KR101984849B1 - Imaging device for multi-exposure laser speckle image and calibration method thereof - Google Patents

Abstract

A multi-exposure laser speckle image acquisition device and a method of correcting the same are disclosed. The present invention has the same amount of light for each exposure time in the multi-exposure laser speckle image acquisition. According to the present invention, blood flow image information for blood flow diagnosis in vivo can be obtained more efficiently and accurately, accurate blood flow image information can be obtained, and skin image diagnosis, image monitoring of a surgical procedure, laser treatment and therapeutic effect monitoring Accurate diagnosis and analysis of diseases associated with blood flow such as diabetes, and the like.

Description

TECHNICAL FIELD [0001] The present invention relates to a multi-exposure laser speckle image acquisition apparatus and a correction method thereof,

The present invention relates to a multi-exposure laser speckle image acquisition apparatus and a correction method thereof, and more particularly, to an apparatus and a method for achieving the same amount of light for each exposure time in a multi-exposure laser speckle image acquisition.

Laser speckle refers to a pattern with an irregular distribution of grains formed by a random interference phenomenon of scattered light when a laser, which is a light source with high coherence, is irradiated to a scattering material. Based on this phenomenon, imaging through the multi-exposure imaging technique can image the flow of blood within the object without an external contrast agent such as a fluorescent material.

However, the conventional multi-exposure imaging technique only acquires a plurality of images with different exposure times, so that there is a problem that the brightnesses of the respective images are different from each other, so that a correct flow of blood flow can not be confirmed.

Patent Document 1 is directed to a quantitative image having a multi-exposure speckle image, and Patent Document 1 discloses a laser light source Discloses a multi-exposure laser speckle contrast imaging system and method that includes a light modulator and a camera, a magnification objective lens and a microprocessor / data acquisition unit and a detector for measurement of the reflected light. Korean Patent Laid-Open Publication No. 2017-0009085 (Samsung Electronics Co., Ltd.), Jan. 201, 2017 Patent Document 2 discloses a laser spec-to-coarse imaging system and method. In Patent Document 2, An image pickup section for picking up a speckle image by photographing the speckle formed by scattering the irradiated laser light from the object with an image sensor and a speckle image obtained by the image pickup section, And a signal processing unit for acquiring a compensated speckle contrast image by compensating for a change due to the motion of the object.

An object of the present invention is to provide a multi-exposure laser speckle image acquiring apparatus and a correction method therefor, which have the same amount of light for each exposure time in the multi-exposure laser speckle image acquisition.

According to an aspect of the present invention, there is provided a multi-exposure laser speckle image collecting apparatus including: a light source unit for irradiating laser light; A light amount adjusting unit for adjusting an amount of laser light irradiated through the light source; An image capturing unit for capturing a plurality of speckle images formed by scattering laser light irradiated through a light source from a target object at different exposure times and acquiring a plurality of speckle images having different exposure times; And a light amount controller for controlling the light amount controller so that the light amount of the laser light irradiated through the light source unit is different for each exposure time when the image is taken a plurality of times with different exposure times through the image capturing unit.

The light amount control unit may control the light amount adjusting unit such that the light amount of the laser light irradiated through the light source unit is different for each exposure time so that a plurality of speckle images having different exposure times have the same brightness value.

The light amount control unit determines the common brightness value based on the light amount value-brightness value information according to the previously obtained exposure time, and determines the light amount based on the light amount value-brightness value information according to the previously obtained exposure time and the determined common brightness value It is possible to control the light amount adjusting unit such that the light amount of the laser light irradiated through the exposure unit becomes different according to the exposure time.

The light amount controller obtains a brightness value range from the minimum brightness value to the maximum brightness value according to the exposure time based on the light amount value-brightness value information according to the previously obtained exposure time, and obtains a brightness value range It is possible to determine a common brightness value.

The light intensity control unit may determine the maximum brightness value as a common brightness value within a brightness value range overlapping among the brightness value range for each exposure time.

