Abstract:
A film scanner that scans an image of a developed film by an imaging device includes a film holder, a film side discriminating unit, and an image processor. The film holder is arranged to hold the developed film with one side thereof faced toward the imaging device. The film side discriminating unit determines which side of the film held by the film holder is an emulsion side. The image processor reverses an image captured from the film to produce an erect image when the film side discriminating unit has determined that the side of the film not facing the imaging device is the emulsion side. Accordingly, the film scanner arranged as above can produce an erect image even if the film strip is placed in the film holder with wrong side thereof faced toward the imaging device.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a film scanner for capturing images formed on a photographing film.  
           [0002]    Recently, images formed on a photographing film are often captured by a film scanner to process and/or store image data in personal computers or the like.  
           [0003]    Generally, the film scanner is provided with a film holder configured to hold a film strip obtained by cutting a 35 mm film or a brownie film for every predetermined numbers of frames. The film holder is inserted into the film scanner and the film strip held in the film scanner is illuminated by a light source so that the image on the film strip is formed on a CCD line sensor by an imaging lens. The CCD line sensor scans the image on the film strip in one direction, or a principal scanning direction, and by moving the line sensor relative to the image in a direction perpendicular to the principal scanning direction, or an auxiliary scanning direction, the whole image on the film strip can be captured.  
           [0004]    In the film scanner mentioned above, it is expected that the film strip be placed in the film holder with the emulsion side, or the front side, thereof faced toward the CCD line sensor so that the film scanner can capture an erect image. However, since the emulsion is applied on a thin and transparent base film, it is quite difficult to discriminate the emulsion side and the base film side of the film strip and the film strip is often inserted into the film holder with the emulsion side located at the wrong side, which causes the film scanner to capture a reversed image.  
           [0005]    Therefore, there is a need for a film scanner that is capable of producing an erect image even if the film strip is held reversely in the film holder.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention is advantageous in that a film scanner is provided that satisfies the above-mention need.  
           [0007]    According to an aspect of the invention there is provided a film scanner that captures an image of a developed film by an imaging device. The film scanner includes a film holder, a film side discriminator, and an image processor. The film holder is arranged to hold the developed film with one side thereof facing toward the imaging device. The film side discriminator determines which side of the film held by the film holder is an emulsion side. The image processor reverses an image captured from the film to produce an erect image when the film side discriminator determines that a side of the film not facing the imaging device is the emulsion side. Accordingly, the film scanner arranged as above can produce an erect image even if the film strip is placed in the film holder with a wrong side thereof facing toward the imaging device.  
           [0008]    Optionally, the discriminator includes a light source arranged to emit a light beam toward a side of the film held in the film holder, and a photo detector arranged to receive the light beam reflected at the side of the film.  
           [0009]    The film side discriminating unit arranged as above can determine which side of the film is the emulsion side based on the characteristic of the light beam received by the photo detector since the light reflecting characteristic of the emulsion side of the film strip differs from that of the other side.  
           [0010]    For example, the emulsion side of the film strip can be determined based on the width of the light beam received by the photo detector, since the light beam reflected at the emulsion side is more diffused and hence becomes wider than the light beam reflected at the other side.  
           [0011]    Specifically, the photo detector may include a two dimensional array having a plurality of photosensitive elements, and the film side discriminator may determine whether the light beam is reflected at the emulsion side of the film based on the number of the photosensitive elements that receive the light beam.  
           [0012]    Optionally, the film side discriminator includes a first light source arranged to emit a first light beam toward a first side of the film held by the film holder, a first photo detector arranged to receive the first light beam reflected at the first side of the film, a second light source arranged to emit a second light beam toward a second side of the film held by the film holder, and a second photo detector arranged to receive the second light beam reflected at the second side of the film. The film side discriminator arranged as above can determine the emulsion side of the film based on the outputs of the first and second photo detectors.  
           [0013]    Further optionally, each of the first and second photo detectors includes a two dimensional array having a plurality of photosensitive elements. In this case, the film side discriminator can determine the emulsion side of the film by comparing the number of the photosensitive elements of the first photo detector that receive the first light beam with the number of the photosensitive elements of the second photo detector that receive the second light beam.  
           [0014]    It should be noted that since the film strip is manufactured by applying the emulsion on a thin base film, the film strip bends such that the emulsion side becomes concave. Therefore, according to some embodiments of the invention, the film side discriminator is arranged so as to determine the emulsion side of the film by detecting a concave side of the film.  
           [0015]    The concave side of the film can be detected, for example, by determining the distances from the imaging device to a plurality of points defined on said film. In exemplary embodiments of the invention, one of the plurality of points is a center reference point defined substantially at a center of one frame of the film and the other points are side reference points each defined in a vicinity of the edges of the frame.  
           [0016]    In some embodiments of the invention, the film side discriminator may includes, an imaging lens located between the imaging device and the film holder and forming an image of the film on the imaging device, and a lens driver that moves the lens along an optical axis thereof to adjust the focus of the imaging lens on the film. The film side discriminator determines positions of a plurality points defined on the film in a direction parallel to the optical axis by adjusting focus of the imaging lens on each of the points, and detects the concave side of the film based on the positions of those points. In exemplary embodiments of the invention, one of the plurality of points is a center reference point defined substantially at a center of one frame of the film and the other points are side reference points each defined in a vicinity of the edges of the frame. 
       
    
    
     BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS  
       [0017]    [0017]FIG. 1 schematically shows a perspective view of a part of a film scanner according to a first embodiment of the invention;  
         [0018]    [0018]FIG. 2 is a front view of the film scanner shown in FIG. 1;  
         [0019]    [0019]FIGS. 3A and 3B schematically show perspective views of a film holder according to the first embodiment of the invention;  
         [0020]    [0020]FIG. 4 is a cross section of the film holder taken along the line IV-IV in FIG. 3B;  
         [0021]    [0021]FIG. 5 is a perspective view of the APS film adapter according to the first embodiment of the invention;  
         [0022]    [0022]FIG. 6 shows a control system of the film scanner according to the first embodiment;  
         [0023]    [0023]FIG. 7 is a flowchart illustrating a sub-routine scanning procedure of the film scanner according to the first embodiment of the invention;  
         [0024]    [0024]FIG. 8 shows a flowchart illustrating a sub-routine FILM STRIP SCANNING PROCEDURE according to the first embodiment of the invention;  
         [0025]    [0025]FIG. 9 shows a flowchart illustrating a sub-routine FILM SIDE CHECKING PROCEDURE according to the first embodiment of the invention;  
         [0026]    [0026]FIG. 10 shows a flowchart illustrating a sub-routine APS FILM SCANNING PROCEDURE according to the first embodiment of the invention;  
         [0027]    [0027]FIG. 11 shows a flowchart illustrating the sub-routine ENDING PROCEDURE according to the first embodiment of the invention;  
         [0028]    [0028]FIG. 12A schematically shows a plane view of one frame on a film strip that is to be scanned by the film scanner according to the second embodiment;  
         [0029]    [0029]FIGS. 12B and 12C schematically show cross sectional views of the frame shown in FIG. 12A along line XIIA-XIIA and line XIIB-XIIB, respectively;  
         [0030]    [0030]FIG. 13 schematically shows a perspective view of a part of the film scanner according a second embodiment of the invention;  
         [0031]    [0031]FIG. 14 schematically shows a front view of the film scanner shown in FIG. 13;  
         [0032]    [0032]FIG. 15 shows a control system of the film scanner according to the second embodiment of the invention; and  
         [0033]    [0033]FIG. 16 shows a flowchart of the sub-routine FILM SIDE CHECKING PROCEDURE according to the second embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0034]    Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.  
         [0035]    [0035]FIG. 1 schematically shows a perspective view of a part of a film scanner  100  according a first embodiment of the invention. FIG. 2 is a front view of the film scanner  100  shown in FIG. 1 observed from a direction indicated by an arrow X.  
         [0036]    The film scanner  100  is provided with a pair of guide rods  102  that is supported within a housing (not shown) of the film scanner  100 . The guide rods  102  are arranged so as to extend horizontally when the film scanner  100  is placed for use.  
         [0037]    A table  101  is slidably mounted to the guide rods  102 . A rack  103  is integrally formed on one of the side surfaces of the table  101  near the bottom edge thereof so as to extend in parallel to the guide rods  102 .  
         [0038]    A main-scanning motor  104  is fixed to the housing (not shown) of the film scanner  100  at a location adjacent to the rack  103 . A spindle shaft of the main-scanning motor  104  is provided with a pinion  105  that is engaged with the rack  103  of the table  101 . The main-scanning motor  104  drives the table  101  back and forth in a direction parallel to the guide rods  102  (i.e., in a auxiliary scanning direction).  
         [0039]    The table  101  includes a base  101   a  and a top plate  101   b  fixed on the base. The base  101   a  has a pair of stepped side walls  101   c  and a holder supporting groove  106  formed between the side walls  101   c  so as to extend in parallel to the guide rods  102 . The holder supporting groove  106  is formed such that a film holder  201  and an APS (advanced photo system) film adapter  301 , which will be described later, can be inserted and thereby held therein.  
         [0040]    First and second holder sensors  120  and  122  are provided to the inner surface of one of the side walls  101   c.  The first holder sensors  120  detects whether a holder (the film holder  201  or the APS film adapter  301 ) is currently inserted into the holder supporting groove  106 . The second holder sensor  122  detects a mark provided on the holder to indicate the type of the holder (i.e., the film holder  201  or the APS film adapter  301 ).  
         [0041]    A rectangular upper scanning window  107   a  is formed to the top plate  101   b,  while a rectangular lower scanning window  107   b  is formed to the base at the bottom of the holder supporting groove  106 . The upper and lower scanning windows  107   a  and  107   b  are formed in substantially the same shape and size, and the lower scanning window  107   b  is located substantially below the upper scanning window  107   a.    
         [0042]    A pre-scanning motor  108  is mounted on one of the side surfaces of the table  101 , preferably, on the side surface on which the rack  103  is formed. The spindle shaft of the pre-scanning motor  108  is provided with a pinion  109  that is to be engaged with a rack formed on the film holder  201  or the APS film adapter  301 , which will be describe later, through an opening  110  formed to the top plate  101   b  of the table  101 .  
         [0043]    It should be noted that both the main-scanning motor  104  and the pre-scanning motor  108  are pulse motors that are driven by pulse signals and revolve for a predetermined angle in response to one pulse of the pulse signal.  
         [0044]    A part of the area within which the table travels along the guide rods  102  is defined as an image reading section  400 . A diffusive light source  401 , an imaging lens  402 , and a CCD line sensor  403  are provided within the image reading section  400 . As shown in FIG. 1, the diffusive light source  401  and the imaging lens  402  are arranged such that the table  101  passes therebetween as it travels along the guide rods  102  to allow the light emitted from the light source  401  passing through the upper and lower scanning windows ( 107   a ,  107   b ). The diffusive light source  401  emits diffused light toward the imaging lens  402 , and the imaging lens  402  converges the light from the diffusing light source  403  to form an optical image on the CCD line sensor  403  located below the imaging lens  402 . The CCD line sensor  403  includes a plurality of CCD elements that generates electrical signals in accordance with the optical image formed thereon. The plurality of CCD elements is arranged linearly and at a constant pitch in a direction perpendicular to the direction in which the table  101  moves and parallel to a plane along which the table  101  moves.  
         [0045]    It should be noted that although only one line sensor  403  is shown in FIG. 1, three line sensors may be provided below the imaging lens  402 , which are sensitive to different colors such as red, green, and blue, to allow the film scanner  100  scanning a color image.  
         [0046]    As shown in FIG. 2, the film scanner  100  is further provided with a film front face detecting unit  500  that includes first and second light emitting devices, or LEDs  501  and  503 , and first and second light detecting devices, or photo diode arrays  502  and  504 . Each of the first and second photo diode arrays  502  and  504  includes a plurality of photo diodes that are two dimensionally arranged.  
         [0047]    The first LED  501  and the first photo diode array  502  are located above the path along which the table  101  travels. The first LED  501  and the first photo diode array  502  are arranged such that, when the table  101  is located therebelow, the light emitted from the first LED  501  passes through the upper scanning window  107   a , reflected at the upper surface of a film held within the table, and then received by the first photo diode array  502 .  
         [0048]    The second LED  503  and the second photo diode array  504  are located below the traveling path of the table  101 , and arranged such that the light emitted from the second LED  503  impinges on the under surface of the film within the table  101  and reflected toward the second photo diode array  504  when the table  101  is located above the second LED  503  and the second photo diode array  504 .  
         [0049]    [0049]FIGS. 3A and 3B schematically show perspective views of a film holder  201  according to the first embodiment of the invention that is to be inserted into the film scanner  100  shown in FIG. 1. FIG. 4 shows a cross section of the film holder taken along the line IV-IV in FIG. 3B together with the film front face detecting unit  500 .  
         [0050]    The film holder  201  shown in FIGS. 3A and 3B is configured to hold a film strip made by cutting a 35 mm film so as to include six photograph frames. It should be noted that,the film holder  201  may be also configured so as to hold brownie films or slide films therein.  
         [0051]    The film holder  201  includes a base  202  and a film presser  203  that is connected to the base  202  by two hinges  206  so as to be movable between an open position, as shown in FIG. 3B, and a closed position as shown in FIG. 3A.  
         [0052]    The film holder  201  is provided with a groove  211  extending in a longitudinal direction thereof. The groove  211  is formed in the vicinity of one side edge of the film holder  201 . As shown in FIG. 4, a rack  212  is formed within the groove, which is to be engaged with the pinion  109  mounted to the pre-scanning motor  108 .  
         [0053]    As shown in FIG. 3B the film holder  201  is further provided with a shallow rectangular film receiving recess  204  for receiving the film strip. The film presser  203  is formed in a shape and size that can be placed within the film receiving recess  204  when moved to the closed position shown in FIG. 3A. The film presser  203  is provided with two protrusions  207  that engage with respective grooves  208  formed to the base  202  when the film presser  203  is moved to the closed position and thereby keep the film holder  201  be closed.  
         [0054]    Each of the base  202  and the film presser  203  is provided with six rectangular frame windows ( 209 ,  210 ) arranged along the longitudinal direction of the film holder  201 . Each frame window ( 209 ,  210 ) is formed as a through hole extending in the thickness direction of the film holder  201 . The size of each frame window  203  corresponds to the size of the photographing frame formed on the film strip.  
         [0055]    A pair of guide rails  205  is formed on the bottom of the film receiving recess  204 . The guide rails  205  are formed near respective sides of the frame windows  209  and extend along the longitudinal direction of the film holder  200 . The film strip is placed between the pair of guide rails  205  in order to prevent displacing in the width direction thereof within the film receiving recess  204 .  
         [0056]    The film presser  203  is provided with two elongated grooves  213  formed at the under surface of the film presser  203  to extend in the longitudinal direction of the film holder  201  near respective sides of the frame windows  210 . When the film holder  201  is closed, the guide rails  205  of the base fits into respective grooves  213  of the film presser  203  and the film strip placed between the guide rails  205  is sandwiched between the bottom of the film receiving recess  204  and the under surface of the film presser  203 .  
         [0057]    [0057]FIG. 5 is a perspective view of the APS film adapter  301  according to the first embodiment of the invention that is to be inserted to the film scanner  100  shown in FIG. 1. The APS film adapter  301  has a substantially parallelepiped form that can be inserted into the holder supporting groove  106  of the film scanner  100 . A pair of flange portions  302  is provided to the APS film adapter  301  at both sides thereof. The flange portions  302  slide on the stepped portions of the side walls  101   c  of the table  101  when the APS film adapter  301  is inserted into the table  101 .  
         [0058]    An elongated groove  303  is formed to the upper surface of one of the flange portions  302 . The groove  303  is located near the side edge of the flange portion  302  and extends in a longitudinal direction of the APS film adapter  301 . A rack  304  is formed within the groove  303 , which is to be engaged with the pinion  109  provided to the pre-scanning motor  108 .  
         [0059]    An opening, or frame window  305 , is formed at substantially the center area of the APS film adapter  301 , which penetrates the APS film adapter  301  from the top surface to the under surface thereof.  
         [0060]    The APS film adapter  301  accommodates an APS film cartridge (not shown) and wind/rewind the film of the APS film cartridge with a built-in motor (not shown) to align arbitrary photograph frame to the frame window  305 .  
         [0061]    A plurality of contact electrodes  306  is provided, in a line, on the upper surface of the APS film adapter  301  in the vicinity of the rear end thereof. The contact electrodes  306  are biased to elastically contact with respective electrodes (not shown) provided to the table  101  as the APS film adapter  301  is inserted into the holder supporting groove  106 . Control signals and power for winding/rewinding the film of the APS film cartridge are provided to the APS film adapter  301  through the contact electrodes  306  for driving the built-in motors (not shown).  
         [0062]    It should be noted that the APS film cartridge can be inserted into the APS film adapter  301  only in a predetermine manner and hence APS film cannot be set to the APS film adapter  301 , with the front and rear faces reversed.  
         [0063]    [0063]FIG. 6 shows a control system of the film scanner  100  shown in FIG. 1.  
         [0064]    The CCD line sensor  403  is driven by a line sensor driving circuit (CCD driver)  141 , which is controlled by a system controller  140 . The output signal generated by the CCD line sensor  403  in accordance with the image formed thereon by the imaging lens  402  is amplified by an amplifier  142 : and then converted into a digital signal by an A/D converter  143 . Then, a predetermined image processing is applied by an image processing circuit  144  to generate an image signal having a predetermined format.  
         [0065]    A memory  145  is provided for storing the processed image signal as an image data. For example, an IC card may be used as the memory  145 . The image signal is applied to an output terminal  147  via an interface circuit  146 . The output signal is transmitted from the I/O terminal  147  to, for example, a (not shown) personal computer.  
         [0066]    The diffusive light source  401  is driven by a light source driving circuit  148 , which is controlled by the system controller  140 .  
         [0067]    The main-scanning motor  104  and the pre-scanning motor  108  are also controlled by the system controller  140  to rotate and thereby move the table  101  or the film holder  201  held in the table  101 .  
         [0068]    The first and second LEDs  501  and  503  of the film front face detecting unit  500  is connected to the system controller  140  via a LED driving circuit  149  and turn on and off in accordance with the control of the system controller  140 . The first and second photo diode arrays  502  and  504  are also connected to the system controller  140  so that the system controller  140  can determine which photo diode of the photo diodes array ( 502 ,  504 ) is receiving light.  
         [0069]    The system controller  140  is further connected with the first and second holder sensor  120  and  122  to determine whether the film holder  201  or the APS film adapter  301  is set to the film scanner  100 .  
         [0070]    The system controller  140  is also connected with an operation panel  152  via an interface  151 . A control signal representing start/end of scanning operation and/or designating a frame to be scanned is input through the operation panel  152 . The system controller  140  stores the instruction input through the operation panel  152  in a RAM  140 M provided therein.  
         [0071]    Further, the system controller  140  detects the position of the table  101  and the film holder  201  based on the number of pulses applied to each of the main-scanning motor  104  and the pre-scanning motor  108  and store the same in the RAM  140 M.  
         [0072]    Next, the operation of the film scanner  100  according to the first embodiment will be described.  
         [0073]    Initially, the film strip to be scanned is set to the film holder  201 . That is, the protrusions  207  of the film presser  203  are disengaged from the grooves  208  of the base  202  to move the film presser  203  to the open position shown in FIG. 3B. Then, the film strip is placed between the guide rails  205  in the film receiving recess  204  with the emulsion side thereof faced against the bottom of the film receiving recess  204 . At this state, the displacement of the film strip in the width direction thereof is restricted by the pair of guide rails  205  while the displacement in the longitudinal direction of the film strip is prevented by the front and rear end of the film receiving groove  204 .  
         [0074]    Then, the film presser  203  is moved to the closed position to be overlaid on the film strip. The protrusions  207  are engaged with the grooves  208  to fix the film presser  203  at the closed position. As a result, the film strip is sandwiched between the base  202  and the film presser  203  as shown in FIG. 4, with the front and rear faces thereof being in contact with the base  202  and the film presser  203 , respectively, and each photograph frame exposing through the respective frame windows ( 209 ,  210 ).  
         [0075]    The film holder  201  is then inserted into the holder supporting groove  106  of the table  101 . Alternatively, the APS film adapter  301  shown in FIG. 5 may be inserted into the table  101 . Then, the scanning procedure of the film scanner  100  is carried out.  
         [0076]    [0076]FIG. 7 is a flowchart illustrating a scanning procedure of the film scanner  100  according to the first embodiment.  
         [0077]    After the main switch of the film scanner  100  is turned on, the system controller  140  waits for insertion of a holder (i.e., the film holder  201  or the APS film holder  301 ) (S 102 ). If no holder is inserted within a predetermined time (S 102 :NO, S 104 :YES), then the film scanning procedure is terminated.  
         [0078]    If the system controller  140  receives a signal from the first sensor  120  that indicates insertion of a holder into the table  101  (S 102 :YES), then the system controller  140  drives the main-scanning motor  104  to move the table to an initial position (S 106 ). The initial position is a position at which the table  101  has not yet reached the scanning position and is apart therefrom by a predetermined distance.  
         [0079]    Then the light source  401  is turned on to emit diffused light (S 108 ). Since the table  101  has not yet reached the scanning position, the light is directly incident on the imaging lens  402 , and is received by the line sensor  403 . Based on the detection results of the line sensor  403 , the image processing circuit  144  generates data for shading compensation (S 110 ).  
         [0080]    In step S 116 , the system controller  140  waits for receipt of a signal from the operation panel  152  instructing operation of the film scanner  100 , i.e., pre-scanning or main-scanning and a frame number, or end of operation. The system controller  140  waits for the signal for a predetermined period of time (S 116 :NO, S 118 :NO).  
         [0081]    If the system controller  140  does not receives the signal within the predetermined period of time (S 118 :YES), then control goes to step S 120  where a sub-routine ENDING PROCEDURE is called. If the system controller  140  receives the signal from the operation panel  152  (S 116 :YES), and if the received signal represents the end of scanning operation (S 122 :YES), then control goes to step S 120 , too.  
         [0082]    If the received signal represents the pre-scanning or the main-scanning (S 122 :NO), then the main-scanning motor  104  is driven to locate the table  101  at a scanning start position (S 124 ). The scanning start position is a position at which an end portion (front end portion) of the scanning window  107   a  is located at the scanning position.  
         [0083]    Next, the system controller  140  judges whether the holder currently inserted into the film scanner  100  is the film holder  201  or the APS holder  301  based on the signal generated by the second holder sensor  122  of the table  101  (S 126 ). If the film holder  201  is currently inserted (S 126 :YES), then the control goes to step S 128  where a sub-routine FILM STRIP SCANNING PROCEDURE is called (S 128 ), while a sub-routine APS FILM SCANNING PROCEDURE is called if the currently inserted holder is the APS film holder  301  (S 126 :NO, S 130 ).  
         [0084]    After step S 128  or  5130  is carried out, the control returns to step S 116 .  
         [0085]    [0085]FIG. 8 shows a flowchart illustrating the FILM STRIP SCANNING PROCEDURE according to the first embodiment of the invention.  
         [0086]    In step S 152 , the film holder  201  is moved by driving the pre-scanning motor  108  to align the frame window ( 209 ,  210 ) corresponding to the designated frame with the scanning window ( 107   a ,  107   b ).  
         [0087]    In step S 154 , it is judged whether the sub-routine FILM SIDE CHECKING PROCEDURE has been executed for the designated frame. If it is not yet executed for the currently designated frame, then the sub-routine FILM SIDE CHECKING PROCEDURE is called (S 154 :NO, S 156 ). In the FILM SIDE CHECKING PROCEDURE, it is determined whether the film strip to be scanned is held in the film holder  201  with the emulsion side thereof faced toward the CCD line sensor  403 , and whether the scanned image should be electronically reversed or not.  
         [0088]    [0088]FIG. 9 shows a flowchart illustrating the FILM SIDE CHECKING PROCEDURE according to the first embodiment of the invention.  
