Three-coordinate mapper and mapping method

Abstract

A three-coordinate mapper, comprising a U-shaped chassis (11) which is formed by successively connecting a front cross-frame, a connecting frame and a rear cross-frame; a square front panel (12); a servo motor (13); a lead screw (14); one ends of four connecting rods (17) are hinged on a periphery of the nut (15); the other end of each of the four connecting rods (17) is hinged to one end of a support rod (18); a driven laser pointer (20) and a left camera (21), a right camera (22), an upper camera (23), and a lower camera (24); an intermediate camera (25) and a driving laser pointer (26); and, a plurality of auxiliary laser pointers (27). The three-coordinate mapper and the mapping method has high measurement precision and fast measurement speed.

Claims

1. A mapping method for a three-coordinate mapper that comprises a chassis, wherein the chassis is a U-shaped frame structure which is formed by successively connecting a front cross-frame, a connecting frame and a rear cross-frame in an end-to-end manner and has an opening on its left side; an end of the front cross-frame is integrally connected with a square front panel arranged vertically; a servo motor is provided at an end of the rear cross-frame; an output shaft of the servo motor is connected to one end of a lead screw, and the other end of the lead screw is connected to a center of a rear surface of the front panel through a bearing; a lead screw is in threaded connection to a nut; one ends of four connecting rods are hinged at positions, corresponding to four sides of the front panel, on a periphery of the nut; the other end of each of the four connecting rods is hinged to one end of a support rod; the other end of each of the four support rods is correspondingly penetrated through a middle portion of one of the four sides of the front panel, with a top end of the support rod penetrated through the left side of the front panel being vertically connected to a bottom surface of a fixed plate, a driven laser pointer and a left camera facing an object to be photographed being provided on the fixed plate, a right camera facing the object to be photographed being provided at a top end of the support penetrated through the right side of the front panel, an upper camera facing the object to be photographed being provided at a top end of the support rod penetrated through the upper side of the front panel, and a lower camera facing the object to be photographed being provided at a top end of the support rod penetrated through the lower side of the front panel; an intermediate camera and a driving laser pointer facing the object to be photographed are provided in a center of a front surface of the front panel; and, a plurality of auxiliary laser pointers facing the object to be photographed are further provided on the front panel in an array manner, comprising the following steps of: 1) determining a reference distance H.sub.k and a reference included angle .sub.k between a reference plane (e) provided in front of a front panel and the front panel, where k=1 . . . M, and M is a number; 2) generating reference spots on the reference plane (e), the reference spots being all spots radiated on the reference plane (e) by auxiliary laser pointers; 3) photographing and storing the reference spots in four reference images; 4) repeating the step 3) M times, wherein each time the four reference images, the reference distance H.sub.k and the reference included angle .sub.k which are corresponding to each other are obtained, and are transmitted to a control unit for storage; 5) photographing a real object and virtual spots, comprising: (1) aligning light beams emitted by a driving laser pointer and a driven laser pointer onto a surface of an object to form two spots, photographing, by an intermediate camera, images of the two spots and transmitting the images to the control unit, driving a servo motor by a main control module in the control unit through a motor driving module, driving four connecting rods to unfold and fold by the servo motor through a lead screw and a nut, driving, by the four connecting rods, four support rods to pass through the front panel to swing about hinge mechanisms, allowing the spot on the surface of the object projected by the driven laser pointer to coincide with the spot on the surface of the object projected by the driving laser pointer so that extension lines of central axes of a left camera, a right camera, a lower camera and an upper camera are allowed to be intersected at the spot, photographing the object simultaneously by the left camera, the right camera, the lower camera and the upper camera to obtain four physical images, and transmitting the physical images to the control unit; (2) bundling and storing, by the control unit, the four physical images obtained in the step (1), a vertical distance H.sub.f from the spot on the surface of the object projected by the driving laser pointer during photographing to the front panel, and a photographing included angle .sub.f between the light beam of the driven laser pointer and the front panel; 6) determining coordinate points, on four reference images, of a point P on the surface of the object corresponding to the front panel; 7) determining a horizontal coordinate and a vertical coordinate of the point P on the surface of the object; wherein the horizontal coordinate and the vertical coordinate of the point P are a horizontal coordinate and a vertical point of an auxiliary laser pointer, corresponding to the spot radiated on the point P, on the front panel; 8) determining a vertical distance h from the point P to the reference plane (e); and 9) repeating the steps 6) to 8) until all coordinate points and vertical distances h corresponding to the front panel of the chassis required to draw the images of the object are obtained.

