Patent Publication Number: US-2023154031-A1

Title: Verification method of dynamic virtual image display distance of user interface and system thereof

Description:
1. FIELD OF THE INVENTION 
     The disclosure relates to a verification method and a system thereof, and more particularly, a verification method of a dynamic virtual image display distance of a user interface and a system thereof. 
     2. Description of the Related Art 
     The head-up display (HUD) is widely used in a vehicle. Accuracy of the HUD will be determined by accuracy of a size of an image projected by the HUD. Common methods for measuring the distance displayed by the virtual image comprises a merging focus method, a reckoning method, and a triangular measurement method. All of the methods cannot achieve the demands for a wide measurement range of lenses, a high measurement speed, and a low equipment requirement. 
     The merging focus method captures a clarity image for testing a virtual image display distance. However, the merging focus method needs to use an equipment with a short focal range to measure the virtual image display distance. Therefore, the merging focus method has a narrow measurement range. Moreover, since lens of the equipment used by the merging focus method needs to adjust focus for merging focus, a speed for measuring the virtual image distance by the merging focus method is slow. In addition, since the merging focus method needs high resolution and multiple lenses, different virtual image display distances need to change lenses having different focuses. In this way, the merging focus method cannot achieve to dynamically and continuously measure different virtual image display distances. In other words, the virtual image display distance of the merging focus method and lenses are one on one. Consequently, the merging focus method needs high requirement for the measurement equipment. 
     The reckoning method and the triangular measurement method utilize the equipment distance and the measured angle to calculate the relation of the images for testing the virtual image display distance. However, since the reckoning method and the triangular measurement method have high requirement for the resolution and the amount of the lenses, the equipment used by the reckoning method and the triangular measurement method for testing the virtual image display distance has high requirement. Furthermore, since the precision of the reckoning method is limited by the error of the image pixel, the precision of the reckoning method is low. 
     Accordingly, how to provide a verification method of the dynamic virtual image display distance of a user interface and a system thereof to solve the problems mentioned above is an urgent subject to tackle. 
     SUMMARY OF THE INVENTION 
     In view of this, the present invention provides a verification method of the dynamic virtual image display distance of a user interface, comprising the following steps: creating a tested image database; wherein the tested image database comprises at least one tested image displayed in at least one standard virtual image display distance; displaying a first tested image in the tested image database by a display element; projecting a first image on a stacked image element by a user interface; wherein the first image is displayed at a first virtual image display distance and the first virtual image display distance is the same with a first standard virtual image display distance of the first tested image; wherein the first image projected by the user interface module is used to be tested whether a first size of a first object of the first image correctly corresponds to the first virtual image display distance; capturing the first tested image and the first image by an image capturing module; performing a first reliability evaluation procedure for recognizing the first size of the first object of the first image and a second size of a tested object of the first tested image by an identifying module; and calculating a first overlap ratio for the first object of the first image and the first tested object of the first tested image by a processing module to verify accuracy of the first virtual image display distance of the user interface. 
     The present invention provides a verification system of the dynamic virtual image display distance for the user interface. The verification system of the dynamic virtual image display distance for the user interface comprises a tested image database, an image capturing module, an identifying module, and a processing module. The tested image database comprises at least one tested image. The first image is displayed in the first standard virtual image display distance. The tested image is the standard image for verifying a first image at a first virtual image display distance projected by a user interface. The image capturing module captures a first tested image of a plurality of tested images in the tested image database and captures the first image projected by the user interface. The first image corresponds to the first virtual image display distance and the first tested image corresponds to the first standard virtual image display distance. The first virtual image display distance is equal to the first standard virtual image display distance. The first image projected by the user interface module is used to be tested whether a first size of the first image correctly corresponds to the first virtual image display distance. The identifying module performs a reliability evaluation for recognizing the first size of a first object of the first image and a second size of a first tested object of the first tested image. The processing module calculates an overlap ratio for the first image and the first tested image to verify accuracy of the first image projected by the user interface according to the first virtual image display distance. 
