantially parallel to the upside of display panel  30 . When activated, image sensor  15  in imaging module  11  captures an image of the face of the viewer. Signal encoder  17  encodes the image signals generated by image sensor  15  and transmits the encoded digital signal to eyelevel tracking module  22 . Eyelevel tracking module  22  processes the encoded digital signal to identify the pupils of the viewer and calculates the direction of a line connecting the pupils, which may be referred to as an eyelevel line. In accordance with a preferred embodiment of the present invention, eyelevel tracking module  22  calculates an angle between the eyelevel line with the horizontal direction and generates a digital tracking signal indicating the direction of the eyelevel line. When the viewer tilts his head, the eyelevel line would be inclined at an angle with the horizontal direction. Display adjustment module  24  processes the digital tracking signal from eyelevel tracking module  22  and adjust the orientation of file  32  accordingly. For example, in response to the viewer tilting his head to right and eyelevel tracking module  22  detecting an angle of five degrees (5°) between the eyelevel line and the horizontal, display adjustment module  24  generates a command to rotate the display of file  32  to the right for an angle of 5° as indicated by element  33  in  FIG. 3 . 
       FIG. 4  is a flowchart illustrating a display adjustment process  100  in accordance with an embodiment of the present invention. By way of example, display adjustment process  100  may be implemented in electronic device  10  shown in  FIG. 1 . However, this is not intended as a limitation on the scope of the present invention. In accordance with the present invention, process  100  may be implemented in other devices having a display adjustment or rotating system, e.g., display adjustment system  20  as shown in  FIG. 2 . In accordance with a preferred embodiment of the present invention, process  100  tracks the eyelevel of the viewer and adjusts the orientation of the display so that a reference line of the display remains substantially parallel to the eyelevel of the viewer. 
     Display adjustment process  100  starts with displaying a document or a file on a display panel, e.g., display panel  30  in electronic device  10  described supra with reference to  FIGS. 1 and 3 , in a step  102 . Initially, a reference line in the display, e.g., a line of text in a text file, is substantially parallel to a reference line, e.g., the topside, of the display panel. 
     In a step  104 , process  100  captures an image of the face of the viewer including the eyes. In accordance with a preferred embodiment of the present invention, step  104  captures the image through an array of photoelectric light sensors. The photoelectric sensor array generates electric signals in response to light images. A signal encoder encodes the electric signals from the sensor array into data packets describing the image. In accordance with an embodiment of the present invention, step  104  repeatedly captures the image of the viewer&#39;s face at a predetermined rate, e.g., a rate ranging between every 50 milliseconds and every 2 seconds. In accordance with a preferred embodiment, the rate of image capturing rate is adjustable. 
     In a step  106 , process  100  processes the data packets to calculate the direction of an eyelevel line that connects the pupils of the viewer. In accordance with a preferred embodiment, step  106  processes the data packets to track the eyelevel line in an integrated circuit chip. In accordance with another preferred embodiment, step  106  tracks the eyelevel line via a software program implemented in a digital signal processing unit, e.g., DSP  12  in electronic device  10  shown in  FIG. 1 . In accordance with yet another preferred embodiment, step  106  tracks the eyelevel line via an embedded firmware. In accordance with one embodiment of the present invention, step  106  calculates an angle between the eyelevel line and the horizontal direction. In accordance with another embodiment of the present invention, step  106  tracks the change in the direction of the eyelevel line. 
     In a step  109 , process  100  checks whether there is any change in the direction of eyelevel line. In response there is no significant change, process  100  returns to step  104  for capturing the next image of the viewer&#39;s face. In response there is a change in the direction of the eyelevel line beyond a predetermined threshold, process  100  proceeds to a subsequent step  112 . In accordance with the present invention, the threshold can take any value, e.g., 1°, 2°, 3°, 4°, 5°, and so on. In accordance with a preferred embodiment, the threshold can be set to different values to accommodate different viewing habits or preferences of the viewers. In accordance with a preferred embodiment, step  109  is implemented in an integrated circuit in an eyelevel tracking module. In accordance with another preferred embodiment, step  109  is implemented via a software program implemented in a digital signal processing unit, e.g., DSP  12  in electronic device  10  shown in  FIG. 1 . In accordance with yet another preferred embodiment, step  109  is implemented via an embedded firmware. 
