Abstract:
An electronic device includes a display unit; a memory unit; and a processing unit electrically connected to the display unit and the memory unit, the processing unit capturing (N+M) frames displayed by the display unit, N and M being positive integers, the N frames having a first resolution, the M frames having a second resolution, the first resolution being larger than the second resolution, the processing unit converting a color space of the (N+M) frames and encoding the (N+M) frames, the processing unit magnifying a size of each of the M frames to be equal to a size of each of the N frames, the processing unit encapsulating and outputting the (N+M) frames.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an electronic device, a display system and an image processing method and, more particularly, to an electronic device, a display system and an image processing method capable of outputting frames to a display device smoothly. 
     2. Description of the Prior Art 
     So far lots of electronic devices (e.g. mobile phone, tablet computer, notebook computer, desktop computer, etc.) are equipped with a wireless communication unit (e.g. Wi-Fi module), such that the electronic devices can communicate with a display device (e.g. TV, monitor, projector, etc.) in a wireless manner. Accordingly, a user can output frames displayed by a display unit of the electronic device to other display devices easily and rapidly in a wireless manner, so as to share videos, photos or other multimedia information with his/her family or friends through the display device. 
     In general, the electronic device will continuously capture frames displayed by the display unit, store the frames into buffer areas of a memory unit, retrieve the frames from the buffer areas, convert a color space of the frames, encode and encapsulate the frames, and then output the frames to the display device. So far the frames captured by the prior art all keep a full resolution of the display unit. However, the calculation efficiency is worse when the frames having the full resolution are used for color space conversion. The frame per second (FPS) maybe about 7 to 10 based on the full resolution of different display units. For the structure and characteristic of human eyes, the human eyes will consider that the frames are continuous only when the FPS is larger than 10 to 12. Therefore, the video displayed by the prior art is usually not smooth enough, such that the user may get a bad feeling on watching the video. 
     SUMMARY OF THE INVENTION 
     The invention provides an electronic device, a display system and an image processing method capable of outputting frames to a display device smoothly, so as to solve the aforesaid problems. 
     According to the claimed invention, an electronic device comprises a display unit, a memory unit and a processing unit. The processing unit is electrically connected to the display unit and the memory unit. The processing unit captures (N+M) frames displayed by the display unit, wherein N and M are positive integers, the N frames have a first resolution, the M frames have a second resolution, and the first resolution is larger than the second resolution. The processing unit converts a color space of the (N+M) frames and encodes the (N+M) frames. The processing unit magnifies a size of each of the M frames to be equal to a size of each of the N frames. The processing unit encapsulates and outputs the (N+M) frames. 
     According to the claimed invention, the electronic device further comprises a wireless communication unit electrically connected to the processing unit. The wireless communication unit is used to communicate with a display device in a wireless manner. The processing unit outputs the (N+M) frames to the display device through the wireless communication unit. 
     According to the claimed invention, the first resolution is a full resolution of the display unit, the second resolution is a half resolution of the display unit, and the size of each of the M frames is equal to one-fourth of the size of each of the N frames. 
     According to the claimed invention, the memory unit comprises (N+M) buffer areas for storing the (N+M) frames. 
     According to the claimed invention, the processing unit stores the (N+M) frames into the (N+M) buffer areas interlacedly according to the first resolution and the second resolution. 
     According to the claimed invention, a display system comprises a display device and an electronic device. The electronic device comprises a wireless communication unit, a display unit, a memory unit and a processing unit. The wireless communication unit is used for communicating with the display device in a wireless manner. The processing unit is electrically connected to the wireless communication unit, the display unit and the memory unit. The processing unit captures (N+M) frames displayed by the display unit, wherein N and M are positive integers, the N frames have a first resolution, the M frames have a second resolution, and the first resolution is larger than the second resolution. The processing unit converts a color space of the (N+M) frames and encodes the (N+M) frames. The processing unit magnifies a size of each of the M frames to be equal to a size of each of the N frames. The processing unit encapsulates the (N+M) frames and outputs the (N+M) frames to the display device through the wireless communication unit. 
     According to the claimed invention, the first resolution is a full resolution of the display unit, the second resolution is a half resolution of the display unit, and the size of each of the M frames is equal to one-fourth of the size of each of the N frames. 
     According to the claimed invention, the memory unit comprises (N+M) buffer areas for storing the (N+M) frames. 
     According to the claimed invention, the processing unit stores the (N+M) frames into the (N+M) buffer areas interlacedly according to the first resolution and the second resolution. 
