CN103606155A - Camera view field calibrating method and device - Google Patents

Abstract

The invention relates to a camera view field calibrating method and device. The device comprises an imaging object, a camera moving supporting assembly and a control computer. The control computer is connected with the camera moving supporting assembly, and a camera to be calibrated is arranged on the camera moving supporting assembly and conducts imaging on the imaging object. The camera view field calibrating method and device can improve test precision.

Description

Camera field of view scaling method and device

Technical field

The invention belongs to photoelectricity test field, relate to a kind of camera field of view scaling method and device, relate in particular to a kind of closely imaging camera field of view scaling method and device.

Background technology

Video camera is generally comprised of optical system, detection system (being generally CCD or cmos device).Camera field of view, has characterized the areas imaging of camera head, is an important indicator of video camera.

At present, the scaling method of the visual field of video camera can be divided into angular field and linear field because of the difference of its define method:

(1) angular field refer to video camera the angular region that can imaging receives.Method of testing is that the installed surface of video camera and turntable plane are fixed, and the object space node of camera optics imaging system is overlapped with spindle central, aims at parallel light tube, makes the asterism borescopic imaging of focal surface of collimator tube place placement in video camera imaging receiving system.Rotating table, one side make the picture in asterism hole from the another side that moves to of video camera photographic images, the angle that now turntable turns over is the field angle 2w of video camera.Because CCD or the COMS of video camera imaging receiving system is generally rectangle, therefore need to after measuring the field angle of a direction, after half-twist, repeats said process, then measure the field angle of another direction.The method need to be in the process of rotating table, and the clear aperture of parallel light tube covers the entrance pupil of video camera all the time.Because video camera installed surface is unique, also cause the difficulty of another direction test.Turntable, parallel light tube are generally all more expensive, so the method economy is poor.

(2) linear field refers to that video camera level installs, under certain camera distance, and the width that video camera institute can imaging reception.Method of testing is apart from camera optics imaging system node, optical axis direction L place, measures vertically with optical axis direction, and the visual field width H of horizontal direction is the horizontal line visual field of video camera.By the imaging aspect ratio of video camera imaging device target surface, can determine the linear field of vertical direction.

Above-mentioned two kinds of methods can be equivalent by following formula:

$w=\arctan \left(\frac{H}{2L}\right)---\left(1\right)$

Due to the node determination difficulty of camera optics system, there is method error in above-mentioned two kinds of methods, fails truly to reflect the scope that video camera institute can imaging reception.

Summary of the invention

In order to solve the above-mentioned technical matters existing in background technology, the invention provides a kind of camera field of view scaling method and device that improves measuring accuracy.

Technical solution of the present invention is: the invention provides a kind of camera field of view scaling method, its special character is: described camera field of view scaling method comprises the following steps:

1) at target target plate center, paste feature circular pattern;

2) adjust the position of video camera, make the circular pattern imaging of feature at target target plate center in the picture centre of video camera shooting; The target target plate of described shot by camera upper and lower, symmetrical, records now the position a of video camera and the horizontal field of view width Pa of video camera video camera when a of position;

3) position of mobile camera to position b, and make the circular pattern imaging of feature at target target plate center in the picture centre of video camera shooting; The target target plate of described shot by camera upper and lower, symmetrical, records the horizontal field of view width Pb of video camera video camera when the b of position and the distance, delta L between position a and position b; The traffic direction of described video camera is vertical with the plane at target target plate place;

4), with Similar Principle of Triangle, according to following formula, calculate the field angle w of video camera:

$w=\mathrm{ac}\tan \left(\frac{\mathrm{Pb}-\mathrm{Pa}}{2\mathrm{\ΔL}}\right).$

For realizing a device for camera field of view scaling method as above, its special character is: described device comprises imageable target, video camera movable support assembly and controls computing machine; Described control computing machine is connected with video camera movable support assembly; Video camera to be calibrated is arranged on video camera movable support assembly and to imageable target and carries out imaging.