     As mentioned above, the verification method of the dynamic virtual image display distance of a user interface and the system thereof of the present invention create the tested image database according to the predetermined virtual image display distance. In addition, the verification method and the system thereof can vary the information of the virtual image display distance according to the object on the road to correspond to the different object at the different distance. Moreover, the verification method and the system thereof perform the reliability evaluation and calculating the overlap ratio for the image which is used to be tested and the tested image, overlap different image information, directly display the images on the user interface, rapidly recognize the images, and promote the accuracy and the stability of the system which is under test. Besides, without extra hardware and without changing lenses, the verification method and the system thereof verify the virtual image display distance by contrasting the image which is under test with the tested image. Consequently, the verification method and the system thereof can reduce the test cost, dynamically and continuously measure the virtual image display distance, promote the verification effect and achieve the automatic verification effect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  is a block diagram of the verification system of the dynamic virtual image display distance for the user interface of the present invention; 
         FIG.  1 B  is a schematic diagram of projecting the image which is under test and the tested image of the present invention; 
         FIG.  1 C  is a schematic diagram of a plurality of tested objects captured by the image capturing module corresponding to a plurality of standard virtual image display distances of the present invention; 
         FIG.  2 A  is a schematic diagram of the first reliability evaluation procedure of the present invention; 
         FIG.  2 B  is a schematic diagram of the second reliability evaluation procedure of the present invention; 
         FIG.  3 A  to  FIG.  3 C  are schematic diagrams of an overlap ratio; and 
         FIG.  4    is the flow diagram of the verification method of the dynamic virtual image display distance of a user interface. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First of all, it should be interpreted that the verification method of the dynamic virtual image display distance of a user interface and the system thereof is utilized to verify the specifications of the user interface before shipping from the factory. Alternatively, the verification method and the system thereof are used to measure the specifications of the user interface after shipping from the factory, but it is not limited thereto in the present invention. Besides, the verification method of the dynamic virtual image display distance of a user interface of the present invention utilizes the user interface as the system which is under test to test and verify the accuracy of the dynamic virtual image display distance of the user interface. In an embodiment of the present invention, the user interface comprises a head-up display. 
     Refer to  FIG.  1 A  and  FIG.  1 B .  FIG.  1 A  is the block diagram of the verification system of the dynamic virtual image display distance for the user interface of the present invention.  FIG.  1 B  is the schematic diagram of projecting the first image according to the first virtual image display distance and projecting the first tested image according to the first standard virtual image display distance. The verification system of the dynamic virtual image display distance for the user interface  1  comprises a tested image database  11 , an image capturing module  12 , an identifying module  13 , and a processing module  14 . The tested image database  11  comprises at least one tested image T. The at least one tested image T is displayed according to at least one standard virtual image display distance D. The tested image T is the standard image for verifying an image I at a virtual image display distance L projected by a user interface module H 1  of a user interface H. As shown in  FIG.  1 B , the image capturing module  12  captures a first tested image T 1  of a plurality of tested images T in the tested image database  11  and captures a first image I 1  projected by the user interface module H 1 , wherein the first tested image T 1  is one of the at least one tested image T. The first image I 1  corresponds to the first virtual image display distance L 1  and the first tested image T 1  corresponds to the first standard virtual image display distance D 1 . The first virtual image display distance L 1  is equal to the first standard virtual image display distance D 1 . The identifying module  13  performs a reliability evaluation for recognizing a first size of a first object of the first image I 1  and a second size of a first tested object of the first tested image T 1 . The processing module  14  calculates an overlap ratio for the first image I 1  and the first tested image T 1  to verify accuracy of the first image I 1  projected by the user interface module H 1  according to the first virtual image display distance L 1 . 
     Refer to  FIG.  1 C .  FIG.  1 C  is the schematic diagram of a plurality of tested objects respectively corresponding to a plurality of standard virtual image display distances measured by the image capturing module. The tested image database  11  is created according to a first tested object A 1  of the first tested image T 1  corresponding to the first standard virtual image display distance D 1 , a second tested object A 2  of the second tested image T 2  corresponding to the second standard virtual image display distance D 2 , and a third tested object A 3  of the third tested image T 3  corresponding to the third standard virtual image display distance D 3  captured by the image capturing module  12 . In other words, in the embodiment, the tested image database  11  is created by a real size of the tested object captured by the image capturing module  12 . 