The light intensity control unit obtains the light intensity value for each exposure time in the light intensity value-brightness intensity information according to the exposure time acquired based on the common brightness value, and calculates the light intensity value for each exposure time based on the light intensity value obtained for each exposure time The light amount control unit can be controlled so that the light amount is different for each exposure time.

The light amount value may be a voltage value corresponding to the rotation angle value or rotation angle value of the light amount control unit.

According to another aspect of the present invention, there is provided a correction method for a multi-exposure laser speckle image collecting apparatus, comprising: irradiating a laser beam onto a target object; And obtaining a plurality of speckle images having different exposure times by photographing the speckle formed by scattering the irradiated laser light from the target object at different exposure times at different times, The obtaining step includes the step of adjusting the light amount of the laser light so that the light amount of the irradiated laser light is different for each exposure time at the time of taking a plurality of times with different exposure times.

The light amount adjustment step may be performed by adjusting the light amount of the laser light so that the light amount of the laser light to be irradiated becomes different for each exposure time so that a plurality of speckle images having different exposure times have the same brightness value.

In the light amount control step, the common brightness value is determined based on the light amount value-brightness value information according to the previously obtained exposure time, and the light amount value-brightness value information according to the previously acquired exposure time and the common light value And adjusting the amount of laser light so that the light amount of the laser light is different for each exposure time.

In the light amount control step, the brightness value range from the minimum brightness value to the maximum brightness value is obtained based on the light amount value-brightness value information according to the previously acquired exposure time, and the brightness value range overlapping with the brightness value range And determining a common brightness value within the range.

The light intensity adjusting step may be performed by determining the maximum brightness value as a common brightness value within a brightness value range overlapping with each other in the brightness value range per exposure time.

In the light amount control step, the light amount value is acquired for each exposure time in the light amount value-brightness value information according to the previously obtained exposure time based on the common brightness value, and the light amount of the laser light irradiated based on the light amount value acquired for each exposure time And adjusting the amount of laser light to be different for each exposure time.

The light amount value may be a voltage value corresponding to the rotation angle value or the rotation angle value.

According to an aspect of the present invention, there is provided a computer program for use in a computer readable recording medium, the computer program causing the computer to execute any one of the methods.

According to the multi-exposure laser speckle image acquiring apparatus and the correction method therefor according to the present invention, blood flow image information for in vivo blood flow diagnosis can be obtained by having the same amount of light for each exposure time in the multi- Efficient and accurate acquisition.

In addition, accurate blood flow image information can be obtained, and it can be applied to various fields such as skin imaging, image monitoring of a surgical procedure, laser treatment and monitoring of therapeutic effect, accurate diagnosis and analysis of diseases associated with blood flow such as diabetes .

1 is a block diagram illustrating a multi-exposure laser speckle image acquisition apparatus according to a preferred embodiment of the present invention.
FIG. 2 is a block diagram for explaining the image collecting apparatus shown in FIG. 1 in more detail.
FIG. 3 is a diagram for explaining an example of the image capturing apparatus shown in FIG. 2. FIG.
4 is a graph for explaining an example of light amount-brightness value information according to the exposure time according to a preferred embodiment of the present invention.
5 is a diagram for explaining a result of an experiment on the performance of the correction operation of the multi-exposure laser speckle image collecting apparatus according to the preferred embodiment of the present invention.
6 is a flowchart illustrating a method of correcting a multi-exposure laser speckle image collecting apparatus according to an exemplary embodiment of the present invention.
FIG. 7 is a flowchart for explaining the plurality of speckle image acquiring steps shown in FIG. 6 in more detail.

Hereinafter, a preferred embodiment of a multi-exposure laser speckle image acquiring apparatus and a correction method therefor according to the present invention will be described in detail with reference to the accompanying drawings.

First, a multi-exposure laser speckle image collecting apparatus according to a preferred embodiment of the present invention will be described with reference to FIG.

1 is a block diagram illustrating a multi-exposure laser speckle image acquisition apparatus according to a preferred embodiment of the present invention.

Referring to FIG. 1, a multi-exposure laser speckle image collecting apparatus 100 according to a preferred embodiment of the present invention irradiates a laser beam to a target object 200.

