Patent Publication Number: US-2012026286-A1

Title: Electronic Apparatus and Image Processing Method

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2010-168553, filed on Jul. 27, 2010, the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments described herein relate generally to an electronic apparatus and an image processing method. 
     BACKGROUND 
     Owing to technological progress in recent years, electronic apparatuses capable of displaying 3D videos for users have been proposed. There are two example methods for realizing the 3D videos. A first example is a frame-sequential scheme, in which an image for the left eye and an image for the right eye are alternately displayed for the user wearing shutter glasses configured to show the image for the left eye to only the left eye and show the image for the right eye to only the right eye, respectively. 
     A second example is a scheme, in which pixels for the left eye and pixels for the right eye as exist within one frame are displayed for the user of naked eyes while using a panel configured to show only the pixels for the left eye to the left eye and show only the pixels for the right eye to the right eye, simultaneously. 
     For example, when displaying the 3D video by the above schemes, the electronic apparatus may be required to perform processes different from those in the case of displaying general 2D video. 
     For example, when performing an image processing on pixels in a frame with reference to pixels in preceding and succeeding frames, an electronic apparatus may be required to perform different processes for a 2D video and for a 3D video. In other words, the 3D video could not be treated only by image processing modules for the 2D video. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A general architecture that implements the various feature of the present invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the present invention and not to limit the scope of the present invention. 
         FIG. 1  illustrates a video output system in an embodiment. 
         FIG. 2  illustrates system configurations of a DTV and shutter glasses in the embodiment. 
         FIG. 3  illustrates a functional block configuration of a video process portion in the embodiment. 
         FIG. 4  illustrates a functional block configuration of a movie-noise reduction process portion in the embodiment. 
         FIG. 5  schematically illustrates the sequence of frame-sequential frames which are delivered alternately for the right eye and the left eye. 
         FIG. 6  illustrates a movie-noise reduction process in the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In general, according to one embodiment, there is provided an electronic apparatus, including: a movie-noise reduction processor configured to successively perform a movie-noise reduction process on an input luminance signal to thereby generate an output luminance signal, the output luminance signal being generated based on the input luminance signal and another output luminance signal having been generated; a frame memory configured to store the output luminance signals; and a signal entry module configured to determine whether or not the input luminance signal is of a 3D video, to select one of the output luminance signals stored in the frame memory such that a frame associated with a selected one of the output luminance signals has no parallax with a frame associated with the input luminance signal, and to enter the selected one of the output luminance signals into the movie-noise reduction processor as the another output luminance signal. 
     Embodiments will be described with reference to the drawings below. 
       FIG. 1  illustrates a video output system  3  in an embodiment. A DTV  1 , shutter glasses  2  and the video output system  3  are shown in  FIG. 1 . 
     In this embodiment, the DTV  1  such as a digital television is exemplified as an electronic apparatus. The DTV  1  is capable of displaying a 3D video to a user who wears the shutter glasses  2 , by alternately displaying an image for the left eye (left-eye image) and an image for the right eye (right-eye image) as have a parallax therebetween (frame-sequential scheme). While the DTV  1  is exemplified as the electronic apparatus in this embodiment, any of various apparatuses such as a DVD (Digital Versatile Disk) player, an HDD (Hard Disk Drive) player, an STB (Set Top Box) and a PC (Personal Computer) can be used as the electronic apparatus. 
     The shutter glasses  2  have shieldable (closable) liquid-crystal shutters for a lens for the left eye and a lens for the right eye, respectively, and the lenses and the shutters may be called the “lens units” in combination. The shutter glasses  2  realize the 3D video for the user by opening/closing the respective shutters of the left and right lens units at different timings based on shutter opening/closing signals which are received from the DTV  1 . For example, when the left-eye image is displayed on the DTV  1 , the shutter of the lens unit for the right eye is closed (brought into a shield state) and the shutter of the lens unit for the left eye is opened (brought into a transmission state), based on the opening/closing signals from the DTV  1 , thereby to show the left-eye image to only the left eye of the user. Besides, when the right-eye image is displayed, the shutter of the lens unit for the left eye is closed and the shutter of the lens unit for the right eye is opened, thereby to show the right-eye image to only the right eye of the user. Owing to these operations, the user perceives the video as a 3D video. 