2. The mapping method for a three-coordinate mapper according to claim 1, wherein the step 1) comprises: (1) activating the driving laser pointer, the intermediate camera, the driven laser pointer, the left camera, the right camera, the lower camera, the upper camera and the auxiliary laser pointers of the mapper; (2) in front of the front panel, providing a reference plane (e) parallel to the front panel; (3) photographing, by the intermediate camera, spots respectively radiated on the reference plane (e) by the driving laser pointer and the driven laser pointer, transmitting the images to the control unit, driving the servo motor by a main control module in the control unit through a motor driving module, driving four connecting rods to unfold and fold by the servo motor through a lead screw and a nut; driving, by the four connecting rods, four support rods to pass through the front panel to swing about hinge mechanisms, and allowing the spot radiated on the reference plane (e) by the driven laser pointer to coincide with the spot radiated on the reference plane (e) by the driving laser pointer so that extension lines of central axes of the left camera, the right camera, the lower camera and the upper camera to be intersected on the spot; and (4) setting a vertical distance from the front panel to the spot as a reference distance H.sub.k, a reference included angle between the projection of the light beam of the driven laser pointer on XZ and XY coordinate planes as k and the side length of the front panel as L, so that the reference distance H.sub.k=tg.sub.kL/2.

3. The mapping method for a three-coordinate mapper according to claim 1, wherein the step 3) comprises: photographing the reference spot on the reference plane (e) by the left camera, the right camera, the lower camera and the upper camera in the four photographing direction in the steps (3) of the step 1), to obtain four reference images of the reference spot radiated on reference plane (e) at different positions, transmitting the four reference images to the main control module of the control unit, and bundling and storing, by the main control module, the four reference images, the reference distance H.sub.k and the reference included angle .sub.k.

4. The mapping method for a three-coordinate mapper according to claim 3, specifically comprising: aligning light beams emitted by the driving laser pointer and the driven laser pointer onto the reference plane (e) to form two spots, photographing, by the intermediate camera, images of the two spots and transmitting the images to the control unit, driving the servo motor by the main control module in the control unit through the motor driving module, driving four connecting rods to unfold and fold by the servo motor through a lead screw and a nut, driving, by the four connecting rods, four support rods to pass through the front panel to swing about hinge mechanisms, swinging the fixed plate to allow the spot on the surface of the reference plane (e) projected by the driven laser pointer to coincide with the spot radiated on the reference plane (e) by the driving laser pointer so that extension lines of central axes of the left camera, the right camera, the lower camera and the upper camera are allowed to be intersected at the spot, photographing the reference plane (e) simultaneously by the left camera, the right camera, the lower camera and the upper camera to obtain four reference images, the reference distance H.sub.k and the reference included angle .sub.k, and transmitting them to the control unit for storage.

5. The mapping method for a three-coordinate mapper according to claim 1, wherein the step 6) comprises: (1) locating position points P1, P2, P3 and P4, on the four physical images, of the point P on the surface of the object; (2) acquiring the same reference included angle .sub.k as the photographing included angle f, acquiring four reference images corresponding to the reference included angle .sub.k, overlapping the reference image photographed by the left camera with the photographed physical image, overlapping the reference image photographed by the right camera with the photographed physical image, overlapping the reference image photographed by the lower camera with the photographed physical image, and overlapping the reference image photographed by the upper camera with the photographed physical image; (3) determining a projection, on an XZ coordinate plane, of a point on the reference image photographed by the left camera overlapped with the position point P1 on the photographed physical image as a point Q1 on the reference image; determining a projection, on the XZ coordinate plane, of a point on the reference image photographed by the right camera overlapped with the position point P2 on the photographed physical image as a point Q2 on the reference image; determining a projection, on a ZY coordinate plane, of a point on the reference image photographed by the lower camera overlapped with the position point P3 on the photographed physical image as a point Q3 on the reference image; and, determining a projection, on the ZY coordinate plane, of a point on the reference image photographed by the upper camera overlapped with the position point P4 on the photographed physical image as a point Q4 on the reference image; and (4) locating coordinate points of the points Q1, Q2, Q3 and Q4 on the front panel.

