CN102193280B - Equal scaling optical correcting method for inclined picture image - Google Patents

Abstract

The invention relates to an equal scaling optical correcting method for an inclined picture image, belonging to the fields of aviation, aviation image measurement, aviation reconnaissance and the like. The invention aims at providing an equal scaling optical correcting method for a large inclined picture image, which can be used for outputting and correcting an image synchronously and performing equal scaling (camera focus/flight height) and unequal scaling correction. When an aerial camera is inclined to take a picture, if a target on the ground vertical to a paper cover is imaged in the camera, the image length of a perigee is larger than that of an apogee; an imaging film is placed in a way that the film is arranged with an angle with the vertical surface of an imaging main optical shaft, and a correcting lens is arranged between the film and the imaging paper. The equal scaling optical correcting method for the inclined picture image has the advantages of convenience in operation, short correcting time, no factitious deformation and the like.

Description

Inclination picture image equal proportion chi optical rectification method

Technical field

The invention belongs to fields such as Aeronautics and Astronautics image measurement and aerial reconnaissance.

Background technology

When airborne survey or aerial reconnaissance, can adopt inclination photograph or left bank, vertical and right bank three to take a picture side by side usually in order to obtain more terrain object image.Perigee and apogean engineer's scale are different when tilting to take a picture, can form trapezoidal after the rectangular target imaging, many inclination pictures be mounted to can form together fan-shaped, three pictures arranged side by side be forward to can forming a loaf of bread shape together, inlay in distant that the some place forms a plurality of same targets if carry out the plane.Can not survey and draw into map.Inlay again after need becoming vertical picture to image rectification.

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 the 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 a certain amount of shadow line behind the image rectification again, loses a certain amount of shadow line when image is output into photo again.Influenced the resolution of image; When corrected digital image, owing to be artificial anamorphose, the anamorphose degree is relevant with programming personnel's level, can produce certain artificial distortion.And need long time to finish this work.At present also do not have a kind of good optical rectification method to correct, particularly to the image of big inclination, be difficult to realize the correction of image equal proportion chi.

Summary of the invention

The purpose of this invention is to provide and a kind ofly in output image, correct, and can carry out the big angle of inclination picture image equal proportion chi optical rectification method that equal proportion chi (camera focus/flying height) and inequality proportion chi are corrected.

The present invention tilt to take a picture at aerial camera, and the target of vertical and paper is in the imaging of aerial camera on the ground, and then perigean picture is grown up long in apogean picture;

The imaging egative film is placed the vertical plane that makes egative film and imaging primary optical axis has angle to place, place between egative film and the imaging sensitive paper and correct lens, after correcting lens imaging, target on the egative film of apogee is near apart from distance of camera lens, then this dot image enlargement factor is big, and the target on the egative film of perigee is far away apart from camera lens, and then this enlargement factor is little, then the image each point engineer's scale of Sheng Chenging will be identical, just becomes the image after the correction.

Good effect of the present invention is: film image or the big tilted image of digital picture are carried out optical rectification, and can carry out equal proportion chi (camera focus/flying height) and the correction of inequality proportion chi.Solved film image and directly corrected problem, had purpose and be and correct directly, corrected in output image, it is easy to operate, the correction time short, do not have artificial distortion etc. a bit.

Directly correct picture film tilted image, form the vertical image of equal proportion chi, form photo in the time of correction.Optical rectification can not cause artificial anamorphose.The loss of image shadow line is little.Can realize equal proportion chi (egative film and photo 1: 1) correction.Be applicable to that mainly big angle of inclination image egative film is corrected to the image of vertical scale, form photo, also can be used for the optical rectification of digital picture image.

Description of drawings

Fig. 1 is the present invention ground network figure that tilts to take a picture;

Fig. 2 is the present invention's light path synoptic diagram that tilts to take a picture;

Fig. 3 is that tilted image of the present invention is corrected light path;

Fig. 4 is that picture was inlayed design sketch before 75 ° of image rectifications of the big inclination of the present invention became 60 °;

Fig. 5 is that picture was inlayed design sketch after 75 ° of image rectifications of the big inclination of the present invention became 60 °.

Embodiment

The present invention tilt to take a picture at aerial camera, and the target of vertical and paper is in the imaging of aerial camera on the ground, and then perigean picture is grown up long in apogean picture;

The imaging egative film is placed the vertical plane that makes egative film and imaging primary optical axis has angle to place, place between egative film and the imaging sensitive paper and correct lens, after correcting lens imaging, target on the egative film of apogee is near apart from distance of camera lens, then this dot image enlargement factor is big, and the target on the egative film of perigee is far away apart from camera lens, and then this enlargement factor is little, then the image each point engineer's scale of Sheng Chenging will be identical, just becomes the image after the correction.

During vertical the photograph, the terrain object of L length in bottom panel length is:

$l^{/}=\frac{f}{H}L$

And its light path is as shown in Figure 2 when tilt taking a picture.

Ground X point director degree is that the length of target imaging on egative film X ' of L is l.

$l=\frac{\cos \mathrm{\γ}}{\cos (\mathrm{\γ}-\mathrm{\α})}*\frac{f}{H}L$

Must be corrected to l=l ' to the each point target length

Vertical target length l on any 1 x ' on the egative film is corrected to the target length l ' of vertical imaging.Should adopt the light path as Fig. 3:

If the correction lens focus is F, then the inclination angle of egative film is that ω, correction object space distance are L for L ', correction image distance ".Through deriving:

$\mathrm{\ω}=\mathrm{arcSin}\frac{F}{\mathrm{\βf}}\frac{H_0}{H}\mathrm{Sin}\left(\mathrm{\α}\right)]$

$\mathrm{\Ω}=\mathrm{arctg}\left(\frac{\mathrm{\β}{H}_0}{H}\frac{\mathrm{tg\ω}}{\mathrm{Cos\α}}\mathrm{Sin\α}\right)$

$L^{/}=F(\frac{1}{\mathrm{\β}}\frac{H_0}{H}\mathrm{Cos\α}+1)$

$L^{//}=F(\frac{\mathrm{\βH}}{H_0\mathrm{Cos\α}}+1)$

In the formula: H ₀Be theoretical level.

H is the practical flight height of egative film.

β is the image enlargement factor

ω---egative film (or digital image display) angle of inclination

Ω---printing paper angle of inclination

L '---egative film is to correcting lens distance

L "---printing paper is to correcting lens distance

F---correct the focal length of lens

F---inclination photograph camera focus

α---the angle of inclination of camera when tilting to take a picture.

The engineer's scale of each point is on the photo that forms after correcting

Be vertical scale, also can be corrected to the picture of arbitrary angle, satisfy the needs of image mosaic.

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

The present invention can directly correct the film negative film, also can digital image display correcting digital image be installed at the seat of negative film

The correction principle is

(the photograph light path as shown in Figure 2 in photograph if aerial camera tilts with the α angle.) vertical and paper L grow on the ground target is in the imaging of aerial camera, then perigean picture is grown up long in apogean picture.Be l _Closely＞l _Far

Imaging egative film placement position as shown in Figure 3, make 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 then this dot image enlargement factor is big, target on the egative film of perigee is far away apart from camera lens, then this enlargement factor is little, and then the image each point engineer's scale of Sheng Chenging will be identical, just becomes the image after the correction.

As Fig. 2.If being α with the angle of inclination, aerial camera takes a picture.The camera half angle of view is ρ.L length perigee and apogean target perpendicular to paper on the ground form l respectively on egative film _CloselyLength l _FarThe image of length.

This egative film is put in as shown in Figure 3 the correcting system.Then the perigee is as l _CloselyWith the apogee as l _FarThe picture that becomes is by correcting camera lens imaging again.Its imaging length is respectively L _CloselyAnd L _Far

Then

Perigee l _CloselyObject distance be L _{Object distance}=L '+f*tg ρ * Sin ω

L _{Object distance}, L ', ω the band as (1) formula get

In like manner: apogee l _FarObject distance be L _{Object distance}=L '-f*tg ρ * Sin ω

L _{Object distance}, L ', ω the band as (2) formula get

So: L _Closely=L _Far

And when vertically taking a picture, L long target imaging length on egative film in ground is

So just tilted image be corrected to vertical photo scale chi image.

The pitching correction is corrected principle with the roll angle and is taken a picture identical with inclination.

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

This method can also be corrected to tilted image the picture at any angle of inclination.Fig. 4 is to be tilt angle alpha that 75 ° of aerial photos are corrected to 60 ° effect picture.

Fig. 4 and Fig. 5 are that 4 aerial photos are mounted to effect together, and it is curved that straight highway is inlayed the back before correction.It is straight to return to after the correction.

$\mathrm{\ω}=\mathrm{arcSin}\left(\frac{F}{\mathrm{\βf}}\frac{H_0}{H}\mathrm{Sin\α}\right)$

$\mathrm{\Ω}=\mathrm{arctg}\left(\frac{\mathrm{\βH}}{H_0}\frac{\mathrm{tg\ω}}{\mathrm{Cos\α}}\right)$

$L^{/}=F(\frac{1}{\mathrm{\β}}\frac{H_0}{H}\mathrm{Cos\α}+1)$

$L^{//}=F(\frac{\mathrm{\βH}}{H_0\mathrm{Cos\α}}+1)$

Claims (1)

1. inclination picture image equal proportion chi optical rectification method is characterized in that:

Tilt to take pictures at the aviation camera, terrain object is in the imaging of aviation camera, and then perigean picture is grown up long in apogean picture;

The imaging egative film is placed the vertical plane that makes egative film and imaging primary optical axis has angle to place, place between egative film and the imaging sensitive paper and correct lens, after correcting lens imaging, target on the egative film of apogee is near apart from correcting lens distance, then this dot image enlargement factor is big, and the target on the egative film of perigee is far away apart from correcting lens, and then this enlargement factor is little, then the image each point engineer's scale of Sheng Chenging will be identical, just becomes the image after the correction;

If the correction focal length of lens is F, then the egative film angle of inclination is

, imaging sensitive paper angle of inclination is

, egative film is that L', imaging sensitive paper are L'' to correcting lens distance to correcting lens distance:

In the formula:

H ₀Be theoretical level

H is the practical flight height of egative film

Be the image enlargement factor

F is aviation camera focal length

Angle of inclination for the aviation camera.

Images