Above-mentioned video camera movable support assembly comprises motorized precision translation stage, five dimension adjustment rack and video camera bearing supports; Described five dimension adjustment racks are arranged on motorized precision translation stage by video camera bearing support; The traffic direction of described motorized precision translation stage is vertical with the plane at imageable target place; Video camera to be calibrated is arranged on five dimension adjustment racks and moves with motorized precision translation stage; Video camera to be calibrated is connected with control computing machine respectively with motorized precision translation stage.

Above-mentioned imageable target comprises target target plate and the circular pattern that is arranged on target target plate center; Video camera to be calibrated is arranged on video camera movable support assembly and to the circular pattern at target target plate center and carries out imaging.

Advantage of the present invention is:

1,, by the horizontal field of view under the different camera distances of mensuration video camera and the spacing between different camera distance, avoided, due to the inaccurate error of bringing in location, camera node position, having improved precision and the repeatability of test.

2, utilize video camera under different camera distances, the similarity of imaging relations, adopts target plate, translation stage can carry out the measurement of camera field of view, and economy is better.

3, compare with the linear field assay method under traditional single image-forming range, by adjusting the attitude of video camera, make under different image-forming ranges, target target plate center images in the picture centre that video camera is taken, make the moving direction of video camera along boresight direction, the operability that has increased test, has also improved measuring accuracy simultaneously.

Accompanying drawing explanation

Fig. 1 is the structural representation of camera field of view caliberating device provided by the present invention;

Wherein:

1-target target plate; 2-motorized precision translation stage; 3-five dimension adjustment racks; 4-video camera bearing support; 5-controls computing machine.

Embodiment

Principle of the present invention is:

This method is by the linear field under mensuration two camera distances and the distance between two camera distances, utilize video camera in the similarity of different camera distance imagings, by Similar Principle of Triangle, thereby the position of Accurate Determining camera node, accurately obtain the camera distance of video camera, realize the demarcation of camera field of view.

The invention provides a kind of camera field of view scaling method, this camera field of view scaling method comprises the following steps:

1) at target target plate center, paste plane mirror, with laser instrument, will adjust motorized precision translation stage, make its traffic direction vertical with target board plane.After adjustment, at target target plate 1 center, paste feature circular pattern;

2) adjust the position of video camera, make the circular pattern imaging of feature at target target plate 1 center in the picture centre of video camera shooting; The target target plate 1 of shot by camera upper and lower, symmetrical, records now the position a of video camera and the horizontal field of view width Pa of video camera video camera when a of position;

3) position of mobile camera to position b, and make the circular pattern imaging of feature at target target plate 1 center in the picture centre of video camera shooting; The target target plate 1 of shot by camera upper and lower, symmetrical, records the horizontal field of view width Pb of video camera video camera when the b of position and the distance, delta L between position a and position b; The traffic direction of video camera is vertical with the plane at target target plate 1 place;

4), with Similar Principle of Triangle, according to following formula, calculate the field angle w of video camera:

$w=\mathrm{ac}\tan \left(\frac{\mathrm{Pb}-\mathrm{Pa}}{2\mathrm{\ΔL}}\right).$

Referring to Fig. 1, it is a kind of for realizing the device of camera field of view scaling method as above that the present invention also provides, and this device comprises imageable target, video camera movable support assembly and controls computing machine 5; Controlling computing machine 5 is connected with video camera movable support assembly; Video camera to be calibrated is arranged on video camera movable support assembly and to imageable target and carries out imaging.

Video camera movable support assembly comprises motorized precision translation stage 2, five dimension adjustment rack 3 and video camera bearing supports 4; Five dimension adjustment racks 3 are arranged on motorized precision translation stage 2 by video camera bearing support 4; The traffic direction of motorized precision translation stage 2 is vertical with the plane at imageable target place; Video camera to be calibrated is arranged on five dimension adjustment racks 3 and with motorized precision translation stage 2 and moves; Video camera to be calibrated is connected with control computing machine 5 respectively with motorized precision translation stage 2.

