KR102240892B1 - Method and apparatus for correcting wavefront distortions of video signal - Google Patents

Abstract

The method for correcting wavefront distortion of an image according to the present invention comprises the steps of generating a double spectrum by configuring an image signal by a plurality of 1D projections, and when the generated double spectrum exceeds a predetermined number, 1D projection of each image signal Computing an average double spectrum by accumulating each of the generated double spectra, restoring phase information in the Fourier space of the original signal using the calculated average double spectrum, and using the restored Fourier phase information. It may include the step of correcting the wavefront distortion of the image signal.

Description

Method for correcting wavefront distortion of video and its apparatus {METHOD AND APPARATUS FOR CORRECTING WAVEFRONT DISTORTIONS OF VIDEO SIGNAL}

The present invention relates to a technique for correcting wavefront distortions of an image signal, and more particularly, a method for correcting wavefront distortions of an image capable of correcting wavefront distortion due to atmospheric distortion using a 1D projection method and a double spectrum, and It's about the device.

As is known, in imaging technology, the resolution of an image is influenced by not only the highest resolution defined by the physical structure of the lens, but also the actual surrounding environment conditions for acquiring the image.

That is, when light or electromagnetic waves of other wavelength bands pass through an atmospheric disturbance or a heterogeneous medium, the shape and direction of the wavefront may be distorted for the electromagnetic waves reflected or excited by the object to be observed.

Therefore, it is difficult to acquire the wavefront information of the electromagnetic wave reflected or emitted from the actual observation object in its original form.In order to solve this problem, the distortion is distorted by using an additional external auxiliary device such as a wavefront measuring device or a wavefront correction device. Wavefront can be corrected.

However, there is a problem that a lot of time, space, and cost are consumed in order to use the additional external auxiliary devices as described above. In addition, when using the additional external auxiliary devices, the arrangement between the devices must be solid. As it becomes sensitive, it is bound to be accompanied by restrictions on the actual environment that can be used.

In addition, due to the cost and complexity of building a system, wavefront distortion correction using these additional external auxiliary devices is currently mostly limited to fields where large capital investments such as military and astronomy are required.

Due to these shortcomings, various efforts are being made everywhere to restore high-quality images using only distorted images acquired through conventional imaging systems. Most of these methods are distorted due to wavefront distortion caused by passing through a heterogeneous medium. It predicts a point spread function and uses it to perform deconvolution on a distorted image.

However, since distortion caused by a non-homogeneous medium such as atmospheric distortion differs for each spatial region, deconvolution must be performed after predicting a jumper function at each point of the image, so its accuracy and image processing speed are inevitably limited.

As another method, there is a lucky guess approach in which several images are acquired, the image quality of each acquired image is checked, and then parts with good quality are accidentally picked up into one high-quality image.

However, the lucky guess approach has the disadvantage of having to acquire a myriad of images to obtain one image because the higher the complexity of the heterogeneous medium, the lower the probability that even a certain part of the image will remain in high quality. It also has a disadvantage that it is impossible to apply at all.

Korean Patent Publication No. 2015-0116617 (Publication date: 2015. 10. 16.)

An object of the present invention is to provide a method and apparatus for correcting wavefront distortion of an image capable of rapidly correcting wavefront distortion of an image without complicated mathematical calculations by using a 1D projection method and a dual spectrum.

An object of the present invention is to provide a method and apparatus for correcting wavefront distortion of an image capable of correcting wavefront distortion of an image at high speed without an additional external auxiliary device by using a 1D projection method and a dual spectrum.

An object of the present invention is to provide a computer-readable recording medium in which a computer program for causing a processor to perform a wavefront distortion correction method of an image is stored.

The problem to be solved by the present invention is not limited to those mentioned above, and another problem to be solved that is not mentioned can be clearly understood by those of ordinary skill in the art from the following descriptions. will be.

According to one aspect, the present invention comprises the steps of generating a double spectrum by configuring an image signal with a plurality of 1D projections, and when the generated double spectrum is more than a predetermined number, generated for each 1D projection of each image signal. Computing an average double spectrum by accumulating each of the double spectra; restoring phase information in the Fourier space of the original signal using the calculated average double spectrum; and the image signal using the restored Fourier phase information. It is possible to provide a method for correcting wavefront distortion of an image, including the step of correcting wavefront distortion.

