WO2019209025A1

WO2019209025A1 - Method and apparatus for processing defective pixels in infrared thermal detector

Info

Publication number: WO2019209025A1
Application number: PCT/KR2019/004954
Authority: WO
Inventors: 방민석; 용초식; 이용운; 김길영
Original assignee: (주)이오시스템
Priority date: 2018-04-27
Filing date: 2019-04-24
Publication date: 2019-10-31
Also published as: KR101918761B1

Abstract

Provided are a method and an apparatus for processing defective pixels in an infrared thermal detector. Reference temperature source thermal data is acquired for each pixel corresponding to detection elements forming the infrared thermal detector, additional temperature source thermal data is acquired for each pixel, and the reactivity of each pixel is calculated on the basis of the acquired reference temperature source thermal data and the acquired additional temperature source thermal data. In addition, defective pixels are extracted on the basis of the reactivity of each pixel.

Description

Bad pixel processing method and device of infrared thermal detector

The present invention relates to an infrared thermal detector, and more particularly, to a method and apparatus for processing a bad pixel of an infrared thermal detector.

Thermal imaging system is a device that detects inherent radiant energy difference (temperature difference) emitted by an object and a background, and performs imaging through electrical signal processing. Since the energy wavelength band of the electromagnetic wave radiated by an object is mostly an infrared region, an infrared thermal detector which converts infrared rays radiated from an object with heat into an electrical signal is used. As an infrared thermal detector, a detector in the form of a read-out integrated circuit (ROIC), in which a number of detection elements are connected in a two-dimensional array such as an image sensor, is generally used.

Infrared thermal detectors are easy to acquire images even in the absence of light, so military surveillance equipment (night vision, observation glasses, etc.), fire control devices (scopes of sight, etc.), night surveillance, non-destructive testing or medical diagnosis of active electronic systems It is used for a purpose.

On the other hand, infrared thermal detectors may partially have defective pixels that do not operate normally due to manufacturing process problems. However, treating them as defective products can increase the manufacturing cost, and therefore, detector manufacturers generally have problems with distribution of defective pixels. According to the classification of the detector is supplied.

Since the bad pixels appear in the form of dots on the screen, the visibility of the thermal image is directly lowered. In particular, since the general infrared detector is not high resolution, if a bad pixel is present, even if it is a small number, it can greatly affect the quality of the thermal image. Therefore, in using an infrared thermal detector, there is a need for a signal processing technique that accurately determines a position of a bad pixel and replaces the value of the bad pixel by using a normal pixel nearby.

There is a method of using an image processing technique to correct defective pixels in an operating environment. One of them is a method using median filtering, which can effectively process bad pixels, but has a disadvantage of blurring the image as a whole. As another method, there is a method of determining a bad pixel by extracting feature information from an image coming into the input, but this may cause a problem of false positive due to complicated processing and incorrectly determining a normal pixel as a bad pixel. Since this can cause a big problem in the exhibition situation, a method of accurately extracting defective pixels is required.

Related prior arts include "pixel correction apparatus and method of a thermal image detector" disclosed in Korean Patent No. 1007405.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus capable of accurately detecting and processing a bad pixel in an infrared thermal detector without using additional equipment.

A method according to an aspect of the present invention includes a method of processing a bad pixel of an infrared thermal detector, comprising: obtaining, by an apparatus, reference temperature source thermal image data for each pixel corresponding to the detection elements constituting the infrared thermal detector; Acquiring, by the device, additional temperature source thermal image data for each pixel; Calculating, by the device, reactivity for each pixel based on reference temperature source thermal image data and additional temperature source thermal image data acquired for each pixel; And extracting, by the device, a bad pixel based on the reactivity of each pixel.

The calculating of the responsiveness for each pixel may include calculating the responsiveness based on an absolute value of a pixel-to-pixel difference between the reference temperature source thermal image data and the additional temperature source thermal image data.

The reference temperature source thermal image data is thermal image data obtained through the infrared thermal image detector in a state where the infrared thermal image detector is covered by a blocking member including a palm or a shutter, and the additional temperature source thermal image data includes a background as a detection target. And thermal image data obtained through the infrared thermal detector.

On the other hand, the reference temperature source thermal image data is thermal image data acquired through the infrared thermal detector with a first background as a detection target, and the additional temperature source thermal image data is a target for detection of a second background different from the first background. The thermal image data may be obtained through the infrared thermal detector.

At least one of the reference temperature source thermal image data and the additional temperature source thermal image data may be thermal image data accumulated in a temporal manner.

The thermal data accumulated over time is,

Where I (n; x, y) is thermal image data obtained by accumulating the output for each pixel (x, y) for n frames, and V denotes the output of the pixel. Indicates the weight.

