Abstract:
An apparatus measures a 3-Dimensional (3D) shape of an object. The apparatus includes a light emitting unit and a light receiving unit that are arranged to face each other with the object disposed in a space defined therebetween, wherein the light transmitting unit being arranged to scan the object, and the light receiving unit being arranged to sense a shadow of the scanned object formed thereon. The apparatus includes a rotation unit arranged to rotate the light emitting unit and the light receiving unit about a same rotational axis by a preset rotation angle until the rotation is fully made by a desired target angle and a shape restoration unit configured to measure a 3D shape of the object using shadows that are obtained for each preset rotation angle.

Description:
RELATED APPLICATION(S) 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2011-0115888, filed on Nov. 08, 2011, which is hereby incorporated by references as if fully set forth herein. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to measurement of a 3-dimensional (3D) shape, and more particularly, to an apparatus and a method for measuring a 3D shape of an object based on shadow information on the object. 
       BACKGROUND OF THE INVENTION 
       [0003]    Generally, breast cancer is adenocarcinoma that occurs in breasts, and is a kind of cancer that occurs most frequently in woman. Much research is being conducted for diagnosing and treating breast cancer. 
         [0004]    Presently, an early diagnosis method of breast cancer that is the most generally used is to detect a foreign tissue of breasts through a mechanical checkup. In addition, there is X-ray mammography which is a more detailed checkup method. However, the X-ray mammography may exert a bad influence on the human body due to frequent overexposure to X-ray. Another method of breast cancer is a microwave tomography that uses weak electromagnetic waves unharmful to the human body without using X-ray. 
         [0005]    In the microwave tomography, weak electromagnetic waves are generated and pass through the inside of a checked-up body (i.e., breast), and thus, the internal image (indicative of distribution of permittivity and conductivity) of the checked-up body is predicted and restored, thereby diagnosing whether there is a tumor in the checked-up body. In such a microwave imaging apparatus, it is important to scan the surface of the checked-up body and measure an accurate 3D shape, for high-quality image restoration, and particularly, 3D image restoration. However, the checked-up body is generally required to be soaked in a water tank containing liquid and a micro imaging apparatus in which a radio wave transmission/reception antenna surrounds the checked-up body has a limitation in mechanical structure, and therefore it is complicated and difficult to measure a 3D shape using the existing scan system. 
       SUMMARY OF THE INVENTION 
       [0006]    In view of the above, the present invention provides an apparatus and a method, which measure the 3D shape of an object based on shadow information on the object. 
         [0007]    In accordance with an aspect of the present invention, there is provided an apparatus for measuring a 3-Dimensional (3D) shape of an object, which includes: a light emitting unit and a light receiving unit that are arranged to face each other with the object disposed in a space defined therebetween, wherein the light transmitting unit being arranged to scan the object, and the light receiving unit being arranged to sense a shadow of the scanned object formed thereon; a rotation unit arranged to rotate the light emitting unit and the light receiving unit about a same rotational axis by a preset rotation angle until the rotation is fully made by a desired target angle; and a shape restoration unit configured to measure a 3D shape of the object using shadows that are obtained for each preset rotation angle. 
         [0008]    In the apparatus, the light emitting unit includes an array of light transmitting elements in rows to irradiate light and scan the object. 
         [0009]    In the apparatus, the light receiving unit includes an array of light sensing elements arranged in rows to sense the shadows of the scanned object by the rows of the light emitting elements. 
         [0010]    In the apparatus, the 3D shape of the object is measured by bright and darkness information of the respective shadows. 
         [0011]    The apparatus further includes an initialization unit configured to initialize the rotated positions of the light emitting unit and the light receiving unit to their starting positions when the object that is disposed in the space start to rotate. 
         [0012]    In the apparatus, the shape restoration unit intersects bright and darkness portions of the shadows to obtain intersection portions of the shadows, each intersection portion being corresponded to a 3D sectional-surface shape of the object, thereby restoring the 3D shape of the object. 
         [0013]    In the apparatus, the light emitting unit and the light receiving unit are deactivated when the rotation is fully made by the desired target angle. 
         [0014]    In the apparatus, the light is one of visible light, infrared light, ultraviolet rays, and laser beam. 
         [0015]    In accordance with another aspect of the present invention, there is provided a method for measuring a 3-Dimensional (3D) object shape, which includes: disposing an object on a space on a panel; scanning the object using light while rotating the panel by a preset angle once; collecting shadows of the scanned object; and restoring a 3D shape of the object using the collected shadows. 
         [0016]    In the method, restoring a 3D shape of the object includes intersecting bright and darkness portions of the shadows to obtain intersection portions of the shadows, each intersection portion being corresponded to a 3D sectional-surface shape of the object, thereby restoring the 3D shape of the object. 
         [0017]    In the method, the scanning of the object is continued until the panel is fully rotated by a desired target angle. 
         [0018]    The method further includes initializing the rotated positions of the panel to its starting position when the object that is disposed in the space starts to rotate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The above and other objects and features of the present invention will become apparent from the following description of embodiments given in conjunction with the accompanying drawings, in which: 
           [0020]      FIG. 1  illustrates a block diagram of an apparatus for measuring a 3D shape of an object in accordance with an embodiment of the present invention; 
           [0021]      FIG. 2  is a partially exploded perspective view of the light emitting unit and the light receiving unit in detail shown in  FIG. 1 ; 
           [0022]      FIG. 3  is a flowchart illustrating a method for measuring a 3D shape of an object in accordance with an embodiment of the present invention; and 
           [0023]      FIGS. 4A to 4D  are diagrams for describing a way of restoring a 3D shape of an object using bright and darkness information of a shadow in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0024]    Hereinafter, an apparatus and method for obtaining 3D shape information of an object by using only shadow information of the object with reference to the accompanying drawings. 
         [0025]      FIG. 1  illustrates a block diagram of an apparatus for measuring a 3D shape of an object in accordance with an embodiment of the present invention. Referring to  FIG. 1 , the apparatus for measuring a 3D shape of an object in accordance with an embodiment includes a light emitting unit  100 , a light receiving unit  110 , a panel  50 , and a rotary actuator  120 . 
         [0026]    The light emitting unit  100  and the light receiving unit  110  are arranged to face each other with an object  102 , e.g., a breast of a human body disposed in a space  108  defined therebetween. The panel  50  is arranged to fixedly support the light emitting unit  100  and the light receiving unit  110  at both sides thereof. The rotary actuator  120  has a rotation axis  115  that is connected to a bottom of the panel  50  to rotate the panel  50  by a preset rotation angle once until the panel  50  is fully rotated by a desired target angle, for example, 180 degrees. 
         [0027]      FIG. 2  illustrates partially exploded perspective views of the light emitting unit  100  and the light receiving unit  110  in detail. 
         [0028]    As shown in  FIG. 2 , the light emitting unit  100  includes an array of light emitting elements  104  arranged in rows  200  to irradiate light and scan the object  102 . The light irradiated from each row  200  of the light emitting elements  104  transmits a transparency surface  106  of the light emitting unit  100 , which is configured to allow transmission of the light, and scan the surface of the object  102 . In the embodiment, for example, the light emitted from the light emitting elements  104  may be visible light, infrared light, ultraviolet rays, laser beams, or the like. 
         [0029]    In a similar manner, the light receiving unit  110  includes an array of light sensing elements  114  arranged in rows  210  to sense the light from the rows  200  of the light emitting elements  104 . When the light emitting unit  100  are triggered to scan the object  102 , the light passes by the object  102  while a portion of the light is blocked by the object  102  and is projected onto a transparency surface  116  of the light receiving unit  110 , thereby casting a shadow  105  for the object  102  across the lighting receiving unit  110 . The light sensing elements  114  then senses the bright and darkness of the shadow  105  across the lighting receiving unit  110  for respective rows  210 . 
         [0030]    Alternatively, the light emitting unit  100  may be substituted with a unit for generating a microwave, and the light receiving unit  110  may be substituted with a unit for detecting the frequency of the microwave from the microwave generating unit. 
         [0031]    The apparatus further includes a shape restoration unit  130 , an initialization unit  140  and a control unit  150 . 
         [0032]    The shape restoration unit  130  restores the 3D shape of the object  102  on the basis of the shadow information that is obtained by the array of the light sensing elements  114  for each rotation angles by the panel  50 . 
         [0033]    The initialization unit  140  initializes the rotated position of the panel  50  to its rotation starting position or its original position where the object  102  is firstly disposed in the space  108  for generating the 3D shape of the object  102  or the rotary actuator  140  starts to rotate the panel  50  under the control of the control unit  150 . 