In the restoring step of the present invention, the phase information in the Fourier space may be restored using a least-squares method.

The correction of the wavefront distortion of the present invention can be applied to an electromagnetic wave band.

The electromagnetic wave band of the present invention may be any one of visible light, infrared light, ultraviolet light, radio frequency, X-ray, and microwave.

The correction of the wavefront distortion of the present invention is applicable to sound waves having waves.

The image signal of the present invention may be any one of an image photographed through a camera, a laser scanning microscope image, a light coherence tomography image, and a confocal microscope image.

According to another aspect, the present invention is a computer-readable recording medium in which a computer program for causing a processor to perform a wavefront distortion correction method of an image is stored, wherein the wavefront distortion correction method comprises a plurality of 1D projections of an image signal. Generating a spectrum; when the generated double spectrum exceeds a predetermined number, calculating an average double spectrum by accumulating each generated double spectrum for each 1D projection of each image signal; and calculating the average double spectrum. It is possible to provide a computer-readable recording medium comprising the steps of restoring phase information in Fourier space of the original signal using a spectrum and correcting wavefront distortion of the image signal using the restored Fourier phase information.

According to another aspect, the present invention comprises a spectrum generator configured to generate a double spectrum by configuring a plurality of 1D projections of an image signal, and, when the generated double spectrum exceeds a predetermined number, 1D projection of each image signal A spectrum average calculation unit that accumulates each generated double spectrum to calculate an average double spectrum, a phase recovery unit that restores phase information in Fourier space of the image signal using the calculated average double spectrum, and a restored Fourier It is possible to provide an image wavefront distortion correction apparatus including an image distortion correction unit for correcting wavefront distortion of the image signal using phase information.

The phase restoration unit of the present invention may restore phase information in the Fourier space using a least squares method.

According to an embodiment of the present invention, by using the 1D projection method and the double spectrum, it is possible to correct the wavefront distortion of an image at high speed without complicated mathematical calculations.

According to an embodiment of the present invention, by using the 1D projection method and the dual spectrum, it is possible to correct the wavefront distortion of an image at high speed without an additional external auxiliary device.

According to the present invention, since wavefront distortion for various objects within a viewing angle can be numerically and independently corrected, quality for all points in an image can be improved.

The present invention does not depend on an additional external auxiliary device and uses only an image signal obtained by a general imaging device, so there is no special limitation on the wavelength, shooting conditions, etc., and can be used in any signal measuring device capable of measuring the amount of light. It has universality.

Since the present invention does not include hardware (ie, an additional external auxiliary device) requiring relatively high stability, it can be immediately applied to a general video system.

The present invention can be used for long-distance detection and monitoring by mounting on satellites, aircraft, and ships, since it is easy to reduce the size and weight of the system because there is no additional external auxiliary device.

The present invention can be applied to all kinds of wavefront distortion that changes with time, so by applying it to a medical imaging system that detects high-resolution biological signals by correcting the wavefront distortion caused by living biological tissues, changes in minute biological signals are reduced to high resolution. Can be observed in real time.

The present invention can be applied to high-resolution image detection in the sea floor or in a flowing liquid because the same method is applicable to wavefront distortion caused by a liquid environment.

1 is a block diagram of an apparatus for correcting wavefront distortion of an image according to an exemplary embodiment of the present invention.
FIG. 2 is a flowchart illustrating a main process of correcting wavefront distortion due to atmospheric disturbance using a 1D projection method and a double spectrum according to an embodiment of the present invention.
3 is an exemplary diagram showing an example of configuring a dual spectrum according to a conventional method.
4 is an exemplary diagram showing an example of configuring a dual spectrum according to an embodiment of the present invention.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and only these embodiments make the disclosure of the present invention complete, and those skilled in the art to which the present invention pertains. It is provided to fully inform the person of the scope of the invention, and the scope of the invention is only defined by the claims.

In describing the embodiments of the present invention, detailed descriptions of known functions or configurations will be omitted except when actually necessary in describing the embodiments of the present invention. In addition, terms to be described later are terms defined in consideration of functions in an embodiment of the present invention, which may vary according to the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout the present specification.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an apparatus for correcting wavefront distortion of an image according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the apparatus for correcting wavefront distortion of an image may include a spectrum generation unit 102, a spectrum average calculation unit 104, a phase restoration unit 106, an image distortion correction unit 108, and the like.

