CN102253572B - Short focus large-frame image equal scale optical correction method - Google Patents

Abstract

The invention discloses a short focus large-frame image equal scale optical correction method, which belongs to the aviation and navigation image measurement field. The purpose of the invention is to provide a short focus large-frame image equal scale optical correction method for the optical correction of a film image and a digital image while outputting the images. An inclination between the aviation image and the vertical ground is determined according to a pitch angle, a roll angle and a yaw angle; a photographic film is imaged at a central position of a correction lens I and a correction lens II, the scale of each point on the photograph after the correction is a vertical scale; the three-degree-of-freedom control of the photographic film and photographic paper is realized by a three-degree-of-freedom platform; the photographic film is arranged according to a perpendicular set angle with an imaging main optical shaft, pitch correction is same as roll correction; the roll correction and the pitch correction are carried out on a two-degree-of-freedom platform to ensure that image deformation caused by two postures can be corrected, thus a positive shot image is formed. By using the optical correction method, man-made image deformation cannot be caused. The equal scale (the ratio of photographic films to photos is 1: 1) can be realized.

Description

The large picture image equal scaling optical correcting method of short focal length

Technical field

The invention belongs to Aeronautics and Astronautics image measurement field.

Background technology

Aeronautics and Astronautics image unstable due to carrier when obtaining causes image fully not vertical, forms the inclination angles such as pitching, roll, driftage, makes the engineer's scale of each point not identical, and airborne survey is exerted an influence.Must correct it, make the engineer's scale of image each point identical.Present image rectification great majority carry out computing machine with numerical approach to be corrected, correct for computing machine, very complicated for film correction operation: as at first will to carry out digitizing to film image, become digital picture, digital picture is corrected, the image after correction is output into photo more again.In whole process, image information will be lost repeatedly, can lose certain shadow line when film image carries out digital conversion, loses again a certain amount of shadow line after image rectification, loses again a certain amount of shadow line when image is output into photo.Affected the resolution of image; When corrected digital image, owing to being artificial anamorphose, the anamorphose degree is relevant with programming personnel's level, can produce certain artificial distortion.Also do not have a kind of good method to carry out optical rectification, particularly to the image of the camera imaging of short focal length, because focal length is very short, the image space is very little, is difficult to realize the correction of image equal-scale.

Summary of the invention

The objective of the invention is film image and digital picture are carried out optical rectification, can carry out the correction of equal-scale, the large picture image equal scaling optical correcting method of the short focal length of correcting to the image of long and short focal length imaging in output image.

Step of the present invention is:

A, determine the inclination angle of aerial image and vertical ground with pitching, roll, crab angle;

B, egative film are imaged on the center of correcting camera lens I and correcting camera lens II, and this picture is imaged on printing paper by correcting camera lens II again;

On the photo that forms after d, correction, the engineer's scale of each point is vertical scale;

The light source of e, light path adopts area source, and it is 3-dimensional freedom platform that the Three Degree Of Freedom of egative film and printing paper is controlled;

F, roll angle are corrected: the placement of imaging egative film is according to placing with the vertical plane set angle of imaging primary optical axis, after correcting lens imaging, target on the egative film of apogee is near apart from distance of camera lens, this dot image enlargement factor is large, target on the egative film of perigee is far away apart from camera lens, this enlargement factor is little, and the image each point engineer's scale that generates will be identical, just becomes the image after correction;

G, pitching correction are corrected identical with the roll angle;

H, roll correction and pitching are corrected to be put into just can correct simultaneously these two anamorphoses that attitude causes on binary platform, formation positive photograph picture.

The present invention is easy to operate, directly corrects the vertical image that the picture film image forms equal-scale, forms photo.Optical rectification can not cause artificial anamorphose.The loss of image shadow line is little.Can realize equal-scale (egative film and photo 1: 1) correction.