The image collecting apparatus 100 photographs the speckle formed by scattering the irradiated laser light from the object 200 a plurality of times at different exposure times and acquires a plurality of speckle images having different exposure times .

At this time, the image capturing apparatus 100 adjusts the light amount of the laser light so that the light amount of the irradiated laser light differs according to the exposure time, when taking a plurality of photographs at different exposure times. In other words, the image capturing apparatus 100 is configured to minimize the influence of the external factors due to the change of the external optical factors with the non-contact method and the high accuracy, and to acquire the more accurate blood flow image information, The light amount of the laser light is corrected by interlocking with the exposure time so as to have the same and constant brightness value at the time of image acquisition. Thus, it is possible to acquire blood flow image information for in vivo blood flow diagnosis more efficiently and accurately.

The target object 200 may be a body tissue or the like. In particular, the target object 200 may be a biotissue that has been exposed due to skin tissue of the hands and feet, surgical techniques, or other factors.

The multi-exposure laser speckle image collecting apparatus according to the preferred embodiment of the present invention will now be described in more detail with reference to FIGS. 2 and 3. FIG.

FIG. 2 is a block diagram for explaining the image collecting apparatus shown in FIG. 1 in more detail, and FIG. 3 is a view for explaining an example of the image collecting apparatus shown in FIG.

2 and 3, the image capturing apparatus 100 includes a light source unit 110, a light source control unit 120, a light amount control unit 130, a light diffusion unit 140, an image capturing unit 150, A light source 160, and a light amount controller 170.

The light source unit 110 irradiates laser light. At this time, the light source unit 110 can use a laser light source of a visible light and a near-infrared light region having high coherence as laser light. Here, the laser light source may be a laser light source having a center wavelength in the vicinity of 632 nm, 780 nm, and 808 nm.

The light source control unit 120 supplies power to the light source unit 110 and controls the operation of the light source unit 110.

The light amount adjusting unit 130 adjusts the amount of laser light irradiated through the light source unit 110. In particular, the light amount control unit 130 may control the amount of laser light irradiated under the control of the light amount control unit 170.

The light diffusing unit 140 allows the laser beam irradiated through the light source unit 110 to have a uniform amount of light spatially distributed to the target object 200.

The image capturing unit 150 includes a lens 151 and an image sensor (not shown), and the speckle formed by scattering the laser light irradiated through the light source unit 110 from the target object 200 is set to an exposure time The image is photographed multiple times. Here, the lens 151 allows the speckle formed by scattering from the target object 200 to be formed on the image sensor. The image sensor is an image sensor having high quantum efficiency in the visible light and near infrared region, and may be a CCD image sensor, a CMOS image sensor, or the like.

The image capturing unit 150 acquires a plurality of speckle images having different exposure times.

The image capturing control unit 160 supplies power to the image capturing unit 150 and controls the operation of the image capturing unit 150. [

The light amount control unit 170 controls the light amount control unit 130 so that the light amount of the laser light irradiated through the light source unit 110 is different for each exposure time, do.

That is, the light amount control unit 170 adjusts the amount of light so that the light amount of the laser light irradiated through the light source unit 110 differs according to the exposure time, so that a plurality of speckle images having different exposure times have the same brightness value, The control unit 130 can be controlled.

More specifically, the light amount controller 170 may determine the common brightness value based on the light amount value-brightness value information according to the previously obtained exposure time. Here, the light amount value may be a rotation angle value of the light amount controller 130, a voltage value corresponding to the rotation angle value of the light amount controller 130, and the like.

That is, the light amount controller 170 obtains a brightness value range from the minimum brightness value to the maximum brightness value according to the exposure time based on the light amount value-brightness value information according to the previously obtained exposure time, It is possible to determine the common brightness value within the brightness value range.

At this time, the light amount controller 170 may determine the maximum brightness value as a common brightness value within a range of overlapping brightness values among the brightness value ranges per exposure time.

The light amount control unit 170 controls the light amount control unit 170 so that the light amount of the laser light irradiated through the light source unit 110 is different according to the exposure time based on the light amount value- (130).

That is, the light amount controller 170 can obtain the light amount value for each exposure time in the light amount value-brightness value information according to the previously obtained exposure time based on the common brightness value. The light amount controller 170 may control the light amount controller 130 such that the light amount of the laser light irradiated through the light source unit 110 is different according to the exposure time based on the light amount value obtained for each exposure time.

Referring now to FIG. 4, the correction operation of the multi-exposure laser speckle image collecting apparatus according to the preferred embodiment of the present invention will be described in more detail.

4 is a graph for explaining an example of light amount-brightness value information according to the exposure time according to a preferred embodiment of the present invention.

As shown in FIG. 4, the light amount controller 170 may first obtain the light amount-brightness value information according to the exposure time.

That is, the light amount controller 170 initializes the light amount controller 130. For example, when the light amount adjusting unit 130 includes a polarizer (not shown), a stepping motor (not shown), and the like, and adjusts the light amount of the laser light through the rotation of the polarizer, ) Rotates the polarizer through the stepping motor, finds the rotation angle at which the light amount of the laser light becomes maximum / minimum, and sets the polarizer to the rotation angle at which the light amount of the laser light becomes minimum, that is, the initial position. The light amount adjusting unit 130 includes a polarizer (not shown), a servo motor (not shown), and the like. When the light amount of the laser light is adjusted through the rotation of the polarizer, Can set the polarizer to the initial position by applying a specific voltage corresponding to the initial position, that is, the rotation angle at which the light amount of the laser light is minimum

Then, the light amount controller 170 increases the light amount of the laser light with respect to each of the exposure times t1, t2, t3, ..., tn (that is, increases the rotation angle of the polarizer or increases the voltage corresponding to the rotation angle And the brightness value is obtained while acquiring the brightness value. Thus, the brightness value-brightness value information according to the exposure time can be obtained. Here, the brightness value may be an average value or a middle value of the brightness values of the pixels of the image sensor of the image capturing unit 150. And, the exposure time may have a value between 0.01 ms and 1,000 ms.

For example, as shown in FIG. 4, the light amount controller 170 increases the light amount of the laser light for each of the exposure times t1, t2, t3, and t4 to obtain a brightness value, Can be obtained.

Then, the light amount controller 170 can determine the common brightness value based on the light amount value-brightness value information according to the obtained exposure time.

That is, the light amount controller 170 obtains the brightness value range from the minimum brightness value to the maximum brightness value according to the exposure time based on the light amount value-brightness value information according to the obtained exposure time, A common brightness value can be determined within a brightness value range.

For example, referring to FIG. 4, the exposure time t1 has a brightness value range of about 5 to about 130, the exposure time t2 has a brightness value range of about 10 to about 220, and the exposure time t3 is about 20 to about 250 The exposure time t4 has a brightness value range of about 50 to about 250. [ The light amount controller 170 may determine the common brightness value within a range of about 50 to about 130 which is a brightness value range overlapping among the brightness value ranges for each exposure time.

At this time, the light amount controller 170 may determine the maximum brightness value as a common brightness value within a range of overlapping brightness values among the brightness value ranges per exposure time.

For example, referring to FIG. 4, the light amount controller 170 may determine the maximum brightness value 130 as a common brightness value within a range of about 50 to about 130, which is a brightness value range overlapping with the exposure time.

Then, the light amount control unit 170 controls the light amount control unit 170 so that the light amount of the laser light irradiated through the light source unit 110 is different according to the exposure time, based on the light amount value-brightness value information according to the obtained exposure time and the determined common brightness value. (130).

For example, when the common brightness value CE is determined as the maximum brightness value 130 within about 50 to about 130 brightness values overlapping with each other in the brightness value range for each exposure time as shown in FIG. 4, the light amount controller 170 (T1_A) determined based on the light amount value-brightness value information and the common brightness value CE at the exposure time t1 when the image capturing unit 150 captures the speckle at the exposure time t1, i.e., the light amount value It is possible to control the light amount adjusting unit 130 such that the light amount of the incident light is irradiated. When the image capturing unit 150 photographs the speckle at the exposure time t2, the light amount control unit 170 controls the light amount control unit 170 to calculate the rotation angle value t2_A (brightness) based on the light amount value-brightness value information and the common brightness value CE at the exposure time t2 ), That is, the quantity of light having the light quantity value is irradiated. When the image capturing unit 150 captures the speckle at the exposure time t3, the light amount control unit 170 controls the light amount control unit 170 such that the light amount value-brightness value information and the rotation angle value t3_A determined based on the common brightness value CE at the exposure time t3 ), That is, the quantity of light having the light quantity value is irradiated. When the image capturing unit 150 captures the speckle at the exposure time t4, the light amount control unit 170 controls the light amount control unit 170 to calculate the rotation angle value t4_A (t4) based on the light amount value-brightness value information and the common brightness value CE at the exposure time t4 ), That is, the quantity of light having the light quantity value is irradiated.

In this way, by controlling the light amount adjusting unit 130 so that the light amount of the laser light irradiated through the light source unit 110 differs according to the exposure time, the plurality of speckle images having different exposure times The same brightness value can be obtained.

The performance of the correction operation of the multi-exposure laser speckle image pick-up apparatus according to the preferred embodiment of the present invention will now be described with reference to FIG.

5 is a diagram for explaining a result of an experiment on the performance of the correction operation of the multi-exposure laser speckle image collecting apparatus according to the preferred embodiment of the present invention.

As a result of performing the correction operation of the multi-exposure laser speckle image collecting apparatus according to the preferred embodiment of the present invention at an exposure time of 0.05 ms to 80 ms, as shown in FIG. 5, It can be confirmed that the large image has a constant brightness.

6 and 7, a method of correcting a multi-exposure laser speckle image collecting apparatus according to a preferred embodiment of the present invention will be described.

6 is a flowchart illustrating a method of correcting a multi-exposure laser speckle image collecting apparatus according to an exemplary embodiment of the present invention.

Referring to FIG. 6, the image capturing apparatus 100 irradiates a laser beam onto a target object 200 (S110).

Thereafter, the image capturing apparatus 100 acquires a plurality of speckle images having different exposure times by photographing a plurality of times at different exposure times while adjusting the amount of laser light for each exposure time (S130).

That is, the image collecting apparatus 100 adjusts the light amount of the laser light so that the light amount of the irradiated laser light is different for each exposure time so that a plurality of speckle images having different exposure times have the same brightness value.

FIG. 7 is a flowchart for explaining the plurality of speckle image acquiring steps shown in FIG. 6 in more detail.

Referring to FIG. 7, the image capturing apparatus 100 may determine a common brightness value based on the light amount-brightness value information according to the previously obtained exposure time (S131).

That is, the image capturing apparatus 100 acquires a brightness value range from the minimum brightness value to the maximum brightness value for each exposure time based on the light amount value-brightness value information according to the previously obtained exposure time, A common brightness value can be determined within a range of overlapping brightness values. At this time, the image capturing apparatus 100 may determine the maximum brightness value as a common brightness value within a brightness value range overlapping among the brightness value ranges per exposure time.

In operation S133, the image capturing apparatus 100 may acquire a light amount value for each exposure time based on the light amount value-brightness value information according to the previously obtained exposure time and the determined common brightness value.

Thereafter, the image capturing apparatus 100 acquires a plurality of speckle images having different exposure times by photographing a plurality of times with different exposure times while adjusting the light amount of the laser light for each exposure time based on the light amount value acquired for each exposure time (S135).

The present invention can also be embodied as computer-readable codes on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, and an optical data storage device. In addition, the computer-readable recording medium may be distributed to computer devices connected to a wired / wireless communication network, and a computer-readable code may be stored and executed in a distributed manner.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the appended claims.