     Refer to  FIG.  1 A  and  FIG.  1 C  again. In a first embodiment of the present invention, the verification system of the dynamic virtual image display distance for the user interface  1  further comprises a storage module  15 , storing a lookup table. The lookup table is created according to the first tested object A 1 , the second tested object A 2 , and the third tested object A 3  captured by the image capturing module  12 . 
     In a second embodiment, the image capturing module  12  captures a first tested object A 1  of the first tested image T 1  corresponding to the first standard virtual image display distance D 1 , a second tested object A 2  of the second tested image T 2  corresponding to the second standard virtual image display distance D 2 , and a third tested object A 3  of the third tested image T 3  corresponding to the third standard virtual image display distance D 3 . The processing module  14  generates a ratio relationship for a plurality of tested objects An(n=1, 2, 3 . . . ) corresponding to a plurality of standard virtual image display distances D according to the size of the first tested object A 1  corresponding to the first standard virtual image display distance D 1 , the size of the second tested object A 2  corresponding to the second standard virtual image display distance D 2 , and the size of the third tested object A 3  corresponding to the third standard virtual image display distance D 3 . The tested image database  11  is created according to the ratio relationship. 
     It should be noted that the amount captured by the image capturing module  12  is taken for an example but not to limit the scope of the present invention to either the first embodiment or the second embodiment. In fact, the amount captured by the image capturing module  12  is determined according to the standard of the accuracy to verify the virtual displaying distance. 
     As shown in  FIG.  1 A  and  FIG.  1 B , the user interface module H 1  is disposed in the user interface H. The user interface H comprises an optical axis (not shown in  FIG.  1 A  and  FIG.  1 B ). After calibrating the optical axis, the user interface H projects the image I on the stacked image element S according to the virtual image display distance L. In details, the image I is projected on the stacked image element S by the user interface module H 1 . Before that, the optical axis of the user interface H needs to be calibrated to ensure the image I can be accurately projected on the stacked image element S. In an embodiment, the stacked image element S comprises a windshield of a vehicle or a stacked image piece of the user interface H. 
     Refer to  FIG.  2 A  and  FIG.  2 B .  FIG.  2 A  and  FIG.  2 B  are the schematic diagram for the first reliability evaluation procedure and the second reliability evaluation procedure of the present invention. In  FIG.  2 A , the identifying module  13  recognizes a plurality of first distances between a plurality of feature vertexes P 1 , P 2 , P 3 , P 4  of the first object O 1  of the first image I 1  and a plurality of vertex positions Q 1 , Q 2 , Q 3 , Q 4  of the first tested object A 1  of the first tested image T 1 . The processing module  14  determines the reliability of the first image I 1  according to the plurality of first distances. 
     In  FIG.  2 B , when the first reliability of the first image I 1  is unreliable in  FIG.  2 A , the user interface module H 1  projects the second image O 2  on the stacked image element S. The image capturing module  12  captures the second image  12  and the first tested image T 1 . The identifying module  13  recognizes a plurality of second distances between a plurality of feature vertexes P 5 , P 6 , P 7 , P 8  of the second object O 2  of the second image  12  and a plurality of vertex positions Q 1 , Q 2 , Q 3 , Q 4  of the first tested object A 1  of the first tested image T 1 . The processing module  14  determines the second reliability of the second image T 2  according to the plurality of second distances. The second image T 2  corresponds to the first virtual image display distance L 1 . In other words, at the same virtual image display distance, the image capturing module  12  captures a new image to calculate the reliability evaluation of the new image. The second image is displayed at a second virtual image display distance, and the second virtual image display distance is the same with a second standard virtual image display distance of a second tested image. The second image projected by the user interface module H 1  is used to be tested whether a second size of the second image correctly corresponds to the second virtual image display distance. 