     According to the claimed invention, an image processing method comprises steps of capturing (N+M) frames displayed by a display unit, N and M being positive integers, the N frames having a first resolution, the M frames having a second resolution, the first resolution being larger than the second resolution; converting a color space of the (N+M) frames and encoding the (N+M) frames; magnifying a size of each of the M frames to be equal to a size of each of the N frames; and encapsulating and outputting the (N+M) frames. 
     According to the claimed invention, the first resolution is a full resolution of the display unit, the second resolution is a half resolution of the display unit, and the size of each of the M frames is equal to one-fourth of the size of each of the N frames. 
     According to the claimed invention, the image processing method further comprises step of storing the (N+M) frames into (N+M) buffer areas of a memory unit. 
     According to the claimed invention, the image processing method further comprises step of storing the (N+M) frames into the (N+M) buffer areas interlacedly according to the first resolution and the second resolution. 
     As mentioned in the above, parts of the captured frames have larger resolution (e.g. full resolution of the display unit) and the other parts of the captured frames have smaller resolution (e.g. half resolution of the display unit). The calculation efficiency can be improved effectively when the frames having smaller resolution are used for color space conversion, so as to increase the frame per second (FPS). Accordingly, the electronic device of the invention can output the frames to the display device smoothly. Furthermore, based on the characteristic of persistence of vision, the frames having larger resolution can enable the whole frames to keep good resolution for human eyes. In other words, a video can be displayed smoothly by the invention and the resolution can be kept good simultaneously. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating a display system according to an embodiment of the invention. 
         FIG. 2  is a functional block diagram illustrating the display system shown in  FIG. 1 . 
         FIG. 3  is a functional block diagram illustrating the memory unit shown in  FIG. 2 . 
         FIG. 4  is a flowchart illustrating an image processing method according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 to 4 ,  FIG. 1  is a schematic diagram illustrating a display system  1  according to an embodiment of the invention,  FIG. 2  is a functional block diagram illustrating the display system  1  shown in  FIG. 1 ,  FIG. 3  is a functional block diagram illustrating the memory unit  124  shown in  FIG. 2 , and  FIG. 4  is a flowchart illustrating an image processing method according to an embodiment of the invention. The image processing method shown in  FIG. 4  can be implemented by the electronic device  12  shown in  FIGS. 1 and 2 . 
     As shown in  FIGS. 1 and 2 , the display system  1  comprises a display device  10  and an electronic device  12 . The display device  10  comprises a wireless communication unit  100 , a display unit  102 , a memory unit  104  and a processing unit  106 , wherein the processing unit  106  is electrically connected to the wireless communication unit  100 , the display unit  102  and the memory unit  104 . The electronic device  12  comprises a wireless communication unit  120 , a display unit  122 , a memory unit  124  and a processing unit  126 , wherein the processing unit  126  is electrically connected to the wireless communication unit  120 , the display unit  122  and the memory unit  124 . The wireless communication unit  120  of the electronic device  12  is used for communicating with the wireless communication unit  100  of the display device  10 . 
     In practical applications, the display device  10  may be a TV, monitor, projector, etc.; the electronic device  12  may be a mobile phone, tablet computer, notebook computer, desktop computer, etc.; the wireless communication units  100 ,  120  may be Wi-Fi modules or other wireless communication modules; the display units  102 ,  122  may be liquid crystal display devices or other display devices; the memory units  104 ,  124  may be memories or other storage devices; and the processing units  106 ,  126  may be processors or controllers with data processing function. In general, the display device  10  and the electronic device  12  may be further equipped with some necessary hardware or software components for specific purposes, such as a power supply, an operating system, applications, an input/output module, etc., and it depends on practical applications. 
     When a user wants to output frames displayed by the display unit  122  of the electronic device  12  to the display unit  102  of the display device  10  in a wireless manner, the user has to make the display device  10  and the electronic device  12  communicate with each other through the wireless communication units  100 ,  120  in a wireless manner. Afterward, the processing unit  126  of the electronic device  12  will start to capture frames displayed by the display unit  122  continuously. 
     In this embodiment, the processing unit  126  captures (N+M) frames displayed by the display unit  122  (step S 10  in  FIG. 4 ), wherein N and M are positive integers, the N frames have a first resolution, the M frames have a second resolution, and the first resolution is larger than the second resolution. Furthermore, the memory unit  124  comprises (N+M) buffer areas for storing the (N+M) frames captured by the processing unit  126 . Preferably, the processing unit  126  may store the (N+M) frames into the (N+M) buffer areas of the memory unit  124  interlacedly according to the first resolution and the second resolution. 
