Patent Publication Number: US-2009220170-A1

Title: Three-dimensional image spreading apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a three-dimensional image spreading apparatus and particularly to an apparatus to unfold the three-dimensional image of an object to become a planar image with three-dimensional characteristics to fully present the object. 
     2. Brief Discussion of the Related Art 
     With continuous advances of technology image processing technique also has great progress and is widely used in living thing identification (ID for short hereinafter) technique. The living thing ID technique aims to make reliable and effective authenticity process of individual person through a computer based on unique physiological characteristics of the person. The present commonly used physiological characteristics includes face, iris, fingerprint and palm print. Face is the most natural and widely used personal ID characteristic in human vision. Hence facial ID is superior to other living thing ID techniques (such as fingerprint ID, iris ID and the like). ID purpose can be achieved without deliberated contact or actions of an ID target. It is less offensive to the targeted ID object. And users can operate the facial ID system covertly or more discreetly. Hence the facial ID system provides significant advantages in the application of security surveillance. 
     The conventional facial ID system usually captures the front image of a user&#39;s face through a video camera and maps against facial data in a system database to perform ID process. The image captured by the video camera could be easily blurred and become not recognizable due to external environmental factors such as light, makeup and the like. Some ill-intentioned persons can even exploit this shortcoming and tamper the facial ID system by wearing a facial mask or placing a photo at a desired location in front of the video camera to fool the ID system and produce an erroneous judgment thereof. This creates a big loophole in the security surveillance system. To remedy this problem, a facial ID system capable of simultaneously capturing the facial images of other visual angles has been developed. For instance, R.O.C. patent publication No. 200709075 entitled “Method and apparatus for detecting and recognizing human faces in set environments” discloses a technique which has a plurality of video cameras positioned at different angles to capture the front, left side and right side facial images of a targeted person. The facial images are analyzed to get required facial characteristics and a resulting image is obtained and sent to a facial ID module which retrieves a mapping facial image for comparison. Finally an ID result for legitimate and illegitimate person is generated. 
     While the patent set forth above can capture the images of a human face at different angles, and facial characteristics can be- obtained to perform ID process to improve the drawbacks of the conventional technique which takes only the front image, it require a number of video cameras, as a result the cost is higher. Moreover, due to environmental constraints installation locations of the video cameras are not always desirable and to fully capturing the facial images could be difficult. Even if all the issues previously discussed are overcome, the images taken at the multiple visual angles become a planar projection in the end. Projection blind spots are easily formed, such as some portions of the facial characteristics could be masked. Hence the resulting image still cannot fully reveal the three-dimensional characteristics. The result leaves a lot to be desired. There are still rooms for improvement. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to solve the aforesaid disadvantages by providing a three-dimensional spreading apparatus to unfold a three-dimensional image to become a complete planar image which has three-dimensional characteristics regardless of environmental constraints. 
     To achieve the foregoing object the three-dimensional image spreading apparatus according to the invention includes an incident element and an emitting element. The incident element has a first reflective portion with a closed circumferential surface, an image inlet, an image outlet and an image transmission passage formed with the first reflective portion. The first reflective portion has a perimeter which gradually shrinks from the image inlet to the image outlet. There is an image capturing zone formed by extending the image inlet outwards. The image emitting element is located in the image transmission passage and has a second reflective portion corresponding to the first reflective portion. The three-dimensional image of an object located in the image capturing zone enters the image transmission passage through the image inlet and forms a circumferential image on the first reflective portion. The circumferential image is reflected to the second reflective portion and reflected thereon to become a planar image to be sent to an image capturing device through the image outlet. The planar image thus formed has comprehensive characteristics of the object, therefore can improve the disadvantages of incomplete image information caused by projection blind spots of the conventional planar image obtained by projection. 
     Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
         FIGS. 1A and 1B  are schematic views of a first embodiment of the invention. 
         FIG. 2  is an operation flowchart of the invention. 
         FIG. 3  is a schematic view of a second embodiment of the invention. 
         FIG. 4  is a schematic view of a third embodiment of the invention. 
         FIG. 5  is a schematic view of a fourth embodiment of the invention. 
         FIG. 6  is a schematic view of the invention with a local image enlarged. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Please refer to  FIGS. 1A and 1B , the three-dimensional image spreading apparatus  1 , according to the invention mainly aims to transform a three-dimensional image S 1  of an object  40  to a planar image S 3 . It includes an incident element  10  and an emitting element  20 . The incident element  10  has a first reflective portion  11  with a closed circumferential surface, and an image inlet  12  and an image outlet  13  at two ends corresponding to each other. There is an image capturing zone A formed by extending the image inlet  12  outwards. The image inlet  12 , the image outlet  13  and the first reflective portion  11  jointly form an image transmission passage  14 . The emitting element  20  includes a seat  22  to hold a second reflective portion  21  corresponding to the first reflective portion  11 . The first reflective portion  11  and the second reflective portion  21  are annular reflective mirrors with perimeters shrinking gradually from the image inlet  12  to the image outlet  13  to become a conical reflection structure. The second reflective portion  21  is parallel with the first reflective portion  11 . 
     The three-dimensional image spreading apparatus  1  further has an image capturing device  30  corresponding to the image outlet  13 . The image capturing device  30  may be a dynamic image recording device (such as a video camera) or a static image recording device (such as a camera or the like). More specifically, the three-dimensional image spreading apparatus  1  is substantially the lens of the image capturing device  30 . When the object  40  (such as a targeted person shown in the drawings) enters the image capturing zone A, the three-dimension image S 1  of the face of the targeted person enters the image transmission passage  14  through the image inlet  12  and projects onto the first reflective portion  11  to generate a circumferential image S 2  which is reflected by the first reflective portion  11  to the second reflective portion  21 , and further is reflected thereon and unfolded to become the planar image S 3  (shown by a planar object  40 a with three-dimensional characteristics indicated in  FIG. 1B ). The planar image S 3  is reflected by the second reflective portion  21  to the image capturing device  30  through the image outlet  13 . Referring to  FIG. 2 , the image capturing device  30  may be linked to an ID system  50 , especially a facial ID system, to identify the planar image S 3  and recognize whether the targeted person in the image capturing zone A is a legitimate person to prevent an ill-intentioned person to move close to the image capturing device  30  by means of another planar facial image (such as a photo) or a facial mask to create an erroneous judgment of the ID system  50 . Moreover, the image capturing device  30  may further be linked to an image reconstruction system  60  to restore the image of the planar image S 3 , so that a security personnel database of the ID system  50  can be set up, or a simulated three-dimensional model of the targeted object  40  can be built to be incorporated with other ID methods, such as mapping the three-dimensional model against face phrenological features to perform facial ID. 
     The first reflective portion  11  of the invention, aside from formed by the circumferential reflective mirror, may also be formed in other embodiments such as a convex mirror, a concave mirror, or a curved mirror consisting of convex and concave mirrors as shown in  FIGS. 3 ,  4  and  5  by various types of first reflective portion  11   a ,  11   b  and  11   c . Through the characteristics of light or image dispersion and converging of the convex and concave mirrors, the three-dimensional image S 1  of the object  40  can be shrunk or enlarged to highlight local characteristics of the object  40 . For instance, in  FIG. 6 , the eye characteristics of the targeted person are enlarged. The lens of the image capturing device  30  may also be replace to alter the types of the first reflective portions  11 ,  11   a ,  11   b  and  11   c  to thwart ill-intentioned persons from knowing the image transformation method of the three-dimensional image spreading apparatus  1  of the invention and trying to tamper the ID system through a selected facial model or mask. Thus ID effect and accuracy of the ID system  50  can be enhanced to further improve the guarding effect of the security surveillance system. It is to be noted that the types of the first reflective portion  11 ,  11   a ,  11   b  and  11   c  shown in the drawings and embodiments previously discussed are not the limitation of the invention. Users can make desired alterations or adjustments according to the local characteristics to be obtained. 
     As a conclusion, the present invention adopts the reflective principle of optics. By means of the first and second reflective portions  11  and  21 , the three-dimension image S 1  of the object  40  in the image capturing zone A can be reflected twice and unfolded to become the planar image S 3  containing three-dimensional characteristics. Compared with the conventional techniques that get merely planar images of various visual angles through projecting images, the number of the image capturing device  30  can be reduced, and installation cost and time also are less. More important, the invention can overcome the image blind spots caused by the conventional image projection approach to fully present the image of the object  40 . 
     While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.