CN106530351B - A kind of method for positioning mass center obtained based on image sensor pixel internal quantum efficiency - Google Patents
A kind of method for positioning mass center obtained based on image sensor pixel internal quantum efficiency Download PDFInfo
- Publication number
- CN106530351B CN106530351B CN201611052886.XA CN201611052886A CN106530351B CN 106530351 B CN106530351 B CN 106530351B CN 201611052886 A CN201611052886 A CN 201611052886A CN 106530351 B CN106530351 B CN 106530351B
- Authority
- CN
- China
- Prior art keywords
- quantum efficiency
- star chart
- pixel
- internal quantum
- pixel internal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/10—Image acquisition modality
- G06T2207/10032—Satellite or aerial image; Remote sensing
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/20—Special algorithmic details
- G06T2207/20048—Transform domain processing
- G06T2207/20056—Discrete and fast Fourier transform, [DFT, FFT]
Landscapes
- Image Processing (AREA)
- Image Analysis (AREA)
Abstract
The present invention relates to a kind of method for positioning mass center obtained based on image sensor pixel internal quantum efficiency, comprising: utilizes imaging sensor acquisition star chart and darkfield image corresponding with acquired star chart, flat field image；Star chart is pre-processed, the star chart after being corrected；The illumination of four-step phase-shifting sine streak is carried out to imaging sensor, obtains the spatial frequency spectrum of the pixel internal quantum efficiency of imaging sensor；Inverse Fourier transform is carried out to the spatial frequency spectrum of the pixel internal quantum efficiency of imaging sensor, obtains the space two-dimensional distribution of pixel internal quantum efficiency；Space two-dimensional distribution based on pixel internal quantum efficiency, carries out resampling to the star chart after correction inside pixel, obtains the star chart after resampling；The absolute mass center of star chart after calculating resampling.
Description
Technical field
It is the present invention relates to astronomy and field of space technology, in particular to a kind of based on quantum effect in image sensor pixel
The method for positioning mass center that rate obtains.
Background technique
The combination of solid state image sensor (CCD, CMOS etc.) and modern information technologies makes astronomical observation and satellite remote sensing skill
Revolutionary change has occurred in art.In digital imaging arts, the appearance of solid state image sensor make data acquisition, analysis, display,
Using becoming very convenient, efficient.Although solid state image sensor is brought greatly in astronomical observation and satellite remote sensing field
It is convenient, but in terms of device performance, however it remains some born defects and problem.For example, in geodesic survey field, people
A main problem considering be the measurement accuracy of image coordinate for determining whether accurate enough the right ascension of celestial body, declination be
's.If single coordinate for analyzing an astronomical target from the angle of digital picture, for intuitive, we are in digital picture itself
Data on the positioning accuracy of pixel scale can only be determined according to pixel.In order to meet high-precision geodesic survey, astronomical survey
The demand of light, uranometry etc., sub-pix even milli pixel, the positioning accuracy of micro-pixels rank are more more and more urgent.
From the perspective of astronomy, fixed star is Point Target.However, due to the presence of diffraction limit and aberration, fixed star
It is the hot spot of limited size by the image formed on focal plane after optical system.This intensity distribution can use a mathematics
Function describes, and here it is the point spread function of optical system.For perfect optical system or non-ideal optical system, system
Point spread function is actually the impulse response of system.For the more satisfactory optical system by aberration correction, point expands
Scattered function is actually an Airy, can pass through this Two dimensional Distribution of Gaussian function approximate fits under normal circumstances.Point
The numerical value of spread function depends on the position of the central point of point spread function.
For a series of point spread function of covering limited areal or pixels, due to being no longer an infinitesimal point,
In order to determine the position of point source, we must position to point spread function or coordinate provide definition.Under normal circumstances, Wo Menqu
The centre coordinate of area indicates the position coordinates of point spread function.This position coordinates is usually obtained using weighted center of gravity method.It is right
In the point spread function of over-sampling, the center-of-mass coordinate that weighted center of gravity method obtains is more accurate.The position of point spread function becomes
The statistic fluctuation of position coordinates caused by change is not apparent.But for the point spread function of threshold sampling or lack sampling, this
Kind statistic fluctuation becomes apparent upon.It is non-uniform that its basic reason, which is pixel internal quantum efficiency,.For high-precision position
Set measurement.This statistic fluctuation is the problem of we must face.