First, the spectrum generator 102 generates a double spectrum by configuring an image signal (e.g., a 2D (two-dimensional) image signal) acquired through an image acquisition device (not shown) into a plurality of 1D (one-dimensional) projections. It can provide functions such as doing.

Here, the image signal may be, for example, any one of an image captured through a camera, a laser scanning microscope image, a light coherence tomography image, and a confocal microscope image.

And, the double spectrum can be defined as in Equation 1 below.

[Equation 1]

,

,

는 1D 투사된 영상

의 푸리에 변환을 공간주파수

,

에 대하여 표현한 것일 수 있다.In Equation 1 above,

,

,

Is a 1D projected image

Fourier transform of spatial frequency

,

It may be an expression of

Next, when the number of dual spectra generated through the spectrum generating unit 102 reaches a predetermined number (eg, N) or more, the spectrum average calculation unit 104 calculates the generated dual spectrum for each 1D projection of each image signal. Each can be accumulated to provide a function such as calculating an average double spectrum.

만큼 흔들렸다면, 해당 영상의 이중 스펙트럼은 아래의 수학식 2와 같이 정의될 수 있다.Since the dual spectrum has a characteristic of correcting the distortion of the image, the wavefront distortion can be corrected through the dual spectrum. For example, the video

If it is shaken by as much, the dual spectrum of the image can be defined as in Equation 2 below.

[Equation 2]

From Equation 2 above, it can be seen that the distortion due to aberration is corrected in the dual spectrum. When the number of image signals acquired using this characteristic is more than a certain number, the dual spectrum configured for each 1D projection of each image signal is respectively By accumulating, it is possible to construct an average double spectrum corrected for wavefront distortion.

는 획득된 영상으로부터 구성한 이중 스펙트럼의 위상 정보를,

는 관찰 대상의 푸리에 위상 정보를,

는

로부터 구성한 이중 스펙트럼의 위상 정보를,

는

로 점퍼짐 함수

의 평균 이중 스펙트럼을 각각 나타낸다.In Equation 2 above,

Is the phase information of the dual spectrum constructed from the acquired image,

Is the Fourier phase information of the object to be observed,

Is

The phase information of the dual spectrum composed from,

Is

Jumper function

The average double spectra of are shown, respectively.

In addition, the phase restoration unit 106 may provide a function of restoring phase information in the Fourier space of the original image signal by using the average double spectrum calculated by the spectrum average calculation unit 104.

For example, the phase restoration unit 106 may restore phase information in Fourier space using the least squares method, and optimization at this time may be defined as in Equation 3 below.

[Equation 3]

subject to

subject to

는 획득된 영상신호로부터 구성한 이중 스펙트럼의 위상 정보를 의미하고,

는 관찰 대상의 푸리에 위상 정보를 의미하며,

는

로부터 구성한 이중 스펙트럼의 위상 정보를 의미한다.In Equation 3 above,

Denotes the phase information of the dual spectrum constructed from the acquired image signal,

Means Fourier phase information of the object to be observed,

Is

It means the phase information of the dual spectrum constructed from.

는

로 점퍼짐 함수

의 평균 이중 스펙트럼을 나타낸다. 따라서, 주어진 수학식 3은 최소자승법을 이용하여

에 가장 가까운

를 구하는 방법을 최적화 식으로 표현할 수 있다. 이때,

로 표현된 조건은 실제 영상이 실수임을 의미할 수 있다.And,

Is

Jumper function

Shows the average double spectrum of. Therefore, given Equation 3, using the least squares method

Closest to

The method of obtaining is can be expressed as an optimization equation. At this time,

The condition expressed as may mean that the actual image is a real number.

Next, the image distortion correction unit 108 may provide a function of correcting the wavefront distortion of the image signal by using the Fourier phase information restored through the phase restoration unit 106. That is, the high-quality signal for the object to be observed can be restored using the Fourier phase information of the distortion-corrected image signal, and the restored high-quality signal can be finally transmitted to the connected image device and visually displayed (displayed). have.