Imageable target comprises target target plate 1 and the circular pattern that is arranged on target target plate 1 center; Video camera to be calibrated is arranged on video camera movable support assembly and to the circular pattern at target target plate 1 center and carries out imaging.

In conjunction with device provided by the present invention, realization of the present invention is carried out following detailed description:

1, at target target plate 1 center, paste plane mirror, with laser instrument, will adjust motorized precision translation stage 2, make its traffic direction vertical with target target plate 1 plane.After adjustment, at target target plate 1 center, paste feature circular pattern.2, video camera being fixed on to five dimension adjustment rack 3, five dimension adjustment racks 3 is fixedly connected with motorized precision translation stage 2 by video camera bearing support 4.Connect and control computing machine 5 and video camera, motorized precision translation stage 2, open and control computing machine 5, video camera, video camera photographic images is shown in and controls computing machine 5.

3, adjust the height of cameramount, make the circular pattern imaging of feature at target target plate 1 center in the picture centre of video camera shooting.Adjust five dimension adjustment racks 3, make the upper and lower, symmetrical of target plate that video camera takes, write down now video camera at the position of motorized precision translation stage 2 a.

4, start motorized precision translation stage 2, make video camera move to b place, adjust five dimension adjustment racks 3, make video camera at position a, position b, the picture centre that the circular pattern imaging of feature at target target plate 1 center is taken in video camera, and the target plate that video camera is taken is upper and lower, symmetrical, makes video camera moving direction consistent with the video camera optical axis.Now write down respectively the distance, delta L of video camera between the horizontal field of view width Pa of position a and the horizontal field of view width Pb of position b and position a and position b.

5,, by Similar Principle of Triangle, the field angle w that obtains video camera is:

$w=\mathrm{ac}\tan \left(\frac{\mathrm{Pb}-\mathrm{Pa}}{2\mathrm{\ΔL}}\right)$ 。

Claims (4)

1. a camera field of view scaling method, is characterized in that: described camera field of view scaling method comprises the following steps:

1) at target target plate center, paste feature circular pattern;

2) adjust the position of video camera, make the circular pattern imaging of feature at target target plate center in the picture centre of video camera shooting; The target target plate of described shot by camera upper and lower, symmetrical, records now the position a of video camera and the horizontal field of view width Pa of video camera video camera when a of position;

3) position of mobile camera to position b, and make the circular pattern imaging of feature at target target plate center in the picture centre of video camera shooting; The target target plate of described shot by camera upper and lower, symmetrical, records the horizontal field of view width Pb of video camera video camera when the b of position and the distance, delta L between position a and position b; The traffic direction of described video camera is vertical with the plane at target target plate place;

4), with Similar Principle of Triangle, according to following formula, calculate the field angle w of video camera:

$w=\mathrm{ac}\tan \left(\frac{\mathrm{Pb}-\mathrm{Pa}}{2\mathrm{\ΔL}}\right).$

2. for realizing a device for camera field of view scaling method claimed in claim 1, it is characterized in that: described device comprises imageable target, video camera movable support assembly and controls computing machine; Described control computing machine is connected with video camera movable support assembly; Video camera to be calibrated is arranged on video camera movable support assembly and to imageable target and carries out imaging.

3. device according to claim 2, is characterized in that: described video camera movable support assembly comprises motorized precision translation stage, five dimension adjustment rack and video camera bearing supports; Described five dimension adjustment racks are arranged on motorized precision translation stage by video camera bearing support; The traffic direction of described motorized precision translation stage is vertical with the plane at imageable target place; Video camera to be calibrated is arranged on five dimension adjustment racks and moves with motorized precision translation stage; Video camera to be calibrated is connected with control computing machine respectively with motorized precision translation stage.

4. according to the device described in claim 2 or 3, it is characterized in that: described imageable target comprises target target plate and the circular pattern that is arranged on target target plate center; Video camera to be calibrated is arranged on video camera movable support assembly and to the circular pattern at target target plate center and carries out imaging.

Images