Patent Publication Number: US-9417059-B2

Title: Distance detecting device and image processing apparatus including the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Korean Patent Application No. 10-2012-0087891, filed on Aug. 10, 2012 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a distance detecting device and an image processing apparatus including the same, and more particularly to a distance detecting device that is capable of easily detecting the distance from an external target and an image processing apparatus including the same. 
     2. Description of the Related Art 
     A request to measure the distance from an external target has been increased. In particular, a request to view a three-dimensional (3D) image, i.e. a stereoscopic image, in addition to a two-dimensional (2D) image has been increased. The distance from an external target may be detected to detect the depth of a 3D image. Various methods of detecting the distance from an external target have been tried. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a distance detecting device that is capable of easily detecting the distance from an external target and an image processing apparatus including the same. 
     In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of a distance detecting device including a first light source to output a first output beam and a second light source to output a second output beam having a wavelength different from that of the first output beam, a scanner to progressively perform first directional scanning and second directional scanning to output the first output beam and the second output beam to an outside, a first detecting unit to convert a first received beam corresponding to the first output beam into a first electric signal, a second detecting unit to convert a second received beam corresponding to the second output beam into a second electric signal, and a controller to detect a distance from an external target based on the first electric signal and the second electric signal. 
     In accordance with another aspect of the present invention, there is provided a distance detecting device including a first light source to output a first output beam and a second light source to output a second output beam having a wavelength identical to that of the first output beam and a polarization direction different from that of the first output beam, a scanner to progressively perform first directional scanning and second directional scanning to output the first output beam and the second output beam to an outside, a light receiving unit to receive a first received beam and a second received beam corresponding to the first output beam and the second output beam from the outside, a first detecting unit to convert the first received beam into a first electric signal, a second detecting unit to convert the second received beam into a second electric signal, and a controller to detect a distance from an external target based on the first electric signal and the second electric signal. 
     In accordance with another aspect of the present invention, there is provided an image processing apparatus including a display unit, a distance detecting unit including a first light source to output a first output beam and a second light source to output a second output beam having a wavelength different from that of the first output beam, a scanner to progressively perform first directional scanning and second directional scanning to output the first output beam and the second output beam to an outside, a first detecting unit to convert a first received beam corresponding to the first output beam into a first electric signal, and a second detecting unit to convert a second received beam corresponding to the second output beam into a second electric signal, the distance detecting unit being configured to detect a distance from an external target based on the first electric signal and the second electric signal, and a controller to control the display unit to display a 3D image using distance information detected by the distance detecting unit. 
     In accordance with yet another aspect of the present invention, there is provided an image processing apparatus including a display unit, a distance detecting unit including a first light source to output a first output beam and a second light source to output a second output beam having a wavelength identical to that of the first output beam and a polarization direction different from that of the first output beam, a scanner to progressively perform first directional scanning and second directional scanning to output the first output beam and the second output beam to an outside, a light receiving unit to receive a first received beam and a second received beam corresponding to the first output beam and the second output beam from the outside, a first detecting unit to convert the first received beam into a first electric signal, and a second detecting unit to convert the second received beam into a second electric signal, the distance detecting unit being configured to detect a distance from an external target based on the first electric signal and the second electric signal, and a controller to control the display unit to display a 3D image using distance information detected by the distance detecting unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a view showing that light for distance detection is projected from an image processing apparatus including a distance detecting device according to an embodiment of the present invention; 
         FIG. 2A  is a view illustrating a scanning method when light is projected from the distance detecting device of  FIG. 1 ; 
         FIG. 2B  is a view illustrating distance information that can be obtained by the distance detecting device of  FIG. 1 ; 
         FIG. 3  is a block diagram showing the internal structure of the distance detecting device of  FIG. 1 ; 
         FIG. 4  is a view showing the internal structure of a distance detecting device according to an embodiment of the present invention; 
         FIGS. 5A and 5B  are views illustrating a distance detecting method of the distance detecting device of  FIG. 3 ; 
         FIG. 6  is a view showing the internal structure of a distance detecting device according to another embodiment of the present invention; 
         FIG. 7  is a view showing the internal structure of a distance detecting device according to yet another embodiment of the present invention; 
         FIG. 8  is a view showing an embodiment in which output beams are scanned by the distance detecting device of  FIG. 1 ; 
         FIG. 9  is a view illustrating that output beams are scanned to an external target according to an output beam scanning method of  FIG. 8 ; 
         FIG. 10  is a view showing another embodiment in which output beams are scanned by the distance detecting device of  FIG. 1 ; 
         FIG. 11  is a view illustrating that output beams are scanned to an external target according to an output beam scanning method of  FIG. 10 ; 
         FIG. 12  is a view showing an embodiment in which a plurality of output beams is scanned by the distance detecting device of  FIG. 1  in an interlaced fashion; 
         FIG. 13  is a block diagram showing the internal structure of a mobile terminal of  FIG. 1 ; and 
         FIG. 14  is a block diagram showing the internal structure of a controller of  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     An image processing apparatus as described in this specification may be an apparatus in which a distance detecting device can be mounted. The image processing apparatus may include a mobile terminal, a television (TV), a set-top box, a media player, a game console, and monitoring camera. Also, the image processing apparatus may include electric home appliances, such as an air conditioner, a refrigerator, a washing machine, a cooking utensil, and a robot cleaner. In addition, the image processing apparatus may include vehicles, such as a bicycle and a car. 
     Meanwhile, a mobile terminal may include a mobile phone, a smart phone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a digital camera, a navigator, a tablet computer, and an e-book terminal. 
     The terms “module” and “unit,” when attached to the names of components, are used herein to help the understanding of the components and thus they should not be considered as having specific meanings or roles. Accordingly, the terms “module” and “unit” may be used interchangeably. 
       FIG. 1  is a view showing that light for distance detection is projected from an image processing apparatus including a distance detecting device according to an embodiment of the present invention. 
     Referring to  FIG. 1 , a mobile terminal  100  is shown as an example of the image processing apparatus. As previously described, a distance detecting device  200  may be mounted in an image processing apparatus, such as a mobile terminal, a TV, a set-top box, a media player, a game console, electric home appliances, and vehicles. Hereinafter, a description will be given based on the mobile terminal  100 . 
     The mobile terminal  100  may include a camera  121  for capturing an image. Also, the mobile terminal  100  may include a distance detecting device  200  for capturing a three-dimensional (3D) image. 
     The camera  121  for acquiring an image of an external target  40  and the distance detecting device  200  for acquiring information regarding the distance from the external target  40  may be provided in a 3D camera  122 . The 3D camera  122  may be a module including the camera  121  and the distance detecting device  200 . 
     Alternatively, the camera  121  and the distance detecting device  200  may be mounted in the mobile terminal  100  as separate modules. 