6. The mapping method for a three-coordinate mapper according to claim 1, wherein the step 8) comprises: (1) acquiring a distance u from the left camera to the coordinate point of the point Q1 on the front panel, a distance v from the right camera to the coordinate point of the point Q2 on the front panel, a distance w from the lower camera to the coordinate point of the point Q3 on the front panel and a distance r from the upper camera to the coordinate point of the point Q4 on the front panel, respectively; (2) calculating a distance h1 between the points Q1 and Q2 by the following formula: h.sub.1=u+vL, and calculating a distance h.sub.2 between the points Q3 and Q4 by the following formula: h.sub.2=w+rL; (3) calculating the area S.sub.12 of a triangle formed by the projections of the points Q1, Q2 and P on the ZX coordinate plane by the following formula: S.sub.12=a1.sup.2sin Bsin C2sin A=a1.sup.2sin Bsin C2sin(180AB), where: a1 is the base of the triangle, a1=h 1=u+vL, A is an angle subtended by the base of the triangle, B is an included angle between a connecting line of the of the point Q1 with the left camera and the base, and C is an included angle between the a connecting line of the point Q2 with the right camera and the base; the angle B=arc tgH/u, and the angle C=arc tgH/v; and the angle A=180BC=180arc tgH/uarc tgH/v; (4) calculating the area S.sub.12 of a triangle formed by the points Q1, Q2 and P by the following formula: S.sub.12=a1h2, where h is the height of the triangle; (5) substituting the formula for calculating the area S.sub.12 of the triangle in the step 3) into the formula for calculating the area S.sub.12 of the triangle in the step 4) to obtain h1:
a1.sup.2sin Bsin C2sin A=a1h12,
h1=a1sin Bsin Csin(180BC), substituting the angle B=arc tgH/u, the angle C=arc tgH/v, A=180BC=180arc tgH/uarc tgH/v and a1=u+vL into the formula for h1:
h1=(u+vL)sin arc tgH/usin arc tgH/vsin(180arc tgH/uarc tgH/v), where h1 is the vertical distance from the point P to the reference plane (e) obtained by the points Q1 and Q2; (6) calculating the area S.sub.34 of a triangle formed by the points Q3, Q4 and P by the following formula: S.sub.34=a2.sup.2sin B2sin C22sin A2=a2.sup.2sin B2sin C22sin(180A2B2), where: a2 is the base of the triangle, a2=h.sub.2=w+rL, A2 is an angle subtended by the base of the triangle, B2 is an included angle between a connecting line of the point Q3 with the lower camera and the base, and C2 is an included angle between a connecting line of the point Q4 with the upper camera and the base; the angle B2=arc tgH/w, and the angle C2=arc tgH/r; and the angle A2=180B2C2=180arc tgH/warc tgH/r; (7) calculating the area S.sub.34 of a triangle formed by projections of the points Q3, Q4 and P on the ZY coordinate plane by the following formula:
S.sub.34=a2h22, where h2 is the height of the triangle; (8) substituting the formula for calculating the area S.sub.34 of the triangle in the step 6) into the formula for calculating the area S.sub.34 of the triangle in the step 7) to obtain h2:
a2.sup.2sin B2sin C22sin A2=ah22,
h2=a2sin B2sin C2sin(180B2C2), substituting the angle B2=arc tgH/w, the angle C2=arc tgH/r, A2=180arc tgH/warc tgH/r and a2=w+rL into the formula for h2:
h2=(w+rL)sin arc tgH/wsin arc tgH/rsin(180arc tgH/warc tgH/r), where h2 is the vertical distance from the point P to the reference plane (e) obtained by the points Q3 and Q4; (9) calculating an arithmetic mean value of the h1 and h2 to obtain the vertical distance h from the point P to the reference plane (e); (10) calculating a depth Z of the point P by the following formula: Z=H.sub.kh; and (11) deciding whether the h is positive or negative: when Luv>0, h is positive, when Luv<0, h is negative, when Lrw>0, h is positive, and when Lrw<0, h is negative.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic structure diagram of a mapper in the prior art;