     The principle for realizing the above 3D video will be described. A human usually looks at an object by the left eye and the right eye of different positions, respectively, and a parallax exists between images watched by the left eye and the right eye. The human can recognize the object looked at, as a 3D object in such a way that the image watched by the left eye and the image watched by the right eye as have the parallax are synthesized in brains. Therefore, the left-eye image and the right-eye image as have the parallax are shown to the respective eyes, whereby a user perceives a video as the 3D video. Using this principle, the shutter glasses  2  realize the 3D video for the user based on the video of the DTV  1 . 
     The video output system  3  has the DTV  1  and the shutter glasses  2 . The user wears the shutter glasses  2  and watches the video displayed on the DTV  1 , whereby he/she can recognize this video as the 3D video. 
     Next, the internal structures of the DTV  1  and the shutter glasses  2  will be described in detail. 
       FIG. 2  illustrates system configurations of the DTV  1  and the shutter glasses  2  in this embodiment. 
     First, the internal structure of the DTV  1  will be described. 
     The DTV  1  includes a control portion  156  which controls the operations of the various portions of the apparatus. A CPU (Central Processing Unit), etc. are built in the control portion  156 . This control portion  156  activates a system control program and various process programs which are stored in a ROM (Read Only Memory)  157  beforehand, in response to a manipulation signal which is inputted from a manipulation portion  116 , or a manipulation signal which is transmitted from a remote controller  117  and received through a reception portion  118 . In accordance with the activated programs, the control portion  156  controls the operations of the various portions of the apparatus by employing the RAM (Random Access Memory)  158  as a work memory. 
     An input terminal  144  feeds a tuner  145  for a digital satellite broadcasting, with a digital satellite television broadcasting signal which has been received by an antenna  143  for receiving digital BS/CS broadcastings. The tuner  145  tunes the received digital broadcasting signal, and transmits the tuned digital broadcasting signal to a PSK (Phase Shift Keying) demodulator  146 . The PSK demodulator  146  demodulates a TS (Transport Stream), and feeds the demodulated TS to a TS decoder  147   a . The TS decoder  147   a  decodes the TS into a digital signal which contains a digital video signal, a digital audio signal and a data signal, and it thereafter delivers this digital signal to a signal processing portion  100 . The “digital video signal” here is a digital signal concerning a video which the DTV  1  can deliver, and the “audio signal” is a digital signal concerning a voice which the DTV  1  can deliver. Besides, the “data signal” is a digital signal concerning information on the broadcasting program of a broadcasting wave as includes, for example, program-related information being information which the DTV  1  uses when an EPG (Electronic Program Guide) being an electronic program table is generated. The program-related information contains such information items as the title of the broadcasting program, the detailed information of the program, and a program start time and a program end time. 
     An input terminal  149  feeds a tuner  150  for a digital terrestrial broadcasting, with a digital terrestrial television broadcasting signal which has been received by an antenna  148  for receiving the digital terrestrial broadcasting. The tuner  150  tunes the received digital broadcasting signal, and transmits the tuned digital broadcasting signal to a corresponding OFDM (Orthogonal Frequency Division Multiplexing) demodulator  151 . The OFDM demodulator  151  demodulates a TS, and feeds the demodulated TS to a corresponding TS decoder  147   b . The TS decoder  147   b  decodes the TS into digital video and audio signals, etc., and it thereafter delivers these signals to the signal processing portion  100 . 
     The antenna  148  is capable of receiving also analog terrestrial broadcasting signals. The received analog terrestrial broadcasting signals are distributed by a distributor, not shown, and are fed to an analog tuner  168 . The analog tuner  168  tunes the received analog broadcasting signals, and transmits the tuned analog broadcasting signal to an analog demodulator  169 . The analog demodulator  169  demodulates the analog broadcasting signal, and delivers the demodulated analog broadcasting signal to the signal processing portion  100 . Besides, with the DTV  1 , for example, also a CATV (Common Antenna Television) can be viewed by connecting a tuner for the CATV to the input terminal  149  to which the antenna  148  is connected. 
     The signal processing portion  100  executes appropriate signal processing for a digital signal delivered from the TS decoder  147   a  or  147   b  or the control portion  156 . More concretely, the signal processing portion  100  separates the digital signal into a video signal, a digital audio signal and a data signal. The separated video signal is delivered to a graphic process portion  152 , and the separated audio signal to an audio process portion  153 . Besides, the signal processing portion  100  converts the broadcasting signal delivered from the analog demodulator  169 , into a video signal and an audio signal of predetermined digital format. The digital converted video signal is delivered to the graphic process portion  152 , and the digital audio signal to the audio process portion  153 . Besides, the signal processing portion  100  executes predetermined digital signal processing, also for input signals from line input terminals  137 . 
     An OSD (On Screen Display) signal generation portion  154  generates an OSD signal for displaying a UI (User Interface) screen or the like, in accordance with the control of the control portion  156 . Besides, the data signal separated from the digital broadcasting signal in the signal processing portion  100  is converted into an OSD signal of appropriate format by the OSD signal generation portion  154 , and the OSD signal is delivered to the graphic process portion  152 . 
     The graphic process portion  152  executes the decode process of the digital video signal delivered from the signal processing portion  100 . The decoded video signal is superposed on and composed with the OSD signal delivered from the OSD signal generation portion  154 , and the resulting signal is delivered to a video process portion  155 . The graphic process portion  152  can also deliver the selected one of the decoded video signal and the OSD signal to the video process portion  155 . 
     The video process portion  155  makes the correction of an image quality for the signal delivered from the graphic process portion  152 , and then converts the resulting signal into an analog video signal in a format displayable by a display portion  120 . The analog converted video signal from the video process portion  155  is displayed on the display portion  120 . The correction of the image quality in the video process portion  155  will be detailed in description taken with reference to  FIG. 3 , et seq. 
     The display portion  120  has an LCD (Liquid Crystal Display) for displaying an image. A backlight  121  illuminates the display portion  120  from the rear. Besides, the backlight  121  is capable of adjusting the luminance of the video to be displayed, in accordance with the intensity of illuminating light or an illumination time period. 
     The audio process portion  153  converts the entered audio signal into an analog audio signal in a format reproducible by a loudspeaker  110 . The analog converted audio signal is delivered to and reproduced by the loudspeaker  110 . 
     A card holder  161  is connected to the control portion  156  through a card I/F (Interface)  160 . A memory card  119  is mountable in the card I/F  160 . The memory card  119  is a storage medium, for example, an SD (Secure Digital) memory card, an MMC (Multimedia Card) or a CF (Compact Flash) card. The memory card  119  mounted in the card holder  161 , and the control portion  156  can write/read information through the card I/F  160 . 
     A USB (Universal Serial Bus) terminal  133  is connected to the control portion  156  through a USB I/F  166 . The USB terminal  133  is used as a general USB-adapted port. A portable telephone, a digital camera, card readers/writers for various memory cards, an HDD, a keyboard, etc. are connected to the USB terminal  133  through, for example, a hub. The control portion  156  can communicate (transmit and receive) information between it and the apparatus which is connected through the USB terminal  133 . 
     An HDD  170  is a magnetic storage medium which is built in the DTV  1 , and stores various information items. 
     A signal transmission portion  162  is, for example, an infrared signal transmission module, and it can transmit the opening/closing signals to the shutter glasses  2  in terms of infrared signals. The control portion  156  senses the display states of the right-eye image and the left-eye image in the 3D video, and transmits the shutter opening/closing signals to the shutter glasses  2  by the signal transmission portion  162  based on the display states of the 3D video. The control portion  156  transmits the opening/closing signals by the signal transmission portion  162  so as to open the shutter for the right eye in the shutter glasses  2  (to bring this shutter into the transmission state) and to close the shutter for the left eye (to bring this shutter into the shield state) when the display portion  120  is displaying the right-eye image, and to close the shutter for the right eye (to bring this shutter into the shield state) and to open the shutter for left eye (to bring this shutter into the transmission state) when the display portion  120  is displaying the left-eye image. 
     Next, the internal structure of the shutter glasses  2  will be described. 
     A control portion  21  performs the control of the whole shutter glasses  2 , and has a built-in MPU (Micro Processing Unit). The control portion  21  is capable of transmitting and receiving signals to and from individual modules connected thereto. 
     A signal reception portion  22  is, for example, an infrared reception module, and receives the opening/closing signals transmitted by the signal transmission portion  162 . In this embodiment, the signal transmission portion  162  and the signal reception portion  22  are the infrared communication modules, and the DTV  1  and the shutter glasses  2  are exemplified as transmitting and receiving the opening/closing signals in terms of infrared radiations. However, this example is not restrictive, but the signal transmission portion  162  and the signal reception portion  22  can be configured of communication modules which conform to various communication standards irrespective of wired or radio schemes. 
     A shutter drive portion  24  is a liquid-crystal drive device which drives a shutter portion  25  made of a liquid crystal. The shutter drive portion  24  drives the respective left and right liquid-crystal shutters of the shutter portion  25  based on the opening/closing signals from the DTV  1  as are received by the signal reception portion  22 . 
     The shutter portion  25  is disposed for the lens units of the shutter glasses  2 , and it is driven by the shutter drive portion  24  so as to switch the shield and transmission in the respective lens units for the right eye and for the left eye. 
     When the signal reception portion  22  of the shutter glasses  2  receive the opening/closing signals, the control portion  21  instructs the shutter drive portion  24  to drive the shutter portion  25  based on the signals. The shutter drive portion  24  switches the shield and transmission of the shutter portion  25  based on the instructions. 
     Next, part of a configuration in the video process portion  155  will be described with reference to  FIGS. 3 and 4 . 
       FIG. 3  illustrates a functional block configuration of the video process portion  155  in an embodiment. 
     In this embodiment, the video process portion  155  subjects a luminance signal in the entered video signal, to a movie-noise reduction process as image processing. The video process portion  155  includes a movie-noise reduction process portion  31 , a frame memory  32  and a selector  33 . 
     The movie-noise reduction process portion  31  subjects an input luminance signal S 1  entered from the process portion of the preceding stage, to the noise reduction process of a movie, and then delivering the processed signal as an output luminance signal S 17 . When the movie-noise reduction process portion  31  executes the noise reduction process for the input luminance signal S 1 , it refers to an image preceding N frames (predetermined number of frames). The detailed configuration of the movie-noise reduction process portion  31  will be described in detail later with reference to  FIG. 4 . 
     The movie-noise reduction process portion  31  delivers the output luminance signal S 17  being the luminance signal subjected to the noise reduction process, to the process portion at the succeeding stage of the video process portion  155  and to the frame memory  32 . The frame memory  32  holds the entered output luminance signal S 17 . This frame memory  32  is, for example, a buffer made of a semiconductor, and it is configured within the video process portion  155 . In this embodiment, the frame memory  32  is exemplified as being configured within the video process portion  155 . However, this is not restrictive, but for example, part of the RAM  158  of the control portion  156  may well be utilized as the frame memory  32 . 
     The selector  33  has the function of selectively delivering the frame stored in the frame memory  32 . When the image existing in the movie-noise reduction process portion  31  is entered as the input luminance signal S 1 , the selector  33  enters the output luminance signal S 3  of an image preceding N frames to the input image, into the movie-noise reduction process portion  31  as signal entry module. 
     In this manner, the movie-noise reduction process portion  31  is fed with the input luminance signal S 1  to be subjected to the movie-noise reduction process, and the output luminance signal S 3  delivered by itself and preceding the N frames, and it executes the movie-noise reduction process for the input luminance signal S 1 , based on the output luminance signal S 3  preceding the N frames. 
     The configuration of the movie-noise reduction process portion  31  and the noise reduction process to be executed, will be described below. 
       FIG. 4  illustrates a functional block configuration of the movie-noise reduction process portion  31  in the embodiment. 
     The movie-noise reduction process portion  31  includes a subtraction portion  314  and an addition portion  326  which receive the input luminance signal S 1 . 
     Besides, the output luminance signal S 3  preceding N frames as has been delivered by the frame memory  32  is fed to the subtraction portion  314 , and an inter-frame difference signal S 5  can be obtained at the output of the subtraction portion  314 . At the succeeding stage of the output of the subtraction portion  314 , there are disposed a limiter  324  which limits the amplitude of the entered signal S 5  to a constant value and then delivers the resulting signal to the succeeding stage thereof, and a multiplication portion  325  which receives the output from the limiter  324 . 