     As shown in  FIG. 3 , the memory unit  124  comprises four buffer areas  124   a - 124   d  for storing four frames  14   a - 14   d  captured by the processing unit  126 , wherein two frames  14   a,    14   c  have the first resolution and the other two frames  14   b,    14   d  have the second resolution. The processing unit  126  stores the four frames  14   a - 14   d  into the four buffer areas  124   a - 124   d  of the memory unit  124  interlacedly according to the first resolution and the second resolution. 
     In this embodiment, the first resolution may be a full resolution of the display unit  122  of the electronic device  12  and the second resolution may be a half resolution of the display unit  122  of the electronic device  12 . For example, if the full resolution of the display unit  122  of the electronic device  12  is equal to 1280*800, the first resolution is equal to 1280*800 and the second resolution is equal to 640*400 accordingly. At this time, the size of each of the frames  14   b,    14   d  having the second resolution is equal to one-fourth of the size of each of the frames  14   a,    14   c  having the first resolution. 
     After storing the captured frames  14   a - 14   d  into the buffer areas  124   a - 124   d  of the memory unit  124  sequentially, the processing unit  126  converts a color space of each of the frames  14   a - 14   d  and encodes the frames  14   a - 14   d  (step S 12  in  FIG. 4 ). Then, the processing unit  126  utilizes a digital magnification algorithm to magnify a size of each of the frames  14   b,    14   d  having the second resolution to be equal to a size of each of the frames  14   a,    14   c  having the first resolution (step S 14  in  FIG. 4 ). Finally, the processing unit  126  encapsulates the frames  14   a - 14   d  and outputs the frames  14   a - 14   d  to the display device  10  through the wireless communication unit  120  (step S 16  in  FIG. 4 ). After receiving the frames  14   a - 14   d,  the display device  10  stores the frames  14   a - 14   d  into the memory unit  104 , decodes the frames  14   a - 14   d  by the processing unit  106 , and displays the frames  14   a - 14   d  by the display unit  102 . In this embodiment, the processing unit  106  of the display device  10  may determine that each of the received frames  14   a - 14   d  has the first resolution or the second resolution according to default indices of the buffer areas  124   a - 124   d  or the resolution of each of the frames  14   a - 14   d.    
     The calculation efficiency can be improved effectively when the frames  14   b,    14   d  having smaller second resolution are used for color space conversion, so as to increase the frame per second (FPS). Through practical experiment, when the second resolution is equal to a half of the first resolution, the FPS of the invention may be increased to be 14 to 17 effectively. Accordingly, the electronic device  12  of the invention can output the frames to the display device  10  smoothly. Furthermore, based on the characteristic of persistence of vision, the frames  14   a,    14   c  having larger first resolution can enable the whole frames to keep good resolution for human eyes. In other words, a video can be displayed smoothly by the invention and the resolution can be kept good simultaneously. 
     It should be noted that the frames  14   b,    14   d  having the second resolution may be also stored into the buffer areas  124   a,    124   c  and the frames  14   a,    14   c  having the first resolution may be also stored into the buffer areas  124   b,    124   d.  Furthermore, the invention may also utilize one of the buffer areas  124   a - 124   d  to store a frame having the first resolution and utilize the other three of the buffer areas  124   a - 124   d  to store frames having the second resolution. Moreover, the number of buffer areas of the invention may be adjusted according to practical applications, so the invention is not limited to the embodiment shown in  FIG. 3 . 
     It should be noted that the aforesaid embodiment utilizes only four frames  14   a - 14   d  to depict the features of the invention. However, after the display device  10  and the electronic device  12  communicate with each other through the wireless communication units  100 ,  120  in a wireless manner, the electronic device  12  will perform the steps S 10 -S 16  in  FIG. 4  repeatedly, so as to output frames displayed by the display unit  122  to the display device  10  smoothly. 
     Still further, the control logic of the image processing method shown in  FIG. 4  can be implemented by software. The software can be executed in any electronic devices with data processing function, such as a mobile phone, a tablet computer, a notebook computer, a desktop computer, etc. Needless to say, each part or function of the control logic may be implemented by software, hardware or the combination thereof. 
     As mentioned in the above, parts of the captured frames have larger resolution (e.g. full resolution of the display unit) and the other parts of the captured frames have smaller resolution (e.g. half resolution of the display unit). The calculation efficiency can be improved effectively when the frames having smaller resolution are used for color space conversion, so as to increase the frame per second (FPS). Accordingly, the electronic device of the invention can output the frames to the display device smoothly. Furthermore, based on the characteristic of persistence of vision, the frames having larger resolution can enable the whole frames to keep good resolution for human eyes. In other words, a video can be displayed smoothly by the invention and the resolution can be kept good simultaneously. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.