Summary of the invention
The statistic fluctuation encountered when it is an object of the invention to overcome high precision position to measure, so that providing one kind can
The method of the absolute mass center of precise measurement asterism picture.
To achieve the goals above, the present invention provides a kind of matter obtained based on image sensor pixel internal quantum efficiency
Heart localization method, comprising:
Step 1) acquires star chart and darkfield image corresponding with acquired star chart, flat field image using imaging sensor；
Step 2), the star chart based on step 1) acquisition, darkfield image corresponding with star chart, flat field image carry out star chart pre-
Processing, the star chart after being corrected；
Step 3) carries out the illumination of four-step phase-shifting sine streak to imaging sensor, obtains amount in the pixel of imaging sensor
The spatial frequency spectrum of sub- efficiency；
Step 4) carries out inverse Fourier to the spatial frequency spectrum of the pixel internal quantum efficiency of the imaging sensor of step 3) acquisition
Transformation obtains the space two-dimensional distribution of pixel internal quantum efficiency；
Step 5), the space two-dimensional based on the obtained pixel internal quantum efficiency of step 4) are distributed, and are obtained to step 2)
Star chart after correction carries out resampling inside pixel, obtains the star chart after resampling；
Step 6), the absolute mass center for calculating the star chart after the obtained resampling of step 5).
In above-mentioned technical proposal, in step 2), the pretreatment includes: to cut the star chart data that step 1) obtains secretly
Field picture data, then again by obtained result divided by flat field image data.
In above-mentioned technical proposal, in step 3), the four-step phase-shifting sine streak is indicated with following formula
Wherein,For the intensity value of each pixel output of imaging sensor, B is background, and A is amplitude, and (u, v) is respectively x
The spatial frequency in direction, the direction y,For the phase of four-step phase-shifting, value 0, pi/2, π, 3 pi/2s；
When being illuminated with four-step phase-shifting striped, the output of imaging sensor is the convolution of pixel internal quantum efficiency and striped,
That is:
Wherein,For the output of imaging sensor, QE (x, y) is expression of the pixel internal quantum efficiency in spatial domain；
The output of described image sensor obtains the frequency spectrum QE (u, v) of pixel internal quantum efficiency by four-step phase-shifting:
Wherein, j is imaginary unit.
In above-mentioned technical proposal, in step 4), the frequency spectrum QE (u, v) for the pixel internal quantum efficiency that step 3) obtains is done
Inverse Fourier transform obtains the real domain data QE (m, n) of pixel internal quantum efficiency, that is,
Wherein, m, n are pixel intrinsic coordinates, it is assumed that several rows of column are equal inside pixel, i.e. m, n=1,2 ..., M.
In above-mentioned technical proposal, star chart is adopted again inside pixel after the correction obtained in step 5) to step 2)
Sample obtains the star chart after resampling, it may be assumed that
Wherein, I2 (p, q；M, n) indicate the star chart after resampling；I1 (p, q) indicates the obtained correction of step 2)
Star chart later.
In above-mentioned technical proposal, in step 6), using analytical function nonlinear least square fitting method or weighting is utilized
Gravity model appoach calculates the absolute mass center of the star chart after the obtained resampling of step 5).
In above-mentioned technical proposal, in step 7), after calculating the obtained resampling of step 5) using weighted center of gravity method
The absolute mass center of star chart includes:
Wherein, (xc,yc) be finally obtained asterism absolute center-of-mass coordinate.
The present invention has the advantages that
The method for positioning mass center obtained based on image sensor pixel internal quantum efficiency of the invention do not increase hardware at
Center coordination precision can be significantly improved under conditions of this.
Detailed description of the invention
Fig. 1 is the schematic diagram of pixel coordinate Yu pixel intrinsic coordinates；
Fig. 2 is the center coordination process obtained based on image sensor pixel internal quantum efficiency
Specific embodiment
Before elaborating to method of the invention, letter is done to some concepts involved in the method for the present invention first
Illustrate.
Pixel coordinate: physically, a pixel is a limited size, the physical entity for having certain area, is used
In indicate location of pixels coordinate be pixel coordinate.
Pixel intrinsic coordinates: in order to improve measurement accuracy, coordinate can be also established inside pixel, the coordinate established is known as
Pixel intrinsic coordinates.Fig. 1 is the schematic diagram of pixel coordinate Yu pixel intrinsic coordinates.
Now in conjunction with attached drawing, the invention will be further described.