Description of drawings

Fig. 1 is that the present invention corrects index path;

In figure, 1 is egative film or digital image display; The 2nd, correct lens; The 3rd, sensitive paper;

Fig. 2 is that the present invention corrects lens principle figure;

In figure, 4 is to correct lens I; The 5th, the image rotation lenses group; The 6th, correct camera lens II;

Fig. 3 is that the present invention does with reflective mirror the correcting system index path that two dimension is controlled platform;

In figure, 7 is picture side's reflective mirrors; The 8th, correct lens; The 9th, the object space reflective mirror; The 10th, sensitive paper; The 11st, negative film;

Fig. 4 is roll photograph light path schematic diagram of the present invention;

In figure, 12 is egative films; The 13rd, the camera optical axis; The 14th, the apogee; The 15th, the perigee; L ' is that the target picture is long;

Fig. 5 is that the short focal length camera image of the present invention is corrected schematic diagram;

In figure, 16 is apogees; The 17th, sensitive paper; The 18th, the perigee; The 19th, right lens; The 20th, the picture that left lens become; 21 image transferring lens groups; The 22nd, left lens; The 23rd, perigee L _CloselyThe 24th, egative film; The 25th, apogee L _FarThe 26th, the compound lens that left lens, right lens and image transferring lens group form;

Fig. 6 is the image before correcting;

Fig. 7 is the image after correcting.

Embodiment

Step of the present invention is:

A, determine the inclination angle of aerial image and vertical ground with pitching, roll, crab angle;

B, egative film are imaged on the center of correcting camera lens I and correcting camera lens II, and this picture is imaged on printing paper by correcting camera lens II again;

On the photo that forms after d, correction, the engineer's scale of each point is vertical scale;

The light source of e, light path adopts area source, and it is 3-dimensional freedom platform that the Three Degree Of Freedom of egative film and printing paper is controlled;

F, roll angle are corrected: the placement of imaging egative film is according to placing with the vertical plane set angle of imaging primary optical axis, after correcting lens imaging, target on the egative film of apogee is near apart from distance of camera lens, this dot image enlargement factor is large, target on the egative film of perigee is far away apart from camera lens, this enlargement factor is little, and the image each point engineer's scale that generates will be identical, just becomes the image after correction;

G, pitching correction are corrected identical with the roll angle;

H, roll correction and pitching are corrected to be put into just can correct simultaneously these two anamorphoses that attitude causes on binary platform, formation positive photograph picture.

Below in conjunction with accompanying drawing, the present invention is done detailed description:

Determine the inclination angle of aerial image and vertical ground with pitching, roll, crab angle.

As: pitching, roll, crab angle be α,

γ, the inclination angle of aerial image and vertical ground be α,

γ.Correct light path as shown in Figure 1.Egative film rotates respectively ω, ε, γ on the XYZ axle

$\mathrm{\ω}=\mathrm{arcSin}\left[\frac{H_0}{\mathrm{\βH}}\frac{F^2}{(\mathrm{\Δ}-2F)f}\mathrm{Sin\α}\right]$

In formula: H ₀Be theoretical level.

H is the practical flight height of egative film.

β is the image enlargement factor

F corrects the focal length of camera lens II for correcting camera lens I

F is the egative film camera focus of taking pictures

Δ is for correcting camera lens I and the centre distance of correcting camera lens II.

Egative film is imaged on the center of correcting camera lens I and correcting camera lens II, and this picture is imaged on printing paper by correcting camera lens II again;

Egative film is imaged on the center of correcting camera lens I and correcting camera lens II, and this picture is again by correcting camera lens II imaging picture on printing paper.Printing paper is Ω, Ψ, P at the corner of XYZ axle

$\mathrm{\Ω}=\mathrm{arctg}\left[\mathrm{\β}\frac{H}{H_0}\frac{\mathrm{tg\ω}}{\mathrm{Cos\α}}\right]$

p＝0

Plate center is correction object distance L apart from the distance of correcting camera lens I ₁

$L_1=\frac{F}{\mathrm{\Δ}-2F}(\frac{H_O}{\mathrm{\βH}}\mathrm{FCos\α}+\mathrm{\Δ}-F)$

Correct camera lens II and arrive the centre distance of imaging printing paper for correcting image distance L ₂

$L_2=\frac{F}{\mathrm{\Δ}-2F}(\frac{\mathrm{\βHF}}{H_0\mathrm{Cos\α}}+\mathrm{\Δ}-F)$

On the photo that forms after correcting, the engineer's scale of each point is

Be vertical scale.

The light source of light path adopts area source, each physical quantity calculating adopt computer program to calculate, the control of each my strength can be adopted automatic control.

The Three Degree Of Freedom of egative film and printing paper is controlled and can be adopted 3-dimensional freedom platform to realize.

Fig. 2 corrects compound lens, corrects camera lens I and corrects camera lens II and adopt imaging lens, and the quality of this camera lens determines image resolution ratio, and the image transfer lens group only plays and converges effect of light.In the situation that the very little Δ=3F of camera focus f is the most desirable, the focal length of correcting camera lens I and correction camera lens II must satisfy F≤f.The focal length of image transfer lens group is

Correct object distance this moment and can correct image distance greater than 3F near 3F, solved the little problem of object space, leave activity space for the image platform.

The ω angle rotates by rotating negative film the correction that printing paper Ω angle realizes roll simultaneously.The ε angle is rotated as square plane mirror Ψ/2 jiaos of correction that realize pitching simultaneously by rotating object space reflective mirror ε/2 jiaos.Can simplify the mechanism of 3DOF platform like this.It corrects light path as shown in Figure 3.

(the photograph light path as shown in Figure 4 in photograph if aerial camera tilts with the α angle.)

The target that on ground, vertical and paper L grow is in the imaging of aerial camera, and perigean picture is grown up long in apogean picture.Be L _Closely＞L _Far

Imaging egative film placement position as shown in Figure 5, the placement of imaging egative film is according to placing with the vertical plane set angle of imaging primary optical axis, making egative film become the ω angle with the vertical plane of imaging primary optical axis.After correcting lens imaging, the target on the egative film of apogee is near apart from distance of camera lens, and this dot image enlargement factor is large, target on the egative film of perigee is far away apart from camera lens, this enlargement factor is little, and the image each point engineer's scale that generates will be identical, just becomes the image after correction.

The pitching correction is identical with roll angle correction principle.

Roll correction and pitching are corrected to be put into just can correct simultaneously these two anamorphoses that attitude causes on binary platform, formation positive photograph picture.

Short focal length camera picture error-correcting effect as shown in Figure 6.

Claims (1)

1. large picture image equal scaling optical correcting method of short focal length is characterized in that:

A, determine the inclination angle of aerial image and vertical ground with pitching, roll, crab angle;

Pitching, roll, crab angle are

, the inclination angle of aerial image and vertical ground is

, egative film rotates respectively on the XYZ axle

:

In formula: H ₀Be theoretical level

H is the practical flight height of egative film

Be the image enlargement factor

F corrects the focal length of camera lens II for correcting the camera lens I

F is the egative film camera focus of taking pictures

△ is for correcting camera lens I and the centre distance of correcting the camera lens II;

B, egative film are imaged on the center of correcting the camera lens I and correcting the camera lens II, and this picture is imaged on printing paper by correcting the camera lens II again;

Printing paper at the corner of XYZ axle is

:

；

Plate center is correction object distance L apart from the distance of correcting the camera lens I ₁

Correct the camera lens II and arrive the centre distance of imaging printing paper for correcting image distance L ₂

The engineer's scale of each point on the photo that forms after d, correction

Be vertical scale;

The light source of e, light path adopts area source, and it is 3-dimensional freedom platform that the Three Degree Of Freedom of egative film and printing paper is controlled;

F, roll angle are corrected: the placement of imaging egative film is according to placing with the vertical plane set angle of imaging primary optical axis, after correcting lens imaging, target on the egative film of apogee is near apart from distance of camera lens, this dot image enlargement factor is large, target on the egative film of perigee is far away apart from camera lens, this enlargement factor is little, and the image each point engineer's scale that generates will be identical, just becomes the image after correction;

G, pitching correction are corrected identical with the roll angle;

H, roll correction and pitching are corrected to be put into just can correct simultaneously these two anamorphoses that attitude causes on binary platform, formation positive photograph picture.

Images