100: Multi-exposure laser speckle image acquisition device,
110: light source part, 120: light source control part,
130: light amount control unit, 140: light diffusion unit,
150: image capturing unit, 151: lens,
160: photographing control unit, 170: light amount control unit,
200: target object

Claims (15)

A light source unit for irradiating laser light;
A light amount adjusting unit for adjusting a light amount of the laser beam irradiated through the light source unit;
An image capturing unit that captures a plurality of speckle images formed by scattering laser light emitted through the light source through a target object at different exposure times and acquiring a plurality of speckle images having different exposure times; And
A light amount control unit for controlling the light amount adjusting unit such that a light amount of the laser light irradiated through the light source unit differs according to an exposure time during a plurality of photographing operations with different exposure times through the image taking unit;
/ RTI >
The light amount control unit controls the light amount adjusting unit such that a plurality of speckle images having different exposure times have the same brightness value, the light amount of the laser light irradiated through the light source unit is different for each exposure time, Based on the light amount value-brightness value information according to the exposure time and the common brightness value based on the previously obtained exposure time, The control unit controls the light amount adjusting unit such that the light amount of the laser light is different according to the exposure time and acquires a brightness value range from the minimum brightness value to the maximum brightness value in each exposure time based on the light amount value- And determines the common brightness value within a range of brightness values overlapping with each other in the brightness value range per exposure time A multi-exposure laser speckle image acquisition device. delete delete delete The method of claim 1,
Wherein the light amount controller determines the maximum brightness value as the common brightness value within a brightness value range overlapping among the brightness value ranges for each exposure time. The method of claim 1,
The light amount control unit obtains a light amount value for each exposure time in the light amount value-brightness value information according to the previously acquired exposure time based on the common brightness value, and calculates the light amount value for each exposure time based on the light amount value obtained for each exposure time And controls the light amount adjusting unit so that the light amount of the laser light to be irradiated becomes different according to the exposure time. The method according to any one of claims 5 to 6,
Wherein the light amount value is a voltage value corresponding to a rotation angle value or a rotation angle value of the light amount control unit. A method of correcting a multi-exposure laser speckle image pick-up apparatus comprising a light source, a light amount control unit, an image pickup unit, and a light amount control unit,
The light source unit irradiating a laser beam onto a target object; And
Capturing a plurality of speckle images having different exposure times by photographing the speckle formed by scattering the irradiated laser light from the object object at different exposure times and acquiring a plurality of speckle images having different exposure times;
/ RTI >
The plurality of speckle image acquiring steps may include a step of acquiring a plurality of speckle images of the plurality of speckle images, wherein the light amount control unit controls the light amount adjusting unit such that, when photographing a plurality of times with different exposure times through the image photographing unit, And controlling the light amount of the laser light,
Wherein the light amount control step controls the light amount adjusting unit such that the light amount of the laser light irradiated through the light source unit is different for each exposure time so that the plurality of speckle images having different exposure times have the same brightness value, Brightness value information according to the exposure time acquired in advance, and determines a common brightness value based on the brightness value information according to the previously acquired exposure time, and calculates a brightness value-brightness value information And controlling the light amount adjusting unit to adjust the light amount of the laser light based on the determined common brightness value so that the light amount of the laser light irradiated through the light source unit differs according to the exposure time, Value - Based on the brightness value information, the maximum brightness at the minimum brightness value per exposure time Correction method of the exposure laser speckle image capturing device obtains the brightness range up to, and exposure time of the gray level range in the gray level range that overlap each other to be made to determine the common brightness, multiple. delete delete delete 9. The method of claim 8,
The light amount adjusting step may include adjusting the light amount of the multi-exposure laser speckle image collecting apparatus, wherein the light amount controlling unit determines the maximum brightness value as the common brightness value within a brightness value range overlapping among the exposure time- Way. 9. The method of claim 8,
The light amount control step may include a step of controlling the light amount control unit to obtain the light amount value for each exposure time in the light amount value-brightness value information according to the previously obtained exposure time based on the common brightness value, And adjusting the light amount of the laser light by controlling the light amount adjusting unit such that the light amount of the laser light irradiated through the light source unit differs according to the exposure time. 14. The method according to any one of claims 12 to 13,
Wherein the light amount value is a voltage value corresponding to a rotation angle value or a rotation angle value. A computer program stored in a computer-readable recording medium for causing a computer to execute a method of correcting a multi-exposure laser speckle image pick-up apparatus according to any one of claims 8, 12, 13,

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