With reference to Fig. 1, it is of the invention based on image sensor pixel internal quantum efficiency obtain method for positioning mass center include with
Lower step:
Step 1) acquires star chart and its corresponding darkfield image using imaging sensor (detector arrays such as CCD, CMOS)
And flat field image, the point spread function of star chart can be lack sampling or threshold sampling；
Step 2), the star chart obtained to step 1) pre-process, star chart after being corrected；Wherein, the pretreatment
It include: that the star chart data that will initially obtain cut darkfield image data, then again by obtained result divided by flat field image number
According to；
Step 3) carries out the illumination of four-step phase-shifting sine streak to imaging sensor, obtains amount in the pixel of imaging sensor
The spatial frequency spectrum of sub- efficiency；
Step 4) carries out inverse Fourier to the spatial frequency spectrum of the pixel internal quantum efficiency of the imaging sensor of step 3) acquisition
Transformation obtains the space two-dimensional distribution of pixel internal quantum efficiency；
Step 5), the space two-dimensional based on the obtained pixel internal quantum efficiency of step 4) are distributed, and are obtained to step 2)
Star chart carries out resampling inside pixel after correction, obtains the star chart after resampling；
Step 6), using analytical function nonlinear least square fitting method or using weighted center of gravity method calculate resampling after
The absolute mass center of star chart.
Each step in the method for the present invention is described further below.
In step 1), imaging sensor (detector arrays such as CCD, CMOS) star chart I0 (p, q) collected can be by
The Convolution of point spread function PSF (x, y) and pixel internal quantum efficiency in the expression QE (x, y) of spatial domain is as follows:
Wherein, p, q are pixel coordinate, it is assumed that the ranks pixel number of imaging sensor is equal, i.e. p, q=1,2 ..., N.
The point spread function of fixed star needs to meet nyquist sampling theorem, i.e.,
2e≤λf/D (2)
Wherein, e indicates that Pixel Dimensions, λ indicate that wavelength, f indicate that focal length, D indicate aperture diameter.
In step 3), four-step phase-shifting sine streak can be indicated with following formula
Wherein,For the intensity value of each pixel output of imaging sensor, B is background, and A is amplitude, and (u, v) is respectively x
The spatial frequency in direction, the direction y,For the phase of four-step phase-shifting, value 0, pi/2, π, 3 pi/2s.It is shone when with four-step phase-shifting striped
When bright, the output of imaging sensor is the convolution of pixel internal quantum efficiency and striped, it may be assumed that
Wherein,For the output of imaging sensor, QE (x, y) is expression of the pixel internal quantum efficiency in spatial domain.
In step 3), the output of imaging sensor obtains the frequency spectrum QE of pixel internal quantum efficiency by following formula four-step phase-shifting
(u, v):
Wherein, j is imaginary unit.
In step 4), inverse Fourier transform is done to the frequency spectrum QE (u, v) for the pixel internal quantum efficiency that step 3) obtains, is obtained
To the real domain data QE (m, n) of pixel internal quantum efficiency, that is,
Wherein, m, n are pixel intrinsic coordinates, it is assumed that several rows of column are equal inside pixel, i.e. m, n=1,2 ..., M.It is herein
Later process is convenient, we indicate space coordinate (x, y) with discrete coordinates.
In step 5) to step 2) obtain correction after star chart resampling is carried out inside pixel, obtain resampling it
Star chart afterwards, it may be assumed that
Wherein, I2 (p, q；M, n) indicate the star chart after resampling；I1 (p, q) indicates the obtained correction of step 2)
Star chart later.
In step 6), it can use the analytical functions such as Gaussian function, Moffat function and minimum two carried out to (7) formula
Multiply fitting, obtains the center-of-mass coordinate after resampling.In addition, in practical applications, in order to improve calculating speed, as a kind of excellent
Implementation is selected, it is also an option that weighted center of gravity method calculates mass center, it may be assumed that
Wherein, (xc,yc) be finally obtained asterism absolute center-of-mass coordinate.
It should be noted last that the above examples are only used to illustrate the technical scheme of the present invention and are not limiting.Although ginseng
It is described the invention in detail according to embodiment, those skilled in the art should understand that, to technical side of the invention
Case is modified or replaced equivalently, and without departure from the spirit and scope of technical solution of the present invention, should all be covered in the present invention
Scope of the claims in.