     As mentioned above, in addition to calculating the distance for determining the reliability, the step for calculating the first reliability evaluation procedure and the second reliability evaluation procedure in  FIG.  2 A  and  FIG.  2 B  further comprises the step for calculating the gradient between each adjacent feature vertexes of the object of the image by processing module  14  to determine the reliability. Moreover, in  FIG.  2 A , the distance of the plurality of feature vertexes P 1 , P 2 , P 3 , P 4  of the first object O 1  of the first image I 1  close to the plurality of vertex positions Q 1 , Q 2 , Q 3 , Q 4  of the first tested object A 1  of the first tested image T 1 ; however, the feature vertex P 1 , P 2 , P 3 , P 4  may be disposed distortedly. Therefore, the processing module  14  determines the gradient between each two adjacent feature vertexes P 1 , P 2 , P 3 , P 4  of the first object O 1  to determine the shape of the first object O 1 ; wherein the gradients comprise an X axial gradient and a Y axial gradient, such as the X axial gradient and the Y axial gradient between the feature vertex P 1  and the feature vertex P 2 , the X axial gradient and the Y axial gradient between the feature vertex P 1  and the feature vertex P 3 , the X axial gradient and the Y axial gradient between the feature vertex P 2  and the feature vertex P 4 , and the X axial gradient and the Y axial gradient between the feature vertex P 3  and the feature vertex P 4 . When the gradient is lower, the first object O 1  is more approximate to a rectangle in shape. Hence, the processing module  14  determines that the first object O 1  has a high reliability. When the gradient is higher, the first object O 1  fails to be approximate to a rectangle in shape. Hence, the processing module  14  determines that the first object O 1  has a low reliability. In another embodiment, as shown in  FIG.  2 B , the plurality of feature vertexes P 5 , P 6 , P 7 , P 8  of the second object O 2  are far away from the plurality of vertex positions Q 1 , Q 2 , Q 3 , Q 4  of the first tested object A 1  of the first tested image T 1 . However, after the processing module  14  calculates the gradient between each two adjacent feature vertexes P 5 , P 6 , P 7 , P 8  and a plurality of second distances between each feature vertex P 5 , P 6 , P 7 , P 8  and each vertex position Q 1 , Q 2 , Q 3 , Q 4 , the gradients between each two adjacent feature vertexes are equal to zero, that is, the shape of the second object O 2  is approximate to the rectangle. As a result, the processing module  14  increases the weight of the gradient, decreases the weight of the plurality of second distances, and determines that the second object O 2  has a high reliability according to the whole weight comprising the gradient and the plurality of second distances. 
     Refer to  FIG.  3 A  to  FIG.  3 C .  FIG.  3 A  to  FIG.  3 C  are the schematic diagrams of the overlap ratio of the present invention. The processing module  14  calculates the overlap ratio for an area overlapping ratio between the first image I 1  and the first tested image T 1 . The area overlapping ratio is generated by calculating the area overlapping ratio between the first object O 1  of the first image I 1  and the first tested object A 1  of the first tested image T 1  divided by the area of the first tested object A 1  of the first tested image T 1 . 
     Refer to  FIG.  4   .  FIG.  4    is the flow diagram of the verification method of the dynamic virtual image display distance of a user interface. The verification method of the dynamic virtual image display distance of a user interface comprises the following steps: in step S 11 , creating a tested image database  11 , wherein the tested image database  11  comprises at least one tested image T displayed according to at least one standard virtual image display distance D; in step S 12 , displaying a first tested image T 1  in the at least one tested image T by a display element M; in step S 13 , projecting a first image I 1  on a stacked image element S by a user interface module H 1 ; wherein the first image I 1  is displayed at a first virtual image display distance L 1  and the first virtual image display distance L 1  is the same with a first standard virtual image display distance D 1  of the first tested image T 1 ; in step S 14 , capturing the first tested image T 1  and the first image I 1  by an image capturing module  12 ; in step S 15 , performing a first reliability evaluation procedure for recognizing a first size of the first image I 1  and a second size of the first tested image T 1  by an identifying module  13 ; in step S 16 , calculating a first overlap ratio for the first image I 1  and the first tested image T 1  by a processing module  14  to verify accuracy of the first virtual image display distance L 1  of the user interface module H 1 , wherein the identifying module  13  performs the reliability evaluation for the first object O 1  of the first image I 1  and the first tested object A 1  of the first tested image T 1 . The reliability evaluation relates to whether the shape of the first object O 1  is approximate to a rectangle. It should be noted that the term “first” is used to illustrate the number for verifying the dynamic virtual image display distance of the user interface H, but not limited thereto. The number is determined by the actual demand for the accuracy of the user interface H. In other words, if the tested image database  11  comprises such as the first tested image T 1 , the second tested image T 2 , and the third tested image T 3 , the method can perform three times of verifying the virtual image display distance L according to the three tested images with the three images which are used to be tested to promote the accuracy of the user interface H. 
     Refer to  FIG.  4    again: the verification method of the dynamic virtual image display distance of a user interface further comprises the step S 10  for calibrating the optical axis of the user interface H. After that, the user interface module H 1  projects the image to the stacked image element S according to the virtual image display distance. In details, in step S 13 , the user interface module H 1  projects the first image I 1  to the stacked image element S. Before that, the optical axis of the user interface H needs to be calibrated to ensure the first image I 1  can be accurately projected on the stacked image element S. In an embodiment, the stacked image element S comprises a windshield of a vehicle or a stacked image piece of the user interface H. 
     Refer to  FIG.  1 C  again. In step S 11  for creating the tested image database  11 , the step S 11  comprises records and captures the plurality of tested objects A 1 , A 2 , A 3  respectively corresponding to the plurality of standard virtual image display distances D 1 , D 2 , D 3  by the image capturing module  12  and generates the plurality of tested images T 1 , T 2 , T 3  according to the plurality of tested objects A 1 , A 2 , A 3 . In the first embodiment of the present invention, the image capturing module  12  is a camera device. The camera device captures the real size of the tested objects A 1 , A 2 , A 3  at different standard virtual image display distances D 1 , D 2 , D 3  and records the size of the tested objects A 1 , A 2 , A 3  as the tested images T 1 , T 2 , T 3 . Besides, the lookup table, comprising the tested images T 1 , T 2 , T 3  corresponding to different standard virtual image display distances D 1 , D 2 , D 3 , is created according to the size of the tested objects A 1 , A 2 , A 3  captured by the image capturing module  12 . Furthermore, the step utilizes the lookup table by an algorithm to promote the accuracy of the following step. 
     In the second embodiment of the present invention, step S 11  for creating the tested image database  11  comprising capturing the first tested object A 1  of the first tested image T 1  corresponding to the first standard virtual image display distance D 1 , the second tested object A 2  of the second tested image T 2  corresponding to the second standard virtual image display distance D 2 , and the third tested object A 3  of the third tested image T 3  corresponding to the third standard virtual image display distance D 3  by the image capturing module  12 . The processing module  14  generates a ratio relationship for a plurality of tested objects An(n=1, 2, 3 . . . ) corresponding to the plurality of standard virtual image display distances D according to the size of the first tested object A 1  corresponding to the first standard virtual image display distance D 1 , the size of the second tested object A 2  corresponding to the second standard virtual image display distance D 2 , and the size of the third tested object A 3  corresponding to the third standard virtual image display distance D 3 . The tested image database  11  is created according to the ratio relationship. 
     In details, in the first embodiment, the step for creating the tested image database  11  records and captures the real size of the tested objects A 1 , A 2 , A 3  of the tested image T 1 , T 2 , T 3  by the image capturing module  12  according to different standard virtual image display distances D 1 , D 2 , D 3 . In the second embodiment, the processing module  14  generates the ratio relationship according to the size of the tested objects A 1 , A 2 , A 3  captured by the image capturing module  12  and the standard virtual image display distance Dn (n=1, 2, 3 . . . ) to derive the size of other tested objects An (n=4, 5, 6 . . . ) corresponding to the standard virtual image display distance and to create the tested image database  11 . In other words, the size of the object in the image with the distance has an inverse ratio. That is, the more the distance is, the smaller the size of the object is, and vice versa. Consequently, each tested object A 1 , A 2 , A 3  corresponding to each standard virtual image display distance D 1 , D 2 , D 3  can be generated by the ratio relationship. Then, the tested image database  11  is created. Moreover, the ratio relationship generated in the second embodiment can be verified in the first embodiment. That is, the ratio relationship between the size of the tested object An (n=1, 2, 3 . . . ) and the standard virtual image display distance Dn (n=1, 2, 3 . . . ) can be verified by contrasting with the size of the tested object An (n=1, 2, 3 . . . ) corresponding to the standard virtual image display distance Dn captured by the image capturing module  12 . 
     After step S 11  for creating the tested image database  11 , step S 12  selects the virtual image display distance L to be verified, selects the standard virtual image display distance D corresponding to the virtual image display distance L, selects the tested image T in the tested image database  11  corresponding to the standard virtual image display distance D, and projects the tested image T on the display element M. In the embodiment, the display element M comprises a display monitor or a projection screen. 
     Refer to  FIG.  1 B  again. In step S 13  for projecting the first image I 1  on the stacked image element S by the user interface module H 1 , the image capturing module  12  simultaneously captures the first image I 1  and the first tested image T 1  displayed in the display element M. The first virtual image display distance L 1  is the same with the first standard virtual image display distance D 1 . Besides, in step  13 , the virtual image display distance L desired to be verified is selected by a user, but not limited to verifying single virtual image display distance. In fact, the method of the present invention verifies a plurality of virtual image display distances L according to the user demand to promote the accuracy of the virtual image display distance projected by the user interface H. 
     Refer to  FIG.  2 A  and  FIG.  2 B  again. In step S 15  for performing the first reliability evaluation procedure, step S 15  recognizes a plurality of feature vertexes P 1 , P 2 , P 3 , P 4  of the first object O 1  in the first image I 1  by the identifying module  13  to determine whether the first object O 1  in the first image I 1  is approximate to a rectangle. In the method of the present invention, the processing module  14  calculates a conformance for the size of the first object O 1  in the first image I 1  with the size of the first tested object A 1  in the first tested image T 1  corresponding to the first virtual image display distance D 1  to verify the accuracy of the size of the first image I 1  projected by the user interface H according to the first virtual image display distance L 1 . Therefore, step  15  confirms the first reliability of the first image I 1 . The first reliability is determined by recognizing whether the first object O 1  in the first image I 1  is approximate to a rectangle by the identifying module  13 . After that, when the first reliability is high, the method performs the following steps. Moreover, since the first tested object A 1  is a rectangle, the processing module  14  calculates the difference between the four feature vertexes P 1 , P 2 , P 3 , P 4  of the first object O 1  in the first image I 1  and the four vertex positions Q 1 , Q 2 , Q 3 , Q 4  of the first tested object A 1  in the first tested image T 1  to generate a plurality of first distances for determining whether the first object O 1  is approximate to a rectangle in step  15 . The plurality of first distances are generated by calculating the difference between each feature vertex P 1 , P 2 , P 3 , P 4  and each vertex Q 1 , Q 2 , Q 3 , Q 4 . The plurality of first distances, P 1  to Q 1 , P 2  to Q 2 , P 3  to Q 3  and P 4  to Q 4 , are generated by the formula for calculating the distance between two points in space coordinate mathematically. If the plurality of first distances are less, the first object O 1  in the first image I 1  is more approximate to a rectangle and the reliability of the first image I 1  is higher. If the plurality of the first distances are more, the first object O 1  in the first image I 1  fails to be more approximate to a rectangle and the reliability of the first image I 1  is lower. 
     Refer to  FIG.  2 B  again. Step S 15  further comprises a step S 151  for capturing a new image I. When the first image I 1  fails to be approximate to a rectangle, the first reliability of the first image I 1  is unreliable and step S 151  performs a second reliability evaluation procedure. The user interface module H 1  projects the second image T 2  on the display element M. The image capturing module  12  captures the four feature vertexes P 5 , P 6 , P 7 , P 8  of the second object O 2  in the second image  12  and the four vertexes Q 1 , Q 2 , Q 3 , Q 4  of the first tested object A 1  in the first tested image T 1 . The identifying module  13  recognizes the four feature vertexes P 5 , P 6 , P 7 , P 8  of the second object O 2  in the second image  12  and the four vertexes Q 1 , Q 2 , Q 3 , Q 4  of the first tested object A 1  in the first tested image T 1 . The processing module  14  generates a plurality of second distances by calculating the difference between each feature vertex P 5 , P 6 , P 7 , P 8  and each vertex position Q 1 , Q 2 , Q 3 , Q 4  to determine whether the second object O 2  is approximate to a rectangle. When the feature vertexes P 1 , P 2 , P 3 , P 4  of the first object O 1  have a large distortion, the first object O 1  in the first image I 1  recognized by the identifying module  13  fails to be approximate to a rectangle. Therefore, the image capturing module  12  needs to capture the new feature vertexes. In addition, the feature vertexes P 1 , P 2 , P 3 , P 4  of the first object O 1  in the first image I 1  are automatically captured by the image recognition algorithm to adjust the accuracy of the reliability evaluation. Moreover, the accuracy of the reliability evaluation can be promoted by adjusting the system parameters or the hardware position to improve the accuracy of the reliability evaluation, such as adjusting the light illumination in the environment or altering the position of the image capturing module  12 , and so on. In addition, step S 15  for performing the reliability evaluation comprises an image performance measure for the image I to improve the accuracy of the virtual image display distance L. The image performance measure for the image I comprises calculating a curvature of field, calculating a resolution, and calculating a color. Besides, recognizing and capturing the feature vertexes P 1 , P 2 , P 3 , P 4  of the first object O 1  in the first image I 1  are determined by contrasting the first image I 1  with the pixel gray value in the ground. The prior art in the image processing field should realize the theorem; therefore, the details are omitted herein. 
     Refer to  FIG.  3 A  to  FIG.  3 C . In step S 16 , the processing module  14  calculates the overlap ratio for the first image I 1  and the first tested image T 1 . The overlap ratio is determined by calculating the area overlapping ratio between the first object O 1  of the first image I 1  and the first tested object A 1  of the first tested image T 1 . When the overlap ratio is lower, the error between the first virtual image display distance L 1  of the user interface H and the first standard virtual image display distance D 1  (target value) is greater; in contrast, the first virtual image display distance L 1  is more accurate. As shown in  FIG.  3 A , when a little part of the first image I 1  overlaps with the first tested image T 1 , the overlap ratio is lower. As shown in  FIG.  3 B , when a large part of the first image I 1  overlaps with the first tested image T 1 , the overlap ratio is high. As shown in  FIG.  3 C , when the first image I 1  almost overlaps with the first tested image T 1 , the overlap ratio is excellent. The formula of the overlap ratio is represented below: 
     The overlap ratio=the area overlapping ratio between the object in the image and the tested object in the tested image/the area of the tested object 
     In step S 16 , the processing module  14  generates a verification result for verifying the accuracy of the virtual image display distance L of the user interface H according to the overlap ratio. For instance, if the area overlap ratio between the object in the image I and the object in the tested image T is 100%, the image I corresponding to the virtual image display distance L (such as 10 meters) projected by the user interface (the system which is under test) H has a 100% reliability. If the area overlap ratio between the object in the image I and the object in the tested image T is 50%, the image I corresponding to the virtual image display distance L projected by the user interface H has a 50% reliability. 
     As mentioned above, regardless of the reliability evaluation in step S 15  or the overlap ratio in step S 16 , the amount of the error is determined by the user demand for the accuracy of the user interface H. That is, if the user needs a high accuracy of the virtual image display distance L of the user interface H, the amount of the error for the reliability and the overlap ratio must be little. If the user would not need a high accuracy of the virtual image display distance L of the user interface H, the amount of the error for the reliability and the overlap ratio can be ignored. The present invention does not limit the amount of the error for the reliability and the overlap ratio. 
     Furthermore, in the embodiment of the present invention, the image I and the tested image T are not limited to be verified at the local terminal (verified by the processing module of the verification system of the dynamic virtual image display distance for the user interface). In another embodiment, the image I and the tested image T captured by the capturing module  12  can be transmitted to a cloud server to be calculated. 
     In summary, the verification method of the dynamic virtual image display distance of a user interface and the system thereof of the present invention creates the tested image database according to the predetermined virtual image display distance. In addition, the verification method and the system thereof can vary the information of the virtual image display distance according to the object on the road to correspond to the different object at the different distance. Moreover, the verification method and the system thereof perform the reliability evaluation and calculating the overlap ratio for the image and the tested image, overlap different image information, directly display the images on the user interface, rapidly recognize the images, and promote the accurate and the stability of the system which is under test. Besides, without extra hardware and without changing lenses, the verification method and the system thereof verify the virtual image display distance by contrasting the image with the tested image. Consequently, the verification method and the system thereof can reduce the test cost, dynamically and continuously measure the virtual image display distance, promote the verification effect, and achieve the automatic verification effect. 
     Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.