     Further, the movie-noise reduction process portion  31  includes an absolute-value detection portion  316  which receives the inter-frame difference signal S 5  from the subtraction portion  314  and which delivers the signal S 9  of the absolute value of the received signal S 5 , and a multiplication portion  320  which receives the inter-frame difference absolute-value signal S 9  from the absolute-value detection portion  316 . Besides, the movie-noise reduction process portion  31  includes an addition portion  315  which receives the input luminance signal S 1  and the output luminance signal S 3  preceding the N frames from the frame memory  32  and which delivers the addition result of the received signals, and an averaging portion  317  which delivers the average value of such addition results. 
     Further, the movie-noise reduction process portion  31  includes a selection portion  328  which receives the three signals of the output luminance signal S 3  preceding the N frames, the input luminance signal S 1  and the average value signal from the averaging portion  317 , and which selects and delivers one of the received signals (or at least two of them, or a plurality of average values, as will be stated later). The selection portion  328  selects signal information corresponding to the image brightness and delivers the signal information to a coefficient generator  318  at a succeeding stage, in order to control the noise reduction process, and it selects and delivers one from among the plurality of signals in accordance with predetermined selection criteria. 
     Further, the movie-noise reduction process portion  31  includes the coefficient generator  318  which receives the signal corresponding to the image brightness from the selection portion  328 , and which generates a coefficient corresponding to the signal and feeds the coefficient to the multiplication portion  320 . In this multiplication portion  320 , a multiplication process is executed based on the coefficient, so as to deliver a corrected inter-frame difference absolute-value signal S 11 . The corrected absolute-value signal S 11  is received by a motion detection circuit  322 . The motion detection circuit  322  detects the motion of the image of a general movie signal from the entered signal, and it generates a cyclic coefficient S 13  which relieves the noise reduction process, in correspondence with the detected motion. The cyclic coefficient S 13  is fed to the multiplication portion  325 . 
     The movie-noise reduction process portion  31  having such a configuration executes an appropriate noise reduction process in accordance with the image brightness (luminance, etc.) and the degree of the motion of the movie signal, as stated below. The value of the inter-frame difference signal S 5  from the subtraction portion  314  is adjusted chiefly by the functions of the multiplication portions  320  and  325 , so as to intensify the noise reduction process when the image is dark and to relieve the noise reduction process when the image is bright. Besides, the motion detection circuit  322  and the multiplication portion  325  relieve the residual image of a screen in such a way that the noise reduction process is interrupted when the motion magnitude of the movie signal is a predetermined magnitude or above, or that the noise reduction process is relieved in proportion to the value of the motion magnitude of the movie signal. 
     Thus, the noise reduction process is stopped or relieved at the bright part of the image, and it is intensified at the dark part of the image, whereby noise is reduced as a whole, and a movie screen of high quality in which the residual image is unobtrusive can be obtained. 
     In the concrete, the input luminance signal S 1  is entered into the subtraction portion  314  together with the output luminance signal S 3  preceding N frames as has been read out of the frame memory  32 , thereby to obtain the inter-frame difference signal S 5 . The inter-frame difference signal S 5  has its amplitude limited to a certain desired value by the limiter  324 , and it is thereafter multiplied by the cyclic coefficient S 13  by the multiplication portion  325 . 
     The cyclic coefficient S 13  is a coefficient which contains the image brightness and the motion component of the movie. When the image becomes bright, the value of the coefficient S 7  of the coefficient generator  318  enlarges, and hence, also the value of the corrected absolute-value signal S 11  enlarges. Thus, the value of cyclic coefficient S 13  becomes small. Accordingly, the multiplication portion  325  makes small the value of the difference signal S 5  having passed through the limiter  324 , thereby to suppress (relieve or stop) the degree of the noise removal process in the calculation portion  326 . 
     Further, the input luminance signal S 1  is subjected to an addition or a subtraction with the difference signal S 5  from the multiplication portion  325 , by the calculation portion  326 , thereby to remove the noise in the movie signal. The calculation portion  326  executes the process of the subtraction or addition, depending upon the sign (plus or minus) of the difference signal from the multiplication portion  325 , so as to remove the noise. 
     On the other hand, the input luminance signal S 1 , the output luminance signal S 3  preceding the N frames, and the average value signal S 6  of the signals S 1  and S 3  are fed to the selection portion  328 , and one of these signals is selected and fed to the coefficient generator  318  by the selection portion  328 . In the coefficient generator  318 , the coefficient S 7  corresponding to the level of the selected signal is delivered, and this coefficient S 7  is multiplied by the inter-frame difference absolute-value signal S 9 , by the multiplication portion  320 . The inter-frame difference absolute-value signal S 11  thus corrected is entered into the motion detection circuit  322 . Here, for example, the coefficient generator  318  generates a value less than one in a case where the input signal level is smaller than a predetermined range, and it generates a value greater than one in a case where the input signal level is larger than the predetermined range. On this occasion, when the input signal level is lower, the corrected absolute-value signal S 11  becomes a value smaller than the absolute-value signal S 9 , and when the input signal level is higher, the corrected absolute-value signal S 11  becomes a value larger than the absolute-value signal S 9 . 
     The motion detection circuit  322  functions to make the value of the cyclic coefficient S 13  smaller as the corrected inter-frame difference absolute-value signal S 11  is larger, so as to lower a noise reduction effect and to diminish the residual image. In other words, when the input signal level is low, the cyclic coefficient S 13  becomes larger than usual, and when the input signal level is high, the cyclic coefficient S 13  becomes smaller than usual. That is, at the dark part where the noise is obtrusive, the noise reduction effect is heightened, and at the bright part where the noise is unobtrusive, the noise reduction effect is lowered to diminish the residual image. 
     In this manner, the movie-noise reduction process portion  31  considers the fact that, even when the noise of the movie signal is at an identical noise level, the obtrusiveness of the noise differs depending upon the image signal level (the image brightness), and it controls the noise reduction effect in correspondence with the image signal level (the image brightness), whereby the movie signal of high quality can be obtained. 
     In this example, the corrected inter-frame difference absolute-value signal S 11  has been obtained using the coefficient generator  318  and the multiplication portion  320 , but the embodiment of the present invention is not restricted to this configuration. For example, the functions of the coefficient generator  318  and the multiplication portion  320  (and further, the functions of the motion detection circuit  322  and the multiplication portion  325 ) are substituted by a CPU and a lookup table incarnated by a RAM or the like, whereby a noise reduction process corresponding to still subtler image signal levels (the image brightnesses) can be realized. 
     For example, part of the movie-noise reduction process stated above is explained in JP-2005-347821-A. 
     In this embodiment, when the movie-noise reduction process portion  31  executes the movie-noise reduction process as to the 2D image (when the input luminance signal S 1  is one of the 2D image), the selector  33  delivers the output luminance signal preceding one frame as is stored in the frame memory  32 , as the output luminance signal S 3  preceding the N frames (N=1 holds in the case of the 2D image). Thus, the movie-noise reduction process portion  31  can execute the movie-noise reduction process based on the directly preceding frame which has no parallax with respect to the frame to be subjected to the movie-noise reduction process. 
     Besides, when the movie-noise reduction process portion  31  executes the movie-noise reduction process as to the 3D video of the frame-sequential scheme in which the left-eye image and the right-eye image are alternately displayed, the selector  33  delivers the output luminance signal preceding two frames as is stored in the frame memory  32 , as the output luminance signal S 3  preceding the N frames (N=2 holds in this case). The reason therefor is as stated below. In the case of the 2D image, the image preceding one frame becomes the directly preceding image. In the case of the 3D video, however, the image preceding one frame to the left-eye image becomes the right-eye image, and the image preceding one frame to the right-eye image becomes the left-eye image, as shown in  FIG. 5 , so that the image preceding one frame becomes the image which has a parallax with respect to the image to be subjected to the movie-noise reduction process. When the above movie-noise reduction process is executed based on the image having the parallax, the inter-frame difference signal S 5  becomes the signal of the inter-frame difference between the images having the parallax therebetween, and the movie-noise reduction process is not executed appropriately. Therefore, the movie-noise reduction process can be appropriately executed by performing the process based on the output luminance signal of the image preceding the two frames as is the image for the identical eye. 
     The selector  33  senses a signal which indicates whether the input video is the 2D video or the 3D video, and which is entered into the video process portion  155 . Thus, it selects whether the output luminance signal preceding one frame is to be delivered to the movie-noise reduction process portion  31  or the output luminance signal preceding the two frames is to be delivered thereto, and it delivers the selected output luminance signal. That is, when the video to be entered is the 2D video, the output luminance signal preceding one frame is delivered, and when the entered video is the 3D video, the output luminance signal preceding the two frames is delivered. In this embodiment, the case where the left-eye image and the right-eye image are alternately displayed is exemplified as the sequence of the frames of the images of the 3D video. On this occasion, it has been stated above that the output luminance signal preceding the two frames is entered into the movie-noise reduction process portion  31 . However, this is not restrictive, but an output luminance signal preceding even-numbered frames such as preceding four frames or preceding six frames may well be entered. Also in this case, a frame which is referred to in the movie-noise reduction process is prevented from becoming a frame which has a parallax with respect to a frame to be subjected to the movie-noise reduction process. 
     Besides, in a case, for example, where the 3D video to be entered is not configured by alternately arraying the left-eye image and the right-eye image, the movie-noise reduction process portion  31  may well execute the movie-noise reduction process based on directly preceding frames which have no parallax therebetween (N=3, 4 . . . may well hold). 
     Next, the flow of the movie-noise reduction process in the embodiment will be described. 
       FIG. 6  illustrates the movie-noise reduction process in this embodiment. 
     First, when the input luminance signal S 1  is entered into the movie-noise reduction process portion  31 , the selector  33  discriminates whether the video relevant to the input luminance signal S 1  is the 2D video or the 3D video (step S 61 ). In this embodiment, it is exemplified that the discrimination of the step S 61  is done by sensing the signal which indicates whether the video is the 2D video or the 3D video, and which is entered into the video process portion  155 . However, this is not restrictive, but the discrimination of the step S 61  may well be done on the basis of, for example, information which indicates whether the video to be entered from the control portion  156  is the 2D video or the 3D video. 
     As stated before, the selector  33  feeds the movie-noise reduction process portion  31  with the output luminance signal S 3  preceding the N frames, among the output luminance signals S 17  delivered from the movie-noise reduction process portion  31  and entered into the frame memory  32 . When the selector  33  has discriminated at the step S 61  that the video to be entered into the video process portion  155  is the 2D video (step S 61 : No), it feeds the movie-noise reduction process portion  31  with the output luminance signal S 3  preceding one frame (step S 62 ). 
     Besides, when the selector  33  has discriminated at the step S 61  that video to be entered into the video process portion  155  is the 3D video (step S 61 : Yes), it feeds the movie-noise reduction process portion  31  with the output luminance signal S 3  preceding the two frames (step S 63 ). 
     After the step S 62  or the step S 63 , the movie-noise reduction process portion  31  executes the movie-noise reduction process as stated above, based on the input luminance signal S 1  and the output luminance signal S 3  preceding the N frames (step S 64 ). 
     The series of processing flow is thus ended. Owing to the processing, the movie-noise reduction process portion is prevented from executing, for example, a process in which the right-eye image is referred to in the movie-noise reduction process of the left-eye image, and the movie-noise reduction process can be appropriately executed for the 3D video. 
     Besides, in this embodiment, the selector  33  discriminates whether the video to be subjected to the movie-noise reduction process is the 2D video or the 3D video, and the movie-noise reduction process can be appropriately executed in both the cases of the 2D video and the 3D video. 
     In the above, the movie-noise reduction process for the 3D video based on the frame-sequential scheme has been exemplified and described. However, this is not restrictive, but a movie-noise reduction process can be executed also for a 3D video based on, for example, a naked-eye scheme. 
     Also in this case, an input luminance signal which is entered into the movie-noise reduction process portion  31  and which is to be subjected to the movie-noise reduction process is divided into a frame in which pixels for the left eye are collected, and a frame in which pixels for the right eye are collected. In the same manner as stated above, the selector  33  enters an image preceding two frames, into the movie-noise reduction process portion  31  as a luminance signal S 3  preceding N frames, and the movie-noise reduction process portion  31  executes the movie-noise reduction process with reference to the entered luminance signal. A process portion at a stage further succeeding to the video process portion  155  merges the frame in which the pixels for the left eye as are delivered from the movie-noise reduction process portion  31  are collected, and the frame in which the pixels for the right eye are collected, into one frame, and it delivers the frame in a state where this frame is deliverable as the 3D video. 
     Besides, in the naked-eye scheme, there is a multi-parallax 3D display which displays videos having still more parallaxes. In a case where, in displaying the 3D video by the naked-eye scheme, pixels having a parallax exist in only one set, the viewable physical range of a user becomes narrow. In the multi-parallax 3D display in the naked-eye scheme, therefore, the viewable physical range of the user is made wider by the display of the videos having a plurality of sets of pixels between/among which parallaxes suitable for grasping the pixels as the 3D video by both the eyes exist. 
     In this case, the plurality of sets exist as the sets of the pixels for the left eye and for the right eye, to be simultaneously displayed. Therefore, the frames which are merged after having been delivered from the movie-noise reduction process portion  31  do not become only two frames, but a plurality of delivered frames are merged. In a case, for example, where two sets of pixels between which the parallax suitable for grasping the pixels as the 3D video by both the eyes exists are existent in an image which is displayed on the display portion  120 , the input luminance signals S 1  are entered into the movie-noise reduction process portion  31  in the sequence of a frame in which the pixels for the left eye, in the first set are collected, a frame in which the pixels for the right eye, in the first set are collected, a frame in which the pixels for the left eye, in the second set are collected, and a frame in which the pixels for the right eye, in the second set are collected. 
     The movie-noise reduction process portion  31  subjects the entered input luminance signal S 1  to the movie-noise reduction process every frame and then delivers the resulting signal. Therefore, in a case, for example, where the frame in which the pixels for the left eye, in the second set are collected is subjected to the movie-noise reduction process, and where the output luminance signal preceding two frames is referred to, the movie-noise reduction process is executed by referring to the frame in which the pixels for the left eye, in the first set are collected. In this case, the movie-noise reduction process is executed by referring to the frame which has the parallax with respect to the frame to be subjected to the process, and an appropriate movie-noise reduction process is not executed. 
     In this embodiment, therefore, the selector  33  switches the frames to which the movie-noise reduction process portion  31  is caused to refer (switches N), in accordance with the number of sets of the pixels between/among which the parallax suitable for grasping the pixels as the 3D video by both the eyes exists. 
     In a case where the number of sets of the pixels between which the parallax suitable for grasping the pixels as the 3D video by both the eyes exists as stated above is two, the left and right selector  33  delivers a luminance signal preceding four frames, as the output luminance signal S 3  preceding the N frames. Thus, the movie-noise reduction process portion  31  can appropriately execute the movie-noise reduction process based on the frame which has no parallax with respect to the frame to be subjected to the process. Besides, in a case where the number of sets is three, the left and right selector  33  delivers a luminance signal preceding six frames, as the output luminance signal S 3  preceding the N frames. 
     In this manner, in the multi-parallax naked-eye 3D display, the video process portion  155  executes the movie-noise reduction process with reference to the frame which precedes to the frame to be subjected to the movie-noise reduction process, double the number of sets of the pixels having the appropriate parallax for grasping the pixels as the 3D video by both the eyes. In other words, the video process portion  155  executes the movie-noise reduction process with reference to the frame which has no parallax with respect to the frame to be subjected to the process. 
     Owing to the above processing, the DTV  1  can appropriately execute the movie-noise reduction process, also for the 3D video of the naked-eye scheme. 
     Although the movie-noise reduction process has been exemplified and described in the embodiments, this is not restrictive, but the embodiments are also applicable to cases where various image processes are executed with reference to images preceding several frames. 
     The present invention is not restricted to the above embodiments, but it can be embodied by modifying constituents within a scope of the invention. For example, several constituents may be omitted from all the constituents in each embodiment, and the constituents of the different embodiments may be properly combined.