Claims (7)
1. a kind of method for positioning mass center obtained based on image sensor pixel internal quantum efficiency, comprising:
Step 1) acquires star chart and darkfield image corresponding with acquired star chart, flat field image using imaging sensor；
Step 2), the star chart based on step 1) acquisition, darkfield image corresponding with star chart, flat field image locate star chart in advance
Reason, the star chart after being corrected；
Step 3) carries out the illumination of four-step phase-shifting sine streak to imaging sensor, obtains quantum in the pixel of imaging sensor and imitates
The spatial frequency spectrum of rate；
Step 4) carries out inverse Fourier's change to the spatial frequency spectrum of the pixel internal quantum efficiency of the imaging sensor of step 3) acquisition
It changes, obtains the space two-dimensional distribution of pixel internal quantum efficiency；
Step 5), the space two-dimensional based on the obtained pixel internal quantum efficiency of step 4) are distributed, the correction obtained to step 2)
Star chart later carries out resampling inside pixel, obtains the star chart after resampling；
Step 6), the absolute mass center for calculating the star chart after the obtained resampling of step 5).
2. the method for positioning mass center according to claim 1 obtained based on image sensor pixel internal quantum efficiency, special
Sign is, in step 2), the pretreatment includes: that the star chart data that step 1) obtains are cut darkfield image data, then
Again by obtained result divided by flat field image data.
3. the method for positioning mass center according to claim 1 obtained based on image sensor pixel internal quantum efficiency, special
Sign is, in step 3), the four-step phase-shifting sine streak is indicated with following formula
Wherein,For the intensity value of each pixel output of imaging sensor, B is background, and A is amplitude, and (u, v) is respectively the direction x, y
The spatial frequency in direction,For the phase of four-step phase-shifting, value 0, pi/2, π, 3 pi/2s；
When being illuminated with four-step phase-shifting striped, the output of imaging sensor is the convolution of pixel internal quantum efficiency and striped, it may be assumed that
Wherein,For the output of imaging sensor, QE (x, y) is expression of the pixel internal quantum efficiency in spatial domain；
The output of described image sensor obtains the frequency spectrum QE (u, v) of pixel internal quantum efficiency by four-step phase-shifting:
Wherein, j is imaginary unit.
4. the method for positioning mass center according to claim 3 obtained based on image sensor pixel internal quantum efficiency, special
Sign is, in step 4), does inverse Fourier transform to the frequency spectrum QE (u, v) for the pixel internal quantum efficiency that step 3) obtains, obtains
To the real domain data QE (m, n) of pixel internal quantum efficiency, that is,
Wherein, m, n are pixel intrinsic coordinates, it is assumed that several rows of column are equal inside pixel, i.e. m, n=1,2 ..., M.
5. the method for positioning mass center according to claim 4 obtained based on image sensor pixel internal quantum efficiency, special
Sign is, star chart carries out resampling inside pixel after the correction obtained in step 5) to step 2), obtain resampling it
Star chart afterwards, it may be assumed that
Wherein, I2 (p, q；M, n) indicate the star chart after resampling；I1 (p, q) is indicated after the obtained correction of step 2)
Star chart, p, q be star chart pixel coordinate, it is assumed that the ranks pixel number of imaging sensor is equal, i.e. p, q=1,2 ..., N.
6. the method for positioning mass center according to claim 5 obtained based on image sensor pixel internal quantum efficiency, special
Sign is, in step 6), calculates step 5) using analytical function nonlinear least square fitting method or using weighted center of gravity method
The absolute mass center of star chart after obtained resampling.