Here, the correction of the wavefront distortion can be applied to an electromagnetic wave band such as visible light, infrared light, ultraviolet light, radio frequency, X-ray, microwave, and the like, and can also be applied to sound waves having waves.

FIG. 2 is a flowchart illustrating a main process of correcting wavefront distortion due to atmospheric disturbance using a 1D projection method and a double spectrum according to an embodiment of the present invention.

Referring to FIG. 2, when an image signal to be corrected is obtained from an image acquisition device (not shown) (step 202), the spectrum generator 102 uses the acquired image signal (eg, 2D image signal) to a plurality of 1D projections. Construct to generate a double spectrum (step 204).

And, in the spectrum average calculation unit 104, when the number of double spectra generated by the spectrum generator 102 reaches a predetermined number (eg, N) or more, each of the double spectra generated for each 1D projection of each image signal is calculated. The average double spectrum is calculated by accumulating (step 206).

Next, the phase restoration unit 106 restores the phase information in the Fourier space of the original image signal using the average double spectrum calculated by the spectrum average calculation unit 104, for example, the phase in the Fourier space using the least squares method. The information is restored (step 208).

Thereafter, the image distortion correction unit 108 corrects the wavefront distortion of the image signal by using the Fourier phase information restored through the phase restoration unit 106 (step 210).

3 is an exemplary diagram showing an example of configuring a dual spectrum according to a conventional method.

Referring to FIG. 3, in the conventional method, the entire acquired signal is expressed as a single vector and arranged by time, and then a double spectrum for each single vector is constructed. When the double spectrum is configured in this manner, the double spectrum is Since it increases in proportion to the square of the measured signal size for each time, the burden of memory for calculation increases.

Accordingly, the conventional method has a problem in that the size of an image that can be restored is limited due to the burden of memory, and a computational speed for restoring the image is also slowed.

4 is an exemplary diagram showing an example of configuring a dual spectrum according to an embodiment of the present invention.

Referring to FIG. 4, for example, a 2D image signal can be expressed as a projection of a 1D projection in several directions. As such, a single 2D image signal can be expressed as a number of 1D projections. It can be expressed as

In this case, the size of each vector is reduced by a ratio of the square root of the number of individual pieces of information compared to the total size of the 2D image. Accordingly, the size of the double spectrum is also reduced by the square root, thereby reducing the memory burden and computation speed.

In addition, since the present invention can perform dual spectrum and phase restoration calculations in parallel by dividing one 2D image into several 1D projections, it is possible to realize parallel processing and high-speed image restoration.

Meanwhile, combinations of each block of the attached block diagram and each step of the flowchart may be performed by computer program instructions. Since these computer program instructions can be mounted on the processor of a general-purpose computer, special purpose computer or other programmable data processing equipment, the instructions executed by the processor of the computer or other programmable data processing equipment are shown in each block or flowchart of the block diagram. Each step creates a means to perform the functions described.

These computer program instructions can also be stored in a computer-usable or computer-readable memory, etc., which can be directed to a computer or other programmable data processing equipment to implement a function in a specific manner, so that the computer-usable or computer-readable memory It is also possible to produce an article of manufacture in which the instructions stored in the block diagram contain instruction means for performing the functions described in each block of the block diagram or each step of the flowchart.

In addition, since computer program instructions can be mounted on a computer or other programmable data processing equipment, a series of operation steps are performed on a computer or other programmable data processing equipment to create a process that is executed by a computer, It is also possible for the instructions to perform possible data processing equipment to provide steps for executing the functions described in each block of the block diagram and each step of the flowchart.

Further, each block or each step may represent a module, segment, or part of code including at least one or more executable instructions for executing the specified logical function(s). It should also be noted that in some alternative embodiments, functions mentioned in blocks or steps may occur out of order. For example, two blocks or steps shown in succession may in fact be performed substantially simultaneously, or the blocks or steps may sometimes be performed in the reverse order depending on the corresponding function.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the technical field to which the present invention pertains, various substitutions, modifications and changes, etc., within the scope not departing from the essential characteristics of the present invention. It will be easy to see that this is possible. That is, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments.