(2) FIG. 2 is a schematic structure diagram of a three-coordinate mapper according to the present invention, when viewed from the top;

(3) FIG. 3 is a top view of FIG. 2;

(4) FIG. 4 is a bottom view of FIG. 2;

(5) FIG. 5 is a schematic structure diagram of a plane e determined by the three-coordinate mapper according to the present invention;

(6) FIG. 6 is a left view of a front panel portion in FIG. 5;

(7) FIG. 7 is a schematic diagram of the actual measurement of the three-coordinate mapper according to the present invention;

(8) FIG. 8 is a top view of FIG. 7; and

(9) FIG. 9 is a left view of FIG. 7;

(10) in which:

(11) TABLE-US-00001 1: tabletop 2: contact 3: Z-direction support plate 4: Y-direction support plate 5: X-direction support plate 6: chassis 10: spot 11: chassis 12: front panel 13: servo motor 14: lead screw 15: nut 16: bearing 17: connecting rod 18: support rod 19: fixed plate 20: driven laser pointer 21: left camera 22: right camera 23: upper camera 24: lower camera 25: intermediate camera 26: driving laser pointer 27: auxiliary laser pointer 28: hinge structure 29: object 30: spot

DETAILED DESCRIPTION OF THE INVENTION

(12) The three-coordinate mapper and the mapping method of the present invention will be described below in detail by embodiments with reference to the accompanying drawings.

(13) As shown in FIGS. 1, 2, 3 and 4, the present invention provides a three-coordinate mapper, including a chassis 11. The chassis 11 is a U-shaped frame structure which is formed by successively connecting a front cross-frame, a connecting frame and a rear cross-frame in an end-to-end manner and has an opening on its left side. An end of the front cross-frame is integrally connected with a square front panel 12 arranged vertically. A servo motor 13 is provided at an end of the rear cross-frame. An output shaft of the servo motor 13 is connected to one end of a lead screw 14, and the other end of the lead screw 14 is connected to a center of a rear surface of the front panel 12 through a bearing 16. A lead screw 14 is in threaded connection to a nut 15. One ends of four connecting rods 17 are hinged at positions, corresponding to four sides of the front panel 12, on a periphery of the nut 15. The other end of each of the four connecting rods 17 is hinged to one end of a support rod 18. The other end of each of the four support rods 18 is correspondingly penetrated through a middle portion of one of the four sides of the front panel 12, wherein a top end of the support rod 18 penetrated through the left side of the front panel 12 is vertically connected to a bottom surface of a fixed plate 19, a driven laser pointer 20 and a left camera 21 facing the object to be photographed are provided on the fixed plate 19, a right camera 22 facing the object to be photographed is provided at a top end of the support 18 penetrated through the right side of the front panel 12, an upper camera 23 facing the object to be photographed is provided at a top end of the support rod 18 penetrated through the upper side of the front panel 12, and a lower camera 24 facing the object to be photographed is provided at a top end of the support rod 18 penetrated through the lower side of the front panel 12. An intermediate camera 25 and a driving laser pointer 26 facing the object to be photographed are provided in a center of a front surface of the front panel 12. A plurality of auxiliary laser pointers 27 facing the object to be photographed are further provided on the front panel 12 in an array manner. The light beams emitted by the plurality of auxiliary laser pointers 27 are different in size.

(14) The intermediate camera 25, the left camera 21, the right camera 22, the upper camera 23, the lower camera 24 and the servo motor 13 are connected to a control unit, respectively.

(15) The overall control portion and the power supply portion of the three-coordinate mapper of the present invention employ the technical solutions disclosed in the Patent No. 201420592944.8 entitled REMOTE CONTROL DEVICE FOR DOLLY BASED ON LASER GUIDANCE.