7. the method for positioning mass center according to claim 6 obtained based on image sensor pixel internal quantum efficiency, special
Sign is, in step 6), the absolute mass center packet of the star chart after the obtained resampling of step 5) is calculated using weighted center of gravity method
It includes:
Wherein, (xc, yc) be finally obtained asterism absolute center-of-mass coordinate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611052886.XA CN106530351B (en) | 2016-11-24 | 2016-11-24 | A kind of method for positioning mass center obtained based on image sensor pixel internal quantum efficiency |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611052886.XA CN106530351B (en) | 2016-11-24 | 2016-11-24 | A kind of method for positioning mass center obtained based on image sensor pixel internal quantum efficiency |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106530351A CN106530351A (en) | 2017-03-22 |
| CN106530351B true CN106530351B (en) | 2019-05-17 |
Family
ID=58357313
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201611052886.XA Active CN106530351B (en) | 2016-11-24 | 2016-11-24 | A kind of method for positioning mass center obtained based on image sensor pixel internal quantum efficiency |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106530351B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110850433A (en) * | 2018-07-25 | 2020-02-28 | 中国人民解放军国防科技大学 | Method for detecting mass center of space debris based on laser reflection tomography technology |
| CN112330669B (en) * | 2020-11-27 | 2022-12-20 | 北京理工大学 | Star point position positioning method of star sensor based on point light source diffraction starburst phenomenon |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101013065A (en) * | 2006-03-21 | 2007-08-08 | 北京航空航天大学 | Pixel frequency based star sensor high accuracy calibration method |
| CN103578088A (en) * | 2013-11-20 | 2014-02-12 | 中国人民解放军海军大连舰艇学院 | Method for processing star image |
| CN105023281A (en) * | 2015-05-25 | 2015-11-04 | 中国科学院空间科学与应用研究中心 | Method for computing center of mass of star map based on point spread function wave front correction |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4195029B2 (en) * | 2005-09-22 | 2008-12-10 | アドバンスド・マスク・インスペクション・テクノロジー株式会社 | Image correction apparatus, pattern inspection apparatus, image correction method, and pattern defect inspection method |
-
2016
- 2016-11-24 CN CN201611052886.XA patent/CN106530351B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101013065A (en) * | 2006-03-21 | 2007-08-08 | 北京航空航天大学 | Pixel frequency based star sensor high accuracy calibration method |
| CN103578088A (en) * | 2013-11-20 | 2014-02-12 | 中国人民解放军海军大连舰艇学院 | Method for processing star image |
| CN105023281A (en) * | 2015-05-25 | 2015-11-04 | 中国科学院空间科学与应用研究中心 | Method for computing center of mass of star map based on point spread function wave front correction |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106530351A (en) | 2017-03-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Apai et al. | High-cadence, high-contrast imaging for exoplanet mapping: observations of the HR 8799 planets with VLT/SPHERE satellite-spot-corrected relative photometry | |
| CN102183214B (en) | Method for optically detecting large-aperture aspherical mirror structure | |
| Bauer-Marschallinger et al. | Optimisation of global grids for high-resolution remote sensing data | |
| CN102496015B (en) | High-precision method for quickly positioning centers of two-dimensional Gaussian distribution spot images | |
| West et al. | A survey and examination of subpixel measurement techniques | |
| McCormac et al. | DONUTS: A science frame autoguiding algorithm with sub-pixel precision, capable of guiding on defocused stars | |
| CN106803892B (en) | A kind of light field high-resolution imaging method based on Optical field measurement | |
| CN103983343B (en) | A kind of satellite platform based on multispectral image tremble detection method and system | |
| CN103017762A (en) | Fast acquisition positioning method for space target of ground-based photoelectric telescope | |
| CN102072706A (en) | Multi-camera positioning and tracking method and system | |
| Reulke et al. | Determination and improvement of spatial resolution of the CCD-line-scanner system ADS40 | |
| EP3698554B1 (en) | Imaging system for environmental acoustic sources | |
| CN106530351B (en) | A kind of method for positioning mass center obtained based on image sensor pixel internal quantum efficiency | |
| Zhang et al. | Accurate star centroid detection for the advanced geosynchronous radiation imager of Fengyun-4A | |
| Antonello et al. | Development of a low-cost sun sensor for nanosatellites | |
| CN108154535B (en) | Camera calibration method based on collimator | |
| CN110363758A (en) | A kind of Optical remote satellite image quality determines method and system | |
| CN104361563A (en) | GPS-based (global positioning system based) geometric precision correction method of hyperspectral remote sensing images | |
| CN115908554A (en) | High-precision sub-pixel simulation star map and sub-pixel extraction method | |
| Danescu et al. | Long baseline stereovision for automatic detection and ranging of moving objects in the night sky | |
| Schwind et al. | An in-depth simulation of EnMAP acquisition geometry | |
| Rowe et al. | Flexion measurement in simulations of Hubble Space Telescope data | |
| CN105547286B (en) | A kind of compound three visual fields star sensor star map simulation method | |
| Kupinski et al. | Relating the statistics of the angle of linear polarization to measurement uncertainty of the Stokes vector | |
| CN103134664B (en) | A kind of camera of optical satellite in-orbit MTF measuring method based on convex reflecting mirror |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |