Abstract:
There is provided a film scanner for scanning images formed on a film, which is provided with an illuminating system that emits collimated light to illuminate the film, and an imaging device that receives the collimated light passed through the film to capture the images formed on the film. The film scanner is further provided with a defect position obtaining system that obtains a plurality of images and obtains position data corresponding to a position of an extraneous substance on the film based on a difference between at least two of the plurality of images, the plurality of images being respectively obtained at different conditions of the collimated light incident on the film, and an interpolating system that performs interpolation.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a film scanner for scanning images formed on a silver-salt film.  
           [0002]    Recently, a film scanner for capturing images on a silver-salt film (hereinafter, referred to as a film) has been developed and used. In general, the film scanner is provided with a light source unit for illuminating the film, an imaging lens, and a CCD line sensor. An image on the film is formed on the CCD line sensor by the imaging lens.  
           [0003]    By scanning the image on the film in a direction in which the CCD line sensor extends (i.e., in a main scanning direction), while the film is moved relative to the CCD line sensor in a direction perpendicular to the main scanning direction (i.e., in an auxiliary scanning direction), a two-dimensional area on the film is scanned.  
           [0004]    Sometimes, there are extraneous substances, for example, foreign particles, or scratches, on the film. Such extraneous substances make defects, such as black spots, in the captured image, thereby an image quality is deteriorated.  
           [0005]    A conventional film scanner which includes a plurality of light sources, for example, two light sources, emitting defused light so as to prevent occurrences of defects in the captured image due to extraneous substances is known. This conventional film scanner captures two images respectively formed using the two light sources each of which emits defused light. In this film scanner, the two captured images are compared to detect differences between the two images in order to identify defects formed in the image. If the defects are detected in the image, the defects are corrected using the two image complementarily.  
           [0006]    However, this film scanner requires the plurality of light sources, which increases cost of the film scanner or a room for such a light source unit. Further, since the diffused light is used, a difference between the two captured images does not clearly appear. Therefore, the defects on the image can not be corrected sufficiently.  
           [0007]    A technique for correcting defects formed on the captured image using an image processing software, such as a photo retouching software running on a personal computer is known. However, in order to correct the image using the photo retouching software, the image has to be input to the personal computer. In addition, an operation of the photo retouching software for correcting defects on the image is generally complicated. In general, some experience is required to correctly use the photo retouching software.  
         SUMMARY OF THE INVENTION  
         [0008]    It is therefore an object of the invention to provide an improved film scanner which is capable of properly correcting defects on an captured image caused by extraneous substances on a film to be scanned.  
           [0009]    According to an aspect of the invention, there is provided a film scanner for scanning images formed on a film, which is provided with an illuminating system that emits collimated light to illuminate the film, and an imaging device that receives the collimated light passed through the film to capture the images formed on the film. The film scanner is further provided with a defect position obtaining system that obtains a plurality of images each of which corresponds to a frame of the film to be scanned using the imaging device, and obtains position data corresponding to a position of an extraneous substance on the film based on a difference between at least two of the plurality of images, the plurality of images being respectively obtained at different conditions of the collimated light incident on the film. The film scanner is further provided with an interpolating system that performs interpolation based on the position data obtained by the defect position obtaining system.  
           [0010]    With this configuration, since the collimated light is used to illuminate the film, a black portion on the scanned image caused by the extraneous subject on the film has sharp edges and relatively high density. Accordingly, the black portion on the scanned image caused by the extraneous subject on the film can be reliably distinguished from other pixels in the captured image.  
           [0011]    By using different conditions of the collimated light incident on the film, the position data can be obtained.  
           [0012]    In a particular case, the illuminating system may be capable of changing an incident angle of the collimated light with respect to the film. In this case, the defect position obtaining system obtains the plurality of images at different incident angles of the collimated light with respect to the film.  
           [0013]    In a particular case, the illuminating system may include a single light source which emits light, and a collimating lens that collimates light emitted by the single light source.  
           [0014]    Optionally, the illuminating system may include a mirror that reflects the collimated light toward the film, and an angle changing system that changes an angle of the mirror with respect to a predetermined plane to change the incident angle of the collimated light with respect to the film.  
           [0015]    Further optionally, the angle changing system may include a motor that rotates the mirror about a rotational axis so as to change the angle of the mirror with respect to the predetermined plane.  
           [0016]    In a particular case, the defect position obtaining system may obtain an image when the incident angle of the collimated light with respect to the film is zero and at least one image when the incident angle of the collimated light with respect to the film is not zero.  
           [0017]    In a particular case, the defect position obtaining system may obtain the position data based on positions of black portions respectively formed on the plurality of images by the extraneous substance on the film.  