(16) In the three-coordinate mapper of the present invention, all the driving laser pointer 26, the intermediate camera 25 and the plurality of auxiliary laser pointers 27 that are arranged in an array with n equidistant rows and n equidistant columns are perpendicular to the front panel 12. The front panel 12 is a square having the length of side of L. The intermediate camera 25 is arranged in the center, and the driving laser pointer 26 is located right below the intermediate camera 25. The left camera 21 is mounted on the fixed plate 19 and located at an intersection of a left edge of the front panel 12 with an x-axis. The driven laser pointer 20 is also mounted on the fixed plate 19 and located right below the left camera 21. The distance from the driven laser pointer 20 to the left camera 21 is equal to the distance from the driving laser pointer 26 to the intermediate camera 25. The fixed pate 19 is integrally formed with a left support rod 18 that can swing. The right camera 22 is mounted on a support rod 18 that can swing at the intersection of the right edge of the front panel 12 with the x-axis. The upper camera 23 is mounted on a support rod 18 that can swing at an intersection of a right edge of the tabletop of the chassis with a y-axis. The lower camera 24 is mounted at a support rod 18 that can swing at an intersection of the right edge of the front panel 12 with the y-axis.

(17) As shown in FIGS. 5 to 9, the present invention provides a mapping method for a three-coordinate mapper, including the following steps.

(18) 1) A reference distance H.sub.k and a reference included angle .sub.k between a reference plane e provided in front of the front panel 12 and the front panel 12 are determined, where k=1 . . . M, including:

(19) (1) The driving laser pointer 26, the intermediate camera 25, the driven laser pointer 20, the left camera 21, the right camera 22, the lower camera 24, the upper camera 23 and the auxiliary laser pointers 27 of the mapper are activated.

(20) (2) In front of the front panel 12, a reference plane e parallel to the front panel 12 is provided.

(21) (3) Spots respectively radiated on the reference plane e by the driving laser pointer 26 and the driven laser pointer 20 are photographed by the intermediate camera 25, and the images are transmitted to the control unit; the main control module in the control unit drives the servo motor 13 through a motor driving module; the servo motor 13 drives four connecting rods 17 to unfold and fold through a lead screw 14 and a nut 15; the four connecting rods 17 drive four support rods 18 to pass through the front panel 12 to swing about hinge mechanisms 28; and the spot radiated on the reference plane e by the driven laser pointer 20 is allowed to coincide with the spot 10 radiated on the reference plane e by the driving laser pointer 26 so that extension lines of central axes of the left camera 21, the right camera 22, the lower camera 24 and the upper camera 23 to be intersected on the spot 10.

(22) (4) A vertical distance from the front panel 12 to the spot 10 is set as a reference distance H.sub.k, a reference included angle between the projections of the light beam of the driven laser pointer 20 on XZ and XY coordinate planes is set as .sub.k and the side length of the front panel 12 is set as L, so that the reference distance H.sub.k=tg.sub.kL/2.

(23) 2) Reference spots are generated on the reference plane e, wherein the reference spots are all spots radiated on the reference plane e by the auxiliary laser pointers 27.

(24) 3) The reference spots are photographed and stored, including:

(25) the reference spot on the reference plane e are photographed by the left camera 21, the right camera 22, the lower camera 24 and the upper camera 23 in the four photographing direction in the steps (3) of the step 1), to obtain four reference images of the reference spot radiated on reference plane e at different positions, the four reference images are transmitted to the main control module of the control unit, and the main control module bundles and stores the four reference images, the reference distance H.sub.k and the reference included angle .sub.k. Specifically:

(26) Light beams emitted by the driving laser pointer 26 and the driven laser pointer 20 are aligned onto the reference plane e to form two spots; the intermediate camera 25 photographs images of the two spots and transmits the images to the control unit; the main control module in the control unit drives the servo motor 13 through the motor driving module; the servo motor 13 drives four connecting rods 17 to unfold and fold through a lead screw 14 and a nut 15; the four connecting rods 17 drive four support rods 18 to pass through the front panel 12 to swing about hinge mechanisms 28; the swing of the fixed plate 19 allows the spot radiated on the surface of the reference plane e by the driven laser pointer 20 to coincide with the spot 30 radiated on the reference plane e by the driving laser pointer 26 so that extension lines of central axes of the left camera 21, the right camera 22, the lower camera 24 and the upper camera 23 are allowed to be intersected at the spot 10; and, the reference plane e is simultaneously photographed by the left camera 21, the right camera 22, the lower camera 24 and the upper camera 23 to obtain four reference images, the reference distance H.sub.k and the reference included angle .sub.k, and the four reference images, the reference distance H.sub.k and the reference included angle .sub.k are transmitted to the control unit for storage.