     In accordance with one embodiment of the present invention, process  100  proceeds to step  109  every time step  104  calculates a direction of the eyelevel line. In this embodiment, process  100  performs step  106  and subsequent step  109  at the same rate as step  104  capturing the image of the viewer. In accordance with another embodiment, process  100  repeatedly performs step  104  and  106  for a plurality of times, e.g., five time, ten times, etc., before proceeding to step  109 . In this embodiment, step  109  checks whether there is a change in an average direction of the eyelevel line calculated from multiple images captured in step  104  and calculated in step  106 . In accordance with a preferred embodiment, process  100  calculates a weighed average direction of the eyelevel line with a weighing factor favoring later images over earlier images. 
     In step  112 , process  100  calculates the extend of the display adjustment in response to the change in the direction of the eyelevel line. In accordance with one embodiment, step  112  generates a command to rotate the display in the same direction and for an angle substantially equal to the change in the direction of the eyelevel line. In accordance with another embodiment, step  112  rotates the display in the same direction as the rotation of the eyelevel line and for an angle corresponding to a range of angles for the rotation of the eyelevel line. For example, in response to the eyelevel line rotating clockwise for an angle in a range between 1° and 5°, step  112  generates a command to rotate the display clockwise for an angle of 2°. Also by way of example, in response to the eyelevel line rotating counterclockwise for an angle between 6° and 10°, step  112  generates a command to rotate the display counterclockwise for an angle of 8°. In accordance with yet another embodiment, step  112  generates a command to rotate the display so that a reference line in the display remains substantially parallel to the eyelevel line. In accordance with the present invention, step  112  can be implemented through hardware, software, or firmware approaches. 
     In a subsequent step  114 , process  100  executes the command generated in step  112  to adjust or rotate the display on the display panel, e.g., display panel  30  shown in  FIG. 3 . Then process  100  returns to step  114  to capture the next image of the viewer. 
     It should be understood that display adjustment process  100  is not limited to being the same as described herein above. For example, process  100  includes a delay mechanism that adjusts the display only after the eyelevel line changes in direction for a time interval longer than a predetermined value, e.g., three seconds, in accordance with an alternative embodiment of the present invention. In this embodiment, sudden and short movement of viewer will be filtered out and not cause the display to rotate, thereby substantially eliminating the jittering of the display. 
     By now it should be appreciated that a device having a display and a method for adjusting the display to accommodate viewer&#39;s motion have been provided. In accordance with the present invention, an electronic device includes a display adjustment mechanism that rotates the display in response to the change of the eyelevel line of the viewer. Therefore, the viewer would be able to view display in a natural orientation regardless of the viewer&#39;s posture. In accordance with the present invention, the display adjustment mechanism includes an imaging module, an eyelevel tracking module, and a display rotation module. The imaging module includes a photoelectric sensor to capture an image of the viewer with the pupils. The eyelevel tracking module calculates a direction of the eyelevel line connecting the pupils. The display rotation module rotates the display in response to the change in the direction of the eyelevel line. The eyelevel tracking module and the display rotation module can be implemented via software, hardware, of firmware. Therefore, it is cost efficient to implement the display adjustment system in various kinds of devices such as, for example, desktop computers, laptop computers, personal digital assistants, mobile telephones, digital media devices, etc. A display adjustment process in accordance with the present invention adjusts the display to accommodate the movement of the viewer, thereby potentially reducing the fatigue and enhancing the viewing experience. In accordance with the present invention, the adjustment of the display in response to viewer&#39;s movement is automatic without viewer&#39;s intervention. Furthermore, the sensitivity, response time, and extent of the display rotation can be tuned to produce stable display for pleasant viewing. 
     While specific embodiments of the present invention have been described herein above, they are not intended as limitations on the scope of the invention. The present invention encompasses those modifications and variations of the described embodiments that are obvious to those skilled in the art. For example, a display adjustment mechanism in accordance with the present invention is not limited being implemented within an electronic device, e.g., a personal computer. The display adjustment mechanism can be implemented in a stand alone apparatus and connected with the electronic device with a wired or wireless connection.