         [0089]    In step S 202 , the first LED  501  of the film front face detecting unit  500  is turned on to irradiate light on the upper surface of the film strip held within the film holder  201 .  
         [0090]    The light reflected by the upper surface of the film strip is received by the first photo diode array  502 . The system controller  140  determines the number of photo diodes of the first photo diode array  502  that has detected the reflected light and stores it into a variable n1 (S 204 ).  
         [0091]    Next, the second LED  503  is turned on (S 206 ). The light emitted from the second LED  503  impinges on the under surface of the film strip and reflected toward the second photo diode array  504 . The system controller  140  determines the number of photo diodes of the second photo diode array  504  that has detected the reflected light and stores it into a variable n2 (S 208 ).  
         [0092]    Next, the system controller  140  judges which side of the film is the emulsion side by comparing the values of n1 and n2. (S 210 ). Since the base of the film is a resin having a relatively flat surface, the light emitted by the LED ( 501 ,  503 ) impinging on the side of the film opposite to the emulsion side will be reflected without being significantly diffused. Thus, the beam spot formed on the photo diode array ( 502 ,  504 ) becomes relatively small, resulting in small number of photo diodes detecting the reflected light.  
         [0093]    On the contrary, if the light emitted by the LED ( 501 ,  503 ) is reflected at the emulsion side of the film strip, the light will be diffused and form a relatively large beam spot on the photo diode array ( 502 ,  504 ), which increases the number of photo diodes that detect the reflected light. Accordingly, it can be determined which side of the film strip is the emulsion side thereof by comparing the values of the variables n1 and n1.  
         [0094]    If the value of n1 is larger than n2 (S 210 :YES), the film strip held in the film holder  201  has the emulsion side thereof faced toward the light source  401 . In other words, the film strip is reversely held in the film holder  201 . Accordingly, the CCD line sensor  403  will obtain an upside down image by scanning the film strip. In this case, the system controller  140  set a REVERSE FLAG (S 212 ), which indicates that the image captured by scanning the film strip should be reversed to obtain an erect image.  
         [0095]    If the value of n1 is not larger than n2 (S 210 :NO), the film strip is held within the film holder  201  with the emulsion side faced toward the CCD line sensor  403  and the film scanner  100  can capture an erect image by scanning the film strip. Therefore, the REVERSE FLAG is cleared in this case so that a process for reversing the captured image will not be carried out later (S 214 ).  
         [0096]    After step S 212  or S 214  is executed, the control returns to the sub-routine FILM STRIP SCANNING PROCEDURE shown in FIG. 8.  
         [0097]    Referring back to FIG. 8, the control goes to step S 158  if it is judged in step S 154  that the sub-routine FILM SIDE CHECKING PROCEDURE has been executed for the currently designated frame.  
         [0098]    In step S 158 , it is judged whether scanning of the currently designated frame has been done before. If pre-scanning or main-scanning of the currently designated frame has not yet been carried out (S 158 :NO), an integration period of the CCD line sensor  403  is determined and stored in the RAM  140 M (S 160 ).  
         [0099]    Next, it is judged whether a main-scanning or a pre-scanning of the designated frame is to be done (S 162 ) and either the main-scanning or the pre-scanning is performed in accordance with the judgment at S 162  (S 164 , S 166 ).  
         [0100]    If the main-scanning is to be done, the main-scanning motor  104  is driven to move the table  101  along the guide rods  102 . As a result, the film strip in the table moves relative to the CCD line sensor in the auxiliary direction and allows the CCD line sensor  403  to scan the whole area of the designated frame (S 164 ).  
         [0101]    If the pre-scanning is to be done, the pre-scanning motor  108  is driven to slide the film holder  201  along the holder supporting groove  106  of the table  101  and thereby allows the CCD line sensor  403  to scan over the designated frame (S 166 ).  
         [0102]    It should be noted that the step angle of the pre-scanning motor  108  is larger than that of the main-scanning motor  104  and hence the scanning pitch in the auxiliary direction is larger in the pre-scanning than in the main-scanning. Accordingly, the time required for the pre-scanning of one frame is shorter than that required for the main-scanning. The pre-scanning may be used for confirming the content of the frame and/or checking the contrast and/or the scanning area of the image before performing the main-scanning.  
         [0103]    In step S 168 , it is determined whether the REVERSE FLAG is on, and only in the case the REVERSE FLAG is on, the image captured in step S 164  or S 166  is reversed by transforming the coordinates of the pixels of the image with one of the following equations (S 170 ):  
         ( X,Y )=( x, −y )   (1)  
         ( X,Y )=(− x, y )   (2)  
         [0104]    where (x, y) represent the coordinate of the pixel of the original image and (X, Y) the coordinate of the pixel of the processed image.  
         [0105]    Since the captured image is reversed as above when the REVERSE FLAG is on, the film scanner  100  according to the embodiment of the invention can provide an erect image even if a user could not distinguish the front face or the emulsion side of the film strip and has placed the film strip into the film holder  201  with the front and rear face reversed.  
         [0106]    After step S 170  is executed, or if it is found that the REVERSE FLAG is not on in step S 168  (S 168 :NO), the control returns to the main procedure shown in FIG. 7.  
         [0107]    [0107]FIG. 10 shows a flowchart illustrating the sub-routine APS FILM SCANNING PROCEDURE according to the first embodiment of the invention. As described before, this sub-routine is executed when the APS film adapter  301  is inserted into the table  101 .  
         [0108]    In step S 252 , it is judged whether the step is executed first time. If step S 252  is executed first time (S 252 :YES), the system controller  140  drives the pre-scanning motor  104  to align the frame window  305  of the APS film adapter  310  with the scanning window ( 107   a ,  107   b ) of the table  101  (S 254 ).  
         [0109]    Next, the (not shown) built-in motor of the APS film adapter  301  is driven to align the designated frame of the APS film with the frame window  305  and hence with the scanning window ( 107   a ,  107   b ) (S 256 ).  
         [0110]    Then, a series of steps S 258 -S 266  are executed to scan the image on the APS film by either the main-scanning or the pre-scanning, which steps are essentially the same as the steps S 158 -S 166  of FIG. 8. Thus, detailed description of the steps S 258  through S 266  is omitted.  
         [0111]    After steps S 258  through S 266  is executed, the control returns to the main procedure shown in FIG. 7.  
         [0112]    [0112]FIG. 11 shows a flowchart illustrating the sub-routine ENDING PROCEDURE according to the first embodiment of the invention. In this procedure, the light source  401  is turned off (S 302 ) and then it is judged whether the film holder  201  is currently held in the table  101  (S 304 ).  
         [0113]    If the film holder  201  is in the table  101  (S 304 :YES), then the film holder  201  is moved back to the most rear position within the table  101  by driving the pre-scanning motor  108  (S 306 ). If the APS film adapter  301  is in the table  101  (S 304 :NO), control signal and power is provided to the APS film adapter  301  through the contact electrodes  306  thereof to drive the (not shown) built-in motor and thereby rewind the film of the (not shown) APS film cartridge (S 308 ).  
         [0114]    After the film holder  201  has been moved back (S 306 ) or the APS film has been rewound (S 308 ), the table  101  is moved back to the most rear position along the guiding rods  102  by driving the main-scanning motor  104  (S 310 ), so that the film holder  201  or the APS film adapter can be removed, and then the control returns to the main procedure shown in FIG. 7.  
         [0115]    Hereinafter, a film scanner according to a second embodiment of the invention, which is a variation of the film scanner  100  according to the first embodiment, will be described. Note that in the following embodiment, elements that are substantially the same as those described in the first embodiment are denoted by the same reference numbers to omit detail descriptions thereof.  
         [0116]    [0116]FIG. 12A schematically shows a plane view of one frame F on the film strip that is to be scanned by the film scanner according to the second embodiment, and FIGS. 12B and 12C schematically show cross sectional view of the frame F along line XIIA-XIIA and line XIIB-XIIB of FIG. 12A, respectively.  
         [0117]    Generally, the film strip bends such that the emulsion side thereof becomes concave. Therefore, if the upper surface of the film strip is concave as shown in solid lines in FIGS.  12 B, the upper surface is the emulsion side of the film strip. On the contrary, if the upper surface is convex as shown in broken lines in FIG. 12B, then the emulsion side is the under surface of the film strip.  
         [0118]    A film scanner according to the second embodiment of the invention determines which side of the film strip is concave, or which side of the film strip is the emulsion side, by measuring the distances from the CCD line sensor  403  to several points defined on the frame F. In the present embodiment, five points P1 through P5 are defined on the frame F as shown in FIG. 12A. The point P3 is defined at substantially the center of the frame. The other points P1, P2, P4 and P5 are defined in the vicinity of the midpoint of each edges of the frame F. (Hereinafter, the points P1 and P5 are referred to as front and rear reference points, respectively, the points P2 and P4 as right and left reference points, respectively, and the point P3 as center reference point.)  
         [0119]    As may be understood from FIGS. 12B and 12C, the distance to the center reference points P3 will be shorter than the distance to the other points if the upper surface of the film strip is concave, while it will be longer if the upper surface of the film strip is convex. Thus, the film scanner according to the second invention determines the convex side, or the emulsion side, of the film strip by comparing the distance to the center reference points P3 with the distances to the other reference points.  
         [0120]    [0120]FIG. 13 schematically show a perspective view of a part of the film scanner  600  according the second embodiment of the invention, and FIG. 14 schematically show a front view of the film scanner shown in FIG. 13 observed from the direction indicated by an arrow X. Further, FIG. 15 shows a control system of the film scanner  600  shown in FIG. 13.  
         [0121]    The film scanner  600  according to the second embodiment of the invention has substantially the same configuration as the film scanner  100  shown in FIG. 1 except that it is not provided with the film front face detecting unit  500  but with a mechanism for moving the imaging lens  402  along the optical axis thereof to automatically adjust the focus on the film strip to be scanned.  