Accordingly, the scope of protection of the present invention should be interpreted by the claims to be described later, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

102: spectrum generator
104: spectrum average calculation unit
106: phase restoration unit
108: image distortion correction unit

Claims (10)

Comprising a plurality of 1D projections of the image signal to generate a double spectrum, and
When the generated double spectrum exceeds a predetermined number, calculating an average double spectrum corrected for wavefront distortion by accumulating each generated double spectrum for each 1D projection of each image signal; and
Restoring phase information in Fourier space of the original signal using the calculated average double spectrum; and
Comprising the step of correcting the wavefront distortion of the image signal using the restored Fourier phase information,
The restoring step is performed by Equation 1
[Equation 1]

subject to

(here,

Denotes the phase information of the dual spectrum constructed from the acquired image signal,

Means Fourier phase information of the object to be observed,

Is

The phase information of the dual spectrum constructed from,

Is

Jumper function

Means the average double spectrum of)
How to correct the wavefront distortion of an image. The method of claim 1,
The restoring step,
A method for correcting wavefront distortion of an image for restoring phase information in the Fourier space using a least squares method. The method of claim 1,
Correction of the wavefront distortion,
Applicable to the electromagnetic wave band
How to correct the wavefront distortion of an image. The method of claim 3,
The electromagnetic wave band,
Visible light, infrared, ultraviolet, radio frequency, X-ray, microwave
How to correct the wavefront distortion of an image. The method of claim 1,
Correction of the wavefront distortion,
Applicable to sound waves with waves
How to correct the wavefront distortion of an image. The method of claim 1,
The video signal,
Any one of an image taken through a camera, a laser scanning microscope image, a light coherence tomography image, and a confocal microscope image
How to correct the wavefront distortion of an image. A computer-readable recording medium in which a computer program for causing a processor to perform a wavefront distortion correction method of an image is stored,
The wavefront distortion correction method,
Comprising a plurality of 1D projections of the image signal to generate a double spectrum, and
When the generated double spectrum exceeds a predetermined number, calculating an average double spectrum corrected for wavefront distortion by accumulating each generated double spectrum for each 1D projection of each image signal; and
Restoring phase information in Fourier space of the original signal using the calculated average double spectrum; and
Comprising the step of correcting the wavefront distortion of the image signal using the restored Fourier phase information,
The restoring step is performed by Equation 2
[Equation 2]

subject to

(here,

Denotes the phase information of the dual spectrum constructed from the acquired image signal,

Means Fourier phase information of the object to be observed,

Is

The phase information of the dual spectrum constructed from

Is

Jumper function

Means the average double spectrum of)
Computer-readable recording medium. A computer program stored in a computer-readable recording medium so that a processor can perform a method of correcting wavefront distortion of an image,
The wavefront distortion correction method,
Comprising a plurality of 1D projections of the image signal to generate a double spectrum, and
When the generated double spectrum exceeds a predetermined number, calculating an average double spectrum corrected for wavefront distortion by accumulating each generated double spectrum for each 1D projection of each image signal; and
Restoring phase information in Fourier space of the original signal using the calculated average double spectrum; and
Comprising the step of correcting the wavefront distortion of the image signal using the restored Fourier phase information,
The restoring step is performed by Equation 3
[Equation 3]

subject to

(here,

Denotes the phase information of the dual spectrum constructed from the acquired image signal,

Means Fourier phase information of the object to be observed,

Is

The phase information of the dual spectrum constructed from,

Is

Jumper function

Means the average double spectrum of)
Computer program. A spectrum generator configured to generate a double spectrum by composing a plurality of 1D projections of an image signal;
When the generated double spectrum exceeds a preset predetermined number, a spectrum average calculator for calculating an average double spectrum corrected for wavefront distortion by accumulating each generated double spectrum for each 1D projection of each image signal;
A phase restoration unit for restoring phase information in Fourier space of the image signal using the calculated average double spectrum;
Including an image distortion correction unit for correcting the wavefront distortion of the image signal using the restored Fourier phase information,
The phase restoration unit performs the restoration according to Equation 4
[Equation 4]

subject to

(here,

Denotes the phase information of the dual spectrum constructed from the acquired image signal,

Means Fourier phase information of the object to be observed,

Is

The phase information of the dual spectrum constructed from,

Is

Jumper function

Means the average double spectrum of)
Image wavefront distortion correction device. The method of claim 9,
The phase recovery unit,
Restoring the phase information in the Fourier space using the least squares method
Image wavefront distortion correction device.

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