CN1320813C - A distortion correction method for lens imaging - Google Patents
A distortion correction method for lens imaging Download PDFInfo
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- CN1320813C CN1320813C CNB031377025A CN03137702A CN1320813C CN 1320813 C CN1320813 C CN 1320813C CN B031377025 A CNB031377025 A CN B031377025A CN 03137702 A CN03137702 A CN 03137702A CN 1320813 C CN1320813 C CN 1320813C
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Abstract
The present invention discloses a distortion correcting method for lens imaging, which belongs to the digital image processing field. The present invention can be conveniently used for various occasions needing frequent focal length setting and can also obtain precise correcting results. The present invention comprises the steps: 1), images are read to generate a group of corresponding image information; 2), people assign correction coefficients k1, k2,... kn (n is any natural number) according to experience or under the condition of man-machine interaction; 3), the aberration quantity of each point in an image is worked out to obtain a corrected image according to the specified values of the correction coefficients k1, k2,... kn; 4), the values of the correction coefficients k1, k2,... kn are dynamically modified according to the correcting effect, the step 3) is executed until a satisfied corrected image is obtained.
Description
Technical field
The present invention relates to digital image processing field, relate in particular to a kind of correcting method for deformation of lens imaging.
Background technology
Generally can there be distortion to a certain degree in the ordinary optical camera lens in imaging, concrete manifestation can be divided into two kinds of situations: pincushion distortion (pin-cushion distortion), and barrel distortion (Barrel distortion).Because the existence of distortion, when camera lens when rectangle is taken, imaging no longer is a rectangle, but shape as shown in Figure 1.After most applications servant saw image after the distortion, big brain-capacity was carried out from dynamic(al) correction it, and the result is the perception that does not influence basically image content, but for computer and a lot of software, this can cause serious consequence.Therefore be necessary the image of distortion is suitably proofreaied and correct.
The method of present existing compensating images distortion, as the applying date be the Chinese patent 98122712.0 on November 26th, 1998, all be to read a correcting sheet earlier, have the chequered with black and white striped of scheduled volume on this correcting sheet, the exact position of black streaking is known.After correcting sheet reads, the chequered with black and white striped of corresponding scheduled volume can be got, after judging calculating, the black streaking position can be got.Then, calculate the exact position of the chequered with black and white striped of this scheduled volume and the difference that image reads the back calculating location, promptly get the amount of distortion of each datum mark.Deposit the amount of distortion of each datum mark in the memory end correcting sheet fetch program.Carry out image when reading, each amount of distortion that is stored in the memory is removed at every turn, to revise the picture distortion that optical system causes.
But there is certain problem in these class methods.What at first, obtain behind its calculating black and white strip is the amount of distortion of several datum marks.This makes that the effect of this distortion correction is not very accurate, can not obtain complete satisfactory correcting image.Secondly, the amount of distortion of each datum mark is stored in the memory.And for varifocal camera lens, distortion is different under different focal lengths.End at focal range produces pincushion distortion, then produces barrel distortion at the other end.Obviously the amount of distortion of each datum mark of getting off of prestoring can not adapt to the distortion that the variation of focal length brings, and after focusing, need read correcting sheet again at every turn, and the amount of distortion of datum mark is calculated.For the occasion of often carrying out focus adjustment, for example digital camera, or PC Camera, this obviously is unpractical.In addition, solve the problem of optical system distortion, the most basic approach is, a strict mathematics model is set up in the generation of distortion, studies the reason of its generation on this basis and finds solution.Under these circumstances, the solution of new optical system distortion is by demand.
Summary of the invention
In order to solve the problems of the prior art and deficiency, the object of the present invention is to provide a kind of easy-to-use flexibly method that distortion is proofreaied and correct to lens imaging.It can be used for various occasions of often carrying out focus adjustment easily, and can be proofreaied and correct the result accurately.
A kind of correcting method for deformation of lens imaging, this method comprises the following steps:
1) carries out image and read, produce one group of corresponding image information;
2) rule of thumb or under the situation of man-machine interaction by the people to correction coefficient k
1, k
2... k
n, n is any natural number, carries out assignment;
3) according to the correction coefficient value k of appointment
1, k
2... k
n, calculate the amount of distortion of each point in the image, the image after obtaining proofreading and correct;
4) dynamically revise correction coefficient value k according to calibration result
1, k
2... k
n, and execution in step 3), until obtaining satisfied correcting image.
Above-mentioned correction coefficient k
1, k
2... k
nDefine by the following step:
Setting amount of distortion is that center of circle O is isotropic for focus point, on certain bar radius OP Mathematical Modeling is set up in distortion;
Some P after set proofreading and correct is positioned at the Q point place on the extended line of OP, OP=r, OQ=R, amount of distortion dr=R-r;
Amount of distortion dr can be expressed as dr=k
1* R+k
2* R
3+ k
3* R
5+ ..., k
1, k
2... k
nBe distortion factor.
The present invention can also proofread and correct image before carrying out step 1) in advance, and described step of proofreading and correct in advance is: 1) obtain the amount of distortion Δ X (i) of each datum mark, and i=1,2,3 ..., M; 2) carry out image and read, produce a corresponding image information; 3) according to described each amount of distortion Δ X (i), described image information is compensated.
The above-mentioned correction in advance can also be with following steps for carrying out: 1) carry out image and read, produce a corresponding image information; 2) obtain the amount of distortion Δ X (i) of each datum mark, i=1,2,3 ..., M; 3) according to described each amount of distortion Δ X (i), described image information is compensated.
The amount of distortion Δ X (i) of above-mentioned each datum mark is produced by the following step:
One correcting sheet is provided, has the chequered with black and white striped of scheduled volume on the correcting sheet, the exact position of described black and white strip is a given value, X (1), X (2), X (3) ... X (M) is referred to as datum mark;
Image read-out is read have on the correcting sheet the chequered with black and white clause pattern of predetermined quantity, produce a corresponding image information;
By correspondence image information, can obtain the position X ｀ (1) of described candy strip after the calculating, X ｀ (2), X ｀ (3) ... X ｀ (M);
The exact position and the image that calculate the chequered with black and white candy strip of this predetermined quantity read the difference of position, back, obtain the amount of distortion Δ X (1) of each datum mark, Δ X (2), Δ X (3) ... Δ X (M);
With the amount of distortion Δ X (1) of each datum mark, Δ X (2), Δ X (3) ... Δ X (M) deposits a memory in.
Because the present invention proposes a kind of Mathematical Modeling that picture distortion is set up to the pin optical lens, and to its method of proofreading and correct.Make the present invention to carry out calibration to the image that has distortion exactly, and can adjust proofreading and correct the result at any time as required.It can be proofreaied and correct imaging in advance with the method that reads the black and white strip correcting sheet, also can carry out manual correction to prior image without any correction at an easy rate.The invention solves focus in the prior art at every turn after, need read correcting sheet again, the problem that the amount of distortion of datum mark is calculated.For the occasion of often carrying out focus adjustment, for example digital camera, or PC Camera can rule of thumb or under the situation of man-machine interaction carry out assignment by the people to distortion factor easily, according to the value of distortion factor image is proofreaied and correct then.It can solve pincushion distortion and barrel distortion, and has easy-to-use characteristics flexibly on using.
Description of drawings
Fig. 1 takes the schematic diagram that distortion takes place for camera lens to rectangle;
Fig. 2 is a workflow diagram of the present invention;
Fig. 3 sets up the schematic diagram of Mathematical Modeling for the present invention.
Embodiment
Referring to Fig. 2, a kind of correcting method for deformation of lens imaging, this method comprises the following steps:
1) carries out image and read, produce one group of corresponding image information;
2) rule of thumb or under the situation of man-machine interaction by the people to correction coefficient k
1, k
2... k
n, n is any natural number, carries out assignment;
3) according to the correction coefficient value k of appointment
1, k
2... k
n, calculate the amount of distortion of each point in the image, the image after obtaining proofreading and correct;
4) dynamically revise correction coefficient value k according to calibration result
1, k
2... k
n, and execution in step 3), until obtaining satisfied correcting image.
Referring to Fig. 3, above-mentioned correction coefficient k
1, k
2... k
nDefine by the following step: suppose to proofread and correct Q point place on the extended line that back point P should be positioned at OP, make OP=r, OQ=R, then amount of distortion dr is defined as:
dr＝R-r
When dr was positive number, pincushion distortion was represented in expression barrel distortion during for negative.
Obviously, the amount of distortion at certain some place is different and different along with its radius.Generally speaking, more near edge of image, it is severe more to distort.
In addition, when R become-during R, i.e. the point on the extended line in the opposite direction, its amount of distortion dr also becomes-dr.
So we can be expressed as dr
dr＝k
1*R+k
2*R
3+k
3*R
5+…
Wherein, k
1, k
2, k
3Deng being coefficient undetermined.For the convenience that illustrates, suppose only to get three of fronts and do approximate:
dr＝k
1*R+k
2*R
3+k
3*R
5
The present invention can carry out assignment by the people to correction coefficient according to experience or under the situation of man-machine interaction.In this case, according to the k of appointment
1, k
2, k
3Value can calculate the image after the correction, and dynamically revises k according to calibration result
1, k
2, k
3Value generally just can reach effect preferably after revising several times.
The present invention is making k
1, k
2, k
3After the value, just can proofread and correct the image that obtains.When the calculation correction image, because parameter or result can be integer just generally, some occurs in the image after proofread and correct and put situation about being calculated never, the method for a kind of " Converse solved " is proposed here.Suppose to want the point in the image behind the calculation correction (a, brightness value b) or color-values, a wherein, b is an integer.We can obtain the radius R of this point, in the formula above the R substitution, obtain dr, and then according to r=R-dr, obtain r.Notice that radius r is the value in the image before correction.Find corresponding points (a ', b ') in so just can the image before correction, because a ' and b ' generally are not integers, we can obtain the brightness value or the color-values of this point by interpolation algorithm.
The present invention can also proofread and correct image before carrying out step 1) in advance, and described step of proofreading and correct in advance is: 1) obtain the amount of distortion Δ X (i) of each datum mark, and i=1,2,3 ..., M; 2) carry out image and read, produce a corresponding image information; 3) according to described each amount of distortion Δ X (i), described image information is compensated.
The described correction in advance can also be carried out with following steps: 1) carry out image and read, produce a corresponding image information; 2) obtain the amount of distortion Δ X (i) of each datum mark, i=1,2,3 ..., M; 3) according to described each amount of distortion Δ X (i), described image information is compensated.
The amount of distortion Δ X (i) of above-mentioned each datum mark is produced by the following step:
One correcting sheet is provided, has the chequered with black and white striped of scheduled volume on the correcting sheet, the exact position of described black and white strip is a given value, X (1), X (2), X (3) ... X (M) is referred to as datum mark;
Image read-out is read have on the correcting sheet the chequered with black and white clause pattern of predetermined quantity, produce a corresponding image information;
By correspondence image information, can obtain the position X ｀ (1) of described candy strip after the calculating, X ｀ (2), X ｀ (3) ... X ｀ (M);
The exact position and the image that calculate the chequered with black and white candy strip of this predetermined quantity read the difference of position, back, obtain the amount of distortion Δ X (1) of each datum mark, Δ X (2), Δ X (3) ... Δ X (M);
With the amount of distortion Δ X (1) of each datum mark, Δ X (2), Δ X (3) ... Δ X (M) deposits a memory in.
Claims (5)
1. correcting method for deformation of lens imaging, this method comprises the following steps:
1) carries out image and read, produce one group of corresponding image information;
2) under the situation of man-machine interaction to correction coefficient k
1, k
2... k
nCarry out assignment, n is any natural number, described correction coefficient k
1, k
2... k
nDefine according to following mode: setting amount of distortion is that center of circle O is isotropic for focus point, on certain bar radius OP Mathematical Modeling is set up in distortion; Suppose that the P point is the point in the image before proofreading and correct, the Q point is to proofread and correct its corresponding point of back, OP=r, OQ=R, amount of distortion dr=R-r; Amount of distortion dr is expressed as dr=k
1* R+k
2* R
3+ k
3* R
5+
3) according to the correction coefficient value k of appointment
1, k
2... k
n, proofread and correct the R value and the formula dr=k of each point in the image of back
1* R+k
2* R
3+ k
3* R
5+ ... calculate the amount of distortion of each point in the image, and then according to r=R-dr, calculate the r value of proofreading and correct corresponding points in the preceding image, the pixel value of r value corresponding points in the image before proofreading and correct is composed to proofreading and correct R value corresponding points in the image of back, image after obtaining proofreading and correct when r value corresponding points do not have pixel value, is obtained the pixel value of these r value corresponding points by interpolation algorithm;
4) dynamically revise correction coefficient value k according to calibration result
1, k
2... k
n, and execution in step 3), until obtaining satisfied correcting image.
2. according to the described correcting method for deformation of lens imaging of claim 1, it is characterized in that, also before carrying out step 1), image proofreaied and correct in advance that described step of proofreading and correct in advance is: 1) obtain the amount of distortion Δ X (i) of each datum mark, i=1,2,3 ..., M; 2) carry out image and read, produce a corresponding image information; 3) according to described each amount of distortion Δ X (i), described image information is compensated.
3. according to the described correcting method for deformation of lens imaging of claim 2, it is characterized in that the amount of distortion Δ X (i) of described each datum mark is produced by the following step:
One correcting sheet is provided, has the chequered with black and white striped of scheduled volume on the correcting sheet, the exact position of described black and white strip is a given value, X (1), X (2), X (3) ... X (M) is referred to as datum mark;
Image read-out is read have on the correcting sheet the chequered with black and white clause pattern of predetermined quantity, produce a corresponding image information;
By correspondence image information, obtain the position X` (1) of described candy strip after the calculating, X` (2), X` (3) ... X` (M);
The exact position and the image that calculate the chequered with black and white candy strip of this predetermined quantity read the difference of position, back, obtain the amount of distortion Δ X (1) of each datum mark, Δ X (2), Δ X (3) ... Δ X (M);
With the amount of distortion Δ X (1) of each datum mark, Δ X (2), Δ X (3) ... Δ X (M) deposits a memory in.
4. according to the described correcting method for deformation of lens imaging of claim 1, it is characterized in that, also before carrying out step 1), image proofreaied and correct in advance that described step of proofreading and correct in advance is: 1) carry out image and read, produce a corresponding image information; 2) obtain the amount of distortion Δ X (i) of each datum mark, i=1,2,3 ..., M; 3) according to described each amount of distortion Δ X (i), described image information is compensated.
5. according to the described correcting method for deformation of lens imaging of claim 4, it is characterized in that the amount of distortion Δ X (i) of described each datum mark is produced by the following step:
One correcting sheet is provided, has the chequered with black and white striped of scheduled volume on the correcting sheet, the exact position of described black and white strip is a given value, X (1), X (2), X (3) ... X (M) is referred to as datum mark;
Image read-out is read have on the correcting sheet the chequered with black and white clause pattern of predetermined quantity, produce a corresponding image information;
By correspondence image information, obtain the position X` (1) of described candy strip after the calculating, X` (2), X` (3) ... X` (M);
The exact position and the image that calculate the chequered with black and white candy strip of this predetermined quantity read the difference of position, back, obtain the amount of distortion Δ X (1) of each datum mark, Δ X (2), Δ X (3) ... Δ X (M);
With the amount of distortion Δ X (1) of each datum mark, Δ X (2), Δ X (3) ... Δ X (M) deposits a memory in.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031377025A CN1320813C (en) | 2003-06-20 | 2003-06-20 | A distortion correction method for lens imaging |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031377025A CN1320813C (en) | 2003-06-20 | 2003-06-20 | A distortion correction method for lens imaging |
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| Publication Number | Publication Date |
|---|---|
| CN1525396A CN1525396A (en) | 2004-09-01 |
| CN1320813C true CN1320813C (en) | 2007-06-06 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB031377025A Expired - Lifetime CN1320813C (en) | 2003-06-20 | 2003-06-20 | A distortion correction method for lens imaging |
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| CN (1) | CN1320813C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109489938A (en) * | 2018-11-15 | 2019-03-19 | 中国科学院光电技术研究所 | Method for detecting optical lens distortion based on auto-collimation imaging method |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8917320B2 (en) * | 2009-03-04 | 2014-12-23 | VISIONx INC. | Digital optical comparator |
| CN103729841B (en) * | 2013-12-18 | 2016-08-24 | 同济大学 | A kind of based on side's target model and the camera distortion bearing calibration of perspective projection |
| JP6746857B2 (en) * | 2019-01-31 | 2020-08-26 | エスゼット ディージェイアイ テクノロジー カンパニー リミテッドＳｚ Ｄｊｉ Ｔｅｃｈｎｏｌｏｇｙ Ｃｏ．，Ｌｔｄ | Image processing device, imaging device, unmanned aerial vehicle, image processing method, and program |
| CN115775282B (en) * | 2023-01-29 | 2023-06-02 | 广州市易鸿智能装备有限公司 | Method, device and storage medium for correcting image distortion at high speed on line |
Citations (4)
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|---|---|---|---|---|
| CN1255803A (en) * | 1998-11-26 | 2000-06-07 | 明碁电脑股份有限公司 | Image sensing device and method able to compensate image distortion |
| US6538691B1 (en) * | 1999-01-21 | 2003-03-25 | Intel Corporation | Software correction of image distortion in digital cameras |
| GB2380887A (en) * | 2001-10-13 | 2003-04-16 | Isis Innovation | Lens distortion correction using correspondence points within images which are constrained to lie on the same epipolar curve |
| WO2003043308A2 (en) * | 2001-11-13 | 2003-05-22 | Koninklijke Philips Electronics N.V. | Method for calibration and correction of radial lens distortion |
-
2003
- 2003-06-20 CN CNB031377025A patent/CN1320813C/en not_active Expired - Lifetime
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1255803A (en) * | 1998-11-26 | 2000-06-07 | 明碁电脑股份有限公司 | Image sensing device and method able to compensate image distortion |
| US6538691B1 (en) * | 1999-01-21 | 2003-03-25 | Intel Corporation | Software correction of image distortion in digital cameras |
| GB2380887A (en) * | 2001-10-13 | 2003-04-16 | Isis Innovation | Lens distortion correction using correspondence points within images which are constrained to lie on the same epipolar curve |
| WO2003043308A2 (en) * | 2001-11-13 | 2003-05-22 | Koninklijke Philips Electronics N.V. | Method for calibration and correction of radial lens distortion |
Non-Patent Citations (1)
| Title |
|---|
| 红外观测仪图像畸变的校正 王欣刚等，光学精密工程，第9卷第1期 2001 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109489938A (en) * | 2018-11-15 | 2019-03-19 | 中国科学院光电技术研究所 | Method for detecting optical lens distortion based on auto-collimation imaging method |
| CN109489938B (en) * | 2018-11-15 | 2021-01-05 | 中国科学院光电技术研究所 | Method for detecting optical lens distortion based on auto-collimation imaging method |
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