         [0122]    The mechanism for moving the imaging lens  402  includes a lens barrel  413 , an AF motor  411 , and a linear position sensor  412 . The imaging lens  402  is mounted to a (not shown) lens frame that is slidably provided into the lens barrel  413 . An extended portion  415  of the (not shown) lens frame protrudes out from the lens barrels  413  and is coupled with a screw  414  attached to the spindle shaft of the AF motor  411 . As the AF motor  411  rotates, the (not shown) lens frame is driven by the screw  414  to slide within the lens barrel  413  and thereby move the imaging lens  402  along the optical axis thereof.  
         [0123]    The linear position sensor  412  is arranged so as to detect the position of the imaging lens  402  along the optical axis thereof and generate an output signal corresponding to the position of the imaging lens  402  or the position of the film strip in the direction of the optical axis of the imaging lens  402 . In the present embodiment, the voltage value of the output signal of the linear position sensor  412  increases as the distance from the CCD line sensor  403  to the point on which the focus is adjusted increases.  
         [0124]    As shown in FIG. 15, the AF motor  411  is connected with the system controller  140 . The system controller  140  controls the rotation of the AF motor  411 , and hence the position of the imaging lens  402  along the optical axis thereof. The system controller  140  controls the position of the imaging lens  402  based on the output signal of the CCD line sensor  403  so that the focus is adjusted for the film strip. For example, the system controller  140  controls the position of the imaging lens  402  such that the contrast of the image captured by the CCD line sensor  403  is optimized.  
         [0125]    The linear position sensor  412  is also connected with the system controller  140 . Thus, the system controller  140  receives the output signal of the linear position sensor  412 , of which voltage indicates the position of the imaging lens  402  and hence the distance from the CCD line sensor  403  to the point where the focus of the imaging lens  402  is adjusted.  
         [0126]    The operation of the film scanner  600  according to the second embodiment is essentially the same as that of the film scanner  100  according to the first embodiment except the sub-routine FILM SIDE CHECKING PROCEDURE. Accordingly, only the sub-routine FILM SIDE CHECKING PROCEDURE according to the second embodiment of the invention will be described hereinafter.  
         [0127]    [0127]FIG. 16 shows a flowchart of the sub-routine FILM SIDE CHECKING PROCEDURE according to the second embodiment of the invention.  
         [0128]    In step S 402 , the system controller  104  drives the pre-scanning motor  108  to move the film holder  201  and thereby align the front reference point P1 on the film strip with the optical axis of the imaging lens  402  (S 402 ). Then, the system controller  140  adjusts the focus of the imaging lens  402  on the front reference point P1 by controlling the position of the imaging lens  402 , and then detects the output voltage V1 of the linear position sensor  412  (S 404 ).  
         [0129]    Next, the film holder  201  is moved to align the center reference point P3 with the optical axis of the imaging lens  402  (S 406 ). Then, the focus of the imaging lens  402  is adjusted on the center reference point P3, and the output voltages V3 of the liner position sensor  412  are detected (S 408 ). The focus of the imaging lens  402  is also adjusted on the right and left reference points P2 and P4, and each time, the output voltage (V2, V4) of linear position sensor  412  is detected (S 410 ).  
         [0130]    Next, the film holder  201  is further moved to align the rear reference point PS with the optical axis of the imaging lens  402  (S 412 ). Then, the focus of the imaging lens  402  is adjusted on the rear reference point P5 and then the output voltage V5 of the linear position sensor  412  is detected (S 414 ).  
         [0131]    Next, in step S 416 , the system controller  140  compares the value of voltage V3, which represents the distance to the center reference point P3, with the average value of the other four voltages (V1, V2, V4, V5), which represents the average distance to the other reference points,(P1, P2, P4, P5).  
         [0132]    If the value of voltage V3 is smaller than the average value of the other four voltages (V1, V2, V4, V5) (S 416 :YES), it indicates that the distance to the center reference point P1 from the CCD line sensor is shorter than the average distance to the other reference points (P1, P2, P4, P5) and hence that the upper side of the film strip is the concave side or the emulsion side. In other words, it indicates that the film strip is reversely held in the film holder  201 . Therefore, in this case, the system controller  140  sets the REVERSE FLAG (S 418 ) so that the image reversing step S 170  of FIG. 8 will be executed later.  
         [0133]    On the contrary, if the value of voltage V3 is not smaller than the average value, which indicates that the under side of the film strip is the concave side or the emulsion side, the REVERESE FLAG is cleared (S 420 ) so that the image reversing step S 170  will not be executed.  
         [0134]    After step S 418  or S 420  is executed, the control returns to the mains procedure shown in FIG. 7.  
         [0135]    The present disclosure relates to the subject matter contained in Japanese Patent Application No. P2002-105982, filed on Apr. 9, 2002, which is expressly incorporated herein by reference in its entirety.