(27) 4) The step 3) is repeated until M sets of the four reference images, the reference distance H.sub.k and the reference included angle .sub.k which are corresponding to each other are obtained, and the four reference images, the reference distance H.sub.k and the reference included angle .sub.k are transmitted to the control unit for storage.

(28) 5) A real object and virtual spots are photographed, including:

(29) (1) Light beams emitted by the driving laser pointer 26 and the driven laser pointer 20 are aligned onto a surface of an object 29 to form two spots; the intermediate camera 25 photographs images of the two spots and transmits the images to the control unit; the main control module in the control unit drives the servo motor 13 through a motor driving module; the servo motor 13 drives four connecting rods 17 to unfold and fold through a lead screw 14 and a nut 15; the four connecting rods 17 drive four support rods 18 to pass through the front panel 12 to swing about hinge mechanisms 28; the spot radiated on the surface of the object 29 by the driven laser pointer (20) is allowed to coincide with the spot 30 radiated on the surface of the object 29 by the driving laser pointer 26 so that extension lines of central axes of the left camera 21, the right camera 22, the lower camera 24 and the upper camera 23 are allowed to be intersected at the spot 30; and, the object 29 is simultaneously photographed by the left camera 21, the right camera 22, the lower camera 24 and the upper camera 23 to obtain four physical images, and the physical images are transmitted to the control unit.

(30) (2) The control unit bundles and stores the four physical images obtained in the step (1), the vertical distance H.sub.f from the spot radiated on the surface of the object 29 by the driving laser pointer 26 during photographing to the front panel 12, and the photographing included angle .sub.f between the light beam of the driven laser pointer 20 and the front panel 12.

(31) 6) Coordinate points, on four reference images, of a point P on the surface of the object 29 corresponding to the front panel 12 are determined, including:

(32) (1) Position points P1, P2, P3 and P4, on the four physical images, of the point P on the surface of the object (29) are located.

(33) (2) The same reference included angle .sub.k as the photographing included angle .sub.f is acquired; four reference images corresponding to the reference included angle .sub.k are acquired; the reference image photographed by the left camera 21 is overlapped with the photographed physical image; the reference image photographed by the right camera 22 is overlapped with the photographed physical image; the reference image photographed by the lower camera 24 is overlapped with the photographed physical image; and the reference image photographed by the upper camera 23 is overlapped with the photographed physical image.

(34) (3) A projection, on an XZ coordinate plane, of a point on the reference image photographed by the left camera 21 overlapped with the position point P1 on the photographed physical image is determined as a point Q1 on the reference image; a projection, on the XZ coordinate plane, of a point on the reference image photographed by the right camera 22 overlapped with the position point P2 on the photographed physical image is determined as a point Q2 on the reference image; a projection, on a ZY coordinate plane, of a point on the reference image photographed by the lower camera 24 overlapped with the position point P3 on the photographed physical image is determined as a point Q3 on the reference image; and, a projection, on the ZY coordinate plane, of a point on the reference image photographed by the upper camera 23 overlapped with the position point P4 on the photographed physical image is determined as a point Q4 on the reference image.

(35) (4) Coordinate points of the points Q1, Q2, Q3 and Q4 on the front panel 12 are located.

(36) 7) A horizontal coordinate and a vertical coordinate of the point P on the surface of the object 29 are determined.

(37) The horizontal coordinate and the vertical coordinate of the point P are a horizontal coordinate and a vertical point of an auxiliary laser pointer, corresponding to the spot radiated on the point P, on the front panel 12.

(38) 8) A vertical distance h from the point P to the reference plane e is determined, including:

(39) (1) A distance u from the left camera 21 to the coordinate point of the point Q1 on the front panel 12, a distance v from the right camera 22 to the coordinate point of the point Q2 on the front panel 12, a distance w from the lower camera 24 to the coordinate point of the point Q3 on the front panel 12 and a distance r from the upper camera 23 to the coordinate point of the point Q4 on the front panel 12 are acquired, respectively.

(40) (2) A distance h.sub.1 between the points Q1 and Q2 is calculated by the following formula: h.sub.1=u+vL, and a distance h.sub.2 between the points Q3 and Q4 is calculated by the following formula: h.sub.2=w+rL.

(41) (3) The area S.sub.12 of a triangle formed by the projections of the points Q1, Q2 and P on the ZX coordinate plane is calculated by the following formula: S.sub.12=a1.sup.2sin Bsin C2sin A=a1.sup.2sin Bsin C2sin(180AB), where:

(42) a1 is the base of the triangle, a1=h.sub.1=u+vL, A is an angle subtended by the base of the triangle, B is an included angle between a connecting line of the of the point Q1 with the left camera (21) and the base, and C is an included angle between the a connecting line of the point Q2 with the right camera (22) and the base;

(43) the angle B=arc tgH/u, and the angle C=arc tgH/v; and

(44) the angle A=180BC=180arc tgH/uarc tgH/v.

(45) (4) The area S.sub.12 of a triangle formed by the points Q1, Q2 and P is calculated by the following formula: S.sub.12=a1h2, where h is the height of the triangle.

(46) (5) The formula for calculating the area S.sub.12 of the triangle in the step 3) is substituted into the formula for calculating the area S.sub.12 of the triangle in the step 4) to obtain h1:
a1.sup.2sin Bsin C2sin A=a1h12,
h1=a1sin Bsin Csin(180BC).

(47) The angle B=arc tgH/u, the angle C=arc tgH/v, A=180BC=180arc tgH/uarc tgH/v and a1=u+vL are substituted into the formula for h1:
h1=(u+vL)sin arc tgH/usin arc tgH/vsin(180arc tgH/uarc tgH/v),

(48) where h1 is the vertical distance from the point P to the reference plane e obtained by the points Q1 and Q2.

(49) (6) The area S.sub.34 of a triangle formed by the points Q3, Q4 and P is calculated by the following formula: S.sub.34=a2.sup.2sin B2sin C22sin A2=a2.sup.2sin B2sin C22sin(180A2B2), where:

(50) a2 is the base of the triangle, a2=h.sub.2=w+rL, A2 is an angle subtended by the base of the triangle, B2 is an included angle between a connecting line of the point Q3 with the lower camera (24) and the base, and C2 is an included angle between a connecting line of the point Q4 with the upper camera (23) and the base;

(51) the angle B2=arc tgH/w, and the angle C2=arc tgH/r; and

(52) the angle A2=180B2C2=180arc tgH/warc tgH/r.

(53) (7) The area S.sub.34 of a triangle formed by projections of the points Q3, Q4 and P on the ZY coordinate plane is calculated by the following formula: S.sub.34=a2h22, where h2 is the height of the triangle.

(54) (8) The formula for calculating the area S.sub.34 of the triangle in the step 6) into the formula for calculating the area S.sub.34 of the triangle in the step 7) to obtain h2:
a2.sup.2sin B2sin C22sin A2=ah22,
h2=a2sin B2sin C2sin(180B2C2),

(55) substituting the angle B2=arc tgH/w, the angle C2=arc tgH/r, A2=180arc tgH/warc tgH/r and a2=w+rL into the formula for h2:
h2=(w+rL)sin arc tgH/wsin arc tgH/rsin(180arc tgH/warc tgH/r),

(56) where h2 is the vertical distance from the point P to the reference plane e obtained by the points Q3 and Q4.

(57) (9) An arithmetic mean value of the h1 and h2 is calculated to obtain the vertical distance h from the point P to the reference plane e.

(58) (10) A depth Z of the point P is calculated by the following formula: Z=H.sub.kh.

(59) (11) It is decided whether the h is positive or negative:

(60) when Luv>0, h is positive,

(61) when Luv<0, h is negative,

(62) when Lrw>0, h is positive, and

(63) when Lrw<0, h is negative.

(64) 9) The steps 6) to 8) are repeated until all coordinate points and vertical distances h corresponding to the front panel 12 of the chassis required to draw the images of the object 29 are obtained.