           [0018]    In a particular case, the defect position obtaining system may obtain the position data based on a difference between positions of black portions of at least two of the plurality of images, the black portions being respectively formed on the plurality of images by the extraneous substance on the film.  
           [0019]    Optionally, the defect position obtaining system may obtain the position data by comparing the distance between the positions of the black portions of the at least two of the plurality of images with a theoretical distance between the positions of the black portions. In this case, the theoretical distance is calculated based on a geometrical condition including incident angles of the collimated light at which the at least two of the plurality of images are obtained.  
           [0020]    Still optionally, the interpolating system may perform the interpolation using one of methods of Nearest Neighbor, Bi-Linear and Bi-Cubic.  
           [0021]    Optionally, the imaging device may include a line image sensor unit for scanning the film in a main scanning direction, and a auxiliary scanning system that moves the film relative to the line image sensor in an auxiliary scanning direction which is perpendicular to the main scanning direction.  
           [0022]    Still optionally, the film scanner may include a storing system that stores an image interpolated by the interpolating system into a memory.  
           [0023]    Still optionally, the memory may be an IC-card.  
           [0024]    In a particular case, the film scanner may include an interface that is used to communicate with an external device so as to output an image interpolated by the interpolating system to the external device.  
           [0025]    According to another aspect of the invention there is provided a film scanner for scanning images formed on a film, which is provided with an illuminating system that emits collimated light to illuminate the film, an imaging device that receives the collimated light passed through the film to capture the images formed on the film. The film scanner is further provided with a defect position obtaining system that obtains position data corresponding to a position of an extraneous substance on the film based on a position of a black portion on an image captured by the imaging device, and an interpolating system that performs interpolation based on the position data obtained by the defect position obtaining system.  
           [0026]    With this configuration, since the collimated light is used to illuminate the film, a black portion on the scanned image caused by the extraneous subject on the film has sharp edges and relatively high density. Accordingly, the black portion on the scanned image caused by the extraneous subject on the film can be reliably distinguished from other pixels in the captured image.  
           [0027]    According to another aspect of the invention, there is provided a film scanner for scanning images formed on a film, which is provided with an illuminating system that emits collimated light to illuminate the film, an imaging device that receives the collimated light passed through the film to capture the images formed on the film, and a defect position obtaining system that obtains a plurality of images each of which corresponds to a frame of the film to be scanned using the imaging device, and obtains position data corresponding to a position of an extraneous substance on the film based on a difference between at least two of the plurality of images, the plurality of images being respectively obtained at different conditions of the collimated light incident on the film.  
           [0028]    According to another aspect of the invention, there is provided a film scanning system for scanning images formed on a film, which is provided with a film scanner that includes an illuminating system which emits collimated light to illuminate the film and which is capable of changing conditions of the collimated light incident on the film, and an imaging device that receives the collimated light passed through the film to capture the images formed on the film. The film scanning system is further provided with an external device that includes an interface for communicating with the film scanner so as to control the film scanner.  
           [0029]    In this structure, the external device includes a defect position obtaining system that obtains a plurality of images each of which corresponds to a frame of the film to be scanned using the imaging device, and obtains position data corresponding to a position of an extraneous substance on the film based on a difference between at least two of the plurality of images, the plurality of images being respectively obtained at different conditions of the collimated light incident on the film. Further, the external device includes an interpolating system that performs interpolation based on the position data obtained by the defect position obtaining system.  
           [0030]    According to another aspect of the invention there is provided a method for correcting defects on a scanned image caused by an extraneous subject on a film, the method includes performing a first scanning to obtain an image of a frame of the film to be scanned at a first incident angle of light incident on the film, performing a second scanning to obtain an image of the frame of the film to be scanned at a second incident angle of light incident on the film, and determining a position of the extraneous subject on the film using the image obtained at the first incident angle of light and the image obtained at the second incident angle of light.  
           [0031]    According to another aspect of the invention there is provided a method for correcting defects on a scanned image caused by an extraneous subject on a film, the method includes performing a first scanning to obtain an image of a frame of the film to be scanned at a first incident angle of light incident on the film, performing a second scanning to obtain at least one image of the frame, the at least one image being obtained at a different incident angle of light incident on the film from the first incident angle, and determining a position of the extraneous subject on the film using the image obtained at the first incident angle of light and the image obtained at the different incident angle of light from the first incident angle. 
       
    
    
     BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS  
       [0032]    [0032]FIG. 1 is a perspective view of a part of a film scanner according to an embodiment of the invention;  
         [0033]    [0033]FIG. 2 is a side view of the part of the film scanner viewed along an arrow Y shown in FIG. 1;  
         [0034]    [0034]FIG. 3 is a perspective view of a film holder in a situation where a hinge cover is opened;  
         [0035]    [0035]FIG. 4 is a perspective view of an appearance of an APS film adapter;  
         [0036]    [0036]FIG. 5 is a circuit diagram of the film scanner according to the embodiment of the invention;  
         [0037]    [0037]FIG. 6 is a flowchart illustrating a scanning operation of the film scanner;  
         [0038]    [0038]FIG. 7 is a flowchart illustrating a command processing called at step S 200  in FIG. 6;  
         [0039]    [0039]FIG. 8 is a flowchart illustrating a correction pre-scan process called at step S 300  in FIG. 7;  
         [0040]    [0040]FIG. 9A schematically shows a relationship of incident angles θ 1 , θ 2  and θ 3  of collimated light with respect to a film F;  
         [0041]    FIGS.  9 B- 9 D are examples of images including shadows cast by a foreign particle M on the Film F obtained using collimated light at incident angles θ 1 , θ 2  and θ 3 , respectively; and  
         [0042]    FIGS.  9 E- 9 G are examples of images including shadows cast by a scratch on the Film F obtained using collimated light at incident angles θ 1 , θ 2  and θ 3 , respectively. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0043]    Hereinafter, an embodiment according to the invention is described with reference to the accompanying drawings.  
         [0044]    [0044]FIG. 1 is a perspective view of a part of a film scanner  1000  according to an embodiment of the invention. FIG. 2 is a side view of the part of the film scanner  1000  viewed along an arrow Y shown in FIG. 1.  
         [0045]    As shown in FIG. 1, the film scanner  1000  includes two guide bars  102  and  102  which are fixed to a casing (not shown) of the film scanner  1000 , and a table  101  which is mounted on the guide bars  102  and  102  and is slidable along the guide bars  102  and  102 .  
         [0046]    On a side surface of the table  101 , a rack  103  is formed. A main motor  104  is fixed to the casing of the film scanner  1000  such that a pinion  105  fixed to a rotational shaft thereof is engaged with the rack  103  of the table  101 . As the main motor  104  is driven, the table  101  moves along the guide bars  102  and  102 .  
         [0047]    In this embodiment, a direction in which a CCD line sensor unit  405  extends is defined as a main scanning direction, while a direction, which is perpendicular to the main scanning direction, in which the table  101  moves is defined as an auxiliary scanning direction.  
         [0048]    As shown in FIG. 1, inside the table  101 , a holder supporting groove  106  is formed in parallel with a direction in which the table  101  moves. As described below, a film holder  201  which is configured to hold a 35 mm film or an APS film adapter  301  which is configured to hold an APS (the Advanced Photo System) film can be inserted in the holder supporting groove  106  (see FIG. 1 and FIG. 4).  
         [0049]    Further, the table  101  has a reading window  107  which penetrates from a top surface to a bottom surface of the table  101 . A frame of the film to be scanned is exposed via the reading window  107 .  
         [0050]    Further, on the side surface of the table  101 , a pre-scan motor  108  is fixed such that a pinion  109  fixed on a rotational shaft of the pre-scan motor  108  is engaged with a rack  212  formed on the film holder  201  when the film holder  201  is inserted in the holder supporting groove  106  or engaged with a rack  304  formed on the APS film adapter  301  when the APS film adapter  301  is inserted in the holder supporting groove  106 .  
         [0051]    The main motor  104  and the pre-scan motor  108  are stepping motors.  
         [0052]    Above the upper surface of the table  101 , a reading optical system  400  is arranged. The reading optical system  400  includes a light source  401  which is positioned such that an optical axis thereof is parallel with the guide bars  102  and  102 . That is, the optical axis of the light source  401  is parallel with a horizontal plane. The reading optical system  400  further includes a collimating lens  402 , a deflecting mirror  403 , an imaging lens  404  located beneath the deflecting mirror  403  and under the table  101 , and a CCD line sensor unit  405  (see FIG. 2). The CCD line sensor unit  405  converts an image formed thereon by the imaging lens  404  to an electronic signal.  
         [0053]    The light source  401  has characteristics equal to or substantially equal to characteristics of a point source of light emitting white light. The collimating lens  402  collimates light emitted by the light source  401  such that the collimated light has a width larger than a width of the reading window  107  in a direction perpendicular to the direction in which the table  101  moves.  
         [0054]    The deflecting mirror  403  is fixed to a rotational shaft of a motor  406  attached to the casing of the film scanner  1000 , and therefore, the deflecting mirror  403  is rotatable about an axis perpendicular to the auxiliary scanning direction. That is, an angle of inclination of the deflecting mirror  403  with respect to the horizontal plane can be controlled.  
         [0055]    In a typical case, the angle of inclination of the deflecting mirror  403  with respect to the horizontal plane is set at  450 . A solid line of the deflecting mirror  403  indicated in FIG. 2 corresponds to this case. In this case, the deflecting mirror  403  reflects the collimated light toward the CCD line sensor unit  405  such that the reflected light proceeding to the CCD line sensor unit  405  is perpendicular to a light receiving surface of the CCD line sensor unit  405 .  
         [0056]    The CCD line sensor unit  405  includes three line sensors for RGB (Red, Green and Blue) components. Each of the line sensors includes a predetermined number of CCD elements arranged in line in the main scanning direction. By reading the image formed on the CCD line sensor unit  405  sequentially along a direction of elongation of the line sensor, a main scanning operation of the image is performed. Thus, a color image is obtained. In this embodiment, the motor  406  is a stepping motor.  
         [0057]    In this embodiment, the film holder  201  holds a 35 mm film strip containing six frames of images. As shown in FIG. 1, the film holder  201  includes a base  202  and a hinge cover  203  which is hinged on the base  202  by a pair of hinges  206  and  206  (see FIG. 3). The 35 mm film strip is held tight between the base  202  and the hinge cover  203  when the hinge cover  203  is closed.  
         [0058]    On an upper surface of the base  202 , a groove  211  is formed along the length of the film holder  201 . The groove  211  has a bottom surface on which the rack  212  is formed. When the film holder  201  is inserted in the holder supporting groove  106  of the table  101 , the pinion  109  of the pre-scan motor  108  engages with the rack  212  on the bottom surface of the groove  211  so as to move the film holder  201  in the auxiliary scanning direction relative to the table  101 .  
         [0059]    [0059]FIG. 3 is a perspective view of the film holder  201  in a situation where the hinge cover  203  is opened. As shown in FIG. 3, on the base  202 , a concave portion  204  having a shallow depth is formed. On the concave portion  204 , the 35 mm film strip is placed. The hinge cover  203  is configured such that it fits in the concave portion  204  when it is closed. Also, Projections  207  and  207  of the hinge cover  203  respectively fit in concave portions  208  and  208  formed on the base  202  along a side of the concave portion  204  when the hinge cover  203  is closed. With this structure, the hinge cover  203  can be keep closed.  
         [0060]    On both of the hinge cover  203  and the base  202 , six frame windows  210  and  209  respectively corresponding to the six images of the film strip are formed along the length of the film holder  201 .  
         [0061]    The concave portion  204  has a bottom surface on which a pair of guide rails  205  and  205  are formed along the length of the film holder  201 . The film strip is inserted into the concave portion  204  with being guided by the pair of rails  205  and  205 . The hinge cover  203  is closed after the film strip is placed on the concave portion  204  properly. With this structure, it becomes possible to hold tight the film strip between the hinge cover  203  and the bottom surface of the concave portion  204 .  
         [0062]    [0062]FIG. 4 is a perspective view of an appearance of the APS film adapter  301 . As shown in FIG. 4, a casing  309  of the APS film adapter  301  generally takes the form of a flat rectangular solid, and has sleeve portions  302  and  302 . As described above, the APS film adapter  301  can be inserted into the holder supporting groove  106  of the table  101 .  
         [0063]    On an upper surface of one sleeve portion  302 , a groove  303  is formed along the length of the APS film adapter  301 . Further, on a bottom surface of the groove  303  the rack  304  is formed throughout the length of the groove  303 .  
         [0064]    Substantially at the center of the film adapter  301 , a frame window  305 , which penetrates from the top surface to a bottom surface of the film adapter  301 , is formed.  
         [0065]    At a front portion of the top surface of the APS film adapter, electrodes  306 , each of which takes the form of a protrusion, are arranged. When the APS film adapter  301  is inserted into the holder supporting groove  106  of the table  101 , electrodes  306  contact with electrodes (not shown) formed in the holder supporting groove  106  of the table  101 . Thus, the APS film adapter  301  and the table  101  are electrically connected to each other.  
         [0066]    In the APS film adapter  301 , an APS cartridge accommodating an APS film is incorporated. Also, in the APS film adapter  301 , an internal motor are arranged. When the APS film adapter  301  is inserted into the holder supporting groove  106 , is becomes possible to control the internal motor in the APS film adapter  301  so that a desired frame of image is selectively exposed through the frame window  305 .  
         [0067]    [0067]FIG. 5 is a circuit diagram of the film scanner  1000  according to the embodiment of the invention. To elements which are equal to elements shown in FIGS.  1 - 4 , the same reference numbers are assigned.  
         [0068]    As shown in FIG. 5, the CCD line sensor unit  405  is driven through a CCD line sensor driver  141  under control of a system controller  140 . An image signal output by the CCD line sensor unit  405  is amplified by an AMP  142 , and the amplified image signal is converted to digital form by a A-D converter  143 . Then, the digital image signal is processed by a image processing circuit  144  to make image data and/or various signals including a composite video signal under control of the system controller  140 .  
         [0069]    A memory  145  is, for example, an IC card, and is used for storing the processed image as image data. The output of the image processing circuit  144  is also transmitted, via an interface circuit  146  (e.g., SCSI or USB), to I/O terminals  147 , which may be connected to an external device such as a personal computer.  
         [0070]    The light source  401  is controlled via a light source driving circuit  148  by the system controller  140 . The main motor  104  is connected to the system controller  140  to control the position of the table  101  via the rack  103  and the pinion  105 . The pre-scan motor  108  is connected to the system controller  140  to control the position of the film holder  201  or the APS film adapter  301 . Further, the motor  406  is connected to the system controller  140  to control the angle of inclination of the deflecting mirror  403 .  
         [0071]    It should be noted that the film scanner  1000  includes various sensors to detect positions of the table  101 , the base  202 , the film holder  201 , and the APS film adapter  301 .  
         [0072]    Next, a scanning operation of the film scanner  100  for capturing images on the film will be described.  
         [0073]    As a preparation for the scanning operation, the film strip is inserted into the film holder  201  through the following steps. Firstly, the hinge cover  203  is opened as indicated in FIG. 3. Then, the film strip is placed on the concave portion  204 . It should be noted that a position of the film strip along a width direction thereof is fixed by the pair of guide rails  205 , and a position of the film strip along the length of the film strip is fixed by front and rear edges of the concave portion  204 . After the film strip is properly placed on the concave portion  204 , the hinge cover  203  is closed, i.e., fitted in the concave portion  204 . The film holder  201  is then inserted into the holder supporting groove  106  to start the scanning operation.  
         [0074]    [0074]FIG. 6 is a flowchart illustrating the scanning operation of the film scanner. FIG. 7 is a flowchart illustrating a command processing called at step S 200  in FIG. 6. FIG. 8 is a flowchart illustrating a correction pre-scan process called at step S 300  in FIG. 7. The processes shown in FIGS.  6 - 8  are performed under control of the system controller  140 .  
         [0075]    The process shown in FIG. 6 is started, for example, when a power switch (not shown) of the film scanner  1000  is turned ON. In step S 101 , it is determined whether the film holder  201  is inserted into the table  101 . If the film holder is not inserted (S 101 :NO), control proceeds to step S 103  to determine whether a predetermined time period has elapsed. If the predetermined time period has elapsed (S 103 :YES), the scanning process is terminated. If the predetermined time period has not elapsed (S 103 :NO), control returns to step S 101 .  
         [0076]    If the film holder  201  is inserted in the table  101  (S 11 :YES), control proceeds to step S 105  where the system controller  140  drives the main motor  104  to move the table  101  to an initial position. In S 107 , it is determined whether the table  101  is located at the initial position. If the table  101  has not yet reached the initial position (S 107 : NO), the main motor  104  is kept driven (S 105 ). If the table  101  has reached the initial position (S 107 : YES), control proceeds to S 109  where the main motor  104  is stopped.  
         [0077]    Next, in step S 111 , the system controller  140  drives the motor  406  to move the deflecting mirror  403  to an initial position in which the angle of inclination of the deflecting mirror  403  with respect to the horizontal plane is 45°. In S 113 , it is determined whether the deflecting mirror  403  is located at the initial position. If the deflecting mirror  403  has not yet reached the initial position (S 113 : NO), the motor  406  is kept driven (S 111 ). If the deflecting mirror  403  has reached the initial position (S 113 : YES), control proceeds to S 115  where the motor  406  is stopped.  
         [0078]    Next, the system controller  140  turns ON the light source  401  to perform “shading correction” based on the output of the CCD line sensor unit  405  which receives light emitted by the light source  401  (S 117 ,S 119 ).  
         [0079]    In step S 121 , it is determined whether a command is entered. If the command is not entered (S 121 :NO), control proceeds to step S 123  to determine whether a predetermined time period has elapsed. If the predetermined time interval has elapsed (S 123 :YES), control proceeds to step S 125  to execute a terminating process. If the predetermined time period has not elapsed (S 123 :NO), control returns to step S 121 .  
         [0080]    If it is determined that the command is entered (S 121 :YES), control proceeds to step S 127  to recognize the entered command. If the entered command is an end command (S 127 :YES), control proceeds to S 125  to execute the terminating process.  
         [0081]    If the entered command is not the end command, i.e., if the entered command is a primary scan command or a pre-scan command (S 127 :NO), control proceeds to step S 129  where the main motor  104  is driven to move the table  101  to a scanning start position. In step S 131 , it is determined whether the table  101  is moved to the scanning start position. If the table  101  is not moved to the scanning start position (S 131 :NO), the main motor  104  is kept driven (S 129 ). If the table  101  is moved to the scanning start position (S 131 :YES), control proceeds to step S 133  to stop the main motor  104 . Then, the command processing is executed (S 200 ).  
         [0082]    In the terminating process, the light source  401  is turned OFF (S 125 ), and the pre-scan motor  108  is driven to move the film holder  201  to an initial position (S 135 , S 137 , S 139 ). Then, the main motor  104  is driven to move the table  101  to the initial position (S 141 , S 143 , S 145 ), and the scanning process is terminated.  
         [0083]    Next, the command processing will be described with reference to FIG. 7. Initially, the system controller  140  drives the pre-scan motor  108  to move the film holder  201  to a scanning start position (S 201 ). The scanning start position is defined as a position where a frame to be scanned is located on an optical axis of the reading optical system  400 . In step S 203 , it is determined whether the film holder  201  is moved to the scanning start position. If the film holder  201  is not moved to the scanning start position (S 203 :NO), the pre-scan motor  108  is kept driven (S 201 ). If the film holder  201  is moved to the scanning start position (S 203 :YES), control proceeds to step S 205  to stop the pre-scan motor  108 .  
         [0084]    In step S 207 , it is determined whether the frame to be scanned (i.e., the frame moved to the position on the optical axis through the steps S 201 - 205 ) has already underwent a pre-scan process. If the frame to be scanned has not underwent the pre-scan process (S 207 :NO), control proceeds to step S 209  to determine accumulation time of the CCD line sensor unit  405 .  
         [0085]    In step S 211 , it is determined whether the film scanner  1000  is set to a correction mode. If the film scanner is set to the correction mode (S 211 :YES), control proceeds to S 213  where it is determined whether a correction pre-scan process has already been executed. If the correction pre-scan process has not already been executed (S 213 :NO), the correction pre-scan process is executed in step S 300 . If the correction pre-scan process has already been executed (S 213 :YES), control proceeds to step S 215  to determine whether the film scanner  1000  is set to a primary scan mode.  
         [0086]    If the film scanner  1000  is set to the primary scan mode (S 215 :YES), a primary scan process is executed in step S 219 . Next, an interpolation process is executed (S 221 ), and control returns to a main process. The interpolation process, which is described in detail later, is a process in which pixels corresponding to defects on the scanned image are interpolated based on position data obtained by the correction pre-scan process (S 300 ) shown in FIG. 8.  
         [0087]    If the film scanner is not set to the primary scan mode (S 215 :NO), the pre-scan process is executed in step S 223 . Next, the interpolation process is executed (S 225 ), and control returns to the main process.  
         [0088]    If the film scanner  1000  is not set to the correction mode (S 211 :NO), control proceeds to S 217  where it is determined whether the film scanner  1000  is set the primary scan mode. If the film scanner  1000  is set to the primary scan mode (S 217 :YES), the primary scan process is executed (S 227 ). If the film scanner  1000  is not set to the primary scan mode (S 217 :NO), the pre-scan process is executed in step S 229 . After the primary scan process (S 227 ) or the pre-scan process (S 229 ) is executed, control returns to the main process without executing the interpolation process.  
         [0089]    In the primary scan process executed in S 219  or S 227 , a fine image of a selected frame is generated. That is, in the primary scan process, an image portion corresponding to a portion of the selected frame that is illuminated with the collimated light is read from the CCD line sensor unit  405 . Thus, the main scanning operation is performed.  
         [0090]    Further, the main scanning operation is executed repeatedly while the table  101  is moved in the auxiliary scanning direction. In this case, auxiliary scanning pitches are relatively small because rotational pitches of the main motor  104  are relatively small. Therefore, a fine image can be generated. Thus, the primary scan process is completed.  
         [0091]    In the pre-scan process executed in S 223  or S 229 , a relatively rough image of the selected frame is obtained. That is, in the pre-scan process, an image portion corresponding to a portion of the selected frame that is illuminated with the collimated light is read from the CCD line sensor unit  405 . Thus, the main scanning operation is performed.  
         [0092]    Further, the main scanning operation is executed repeatedly while the film holder  201  inserted in the holder supporting groove  106  is moved in the auxiliary scanning direction. In this case, auxiliary scanning pitches are relatively large because rotational pitches of the pre-scan motor  108  are relatively large. Therefore, the relatively rough image is generated. Thus, the pre-scan process is completed. It should be noted that the relatively rough image generated through, the pre-scan process is used for the purpose of checking, for example, the subject on the selected frame, the density of the image, or a reading position of the selected frame.  
         [0093]    Next, the correction pre-scan process executed in S 300  in FIG. 7 will be described in detail with reference to FIG. 8. In step S 301 , the motor  406  is driven to move the deflecting mirror  403  to its initial position in which the angle of inclination of the deflecting mirror  403  with respect to the horizontal plane is an angle α 1 (45°). In step S 303 , it is determined whether the deflecting mirror  403  is moved to the initial position. If the deflecting mirror  403  is not moved to the initial position (S 303 :NO), the motor  406  is kept driven (S 301 ). If the deflecting mirror  403  is moved to the initial position (S 303 :YES), control proceeds to step S 305  to stop the motor  406 .  
         [0094]    Next, the system controller  140  starts to drive the pre-scan motor  108  to move the selected frame to the scanning start position (S 307 ). In step S 309 , it is determined whether the selected frame is moved to the scanning start position. If the selected frame is not moved to the scanning start position (S 309 :NO), the pre-scan motor  108  is kept driven (S 307 ). If the selected frame is moved to the scanning start position (S 309 :YES), control proceeds to step S 311  to stop the pre-scan motor  108 .  
         [0095]    In step S 313 , the pre-scan process is started to obtain a relatively rough image of the selected frame. The obtained image is then stored in, for example, the memory  145  as image data (S 315 ).  
         [0096]    In step S 317 , it is determined whether the pre-scan process is executed a predetermined number of times. If the pre-scan process does not executed the predetermined number of times (S 317 :NO), control proceeds to S 323  to slightly change the angle of inclination of the deflecting mirror  403  to an angle α 2 .  
         [0097]    That is, in step S 323 , the system controller  140  starts to drive the motor  406 . In step S 325 , it is determined whether the angle of inclination of the deflecting mirror  403  reaches the angle α 2 . If the angle of inclination of the deflecting mirror  403  does not reach the angle α 2 (S 325 :NO), the motor  406  is kept driven (S 323 ). If the angle of inclination of the deflecting mirror  403  reaches the angle α 2 (S 325 :YES), control proceeds to step S 327  to stop the motor  406 .  
         [0098]    In this embodiment, the predetermined number of times that the pre-scan processes are executed on the same frame of image is three. The three pre-scan processes are executed at angles of inclination of α 1 , α 2  and α 3 , respectively (see FIG. 9A). Thus, three pre-scan images on the same frame of image are obtained.  
         [0099]    It should be noted that a position of the film holder  201  relative to the CCD line sensor unit  405  in the auxiliary scanning direction (i.e., a scanning start position in the auxiliary scanning direction) may be adjusted when the angle of inclination of the deflecting mirror  403  is changed so as to obtain the same pre-scan image of the frame at the changed angle of inclination of the deflecting mirror  403 .  
         [0100]    If it is determined that the pre-scan processes are executed the predetermined number of times (S 317 :YES), control proceeds to S 319  where the position data of pixels corresponding to the extraneous subjects on the frame (i.e., pixels targeted for interpolation) is obtained. Then, the interpolation process is executed on the pixels corresponding to the extraneous subjects on the frame (S 321 ).  
         [0101]    Next, the process for obtaining the position data for interpolation executed through the steps shown in FIG. 8 will be described in detail with reference to FIGS.  9 A- 9 G.  
         [0102]    [0102]FIG. 9A, which is a side view of a part of the film scanner viewed along the arrow Y shown in FIG. 1, schematically shows a relationship of incident angles θ 1 , θ 2  and θ 3  of the collimated light with respect to a film F. Three incident angles θ 1 , θ 2  and θ 3  correspond to angles of inclination α 1 , α 2  and α 3  of the deflecting mirror  403  at which the three pre-scan images are obtained. As shown in FIG. 9A, a foreign particle M on the Film F cast a shadow B 1  on the CCD line sensor unit  405  when the film F is illuminated with the collimated light at the incident angle θ 1 . FIG. 9B (an image G 1 ) shows a portion of the scanned image including the shadow B 1  obtained using the collimated light at the incident angle θ 1  (θ 1 =0°).  
         [0103]    The foreign particle M on the Film F cast a shadow B 2  on the CCD line sensor unit  405  when the film F is illuminated with the collimated light at the incident angle θ 2 . FIG. 9C (an image G 2 ) shows the same portion of the scanned image as the image G 1  when the pre-scan image is obtained using the collimated light at the incident angle θ 2  (0°&lt;θ 2 )  
         [0104]    The foreign particle M on the Film F cast a shadow B 3  on the CCD line sensor unit  405  when the film F is illuminated with the collimated light at the incident angle θ 3 . FIG. 9D (an image G 3 ) shows the same portion of the image as the image G 1  when the pre-scan image is obtained using the collimated light at the incident angle θ 3  (θ 2 &lt;θ 3 )  
         [0105]    FIGS.  9 E- 9 G are the other examples of images including shadows cast by, for example, a scratch, on the Film F obtained using collimated light at incident angles θ 1 , θ 2  and θ 3 , respectively.  
         [0106]    As can be seen FIG. 9A, the shadows B 1 -B 3  (black pixels) appear at different positions on the same frame of image because the foreign particle M on the film receives light from different angles. Therefore, by comparing three images G 1 -G 3  to detect a mismatch between the positions of shadows included in at least two of the images G 1 -G 3 , pixels corresponding to the detected mismatch can be determined as defects caused by the foreign particle M.  
         [0107]    It should be noted that shift amounts among the positions of the shadows B 1 -B 3  can be obtained theoretically based on a geometrical condition including incident angles θ 1 -θ 3  of the collimated light. Therefore, the obtained shift amount may be taken into account to determine whether the detected mismatch corresponds to the defects caused by the foreign particle M.  
         [0108]    In this embodiment, incident angles which have different signs and the same absolute value are considered as different incident angles.  
         [0109]    If the pixels consisting the shadow B 1  are determined as the defects in this way, pixels consisting the shadow B 1  and a predetermined number of pixels surrounding the shadow B 1  are determined as pixels targeted for the interpolation. Thus, the position data for the interpolation is obtained.  
         [0110]    The interpolation process executed in S 221 , S 225  or S 321  may be a process using, for example, Nearest Neighbor, Bi-Linear, or Bi-Cubic. Nearest Neighbor is a method in which pixel data of a pixel nearest a target pixel (i.e., a pixel targeted for the interpolation) is used as pixel data of the target pixel.  
         [0111]    Bi-Linear is a method in which pixel data of the target pixel is obtained by a weighted average of pixel data of four pixels adjacent to the target pixel according to distances between the target pixel and pixels adjacent to the target pixel.  
         [0112]    Bi-Cubic is a method in which pixel data of the target pixel is obtained by a weighted average of pixel data of sixteen pixels surrounding the target pixel.  
         [0113]    By executing the interpolation process, black pixels appeared on the image due to the extraneous subject on the film can be removed.  
         [0114]    While the operation of the present invention is described with respect to the Nearest Neighbor, Bi-Linear, or Bi-Cubic process, the invention is not limited to the use of such processes, and other processes may be utilized without departing from the scope and/or spirit of the invention.  
         [0115]    As described above, since collimated light is used to illuminate the film in this embodiment, a black portion on the captured image caused by the extraneous subject on the film has sharp edges and relatively high density. Accordingly, the black portion caused by the extraneous subject on the film can be reliably distinguished from other pixels in the captured image. Further, by comparing at least two images respectively captured using collimated light having different incident angles, the position data of pixels corresponding to the extraneous subject on the film, i.e., pixels targeted for the interpolation, are obtained.  
         [0116]    In the embodiment, two kinds of film adapters ( 201  and  301 ) are described, however, it is appreciated that another type of film adapter for holding, for example, a “brownie” type film, or a slide film, may be employed.  
         [0117]    Although the three images of the same frame at different incident angles of the collimated light are obtained by performing the pre-scan process in the above-mentioned embodiment, it is appreciated that the three images of the same frame may be obtained by performing the primary scanning process.  
         [0118]    According to the embodiment of the invention, only one light source is required to identify pixels corresponding to the extraneous subject on the film. Therefore, cost and/or a room for accommodating the light source unit in the film scanner can be reduced.  
         [0119]    According to the embodiment of the invention, high quality images can be obtained.  
         [0120]    It is appreciated that processes shown in FIGS.  6 - 8  may be performed under control of the external device (for example, a personal computer) which is connected to the film scanner  1000  via the I/O terminals  147 . In this case, a computer program for performing such processes shown in FIGS.  6 - 8  executes on the external device.  
         [0121]    The present disclosure relates to the subject matter contained in Japanese Patent Application No. P2002-119469, filed on Apr. 22, 2002, which is expressly incorporated herein by reference in its entirety.