         [0034]    The control unit  150  may activate sequentially or collectively the light emitting elements unit  104  to scan the object  102  by irradiating light from the rows of the light emitting elements  104 . The light receiving unit  120  may also be controlled by the control unit  150  to activate the light sensing elements  114  in synchronization with the light emitting elements  104  in rows. Alternately, the light sensing elements  114  in the light receiving unit  110  may always remain activated. 
         [0035]    The control unit  150  also deactivates the light emitting unit  100  and the light receiving unit  110  when the panel  50  has fully rotated by the desired target angle according to the driving of the rotary activator  120 . 
         [0036]    An operation of the apparatus for measuring a 3D shape having the above-described structure will now be described with reference to  FIG. 2 . 
         [0037]      FIG. 3  is a flowchart illustrating a method for generating a 3D shape of the object in accordance with the embodiment of the present invention. 
         [0038]    First, in operation  300 , the object  102  is disposed at a central position of the space  108  on the panel  50  defined between the light emitting unit  100  and the light receiving unit  110 . 
         [0039]    In operation  302 , the initialization unit  140  then initializes the positions of the light emitting unit  100  and the light receiving unit  110  by returning the panel  50  to its original position, if necessary. 
         [0040]    Subsequently, in operation  304 , the control unit  150  activates the light emitting unit  100  and the light receiving unit  110  so that each row of the light emitting elements  102  arranged in the light emitting unit  100  scans the object  102  by irradiating the light, whereby the shadow  105  of the object  102  is formed across the surface  114  of the light receiving unit  110 . 
         [0041]    In operation  306 , the light sensing elements  114  senses bright and darkness of the shadow  105  for each row to produce shadow information having “0” and “1” indicative of the bright and darkness of the shadow  105 . The shadow information is then provided to the shape restoration unit  130  for temporally storing thereof. 
         [0042]    The control unit  150  controls the rotary actuator  120  to rotate the panel  50  by a preset rotation angle in operation  308 . Therefore, the light emitting unit  100  and the light receiving unit  110  is rotated by the preset rotation angle. 
         [0043]    The rotation is performed until the panel  50  is fully rotated by the desired target angle of 180 degrees in operation  310 . When it is determined in operation  310  that the panel  50  has not rotated by 180 degrees, the method returns to operation  306  to repeatedly perform the rotation of the panel  50  until the panel  50  is fully rotated by 180 degrees. Therefore, the shape restoration unit  130  obtains the shadow information having bright and darkness portions of the shadow  105  for each rotation of the preset rotation angle, and temporally stores the shadow information. 
         [0044]    When it is determined in operation  310  that the panel  50  has fully rotated by 180 degrees, the control unit  150  controls the rotary actuator  120  to stop the rotation of the rotation axis  115  and simultaneously deactivates the light emitting unit  100  and the light receiving unit  110  in operation  312 . 
         [0045]    Subsequently, the shape restoration unit  140  restores a 3D shape of the object  102  by combining the stored shadow information in operation  314 . 
         [0046]    A process of a 3D shape restoration by the shape restoration unit  140  will now be described with reference to  FIGS. 4A to 4D . 
         [0047]      FIGS. 4A to 4D  are diagrams illustrating a process of the 3D shape restoration of the object  102  in accordance with an embodiment of the present invention. 
         [0048]      FIGS. 4A to 4C  represent shadow information that has been obtained by scanning the object  102  using one row of the light emitting elements  104  at respective rotation angles θ. In  FIGS. 4A to 4C , a virtual plane  340  is generated on a path on which the light from one row  200  of the light transmitting elements  104  is radiated onto a corresponding row  210  of the light sensing elements  114 . The virtual plane  340  has a dark portion  330  in which a shadow is generated and a bright portion  320  except the shadow, both of which represent the shadow information of the object  102 . 
         [0049]    The obtained shadow information is then combined by intersecting the virtual planes  340  in  FIGS. 4A to 4C , thereby obtaining an intersection portion  350  of the dark portions  330  as shown in  FIG. 4D . The intersection portion  350  becomes the shape of a sectional surface of the object  102  to be restored. In this way, respective sectional-surface shapes of the object  102  are obtained for all rows of the light emitting and receiving elements  104  and  114 . All the sectional-surface shapes are then combined and therefore a 3D shape of the object  102  is restored. 
         [0050]    As described above, the embodiment measures the 3D shape of the object through a simple mechanical and driving structure without the interference of a radio wave transmission/reception antenna and a water tank containing liquid. 
         [0051]    While the invention has been shown and described with respect to the embodiments, the present invention is not limited thereto. It will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims.