Patent Publication Number: US-2017374222-A1

Title: Image reading method and image reading apparatus

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an image reading method and an image reading apparatus. 
     Description of the Related Art 
     An image reading apparatus which can read an image of an object mounted on a mounting table by picking up an image of the object from above has been conventionally known. 
     Japanese Patent Application Laid-Open No. 2007-67966 discloses an image reading apparatus for recognizing an exact region of an original. The image reading apparatus includes a display panel as an original mounting surface, and is capable of displaying a sheet marker on the display panel according to various inputted conditions such as the size of the original whose image is to be picked up, and reading an image of the original after the user sets the original within an area indicated by the sheet marker. 
     However, the image reading apparatus disclosed in Japanese Patent Application Laid-Open No. 2007-67966 has difficulty in reading the exact image of the original because there is a limit to how accurate the user can set the original according to the sheet marker. Moreover, the image reading apparatus forces the user to perform cumbersome work of setting the original according to the sheet marker. 
     SUMMARY OF THE INVENTION 
     In view of this, an object of the present invention is to provide an image reading method and an image reading apparatus which enables accurate and easy reading of an image of an object mounted on a mounting surface. 
     The present invention includes obtaining a pickup image by performing image pickup of an object mounted on a mounting surface with an imaging unit; and extracting an image of the object from the pickup image, based on a brightness difference between the image of the object and an image of a shadow of the object in the pickup image. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a schematic perspective view of an image reading apparatus according to a first embodiment. 
         FIG. 1B  is a schematic xy cross-sectional view of the image reading apparatus according to the first embodiment. 
         FIG. 1C  is a schematic yz cross-sectional view of the image reading apparatus according to the first embodiment. 
         FIG. 2A  is a view illustrating how a shadow portion of an original is appropriately formed in the image reading apparatus according to the first embodiment. 
         FIG. 2B  is a view illustrating how the shadow portion of the original is appropriately formed in the image reading apparatus according to the first embodiment. 
         FIG. 2C  is a view illustrating how the shadow portion of the original is appropriately formed in the image reading apparatus according to the first embodiment. 
         FIG. 3A  is a view illustrating an example of an image reading operation of the image reading apparatus according to the first embodiment. 
         FIG. 3B  is a view illustrating an example of the image reading operation of the image reading apparatus according to the first embodiment. 
         FIG. 3C  is a view illustrating an example of the image reading operation of the image reading apparatus according to the first embodiment. 
         FIG. 4  is a flowchart of an operation of the image reading apparatus in an image reading method of the first embodiment. 
         FIG. 5A  is a schematic perspective view of an image reading apparatus according to a second embodiment. 
         FIG. 5B  is a schematic xy cross-sectional view of the image reading apparatus according to the second embodiment. 
         FIG. 5C  is a schematic yz cross-sectional view of the image reading apparatus according to the second embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Preferred embodiments of an image reading method and an image reading apparatus in the present invention will now be described in detail in accordance with the accompanying drawings. 
     Note that, in the drawings described below, objects may be illustrated in scales different from the actual ones to facilitate the understandings of the present invention. 
     First Embodiment 
       FIGS. 1A, 1B, and 1C  are respectively a schematic perspective view, a schematic xy cross-sectional view, and a schematic yz cross-sectional view of an image reading apparatus  100  in a first embodiment. 
     Note that, in this description, an x-axis is defined as a direction perpendicular to a mounting surface  103   a  of the image reading apparatus  100 , and a y-axis and a z-axis are defined as directions orthogonal to each other in a plane including the mounting surface  103   a.    
     The image reading apparatus  100  includes a mounting table  101 , a screen surface (projection surface, white member)  102 , a transparent plate (light transmitting member)  103 , a main body  104 , an imaging unit  105 , an image processing unit (processing unit)  120 , and a control unit  130 . 
     As illustrated in  FIGS. 1A to 1C , the screen surface  102  and the main body  104  are provided on the mounting table  101 . 
     Moreover, the transparent plate  103  is disposed on the screen surface  102 , and an original  107  is mounted on the mounting surface  103   a  of the transparent plate  103 . Accordingly, the screen surface  102  and the mounting surface  103   a  are parallel to each other and are spaced away from each other in the x-axis direction. 
     In the main body  104 , there are provided: the imaging unit  105  including a not-illustrated lens element and a not-illustrated area imaging element (imaging element); the image processing unit  120 ; and the control unit  130 . In the imaging unit  105 , the lens element focuses light reflected from the original  107  onto the area imaging element. The imaging unit  105  thereby performs image pickup to obtain an image including the original  107 . 
     Note that the imaging unit  105  is disposed at such a position that the imaging unit  105  can pick up the image of the mounting surface  103   a  from an oblique upper side thereof. In other words, the center position of the area imaging element of the imaging unit  105  is off the normal to the original  107 . 
     As illustrated in  FIGS. 1A to 1C , in the image reading apparatus  100 , when the original  107  is mounted on the mounting surface  103   a , a shadow portion  102   a  is formed on the screen surface  102  by illuminating the original  107  by an illuminating apparatus  106  provided outside the image reading apparatus  100 . 
     In the image reading apparatus  100  in the embodiment, at least parts of at least one of short sides and at least one of long sides of the original  107  can be clearly detected by using this shadow portion  102   a.    
       FIGS. 2A, 2B, and 2C  illustrate how the shadow portion  102   a  is appropriately generated to clearly detect at least the parts of at least one short side and at least one long side of the original  107  in the image reading apparatus  100  in the embodiment. 
     In this embodiment, the original  107  is assumed to be a rectangular original with a size such as A4 or B4 (predetermined rectangular size) defined in a general standard, and vertices of the original  107  are referred to as vertex A (first vertex), vertex B (second vertex), vertex C (third vertex), and vertex D (fourth vertex). 
     As illustrated in  FIG. 2A , the imaging unit  105  is assumed to be disposed such that the center of the area imaging element is at the position of the point P (first position). Then, a first plane denotes a plane including a segment PA (first segment) and a segment PB (second segment), a second plane denotes a plane including the segment PB and a segment PC (third segment), a third plane denotes a plane including the segment PC and a segment PD (fourth segment), and a fourth plane denotes a plane including the segment PD and the segment PA. 
     Provided that regions which are on the opposite sides of the first, second, third, and fourth planes to the original  107  (hereafter, also referred to as original  107  opposite side) are first, second, third, and fourth regions, a region where the first to fourth regions overlap is defined as a region  109 . 
     In other words, the region  109  can be considered as a pyramid whose apex is the point P and whose base is at infinity on the upper side. 
       FIG. 2C  illustrates a cross-sectional view obtained by cutting the region  109  along a certain plane S which is parallel to the mounting surface  103   a  and which is farther away from the mounting surface  103   a  than the point P is. Note that, in  FIG. 2C , the point P where the imaging unit  105  is disposed is assumed to be directly above the center of the rectangular original  107  in the x-axis direction for simplification, and intersections where extended lines of the segments PA, PB, PC, and PD intersect the plane S are referred to as A′, B′, C′, and D′, respectively. Moreover, regions around the region  109  on the plane S (that is, regions outside the pyramid  109 ) are referred to as R 1 , R 2 , . . . , and R 8 . 
     First, when one illuminating apparatus  106  is disposed in the region R 2  which is at the original  107  side of the first plane and which is at the original  107  opposite side of the second and fourth planes, the shadow portion  102   a  is formed on the screen surface  102 , outside the long side AB of the original  107 , such that the imaging unit  105  can pick up the image of the shadow portion  102   a . However, no shadow portion  102   a  is formed on the screen surface  102 , outside the other sides BC, CD, and DA (at such positions that the imaging unit  105  can pick up the image of the shadow portion  102   a ). 
     Similarly, when one illuminating apparatus  106  is disposed in the regions R 4 , R 5 , or R 7  which is at the original  107  side of the second, third, or fourth plane and which is at the original  107  opposite side of the other planes, the shadow portion  102   a  is formed on the screen surface  102 , outside one of the sides of the original  107 , such that the imaging unit  105  can pick up the image of the shadow portion  102   a . However, no shadow portion  102   a  is formed on the screen surface  102 , outside the other sides (at such positions that the imaging unit  105  can pick up the image of the shadow portion  102   a ). 
     Accordingly, in order to form the shadow portion  102   a  on the screen surface  102  outside at least the parts of at least one short side and at least one long side of the original  107  such that the imaging unit  105  can pick up the image of the shadow portion  102   a  by using one illuminating apparatus  106 , the illuminating apparatus  106  may be disposed in the regions R 1 , R 3 , R 6  or R 8  out of the regions R 1  to R 8 . 
     Specifically, one illuminating apparatus  106  may be disposed in any of the region R 1  which is at the original  107  side of the first and second planes and which is at the original  107  opposite side of the third and fourth planes, the region R 3  which is at the original  107  side of the first and fourth planes and which is at the original  107  opposite side of the second and third planes, the region R 6  which is at the original  107  side of the second and third planes and which is at the original  107  opposite side of the first and fourth planes, and the region R 8  which is at the original  107  side of the third and fourth planes and which is at the original  107  opposite side of the first and second planes. 
     Note that it is described outside “at least the parts of” the short side and the long side due to the following reason. When the original is illuminated from the regions R 1 , R 3 , R 6 , or R 8 , an image of a boundary between the imagable shadow portion  102   a  and the side of the original along which the imagable shadow portion  102   a  is formed cannot be picked up over the entire length of this side (each of the long side and the short side) because the height of the mounting surface  103   a  and the height of the screen surface  102  are different. 
     Meanwhile, when there are two or more illuminating apparatuses  106 , one of the illuminating apparatuses  106  is disposed in the region R 1 , R 2 , R 3 , R 6 , R 7 , or R 8  which is at the original  107  side of the first plane including the long side AB of the original  107  or the third plane including the long side CD of the original  107 . Then, another one of the illuminating apparatuses  106  is disposed in the region R 1 , R 3 , R 4 , R 5 , R 6 , or R 8  which is at the original  107  side of the second plane including the short side BC of the original  107  or the fourth plane including the short side DA of the original  107 . The shadow portion  102   a  can be thereby formed on the screen surface  102 , outside at least the parts of at least one short side and at least one long side of the original  107 , such that the imaging unit  105  can be image the shadow portion  102   a.    
     Meanwhile, when the illuminating apparatuses  106  are disposed inside the region  109 , that is at the original  107  opposite side of all of the first to fourth planes, no shadow portion  102   a  is formed on the screen surface  102 , outside any of the four sides of the original  107 , such that the imaging unit  105  can pick up the image of the shadow portion  102   a.    
     The region which includes the point P where the imaging unit  105  is disposed and which is above, in the x-axis direction, a fifth plane parallel to the mounting surface  103   a  is described above. 
     In a portion below the fifth plane in the x-axis direction, by disposing the illuminating apparatus  106  at any position in a fifth region between the fifth plane and a sixth plane including the mounting surface  103   a , the shadow portion  102   a  can be formed on the screen surface  102 , outside at least the parts of at least one short side and at least one long side of the original  107 , such that the imaging unit  105  can pick up the image of the shadow portion  102   a.    
     As described above, in the image reading method in the embodiment, the shadow portion  102   a  can be formed on the screen surface  102 , outside at least the parts of at least one short side and at least one long side of the original  107 , such that the imaging unit  105  can pick up the image of the shadow portion  102   a , by disposing at least one portion of at least one illuminating apparatus  106  in the region (hereafter, referred to as detectable region) at the original  107  side of at least two of the first, second, third, and fourth planes, the two planes respectively including adjoining two sides (specifically, the short side and the long side) of the original  107 . 
     The image processing unit  120  processes a pickup image obtained by performing image pickup in this state, and can thereby detect at least the parts of at least one short side and at least one long side of the original  107 , from the brightness difference between the original  107  and the shadow portion  102   a.    
     Note that any point in the fifth region is in the detectable region. 
     Then, the image processing unit  120  selects a standard size with a length closest to the length of at least the parts of at least one short side and at least one long side of the detected original  107 , from size information on predetermined standards stored in a not-illustrated storage unit. The size, position, and orientation of the original  107  (rectangular boundary  108  in  FIGS. 3A to 3C ) are thereby determined (obtained). 
     Then, the image processing unit  120  can read the image of the original  107  by cropping (performing extraction on) the image information obtained in the image pickup by the imaging unit  105 , based on the determined size, position, and orientation of the original  107 . 
       FIGS. 3A, 3B, and 3C  illustrate examples of the aforementioned image reading operation of the image reading apparatus  100  in the embodiment. 
     Note that  FIG. 3A  illustrates the case where the shadow portion  102   a  is formed on the screen surface  102 , outside all of the four sides of the original  107 , such that the imaging unit  105  can pick up the image of the shadow portion  102   a .  FIG. 3B  illustrates the case where the shadow portion  102   a  is formed on the screen surface  102 , outside two long sides and one short side of the original  107 , such that the imaging unit  105  can pick up the image of the shadow portion  102   a .  FIG. 3C  illustrates the case where the shadow portion  102   a  is formed on the screen surface  102 , outside one long side and one short side of the original  107 , such that the imaging unit  105  can pick up the image of the shadow portion  102   a.    
     First, when the illuminating apparatus  106  illuminates the original  107 , the shadow portion  102   a  is formed on the screen surface  102 , outside, for example, all four sides of the original  107 . 
     Then, the imaging unit  105  obtains an image  110  by performing image pickup of the original  107  and the shadow portion  102   a.    
     Next, the image processing unit  120  processes the obtained image  110  to detect a boundary  111  between the original  107  and the shadow portion  102   a  from the brightness difference therebetween. Then, the obtained boundary  111  is compared with standard sizes to determine the rectangular boundary  108  corresponding to the size, position, and orientation of the original  107 . 
     Next, the image  110  is cropped based on the rectangular boundary  108  and the image of the original  107  can be thus read. 
     Moreover, as long as the conditions described above are satisfied, at least the parts of at least one short side and at least one long side of the original  107  can be detected not only indoors but also outdoors, by using, for example, sunlight. 
     Furthermore, at least the parts of at least one short side and at least one long side of the original  107  can be detected also in a room provided with the illuminating apparatus  106  so large as to cover the inside and outside of the detectable region. 
     Moreover, as long as the conditions described above are satisfied, at least the parts of at least one short side and at least one long side of the original  107  can be detected also in a room using indirect illuminating in which a light diffusing plate or a reflection plate is disposed on a ceiling and light is incident on the light diffusing plate or the reflection plate. 
     Furthermore, as long as the conditions described above are satisfied, at least the parts of at least one short side and at least one long side of the original  107  can be detected also outdoors under a cloudy sky. 
     Note that, although the object whose image is to be picked up is considered to be the rectangular original in the embodiment, the object is not limited to this and may be a three-dimensional object with a certain thickness as long as it has a rectangular shape and a size based on a certain standard. In other words, the object may be a three-dimensional object whose cross section parallel to the mounting surface  103   a  is a rectangle. 
     In summary, in the image reading method in the embodiment, the four planes are defined for the respective sides of the original  107  as the planes including the sides of the original  107  and the position of the imaging unit  105 . The positional relationships among an illumination light source, the original  107 , and the imaging unit  105  are set such that at least one illumination light source is at least partially located in the region on the original  107  side of at least two of the four planes, the two planes respectively including two adjoining sides of the original  107 . Then, image pickup of the original  107  is performed and the image of the original  107  can be read from the obtained image. 
     The illumination light source herein includes illuminating apparatuses such as a fluorescent lamp and a LED, the sun, a light diffusing plate, a reflection plate, a cloudy sky, and the like. 
     Next, the darkness and size of the formed shadow portion  102   a  are discussed. 
     The distance between the mounting surface  103   a  and the screen surface  102  in the vertical direction, that is the thickness of the transparent plate  103  is denoted by d 1 . 
     In this case, the size and darkness of the shadow portion  102   a  greatly depends on d 1  and secondly depends on the distance between the illuminating apparatus  106  and the mounting surface  103   a.    
     Specifically, when d 1  is small, the shadow portion  102   a  is dark but the area of the shadow portion  102   a  is small. Accordingly, depending on the imaging resolution of the imaging unit  105 , the boundary  111  of the original  107  is difficult to detect. Hereafter, such a state of the shadow portion  102   a  is referred to as dark-small state. 
     Meanwhile, when d 1  is large, the area of the shadow portion  102   a  is large but the shadow portion  102   a  is light. Accordingly, the brightness difference between the original  107  and the shadow portion  102   a  in the boundary  111  of the original  107  is insufficient and the detection of the boundary  111  of the original  107  is difficult also in this case. Hereafter, such a state of the shadow portion  102   a  is referred to as light-large state. 
     The image reading apparatus  100  in the embodiment satisfies the following conditional expression (1): 
       60 &lt;d 1 ×K&lt; 3000  (1)
 
     where K is the imaging resolution of the imaging unit  105  in dots per inch (dpi). Note that the unit of d 1  is mm in this expression. 
     The image reading apparatus  100  in the embodiment can generate the shadow portion  102   a  having appropriate darkness and area by satisfying the aforementioned conditional expression (1). 
     Note that the image reading apparatus  100  in the embodiment more preferably satisfies the following conditional expression (1a): 
       150 &lt;d 1 ×K&lt; 1800  (1a).
 
     In the image reading apparatus  100  in the embodiment, d 1  is 1 mm and K is 300 dpi. Accordingly, d 1 ×K=300, and not only the expression (1) but also the expression (1a) is satisfied. 
       FIG. 4  illustrates a flowchart of an operation of the image reading apparatus  100  in the image reading method of the embodiment. 
     First, when the image reading apparatus  100  starts the operation (S 10 ), the control unit  130  starts to detect whether the original  107  is mounted on the mounting surface  103   a  (S 11 ). 
     When the control unit  130  detects that the original  107  is mounted on the mounting surface  103   a  (Yes in S 12 ), the imaging unit  105  performs the image pickup (S 13 ). 
     Next, the image processing unit  120  performs image processing on the image  110  obtained by the image pickup and determines the position of the rectangular boundary  108  of the original  107  in the picked-up image  110  by comparing the result of the image processing with numerical values of predetermined standards (S 14 ). 
     When the image processing unit  120  cannot determine the rectangular boundary  108  of the original  107  (No in S 14 ), an error message such as “please rearrange the original” is outputted (S 15 ) and the processing returns to S 11 . 
     When the image processing unit  120  determines the rectangular boundary  108  of the original  107  (Yes in S 14 ), the image processing unit  120  crops an image from the image  110  (S 16 ). Then, the cropped image corresponding to the original  107  is stored in a not-illustrated storage device (S 17 ) and the operation of the image reading apparatus  100  is ended (S 18 ). 
     The image processing unit  120  performs processing on the picked-up image and sends the image to the not-illustrated storage device such as an SD card. Moreover, the image reading apparatus can be used as a photocopier or an image scanner by sending the image to a printer, a personal computer, or the like. 
     Second Embodiment 
       FIGS. 5A, 5B, and 5C  are respectively a schematic perspective view, a schematic xy cross-sectional view, and a schematic yz cross-sectional view of an image reading apparatus  200  in a second embodiment. 
     Note that the image reading apparatus  200  in the second embodiment has the same configuration as the image reading apparatus  100  in the first embodiment except for the point that the image reading apparatus  200  newly includes a projector unit (illuminating unit, projection unit)  206 . Accordingly, the same parts are denoted by the same reference numerals and description thereof is omitted. 
     As illustrated in  FIGS. 5A to 5C , in the image reading apparatus  200  in the embodiment, the projector  206  is provided in the main body  104  and includes a light source apparatus, an image display element, and a lens element which are not illustrated. 
     In the projector  206 , a light flux emitted from the light source apparatus passes through the image display element and is then guided by the lens element such that an image is projected on the mounting surface  103   a  of the transparent plate  103 . 
     Note that the projector  206  is disposed at such a position that the projector  206  projects the image on the mounting surface  103   a  from the oblique upper side thereof. 
     The projector  206  can be used for various applications such as projecting, on the mounting surface  103   a , an image to guide a user on how to operate the image reading apparatus  200  and displaying, on the mounting surface  103   a , a preview of an image picked up by the imaging unit  105 . 
     Moreover, the projector  206  can illuminate on the original  107  by projecting a white image (white light) on the mounting surface  103   a  and form the shadow portion  102   a  on the screen surface  102  as in the first embodiment. 
     In the image reading apparatus  200  in the embodiment, the projector  206  is provided in the main body  104  to be located in the fifth region between the fifth plane and the sixth plane, the fifth plane including the point P where the center of the area imaging element of the imaging unit  105  is located and being parallel to the mounting surface  103   a , the sixth plane including the mounting surface  103   a.    
     This allows the projector  206  to form the shadow portion  102   a  on the screen surface  102 , outside at least the parts of at least one short side and at least one long side of the original  107 , such that the imaging unit  105  can pick up the image of the shadow portion  102   a.    
     This is because the position of the projector  206  is at the original  107  side of the fifth plane and is thus inevitably on the original  107  side of two of the four planes which include the point P (position where the imaging unit is disposed) and which respectively include the sides of the original on the mounting surface  103   a , the two planes respectively including two adjoining sides of the original  107 . 
     Then, the image processing unit  120  performs image processing on the image obtained in the image pickup performed in this state and can thereby detect at least the parts of at least one short side and at least one long side of the original  107 , from the brightness difference between the original  107  and the shadow portion  102   a.    
     Then, the image processing unit  120  selects a standard size with a length closest to the length of at least the parts of at least one short side and at least one long side of the detected original  107 , from the sizes of sheets in predetermined standards stored in a not-illustrated storage unit to determine the size, position, and orientation (rectangular boundary  108  in  FIGS. 3A to 3C ) of the original  107 . 
     Then, the image processing unit  120  crops an image from the image obtained in the image pickup by the imaging unit  105 , based on the determined size, position, and orientation of the original  107 , and can thereby read the image of the original  107 . 
     Note that an example of the aforementioned image reading operation of the image reading apparatus  200  in the embodiment is as illustrated in  FIGS. 3A to 3C  like the first embodiment. 
     Moreover, although the object whose image is to be picked up is considered to be the rectangular original in the embodiment, the object is not limited to this and may be a three-dimensional object with a certain thickness as long as it has a rectangular shape and a size based on a certain standard. In other words, the object may be a three-dimensional object whose cross section parallel to the mounting surface  103   a  is a rectangle. 
     Next, the darkness and size of the formed shadow portion  102   a  are discussed. In the image reading apparatus  200  in the embodiment, d 1  is 2 mm and K is 400 dpi. Accordingly, d 1 ×K=800, and not only the expression (1) but also the expression (1a) is satisfied. 
     Hence, in the image reading apparatus  200  in the embodiment, it is possible to generate the shadow portion  102   a  having appropriate darkness and area. 
     Moreover, a flowchart of the operation of the image reading apparatus  200  in the image reading method of the embodiment is as illustrated in  FIG. 4  like the first embodiment. 
     Note that the projector  206  may display states corresponding to the operation flow of the image reading apparatus  200  in the embodiment, as messages on the mounting surface  103   a.    
     The image processing unit  120  performs processing on the picked-up image and sends the image to the not-illustrated storage device such as an SD card. In this case, the projector  206  may display a preview of the picked-up image on the mounting surface  103   a  to allow the user to check the image. 
     Moreover, the image reading apparatus can be used as a photocopier or an image scanner by sending the picked-up image to a printer, a personal computer, or the like. 
     The image reading apparatus  200  in the embodiment has the following characteristic. The intensity of illumination light emitted from the projector  206  is constant, differently from in the image reading apparatus  100  in the first embodiment. This facilitates control of generation of the shadow portion  102   a , and simplification of processing in a later stage can be achieved more easily. 
     Moreover, the shadow portion  102   a  can be appropriately emphasized by appropriately controlling the intensity of the illumination light emitted from the projector  206 . 
     Furthermore, the illumination light emitted from the projector  206  and the illumination light emitted from the external illuminating apparatus  106  or the like may be used together. 
     Note that the surface of the transparent plate  103  generally has a reflectivity of about 10%. Accordingly, in the image reading apparatuses  100  and  200  in the first and second embodiments, the illumination light emitted from the illuminating apparatus  106  and/or the projector  206  is not only diffusely reflected by the original  107  and the screen surface  102  but also may be totally reflected on the mounting surface  103   a  and travel toward the user. 
     Accordingly, the user may be dazzled by the total reflection light and have difficulty in performing the operation. In view of this, anti-reflection processing may be performed, specifically, anti-reflection film may be applied on the mounting surface  103   a  (that is, on an upper surface of the transparent plate  103 ) and/or a lower surface of the transparent plate  103 . 
     Note that the anti-reflection film may be applied by using a method such as a method of depositing a dielectric material in a manufacturing process of the transparent plate  103 . 
     Although preferable embodiments of the present invention have been described above, the present invention not limited to these embodiments and various changes and modifications can be made within the scope of the gist of the present invention. 
     For example, a mesh or the like may be used instead of the transparent plate  103 . Moreover, instead of providing the screen surface  102  on the mounting table  101 , a transparent plate  103  with a while paint applied on a lower surface may be provided on the mounting table  101 . In this case, an upper surface (first surface) of the transparent plate  103  is the mounting surface  103   a  and the lower surface (second surface) facing the upper surface is the screen surface  102 . 
     The present invention can provide the image reading method and an image reading apparatus which enables accurate and easy reading of an image of an object mounted on the mounting surface. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2016-126796, filed Jun. 27, 2016, which is hereby incorporated by reference herein in its entirety.