Patent Publication Number: US-2015085083-A1

Title: Image-capturing system with dual lens camera

Description:
CROSS-REFERENCE 
     This application claims the priority of Taiwan Patent Application No. 102134594, filed on Sep. 25, 2013. 
     TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to an image-capturing system, and especially to an image-capturing system with a dual lens camera. 
     BACKGROUND OF THE INVENTION 
     With the development of technology, a variety of electronic products were made through automation processes. A prior art appearance inspection for the products is performed mainly by using artificial visual inspection. However, reliability of the artificial visual inspection varies, and the quality of the inspection will change with inspector&#39;s ability and mental statuses. Therefore, a machine vision has been developed in recent years, thereby replacing the unreliable artificial inspection. 
     The machine vision is a product developed mainly for the demand of the visual inspections on automated production lines with multi-functions, such as a defect detection of goods quality, an apparent size measurement, a count of workpieces, an identification confirmation, and so on. Users can carry out high-speed, precise, and various inspection functions of the machine vision via an image process controller, so as to solve erroneous recognitions due to the inspector&#39;s fatigue or negligence on the production line, or to identify the defects of goods that human eyes are unable to identify, thereby further upgrading the goods quality on the production line, increase production efficiency of equipments, and reducing labor costs. 
     In recent years, the machine vision has gradually applied in an automobile safety warning system with functions, such as a lane departure warning, a front barrier identification, or a judgment of the vehicle in front being too close, and so on. However, the machine vision utilizing image capture is easy to misjudge indicating lines or traffic signs on the road to be the barriers. Thus, the machine vision requires an ability of distance calculation with depth information in order to prevent the misjudgment. Because of this, the detection range of the existing automobile safety warning system is mostly within a close range. On the other hand, the machine vision can also be utilized as a car video recorder. However, the car video recorder focuses on an ultra wide-angle image capture, but it does not require the function of the distance detection. Thus, lenses which are selected for the both are quite different, and a balance therebetween can not be achieved, still having a shortcoming for the usage. 
     SUMMARY OF THE INVENTION 
     Accordingly, an objective of the present invention is to provide an image-capturing system with a dual lens camera, which has an ultra wide-angle mode and a stereoscopic mode to completely solve the shortcoming that an optimal lens selection for the automobile safety warning system can not be achieved. 
     Another objective of the present invention is to provide an image-capturing system with a dual lens camera, which can capture a position of an object by the ultra wide-angle mode and then switches to the stereoscopic mode to calculate a distance of the object, thereby providing complete monitoring functions. 
     To achieve the foregoing objectives, according to an aspect of the present invention, an image-capturing system with a dual lens camera provided in the present invention includes a first lens, a second lens, an actuating module, a control unit, and an image processing unit. The first lens is utilized to capture a first image, and has a first visibility range. The second lens is disposed away from the first lens with a predetermined distance. The second lens is utilized to capture a second image, and has a second visibility range. The actuating module is coupled to the first lens and the second lens, and utilized to rotate the first lens and the second lens. The control unit is electrically coupled to the actuating module, and utilized to control the actuating module to rotate the first lens and the second lens such that the first visibility region overlaps the second visibility region to define an overlapping range which has a first mode and a second mode according to a size of the overlapping region. The image processing unit is electrically coupled to the control unit and receives the first image and the second image. The image processing unit stitches the first image and the second image for forming an ultra wide-angle image in the first mode; the image processing unit processes the first image and the second image into a stereoscopic image in the second mode. 
     In one preferred embodiment, the overlapping range in the first mode is smaller than the overlapping range in the second mode. Furthermore, the overlapping range in the second mode has a smallest range. 
     In one preferred embodiment, the first lens and the second lens are disposed on a platform, and the platform is substantially horizontal. In the embodiment, the actuating module comprises a first motor and a second motor, which are respectively coupled to the first lens and the second lens for respectively rotating the first lens and the second lens. Preferably, the first motor and the second motor are stepper motors. Moreover, the actuating module further includes a gyroscopes and/or an accelerometer for keeping the platform horizontal. 
     To achieve the another objective mentioned above, the present invention provides an image-capturing system for measuring a position and a distance of an object relative to the system. The system includes a first lens, a second lens, an actuating module, a control unit, and an image processing unit. The first lens is utilized to capture a first image, and has a first visibility range. The second lens is disposed away from the first lens with a predetermined distance. The second lens is utilized to capture a second image, and has a second visibility range. The actuating module is coupled to the first lens and the second lens, and utilized to rotate the first lens and the second lens, so that the object is within the first image and/or the second image. The control unit is electrically coupled to the actuating module, and utilized to control the actuating module to rotate the first lens and the second lens such that the first visibility region overlaps the second visibility region to define an overlapping range which has a first mode and a second mode according to a size of the overlapping region. The image processing unit is electrically coupled to the control unit and receives the first image and the second image. The image processing unit stitches the first image and the second image for forming an ultra wide-angle image in the first mode, and obtains the position of the object relative to the system. The image processing unit processes the first image and the second image into a stereoscopic image in the second mode, and calculates the distance of the object relative to the system. 
     In the embodiment, the overlapping range in the first mode is smaller than the overlapping range in the second mode. Moreover, the object is located at the overlapping range in the second mode. 
     In comparison with the prior art, the present invention employs the two lenses being capable of rotating by the control unit, so as to simultaneously have the ultra wide-angle mode and the stereoscopic mode; thus, the shortcoming that an optimal lens selection for the automobile safety warning system can not be achieved is completely solved. In addition, by means of the control unit controlling the rotation of the two lenses, the position of the object can firstly be found out by the ultra wide-angle mode, and secondly, the distance of the object can be determined by the stereoscopic mode, in order to provide an intelligent monitor function. 
     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a functional block diagram illustrating an image-capturing system with a dual lens camera of a first preferred embodiment of the present invention; 
         FIG. 2  depicts a top view schematically illustrating the image-capturing system with a dual lens camera of the embodiment; 
         FIG. 3  depicts a top view schematically illustrating the image-capturing system with a dual lens camera of the first embodiment in the first mode; 
         FIG. 4  depicts a top view schematically illustrating the image-capturing system with a dual lens camera of the first embodiment in the second mode; 
         FIG. 5  depicts a functional block diagram illustrating the image-capturing system of the second embodiment of the present invention monitoring an object; 
         FIG. 6  depicts a top view schematically illustrating the image-capturing system with a dual lens camera of the second embodiment in the first mode; and 
         FIG. 7  depicts a top view schematically illustrating the image-capturing system with a dual lens camera of the second embodiment in the second mode. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described in detail with reference to a few preferred embodiments thereof as illustrated in the accompanying drawings. The same reference numerals refer to the same parts or like parts throughout the various figures. 
     The image-capturing system with a dual lens camera of the present invention is not limited to the applications of the automobile safety warning system and the car video recorder. Others, such as machine vision of a robot, a security monitoring system, and the goods inspection on the production line, and so on, are within the scope of the present invention. Referring to  FIG. 1 ,  FIG. 1  depicts a functional block diagram illustrating an image-capturing system with a dual lens camera of a first preferred embodiment of the present invention. The image-capturing system  100  with a dual lens camera of the embodiment includes a first lens  122 , a second lens  124 , an actuating module  140 , a control unit  160 , and an image processing unit  180 . 
     Referring to  FIG. 1  and  FIG. 2 ,  FIG. 2  depicts a top view schematically illustrating the image-capturing system with a dual lens camera of the embodiment. The first lens  122 , otherwise known as a left lens, is utilized to capture a first image (not shown), and the first lens  122  has a first visibility range I, i.e. a range within a visual angle of the first lens  122 . The second lens  124 , otherwise known as a right lens, is disposed away from the first lens  122  with a predetermined distance D. The second lens  124  utilized to capture a second image (not shown), and has a second visibility range II, i.e. a range within a visual angle of the second lens  124 . 
     In the embodiment, the first lens  122  and the second lens  124  employ the same lens; that is, they have the same visual angle and performance. More specifically, the first lens  122  and the second lens  124  can be Charge-coupled Device (CCD) cameras or Complementary Metal-Oxide Semiconductor (CMOS) cameras. In the embodiment, the first lens  122  and second lens  124  are disposed on a platform  190 , and the platform  190  is substantially horizontal. Preferably, the platform  190  is a printed circuit board (PCB), and the above-mentioned control unit  160  and image processing unit  180  can be disposed on the printed circuit board. 
     As shown in  FIG. 1 , the actuating module  140  is coupled to the first lens  122  and the second lens  124 , and the actuating module  140  is utilized to rotate the first lens  122  and the second lens  124 , i.e. to change shooting angles of the first lens  122  and the second lens  124 . In the embodiment, the actuating module  140  includes a first motor  142  and a second motor  144 , which are respectively coupled to the first lens  122  and the second lens  124  for respectively rotating the first lens  122  and the second lens  124 . Specifically, the first motor  142  and the second motor  144  are stepper motors, both of which are used for precisely controlling angles of rotation of the first lens  122  and the second lens  124 . 
     Referring to  FIG. 1  and  FIG. 2 , the control unit  160  is electrically coupled to the actuating module  140 , and utilized to control the actuating module  140  to rotate the first lens  122  and the second lens  124  such that the first visibility region I overlaps the second visibility region II to define an overlapping range  0 , which has a first mode and a second mode according to the size of the overlapping region  0 . The following will explain the above-mentioned modes in detail with  FIGS. 3 and 4 . 
       FIG. 3  depicts a top view schematically illustrating the image-capturing system with a dual lens camera of the first embodiment in the first mode;  FIG. 4  depicts a top view schematically illustrating the image-capturing system with a dual lens camera of the first embodiment in the second mode. Referring to  FIG. 3  and  FIG. 4 , in the preferred embodiment, the overlapping range O 1  in the first mode ( FIG. 3 ) is smaller than the overlapping range O 2  in the second mode ( FIG. 4 ). Referring to  FIG. 1 , the image processing unit  180  is electrically coupled to the control unit  160  and receives the first image and the second image. 
     In the first mode, the image processing unit  180  stitches the first image and the second image for forming an ultra wide-angle image. That is to say, the image processing unit  180  compares overlapping portions (i.e. part of the image within the overlapping range O 1 ) of the first image and the second image, and thus it has a foundation for aligning the two images. Subsequently, it stitches the two images from their overlapping portions, so as to form an ultra wide-angle image. It is worth mentioning that the angles of the outward rotation of the first lens  122  and the second lens  124  can be controlled via the control unit  160 . When the overlapping range O 1  of the shooting angles with the rotation reaches a critical edge, the widest ultra wide-angle image is available. Meanwhile, the overlapping range O 1  in the second mode has a smallest range. Accordingly, the first lens  122  and the second lens  124  need not employ the ultra wide-angle lenses, or even fish-eye lenses, thereby avoiding the problem of image distortion. 
     In the second mode, the image processing unit  180  processes the first image and the second image into a stereoscopic image. Specifically, in order to calculate the depth information of the object by the image processing unit  180 , the object must be located at the overlapping range O 2  for simultaneously appearing in the first image and the second image. 
     Under this condition, the depth information of the object can be calculated through algorithms. 
     It is worth mentioning that because when the first lens  122  and the second lens  124  are not positioned on a same horizontal plane, the image processing unit  180  needs to perform horizontal and vertical calibrations for the first image and the second image correction during processing the stereoscopic image. Thus, there is a problem of a heavy computational load. Accordingly, the actuating module  160  of the image-capturing system  100  of the embodiment further includes a gyroscopes and/or an accelerometer, which are utilized to keep the platform  190  horizontal, so as to improve the efficiency of the image processing unit  180  processing the stereoscopic image. That is to say, the actuating module  160  can further includes a triaxial motor (not shown) for keeping the platform  190  horizontal. However, except for the gyroscopes and the accelerometer, the actuating module  160  can further includes a magnetometer for improving the sensing of position. 
     The image-capturing system of a second embodiment of the present invention will be explained in the following. Referring to  FIG. 5 ,  FIG. 5  depicts a functional block diagram illustrating the image-capturing system of the second embodiment of the present invention monitoring an object. The image-capturing system  200  of the second embodiment can be utilized to measure a position and a distance of the object  300  relative to the system  200 . Similarly, the image-capturing system  200  includes a first lens  122 , a second lens  124 , an actuating module  140 , a control unit,  160  and an image processing unit  180 . Amongst these elements, the descriptions of the elements similar to the first embodiment have been explained as above mention, so we need not go into detail herein. 
     Referring to  FIG. 6  and  FIG. 7 ,  FIG. 6  depicts a top view schematically illustrating the image-capturing system with a dual lens camera of the second embodiment in the first mode;  FIG. 7  depicts a top view schematically illustrating the image-capturing system with a dual lens camera of the second embodiment in the second mode. The first lens  122  is utilized to capture a first image, and has a first visibility range I. The second lens  124  is disposed away from the first lens  122  with a predetermined distance D, and utilized to capture a second image. The second lens  124  has a second visibility range II. 
     As shown in  FIGS. 5-7 , the actuating module  140  is coupled to the first lens  122  and the second lens  124 , and the actuating module  140  is utilized to rotate the first lens  122  and the second lens  124 , so that the object  300  is within the first image and/or the second image. 
     Similarly, the control unit  160  is electrically coupled to the actuating module  140 , and utilized to control the actuating module  140  to rotate the first lens  122  and the second lens  124  such that the first visibility region I overlaps the second visibility region II to define an overlapping range O, which has a first mode and a second mode according to the size of the overlapping region O. 
     The image processing unit  180  is electrically coupled to the control unit  160  and receives the first image and the second image. In the first mode, the image processing unit  180  stitches the first image and the second image for forming an ultra wide-angle image, and obtaining the position, i.e. an azimuth A of the object  300  relative to the system  200 . In the second mode, the image processing unit  180  processes the first image and the second image into a stereoscopic image, and calculates the distance d of the object  300  relative to the system  200 . As mentioned above, the overlapping range O 1  in the first mode is smaller than the overlapping range O 2  in the second mode. 
     Specifically, the processes with regard to the image-capturing system  200  of the second preferred embodiment monitoring the object  300  will be described in the following. The image-capturing system  200  is firstly in the ultra wide-angle mode, i.e. a searching mode as shown in  FIG. 6 . That is, the actuating module  140  rotates the first lens  122  and the second lens  124 , or rotates the whole platform  190 . When the object  300  is found on the first image and/or the second image, the first lens  122  and the second lens  124  are rotated inwardly to switch to the stereoscopic mode as shown in  FIG. 7 . Meanwhile, the object  300  is positioned at the overlapping range O 2  in the second mode, and then the distance d of the object  300  can be calculated via algorithms. 
     In summary, the present invention employs the two lenses  122  and  124  being capable of rotating by the control unit, so as to simultaneously have the ultra wide-angle mode and the stereoscopic mode; thus, the shortcoming that an optimal lens selection for the automobile safety warning system can not be achieved is completely solved. In addition, by means of the control unit  160  controlling the rotation of the two lenses  122  and  124 , the position of the object  300  can firstly be found out by the ultra wide-angle mode, and secondly, the distance d of the object  300  can be determined by the stereoscopic mode, in order to provide an intelligent monitor function. 
     While the preferred embodiments of the present invention have been illustrated and described in detail, various modifications and alterations can be made by persons skilled in this art. The embodiment of the present invention is therefore described in an illustrative but not restrictive sense.