     In this embodiment, the distance detecting device  200  outputs a plurality of output beams to the external target  40  using a plurality of light sources to output beams of different wavelengths, receives a plurality of received beams scattered or reflected by the external target  40 , and detects a distance using the difference between the output beams and the received beams. In particular, a two-dimensional (2D) scanner capable of progressively performing first directional scanning and second directional scanning is used to output a plurality of output beams to the external target  40 . Consequently, it is not necessary to use a plurality of scanners, and therefore, it is possible to miniaturize the distance detecting device  200 . Also, it is possible to reduce manufacturing cost. A scanner and other components will hereinafter be described with reference to  FIG. 2A . 
       FIG. 2A  is a view illustrating a scanning method when light is projected from the distance detecting device of  FIG. 1 . 
     Referring to  FIG. 2A , the distance detecting device  200  may include a first light source  210 , a second light source  215 , a light reflecting unit  214 , a light wavelength splitting unit  219 , and a scanner  240 . 
     In  FIG. 2A , the number of wavelengths of light output from the distance detecting device  200  is illustrated as being  2 . Accordingly, the first light source  210  and the second light source  215 , which outputs beams of different wavelengths, are illustrated. 
     The first light source  210  and the second light source  215  may output beams of infrared wavelengths as beams of different wavelengths. However, the present invention is not limited thereto. For example, the first light source  210  and the second light source  215  may output beams of visible wavelengths. Hereinafter, a description will be given based on beams of infrared wavelengths. 
     When the intensity of light output from a light source is increased, the visual power of a person, as the external target, may be lowered due to the light incident upon eyes of the person. On the other hand, when the intensity of light output from the light source is decreased, the light is scattered or reflected by the external target, and therefore, the intensity of light received by the distance detecting device  200  may be decreased. As a result, accuracy in information regarding the distance from the external target detected based on the difference between the output light and the received light may be lowered. In this embodiment, a plurality of light sources is used to prevent lowering in visual power of a person and to improve accuracy in detection of information regarding the distance from the external target, thereby solving the above problems. 
     As shown in  FIG. 2A , therefore, two light sources may be used. However, various numbers of light sources may also be used. 
     When light from the first light source  210  and the second light source  215  is projected to the external target, it is important to collimate light. To this end, a laser diode may be used. However, the present invention is not limited thereto. Various examples may be possible. 
     The first light source  210  and the second light source  215  may simultaneously output beams of different wavelengths. 
     A first output beam output from the first light source  210  may be reflected by the light reflecting unit  214 , transmitted through the light wavelength splitting unit  219 , and incident upon the scanner  240 . On the other hand, a second output beam output from the second light source  215  may be reflected by the light wavelength splitting unit  219  and incident upon the scanner  240 . 
     The light wavelength splitting unit  219  may reflect or transmit light based on wavelengths of the light. The light wavelength splitting unit  219  may be realized by, for example, a dichroic mirror. If the wavelength of the first output beam output from the first light source  210  is shorter than that of the second output beam output from the second light source  215 , the light wavelength splitting unit  219  may transmit the first output beam of the shorter wavelength and reflect the second output beam of the longer wavelength. 
     Meanwhile, the scanner  240  may receive the first output beam from the first light source  210  and the second output beam from the second light source  215  and progressively and repeatedly perform first directional scanning and second direction scanning to the outside. 
     As shown in  FIG. 2A , the scanner  240  perform horizontal scanning from left to right, vertical scanning from top to bottom, horizontal scanning from right to left, and vertical scanning from top to bottom with respect to the external target  40  within a region that can be scanned. This scanning operation is repeatedly performed with respect to the entirety of the external target  40 . 
     Meanwhile, the first output beam and the second output beam output to the external target  40  may be scattered or reflected by the external target  40  and incident upon the distance detecting device  200 . For example, the scanner  240  may receive the first received beam corresponding to the first output beam and the second received beam corresponding to the second output beam. 
     The distance detecting device  200  may detect a distance based on the difference between the first and second output beams and the first and second received beams. A distance detection method will hereinafter be described with reference to  FIG. 5A  and the following drawings. 
     Meanwhile, distance information calculated by the distance detecting device  200  may be expressed as a brightness image  65  as shown in  FIG. 2B . Various distance values of the external target  40  may be indicated as corresponding brightness levels. In case of a short distance, a brightness level may be high (bright). In case of a long distance, a brightness level may be low (dark). 
       FIG. 3  is a block diagram showing the internal structure of the distance detecting device of  FIG. 1 . 
     Referring to  FIG. 3 , the distance detecting device  200  may include a first light source  210 , a second light source  215 , a scanner  240 , a first light source driving unit  260 , a second light source driving unit  265 , a scanner driving unit  245 , a controller  270 , a memory  272 , a first detecting unit  280 , and a second detecting unit  285 . 
     The first light source  210  and the second light source  215  output beams of different wavelengths. The first light source  210  may output a first output beam of a first wavelength, and the second light source  215  output a second output beam of a second wavelength. 
     The first light source driving unit  260  may drive the first light source  210  according to a control signal of the controller  270 . For example, when the distance detecting device  200  is operated, the first light source driving unit  260  may output a pulse signal to the first light source  210 . Meanwhile, a pulse amplitude modulation (PAM) type or pulse width modulation (PWM) type pulse signal may be applied to the first light source  210 . As a result, the intensity of light output from the first light source  210  may be decided. 
     Meanwhile, the second light source driving unit  265  may drive the second light source  215  according to a control signal of the controller  270  in a manner similar to the first light source driving unit  260 . For example, when the distance detecting device  200  is operated, the second light source driving unit  265  may output a pulse signal to the second light source  215 . 
     As previously described, the scanner  240  may receive the first output beam from the first light source  210  and the second output beam from the second light source  215  and progressively and repeatedly perform first directional scanning (horizontal scanning) and second direction scanning (vertical scanning) to the outside. 
     The scanner driving unit  245  may control the horizontal scanning and the vertical scanning of the scanner  240 . For example, the scanner driving unit  245  may control the horizontal scanning and the vertical scanning to be performed with respect to a scanning region of the external target  40 . 
     Meanwhile, the scanner driving unit  245  may generate a feedback signal of the horizontal scanning and a feedback signal of the vertical scanning and transmit the generated feedback signals to the controller  270 . The controller  270  may control the scanner driving unit  245  based on the feedback signals so that no error is generated during scanning of the scanner  240 . 
     The first detecting unit  280  converts a first received beam received from the external target  40  into a first electric signal. To this end, the first detecting unit  280  may include a photodiode to convert an optical signal into an electric signal. In particular, the first detecting unit  280  may include a photodiode exhibiting a high photoelectric efficiency, such as an Avalanche photodiode to convert a weak beam scattered by the external target  40  and received from the external target  40  into voltage. 
     The second detecting unit  285  converts a second received beam received from the external target  40  into a second electric signal in a manner similar to the first detecting unit  280 . However, the second detecting unit  285  receives a second received beam, which has a wavelength different from that of the first received beam, and converts the second received beam into a second electric signal unlike the first detecting unit  280 . To this end, the second detecting unit  285  may include a photodiode, particularly an Avalanche photodiode. 
     The controller  270  controls operations of the first light source driving unit  260 , the second light source driving unit  265 , and the scanner driving unit  245 . 
     Meanwhile, the controller  270  receives the first electric signal and the second electric signal from the first detecting unit  280  and the second detecting unit  285  and calculates the distance from the external target  40  based thereupon. 
     Specifically, the controller  270  may calculate first distance information using the difference between the electric signal of the first output beam and the first electric signal of the first received beam. In particular, 2D scanning is progressively performed with respect to the external target  40 , and therefore, first distance information regarding each specific region of the external target  40  may be progressively calculated. 
     On the other hand, the controller  270  may calculate second distance information using the difference between the electric signal of the second output beam and the second electric signal of the second received beam. In particular, 2D scanning is progressively performed with respect to the external target  40 , and therefore, second distance information regarding each specific region of the external target  40  may be progressively calculated. 
     Finally, the controller  270  may final distance information regarding each region of the external target using the calculated first distance information and second distance information. 
     As another example, the controller  270  may add the electric signal of the first output beam and the electric signal of the second output beam, add the first electric signal of the first received beam and the second electric signal of the second received beam, and calculate distance information using the difference between the added electric signals of the output beams and the added electric signals of the received beams. In particular, 2D scanning is progressively performed with respect to the external target  40 , and therefore, distance information regarding each specific region of the external target  40  may be progressively calculated as final distance information. 
     The memory  272  may store data necessary to control various operations of the distance detecting device  200 . In particular, the memory  272  may store the electric signal of the first output beam and the electric signal of the second output beam and output the stored electric signal to the controller  270  for distance calculation. 
     Also, the memory  272  may store distance information regarding each specific region of the external target  40  when distance from the external target  40  is calculated and finally store distance information regarding the entirety of the external target  40 . 
       FIG. 4  is a view showing the internal structure of a distance detecting device according to an embodiment of the present invention. 
     Referring to  FIG. 4 , the distance detecting device may include a first light source  210 , a first condensing unit  212 , a light reflecting unit  214 , a second light source  215 , a second condensing unit  217 , a light wavelength splitting unit  219 , a scanner  240 , a polarized beam converting unit  250 , a second light reflecting unit  255 , a third light reflecting unit  256 , a first detecting unit  280 , a first polarized beam splitting unit  282 , a second detecting unit  285 , and a second polarized beam splitting unit  287 . 
     Hereinafter, a description will be given based on the other units excluding the units (the first light source  210 , the second light source  215 , the scanner  240 , the first detecting unit  280 , and the second detecting unit  285 ) described with reference to  FIG. 3 . 
     The first condensing unit  212  and the second condensing unit  217  collimate output beams output from the first light source  210  and the second light source  215 , respectively. To this end, the first condensing unit  212  and the second condensing unit  217  may include collimate lenses to collimate the beams of the corresponding wavelengths. 
     The first output beam, having passed through the first condensing unit  212 , passes through the first polarized beam splitting unit  282 . 
     In a case in which the first output beam and the first received beam of the same wavelength have different polarized beams, the first polarized beam splitting unit  282  splits advancing directions of the first output beam and the first received beam according to the polarized beam directions thereof. For example, in a case in which the first output beam is an output beam of a P polarized state, the first polarized beam splitting unit  282  transmits the first output beam, and, in a case in which the first reflected beam is a received beam of an S polarized state, the first polarized beam splitting unit  282  reflects the first reflected beam. Afterward, the first polarized beam splitting unit  282  transmits the first received beam to the first detecting unit  280 . This polarized beam splitting unit may be called a polarized beam splitter. 
     On the other hand, the second polarized beam splitting unit  287  is operated in a manner similar to the first polarized beam splitting unit  282 . That is, in a case in which the second output beam and the second received beam of the same wavelength have different polarized beams, the first polarized beam splitting unit  282  splits advancing directions of the second output beam and the second received beam according to the polarized beam directions thereof. For example, in a case in which the second output beam is an output beam of a P polarized state, the second polarized beam splitting unit  287  transmits the second output beam, and, in a case in which the second reflected beam is a received beam of an S polarized state, the second polarized beam splitting unit  287  reflects the second reflected beam. Afterward, the second polarized beam splitting unit  287  transmits the second received beam to the second detecting unit  285 . 
     The light reflecting unit  214  reflects the first output beam having passed through the first polarized beam splitting unit  282  to the scanner  240  and reflects the first received beam received through the scanner  240  to the first polarized beam splitting unit  282 . The light reflecting unit  214  may reflect beams of different wavelengths in addition to the first output beam. To this end, the light reflecting unit  214  may include a total mirror. 
     The light wavelength splitting unit  219  may reflect or transmit light on a per wavelength basis. For example, the light wavelength splitting unit  219  may be realized by a dichroic mirror. Specifically, the light wavelength splitting unit  219  may transmit a beam of a first wavelength and reflect a beam of a second wavelength. 
     Consequently, the light wavelength splitting unit  219  may transmit the first output beam to the scanner  240  and reflect the second output beam to the scanner  240 . 
     Also, the light wavelength splitting unit  219  may transmit the first received beam to the light reflecting unit  214  and reflect the second received beam to the second polarized beam splitting unit  287 . 
     The polarized beam converting unit  250  may convert polarization directions of the output beams and polarization directions of the received beams. 
     For example, the polarized beam converting unit  250  may provide phase difference to control the polarization directions. The polarized beam converting unit  250  may convert a linearly polarized beam into a circularly polarized beam or a circularly polarized beam into a linearly polarized beam. 
     Specifically, the polarized beam converting unit  250  converts the first and second output beams, which are P polarized beams, into first and second output beams of circularly polarized beams. Consequently, the scanner  240  may output the first and second output beams of circularly polarized beams to the outside and receive first and second received beams of circularly polarized beams from the outside. On the other hand, the polarized beam converting unit  250  converts the first and second received beams of circularly polarized beams received through the scanner  240  into first and second received beams of S polarized beams. Consequently, the polarized beam converting unit  250  may be called a quarter wavelength plate. 
     As another example, the polarized beam converting unit  250  may output the first and second output beams of P polarized beam without conversion and convert the first and second received beams of P polarized beams received from the scanner  240  into first and second received beams of S polarized beams. 
     The second light reflecting unit  255  reflects the first output beam having passed through the polarized beam converting unit  250  to the scanner  240  and reflects the first and second received beams received through the scanner  240  to the polarized beam converting unit  250 . The second light reflecting unit  255  may reflect beams of different wavelengths in addition to the first and second output beams. To this end, the second light reflecting unit  255  may include a total mirror. 
     The third light reflecting unit  256  reflects the first and second output beams having passed through the second light reflecting unit  255  to the scanner  240  and reflects the first and second received beams received through the scanner  240  to the second light reflecting unit  255 . The third light reflecting unit  256  may reflect beams of different wavelengths in addition to the first and second output beams. To this end, the third light reflecting unit  256  may include a total mirror. 
     Meanwhile, in the distance detecting device of  FIG. 4 , an optical path of the first and second output beams and an optical path of the first and second received beams may partially overlap. A distance detecting device configured to have a structure in which an optical path of output beams and an optical path of received beams are partially overlap may be called a coaxial optical system. This distance detecting device may have a compact size, may be strong against external light, and may exhibit a high signal to noise ratio. 
     On the other hand, the optical path of the first and second output beams and the optical path of the first and second received beams may be completely separated from each other. A distance detecting device configured to have a structure in which an optical path of output beams and an optical path of received beams are completely separated from each other may be called a separated optical system, which will hereinafter be described with reference to  FIG. 7 . 
       FIGS. 5A and 5B  are views illustrating a distance detecting method of the distance detecting device of  FIG. 3 . 
     The controller  270  of the distance detecting device may calculate distance information based on phase difference, time difference, and pulse counting between an electric signal of an output beam and an electric signal of a received beam. 
       FIG. 5A  illustrates a distance calculating method based on the time difference. In  FIG. 5A , Tx indicates a pulse signal of an output beam, and Rx indicates a pulse signal of a received beam. As shown in  FIG. 5A , a distance information level may be calculated based on the time difference Δt between the pulse signal of the output beam and the pulse signal of the received beam. For example, when the time difference is large, which means that the external target  40  is distant, the distance information level may be set to high, and therefore, a brightness level may be set to low. On the other hand, when the time difference is small, which means that the external target  40  is near, the distance information level may be set to low, and therefore, a brightness level may be set to high. 
     On the other hand, a pulse counting method is similar to  FIG. 5A  except that the pulse counting method uses the number of pulses (pulse counting) based on the difference between repetitive pulses corresponding to an output beam and repetitive pulses corresponding to a received beam. When the number of pulses is large, which means that the external target  40  is distant, the distance information level may be set to high. On the other hand, when the number of pulses is small, which means that the external target  40  is near, the distance information level may be set to low. 
       FIG. 5B  illustrates a distance calculating method based on the phase difference. In  FIG. 5B , Tx indicates a phase signal of an output beam, and Rx indicates a phase signal of a received beam. As shown in  FIG. 5B , a distance information level may be calculated based on the phase difference Φ between the phase signal of the output beam and the phase signal of the received beam. For example, when the phase difference is large, which means that the external target  40  is distant, the distance information level may be set to high. On the other hand, when the phase difference is small, which means that the external target  40  is near, the distance information level may be set to low. 
     Setting of the distance information level is performed with respect to each region of the external target  40  while the horizontal scanning and the vertical scanning are performed with respect to the external target  40  as previously described. That is, it is possible to detect the distance information level with respect to each region of the external target  40 . 
       FIG. 6  is a view showing the internal structure of a distance detecting device according to another embodiment of the present invention 
     The distance detecting device of  FIG. 6  is similar to that of  FIG. 4  except that some units are omitted. That is, the distance detecting device of  FIG. 6  uses a polarized beam splitting unit unlike that of  FIG. 4 . 
     Referring to  FIG. 6 , the distance detecting device may include a first light source  210 , a first condensing unit  212 , a light reflecting unit  214 , a second light source  215 , a second condensing unit  217 , a light wavelength splitting unit  219 , a scanner  240 , a polarized beam converting unit  250 , a second light reflecting unit  255 , a third light reflecting unit  256 , a first detecting unit  280 , a polarized beam splitting unit  283 , and a second light wavelength splitting unit  284 . 
     The first condensing unit  212  and the second condensing unit  217  collimate output beams output from the first light source  210  and the second light source  215 , respectively. 
     The first output beam, having passed through the first condensing unit  212 , is reflected by the light reflecting unit  214  and is transmitted to the light wavelength splitting unit  219 . On the other hand, the second output beam, having passed through the second condensing unit  217 , is transmitted to the light wavelength splitting unit  219 . 
     The light wavelength splitting unit  219  may transmit the first output beam and reflect the second output beam. Afterward, the light wavelength splitting unit  219  may transmit the first output beam and the second output beam to the scanner  240 , specifically to the polarized beam splitting unit  283 . 
     The polarized beam splitting unit  283  may transmit a beam of a P polarized state and reflect a beam of an S polarized state. Consequently, the polarized beam splitting unit  283  transmits the first and second output beams of a P polarized state to the scanner  240  and reflects first and second received beams of an S polarized state to the second light wavelength splitting unit  284 . 
     The polarized beam converting unit  250  may convert polarization directions of the output beams and polarization directions of the received beams as shown in  FIG. 4 . The polarized beam converting unit  250  was previously described in detail with reference to  FIG. 4 , and therefore, a description thereof will be omitted. 
     Meanwhile, the second light wavelength splitting unit  284  may reflect or transmit light on a per wavelength basis. For example, the second light wavelength splitting unit  284  may be realized by a dichroic mirror. Specifically, the second light wavelength splitting unit  284  may reflect a beam of a first wavelength and transmit a beam of a second wavelength. 
     Consequently, the second light wavelength splitting unit  284  may reflect the first received beam to the first detecting unit  280  and transmit the second received beam to the scanner  240  to the second detecting unit  285 . 
     On the other hand, the second light wavelength splitting unit  284  may transmit a beam of a first wavelength and reflect a beam of a second wavelength in the same manner as the light wavelength splitting unit  219 . In this case, the positions of the first detecting unit and the second detecting unit may be changed. 
     The distance detecting device of  FIG. 6 , using a polarized beam splitting unit  283 , may partially separate an optical path of the output beams and an optical path of the received beams from each other. Consequently, the light wavelength splitting unit  219  may transmit or reflect only the output beams, and the second light wavelength splitting unit  284  may transmit or reflect only the received beams. That is, the light wavelength splitting unit  219  may be designed to transmit only a P polarized beam, and the second light wavelength splitting unit  284  may be designed to transmit only an S polarized beam. 
       FIG. 7  is a view showing the internal structure of a distance detecting device according to yet another embodiment of the present invention. 
     Referring to  FIG. 7 , the distance detecting device has a structure in which an optical path of an output beam and an optical path of a received beam are completely separated from each other unlike those of  FIGS. 4 and 6 . 
     Referring to  FIG. 7 , the distance detecting device uses a plurality of light sources, e.g. n light sources LD1, LD2, . . . , and LDn. 
     Consequently, a condensing unit, a light reflecting unit TM, and a plurality of light wavelength splitting units DM1, DM2, and DM(n−1) are used with respect to the n light sources. 
     A plurality of output beams output from the plurality of light sources is transmitted to the scanner  240  via the plurality of light wavelength splitting units. The scanner  240  outputs the plurality of output beams to an external target through horizontal scanning and vertical scanning. 
     Beams scattered or reflected by the external target are received through a light receiving unit  292 , not the scanner  240 . The received beams are transmitted to corresponding detecting units PD1, PD2, . . . , and PDn via n light wavelength splitting units DMa, DMb, . . . , and DMn. 
     Meanwhile, in  FIG. 7 , the output beams are output along path  1 , the received beams are received along path  2 . Consequently, the optical path of the output beams and the optical path of the received beams are completely separated from each other. That is, a light output unit  710  and a light receiving unit  720  are completely separated from each other. 
     As a result, the polarized beam converting unit  250  described with reference to  FIGS. 4 and 6  may be used. 
     Meanwhile, since the optical paths are separated from each other, a beam output from the first light source may be a P polarized output beam of a first wavelength, and a beam output from the second light source may be an S polarized output beam of a first wavelength. That is, even beams having the same wavelength may be output from different light sources if the beams having the same wavelength have different polarization directions. 
     In this case, it is necessary for the light wavelength splitting units DMa and DMb of  FIG. 7  to perform slitting based on the polarization, not based on the wavelength. For this reason, the light wavelength splitting units DMa and DMb may be replaced by polarized beam splitting units. 
     The polarized beam splitting unit DMa may reflect the P polarized output beam of the first wavelength to the first detecting unit PD1 and transmit the S polarized output beam of the first wavelength to the polarized beam splitting unit DMb. 
     Also, the light wavelength splitting unit DMb may reflect an S polarized received beam of the first wavelength to the second detecting unit PD2 and transmit a beam of the other wavelength to the light wavelength splitting unit DMc. 
     Hereinafter, various methods of improving resolution during scanning of the distance detecting device according to the embodiment of the present invention will be discussed. 
     Referring to  FIG. 2A , the 2D scanner  240  receives the first output beam from the first light source  210  and the second output beam from the second light source  215  and output the first and second output beams to the external target as multiple beams. That is, the 2D scanner  240  performs horizontal scanning at a horizontal scanning frequency and vertical scanning at a vertical scanning frequency. At this time, the horizontal scanning and the vertical scanning may be progressively and repeatedly performed. 
     A horizontal scanning frequency fh of the first and second output beams output from the 2D scanner  240  may be defined as Mathematical expression 1 below. 
     
       
         
           
             
               
                 
                   fh 
                   = 
                   
                     number 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     of 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     vertical 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     lines 
                     ⁢ 
                     
                         
                     
                     × 
                     
                       fv 
                       2 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Mathematical 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     expression 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     1 
                   
                   ] 
                 
               
             
           
         
       
     
     where, fv is a vertical scanning frequency. 
     For example, the vertical scanning frequency fv may be a frequency corresponding to a screen refresh rate, for example, 60 Hz. 
     The horizontal scanning frequency fh of interlaced scan may be half that of progressive scan. 
     In order to increase the horizontal scanning frequency, it is necessary to increase the size of the 2D scanner or considerably reducing the size of a mirror provided in the 2D scanner. 
     Meanwhile, Table 1 below shows a relationship among resolution, horizontal scanning frequency, and vertical scanning frequency. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 Horizontal 
                 Vertical 
                   
               
               
                   
                   
                 scanning 
                 scanning 
                 Refresh 
               
               
                 No 
                 Resolution 
                 frequency 
                 frequency 
                 rate 
               
               
                   
               
             
            
               
                 1 
                 QVGA (320 × 
                  7200 Hz 
                 60 Hz 
                 60 Hz 
               
               
                   
                 240) 
               
               
                 2 
                 VGA (6400 × 
                 14400 Hz 
                 60 Hz 
                 60 Hz 
               
               
                   
                 480) 
               
               
                 3 
                 WVGA (800 × 
                 14400 Hz 
                 60 Hz 
                 60 Hz 
               
               
                   
                 480) 
               
               
                 4 
                 SVGA (800 × 
                 18000 Hz 
                 60 Hz 
                 60 Hz 
               
               
                   
                 600) 
               
               
                 5 
                 XGA (1024 × 
                 23040 Hz 
                 60 Hz 
                 60 Hz 
               
               
                   
                 768) 
               
               
                   
               
            
           
         
       
     
     It can be seen from Table 1 that the horizontal scanning frequency is increased as the resolution of an external target is increased. 
     Hereinafter, a description will be given of a distance detecting device that is capable of increasing the resolution of output beams (multiple beams) output to the external target without increasing the horizontal scanning frequency. 
       FIGS. 8 and 9  illustrate horizontal scanning of output beams output from the respective light sources with respect to different horizontal lines, and  FIGS. 10 and 11  illustrate horizontal scanning of output beams output from the respective light sources with respect to different scanning regions. 
       FIG. 8  is a view showing an embodiment in which output beams are scanned by the distance detecting device of  FIG. 1 . 
     Referring to  FIG. 8 , a plurality of output beams  801 ,  802 , and  803  output from a plurality of light sources is incident upon the 2D scanner  240  of the distance detecting device according to the embodiment of the present invention at different incident angles. 
     In a case in which, for example, 3 output beams are output, a first output beam (Beam 1)  801  may be incident upon the 2D scanner  240  at an incident angle θ1, a second output beam (Beam 2)  802  may be incident upon the 2D scanner  240  at an incident angle θ2, and a third output beam (Beam 3)  803  may be incident upon the 2D scanner  240  at an incident angle θ3. 
     The 2D scanner  240  outputs the incident output beams to the external target as a plurality of output beams having different exit angles through 2D scanning. That is, the 2D scanner  240  may perform horizontal scanning with respect to the different horizontal lines using the output beams output from the respective light sources. 
     According to embodiments, the number of output beams scanned is not limited. Hereinafter, an embodiment using the 2D scanner  240  will be described. However, the present invention may be applied to a case in which one-dimensional (1D) scanner, such as a vertical or horizontal scanner. 
     For example, the 2D scanner  240  may output the first output beam  801  incident at the incident angle θ1 to the external target as a first output beam  804  having an exit angle θ4 to scan the external target. 
     Also, the 2D scanner  240  may output the second output beam  802  incident at the incident angle θ2 to the external target as a second output beam  805  having an exit angle θ5 to scan the external target. 
     Also, the 2D scanner  240  may output the third output beam  803  incident at the incident angle θ3 to the external target as a third output beam  806  having an exit angle θ6 to scan the external target. 
     At this time, the output beams  804 ,  805 , and  806  may be scanned with respect to the external target. The output beams  804 ,  805 , and  806  may be scanned at the same horizontal scanning frequency and vertical scanning frequency. 
     Also, intervals of the output beams  804 ,  805 , and  806  output to the external target may be set in a per pixel basis. For example, the output beams  804 ,  805 , and  806  output to the external target may be scanned at intervals of 1 pixel. 
     According to embodiments, in order to uniformalize the intervals of the output beams  804 ,  805 , and  806 , differences among exit angles of the output beams may be set to be uniform. 
     For example, in order to set the intervals of the output beams  804 ,  805 , and  806  to 1 pixel, a difference value between the exit angle θ4 and the exit angle θ5 and a difference value between the exit angle θ5 and the exit angle θ6 may be set to be uniform. 
       FIG. 9  is a view illustrating that output beams are scanned to the external target according to the output beam scanning method of  FIG. 8 . 
     Referring to  FIG. 9 , the distance detecting device according to the embodiment of the present invention may output a plurality of output beams  804 ,  805 , and  806  having different exit angles to the external target through 2D scanning. 
     Consequently, the distance detecting device according to the embodiment of the present invention may simultaneously scan output beams to form a plurality of scanning lines. Consequently, it is possible to obtain a depth of the external target at high resolution without increasing the horizontal scanning frequency. 
     For example, referring to Table 1 above, a resolution is 320×240 at a horizontal scanning frequency of 7200 Hz in a case in which the output beams are not scanned. On the other hand, in a case in which the output beams are simultaneously scanned to form a plurality of scanning lines according to the embodiment of the present invention, it is possible to increase a resolution to 800×600 at a horizontal scanning frequency of 7200 Hz. 
     Also, in the distance detecting device according to the embodiment of the present invention, output beams generated using a plurality of light sources are scanned to the target, and therefore, it is possible to obtain a depth of the external target at high resolution without modifying the scanner. 
       FIG. 10  is a view showing another embodiment in which output beams are scanned by the distance detecting device of  FIG. 1 . 
     Referring to  FIG. 10 , a plurality of output beams  1001 ,  1002 , and  1003  output from a plurality of light sources is incident upon the 2D scanner  240  of the distance detecting device according to the embodiment of the present invention at different incident angles. 
     In a case in which, for example, 3 output beams are output, a first output beam (Beam 1)  1001  may be incident upon the 2D scanner  240  at an incident angle θ1, a second output beam (Beam 2)  1002  may be incident upon the 2D scanner  240  at an incident angle θ2, and a third output beam (Beam 3)  1003  may be incident upon the 2D scanner  240  at an incident angle θ3. 
     The 2D scanner  240  outputs the incident output beams to an external target as a plurality of output beams having different exit angles through 2D scanning. That is, the 2D scanner  240  may perform horizontal scanning with respect to the different scanning regions using the output beams output from the respective light sources. 
     According to embodiments, the number of output beams scanned is not limited. Hereinafter, an embodiment using the 2D scanner  240  will be described. However, the present invention may be applied to a case in which one-dimensional (1D) scanner, such as a vertical or horizontal scanner. 
     For example, the 2D scanner  240  may output the first output beam  1001  incident at the incident angle θ1 to the external target as a first output beam  1004  having an exit angle θ4 to scan the external target. 
     Also, the 2D scanner  240  may output the second output beam  1002  incident at the incident angle θ2 to the external target as a second output beam  1005  having an exit angle θ6 to scan the external target. 
     Also, the 2D scanner  240  may output the third output beam  1003  incident at the incident angle θ3 to the external target as a third output beam  1006  having an exit angle θ5 to scan the external target. 
     At this time, the output beams  1004 ,  1005 , and  1006  may be simultaneously scanned with respect to the corresponding scanning regions  1007 ,  1008 , and  1009 . The output beams  1004 ,  1005 , and  1006  may be scanned at the same horizontal scanning frequency and vertical scanning frequency. 
     Also, the scanning regions of the external target, to which the output beams  1004 ,  1005 , and  1006  are output, may be variously set according to embodiments. Also, the exit angles of the output beams  1004 ,  1005 , and  1006  may be set based on the scanning regions. 
       FIG. 11  is a view illustrating that output beams are scanned to an external target according to the output beam scanning method of  FIG. 10 . 
     Referring to  FIG. 11 , the distance detecting device according to the embodiment of the present invention may output a plurality of output beams  1004 ,  1005 , and  1006  having different exit angles to corresponding scanning regions  1007 ,  1008 , and  1009  of the external target through 2D scanning. 
     The output beams  1004 ,  1005 , and  1006  may be simultaneously scanned with respect to the corresponding scanning regions  1007 ,  1008 , and  1009  of the external target. The output beams  1004 ,  1005 , and  1006  may be scanned at the same horizontal scanning frequency and vertical scanning frequency. 
     Consequently, the distance detecting device according to the embodiment of the present invention may simultaneously scan output beams to the respective scanning regions to form a plurality of scanning lines. Consequently, it is possible to obtain a depth of the external target at high resolution without increasing the horizontal scanning frequency. 
       FIG. 12  is a view showing an embodiment in which a plurality of output beams is scanned by the distance detecting device of  FIG. 1  in an interlaced fashion. 
     Referring to  FIG. 12 , the 2D scanner according to the embodiment of the present invention may scan a plurality of output beams to an odd frame  1201  and a plurality of output beams to an even frame  1202  to form a superposed frame  1203 . During scanning of the odd frame  1201 , odd lines are scanned. During scanning of the even frame  1202 , even lines are scanned. 
     At this time, the 2D scanner may output the output beams in the same manner as shown in  FIG. 8 . 
     Also, line intervals of the output beams scanned to the odd frame  1201  and the even frame  1202  may be equal. For example, intervals of a plurality of output beams output to the odd frame  1201  and the even frame  1202  may be set on a per pixel basis. For example, a plurality of output beams scanned to the odd frame  1201  and the even frame  1202  may be scanned at intervals of 1 pixel. 
     In order to uniformalize the intervals of a plurality of output beams output to the odd frame  1201  and the even frame  1202 , differences among exit angles of a plurality of output beams output from the 2D scanner  240  may be set to be uniform as previously described. 
     For example, in order to set the intervals of the output beams  804 ,  805 , and  806  to 1 pixel, a difference value between the exit angle θ4 and the exit angle θ5 and a difference value between the exit angle θ5 and the exit angle θ6 may be set to be uniform. 
     In a case in which the superposed frame includes the odd frame and the even frame, scanning phase difference between the odd frame  1201  and the even frame  1202  may be π. 
     Consequently, the distance detecting device according to the embodiment of the present invention scans the plurality of output beams to the odd frame and the even frame to form the superposed frame. Consequently, the distance detecting device according to the embodiment of the present invention outputs the output beams in an interlaced scanning fashion at improved resolution, thereby increasing a refresh rate. 
     For example, in a conventional distance detecting device having a horizontal scanning frequency of 7200 Hz, a vertical scanning frequency (refresh rate) of 60 Hz, and 480 vertical lines, the refresh rate is reduced to increase a vertical resolution to 576 lines, or it is necessary to use a scanner having a vertical resolution of 576 lines. 
     When the refresh rate is reduced, however, depth detecting accuracy may be lowered. 
     In the distance detecting device according to the embodiment of the present invention, on the other hand, the output beams are scanned to the odd frame and the even frame to form the superposed frame. Consequently, it is possible to increase a vertical resolution to 576 lines while increasing a vertical scanning frequency (refresh rate) to 100 Hz at the same horizontal scanning frequency of 7200 Hz. 
     Consequently, the embodiment of the present invention has the effect of detecting depth of the external target at high resolution without increasing the horizontal scanning frequency. 
       FIG. 13  is a block diagram showing the internal structure of the mobile terminal of  FIG. 1 . 
     Referring to  FIG. 13 , the mobile terminal  100  may include a wireless communication unit  110 , an audio/video (A/V) input unit  120 , a user input unit  130 , a sensing unit  140 , an output unit  150 , a memory  160 , an interface unit  170 , a controller  180 , and a power supply unit  190 . 
     The wireless communication unit  110  may include a broadcast receiving module  111 , a mobile communication module  113 , a wireless Internet module  115 , a near field communication (NFC) module  117 , and a global positioning system (GPS) module  119 . 
     The broadcast receiving module  111  may receive a broadcast signal and/or broadcast-related information from an external broadcast management server through a broadcast channel. Here, the broadcast channel may include a satellite channel and a terrestrial channel. 
     The broadcast signal and/or broadcast-related information received through the broadcast receiving module  111  may be stored in the memory  160 . 
     The mobile communication module  113  transmits and receives a wireless signal to and from at least one selected among from a base station, an external terminal, and a server on a mobile communication network. Here, the wireless signal may include a voice call signal, a video communication call signal, and various types of data based on text/multimedia message transmission and reception. 
     The wireless Internet module  115  is a module for wireless Internet connection. The wireless Internet module  115  may be mounted inside or outside the mobile terminal  100 . 
     The NFC module  117  may perform a near field communication. In a case in which the NFC module  117  is within a predetermined distance from an NFC device (not shown), i.e. the NFC module  117  performs tagging, the NFC module  117  may receive data from the NFC device. 
     The GPS module  119  may receive position information from a plurality of GPS artificial satellites, 
     The A/V input unit  120  is provided for audio signal or video signal input. The A/V input unit  120  may include a camera  121 , a distance detecting unit  200 , and a microphone  123 . 
     The distance detecting unit  200  according to the embodiment of the present invention may be a subminiature distance detecting device as shown in  FIG. 4, 6 , or  7 . Also, the distance detecting unit  200  according to the embodiment of the present invention may be a distance detecting device adopting the scanning method as shown in  FIGS. 8 and 9  or  FIGS. 10 and 11 . Meanwhile, the distance detecting unit  200  may be provided in a 3D camera  122  together with the camera  121 . 
     Meanwhile, the calculated distance information may be transmitted to the controller  180  so that calculated distance information is used to display, particularly, a 3D image during the reproduction of multimedia or is transmitted to the outside. 
     The user input unit  130  generates key input data input by a user to control the operation of the terminal. To this end, the user input unit  130  may include a key pad, a dome switch, and a touch pad (static pressure or electrostatic). Particularly in which the touch pad forms a layered structure together with a display unit  151 , which will hereinafter be described, an assembly of the touch pad and the display unit  151  may be called a touch screen. 
     The sensing unit  140  may sense the present state of the mobile terminal  100 , such as an open or closed state of the mobile terminal  100 , the position of the mobile terminal  100 , and whether user contact has been performed, to generate a sensing signal to control the operation of the mobile terminal  100 . 
     The sensing unit  140  may include a proximity sensor  141 , a pressure sensor  143 , and a motion sensor  145 . The motion sensor  145  may sense the motion or position of the mobile terminal  100  using an acceleration sensor, a gyro sensor, and a gravity sensor. In particular, the gyro sensor is a sensor to measure angular velocity. The gyro sensor may sense a direction (angle) rotated from a reference direction. 
     The output unit  150  may include a display unit  151 , an acoustic output module  153 , an alarm unit  155 , and a haptic module  157 . 
     The display unit  151  outputs, i.e., displays, information processed by the mobile terminal  100 . 
     Meanwhile, in a case in which the display unit  151  and the touch pad are disposed as a layered structure to form a touch screen as previously described, the display unit  151  may be used as an input device that allows a user to input information by touch in addition to an output device. 
     The acoustic output module  153  outputs audio data received from the wireless communication unit  110  or stored in the memory  160 . The acoustic output module  153  may include a speaker and a buzzer. 
     The alarm unit  155  outputs a signal to inform generation of an event of the mobile terminal  100 . For example, the alarm unit  155  may output signal in the form of vibration. 
     The haptic module  157  generates various tactile effects that a user can feel. A representative example of the tactile effects generated by the haptic module  157  is a vibration effects. 
     The memory  160  may store a program for processing or controlling of the controller  180  or temporarily store input or output data (for example, phonebooks, messages, still images, motion images, etc.). 
     The interface unit  170  interfaces between the mobile terminal  100  and all external devices connected to the mobile terminal  100 . The interface unit  170  may receive data or power from the external devices and transmit the received data or power to the respective components of the mobile terminal  100 . Also, data from the mobile terminal  100  may be transmitted to the external devices via the interface unit  170 . 
     The controller  180  controls operations of the respective components of the mobile terminal  100 , thereby controlling overall operation of the mobile terminal  100 . For example, the controller  180  may perform control or processing for voice communication, data communication, and video communication. Also, the controller  180  may include a multimedia reproduction module  181  to reproduce multimedia. The multimedia reproduction module  181  may be incorporated into the controller  180  in the form of hardware. Alternatively, the multimedia reproduction module  181  may be configured in the form of software separately from the controller  180 . The operation of the controller  180  for multimedia reproduction will hereinafter be described in detail with reference to  FIG. 14 . 
     The power supply unit  190  supplies external power or internal power to the respective components of the mobile terminal  100  under control of the controller  180 . 
     The mobile terminal  100  with the above-stated construction may be configured such that the mobile terminal  100  can be operated in a communication system that is capable of data through frames or packets, including a wired or wireless communication system and a satellite-based communication system. 
     The block diagram of  FIG. 13  shows the components constituting the mobile terminal  100  according to the embodiment of the present invention. The respective components in the block diagram may be integrated, added, or omitted according to the specification of an actually realized mobile terminal  100 . That is, two or more components may be combined into a single unit as needed, or one component may be divided into two or more components as needed. Also, functions performed by the respective blocks are illustrated to describe the embodiment of the present invention, and therefore, concrete operations or devices of the respective blocks do not restrict the right scope of the present invention. 
       FIG. 14  is a block diagram showing the internal structure of the controller of  FIG. 13 . 
     Referring to  FIG. 14 , the controller  180  according to the embodiment of the present invention may include a demultiplexing unit  310 , an image processing unit  320 , a processor  330 , an on screen display (OSD) generation unit  340 , a mixer  345 , a frame rate converter  350 , and a formatter  360  for multimedia reproduction. In addition, the controller  180  may include an audio processing unit (not shown) and a data processing unit (not shown). 
     The demultiplexing unit  310  demultiplexes an input stream. For example, in a case in which MPEG-2 TS is input, the demultiplexing unit  310  may demultiplex the input MPEG-2 TS into image, voice, and data signals. Here, the stream signal input to the demultiplexing unit  310  may be a stream signal output from the broadcast receiving module  111 , the wireless Internet module  115 , or the interface unit  170 . 
     The image processing unit  320  may perform image processing with respect to the demultiplexed image signal. To this end, the image processing unit  320  may include an image decoder  325  and a scaler  335 . 
     The image decoder  325  decodes the demultiplexed image signal. The scaler  335  may scale resolution of the decoded image signal in consideration of an image output from the display unit  151 . 
     The image decoder  325  may include decoders of different standards. 
     The processor  330  may control overall operation of the mobile terminal  100  or the controller  180 . For example, the processor  330  may control the broadcast receiving module  111  to tune a radio frequency (RF) broadcast corresponding to a channel selected by a user or a previously stored channel. 
     Also, the processor  330  may control the mobile terminal  100  according to user command input through the user input unit  130  or an internal program. 
     Also, the processor  330  may control data transmission to a network interface unit  135  or the interface unit  170 . 
     Also, the processor  330  may control operations of the demultiplexing unit  310 , the image processing unit  320 , and the OSD generation unit  340  in the controller  180 . 
     The OSD generation unit  340  generates an OSD signal according to user input or even without user input. For example, the OSD generation unit  340  may generate a signal to display various kinds of information in the form of graphs or text in an image output to the display unit  1551  based on a user input signal. The generated OSD signal may include various kinds of data, such as a user interface screen, various menu screens, widgets, and icons. Also, the generated OSD signal may include 2D objects or 3D objects. 
     The mixer  345  may mix the OSD signal generated by the OSD generation unit  340  and the image signal decoded through image processing of the image processing unit  320 . The mixed image signals are transmitted to the frame rate converter  350 . 
     The frame rate converter (RFC)  350  may convert a frame rate of the input image. On the other hand, the frame rate converter  350  may directly output the input image without frame rate conversion. 
     The formatter  360  may receive the signals mixed by the mixer  345 , i.e. the OSD signal and the decoded image signal, change formats of the signals so that the signals are suitable for the display unit  151 , and output the signals, the formats of which have been changed. 
     Also, the formatter  360  may divide a 2D image signal and a 3D image signal from each other for 3D image display. Also, the formatter  360  may change the format of the 3D image signal or convert the 2D image signal into the 3D image signal. 
     Meanwhile, the formatter  360  may use the distance information calculated by the distance detecting unit  200  during 3D image display. Specifically, when the size of a distance information level is large, which means that an external target is distant, the formatter  360  may set a depth information level to low. That is, the formatter  360  may set the depth information level so that the depth information level is inversely proportional to the distance information level. Also, the formatter  360  may change a 2D image into a 3D image using the depth information and output the 3D image. 
     When the external target is distant, and the distance information level is high, therefore, the formatter  360  may set the depth information level to low so that the external target is depressed during 3D image display. On the other hand, when the external target is near, and the distance information level is low, therefore, the formatter  360  may set the depth information level to high so that the external target protrudes during 3D image display. 
     Meanwhile, the audio processing unit (not shown) in the controller  180  may perform voice processing with respect to the demultiplexed voice signal. To this end, the audio processing unit (not shown) may include various decoders. 
     Also, the audio processing unit (not shown) in the controller  180  may adjust base, treble, and volume. 
     In  FIG. 14 , the signals from the OSD generation unit  340  and the image processing unit  320  are mixed by the mixer  345  and are 3D processed by the formatter  360 . However, the present invention is not limited thereto. For example, the mixer may be disposed after the formatter. That is, the output of the image processing unit  320  may be 3D processed by the formatter  360 , the OSD generation unit  340  may perform 3D processing together with OSD generation, and the respectively processed 3D signals may be mixed by the mixer  345 . 
     The block diagram of  FIG. 14  shows the components constituting the controller  180  according to the embodiment of the present invention. The respective components in the block diagram may be integrated, added, or omitted according to the specification of an actually realized controller  180 . 
     In particular, the frame rate converter  350  and the formatter  360  may not be disposed in the controller  180  but may be separately provided. 
     Constructions and methods of the embodiments as previously described are not limitedly applied to the image processing apparatus including the distance detecting device according to the embodiment of the present invention. All or some of the embodiments may be selectively combined so that the embodiments can be variously modified. 
     As is apparent from the above description, a distance detecting device according to an embodiment of the present invention or an image processing apparatus including the distance detecting device outputs a plurality of beams to an external target using a plurality of light sources having different wavelengths, receives a plurality of beams scattered or reflected by the external target, and detects the distance from the external target using the difference between the output beams and the received beams. 
     In particular, a 2D scanner capable of progressively performing first directional scanning and second directional scanning is used to output a plurality of output beams to the outside. Consequently, it is not necessary to use a plurality of scanners, and therefore, it is possible to miniaturize the distance detecting device. Also, it is possible to reduce manufacturing cost. 
     Also, a laser diode is used as each light source. Consequently, it is possible to increase a measurable distance and to improve distance resolution. 
     Also, since a plurality of light sources is used, it is possible to adjust the intensity of light output from the light sources so that the output light does not have a harmful influence on a human body and to improve accuracy in detecting distance information. 
     Also, in a case in which a plurality of light sources having different wavelengths is used, polarization directions of output beams and received beams are differently set so that a path of the output beams and a path of the received beams overlap, thereby miniaturizing the distance detecting device. 
     Also, when polarization directions of output beams and received beams are differently set in a case in which a plurality of light sources having different wavelengths is used, it is possible to use only a polarized beam splitting unit that can be commonly used for the output beams and the received beams, thereby reducing manufacturing cost. 
     In accordance with an embodiment of the present invention, output beams output from the respective light sources are horizontally scanned with respect to different horizontal lines. Consequently, it is possible to obtain a depth of an external target at high resolution without increasing a horizontal scanning frequency. 
     In accordance with another embodiment of the present invention, output beams output from the respective light sources are scanned with respect to different scanning regions. Consequently, it is possible to obtain a depth of an external target at high resolution without increasing a horizontal scanning frequency. 
     A distance detecting device according to yet another embodiment of the present invention or an image processing apparatus including the distance detecting device outputs a plurality of output beams to an external target using first and second light sources having the same wavelengths and different polarization directions, receives a plurality of received beams scattered or reflected by the external target, and detects the distance from the external target using the difference between the output beams and the received beams. In this case, a path of the output beams and a path of the received beams are separated from each other, and it is possible to improve accuracy in detecting the distance. 
     Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.