The extracting of the defective pixels may include calculating an absolute value of a difference between the responsiveness of the current pixel and the responsiveness of the neighboring pixels to determine whether the defective pixel is a bad pixel; Comparing the absolute value with a preset threshold; And determining that the current pixel is a bad pixel when the absolute value is greater than the threshold.

The threshold value may be set based on a difference between an average value of reference temperature source thermal image data for each pixel and an average value of additional temperature source thermal image data for each pixel.

The extracting of the defective pixel may include obtaining an average of responsiveness with respect to neighboring pixels of the current pixel to determine whether the defective pixel; Calculating an absolute value of a difference between an average of the reactivity of the current pixel and the reactivity of the neighboring pixels; Comparing the absolute value with a preset setting value; And determining that the current pixel is a bad pixel when the absolute value is greater than the set value.

The set value may be a value set based on a standard deviation of responsiveness of the surrounding pixels and a sensitivity for determining a sensitivity of a bad pixel.

The method may further include, after the extracting of the defective pixel, replacing the defective pixel by using a surrounding normal pixel.

The acquiring of the reference temperature source thermal image data and the acquiring of the additional temperature source thermal image data may include the reference temperature source thermal image data and the additional temperature source thermal image data, respectively, while the equipment to which the infrared thermal image detector is applied moves. Can be obtained.

The step of calculating the reactivity for each pixel and extracting the defective pixel may be performed when a difference between the average value of the obtained reference temperature source thermal image data and the average value of the additional temperature source thermal image data is greater than or equal to a preset value. Can be.

According to another aspect of the present invention, there is provided an apparatus for processing a bad pixel of an infrared thermal detector, comprising: an input / output unit configured to receive data acquired for each pixel corresponding to detection elements constituting the infrared thermal detector; And a processor connected to the input / output unit and configured to process defective pixels of the infrared thermal detector based on the input data, wherein the processor includes reference temperature source thermal image data and additional temperature for each pixel based on the input data. Acquiring original thermal image data, calculating reactivity of each pixel based on the reference temperature source thermal image data and the additional temperature source thermal image data, and extracting a defective pixel based on the reactivity of each pixel.

The processor may be configured to calculate the reactivity based on an absolute value of a difference between the reference temperature source thermal image data and the additional temperature source thermal image data.

The reference temperature source thermal image data is thermal image data obtained through the infrared thermal detector in a state where the infrared thermal detector is covered with a palm or a shutter, and the additional temperature source thermal image data is the infrared thermal detector with a background as a detection object. Or the reference temperature source thermal image data is thermal image data obtained through the infrared thermal detector using a first background as a detection target, and the additional temperature source thermal image data is different from the first background. The image may be thermal image data obtained through the infrared thermal detector using a second background as a detection object.

At least one of the reference temperature source thermal image data and the additional temperature source thermal image data may be thermal image data accumulated in time, and the thermal image data accumulated in time may be

Acquired based on the condition of, I (n; x, y) is the thermal image data accumulated for n frames of the output for each pixel (x, y), V denotes the output of the pixel, a is a weight Indicates.

The processor may further include: a first method of determining that the current pixel is a bad pixel when an absolute value of a difference between a responsiveness of a current pixel and a reactivity of a neighboring pixel to determine whether the bad pixel is greater than a preset threshold; and A second method of determining that the current pixel is a bad pixel when the absolute value of the difference between the average of the reactivity of the neighboring pixels of the current pixel and the reactivity of the current pixel for determining whether the defective pixel is larger than a preset setting value. It may be configured to extract a bad pixel based on one of the methods.

The apparatus may further include a memory configured to store the result of the bad pixel extraction by the processor for each pixel. In this case, the processor may be configured to replace the defective pixel by using the normal pixel around the pixel extracted as the defective pixel based on the extraction result stored in the memory.

According to an embodiment of the present invention, the defective pixel of the infrared thermal detector used in thermal imaging equipment can be easily detected without using a separate equipment such as a black body. In particular, in the environment in which the infrared thermal detector is operated, a bad pixel can be easily detected and the detected bad pixel can be corrected.

1 is an exemplary view showing an image of a reactivity calculated using a reference temperature source and an additional temperature source in an embodiment of the present invention.

2 is a diagram illustrating a bad pixel and a neighboring pixel according to an exemplary embodiment of the present invention.

3 is another exemplary view illustrating a bad pixel and a neighboring pixel according to an exemplary embodiment of the present invention.

4 is a flowchart illustrating a bad pixel processing method according to an exemplary embodiment of the present invention.

5 is a structural diagram of a bad pixel processing apparatus according to an exemplary embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

Hereinafter, a method and apparatus for processing a bad pixel of an infrared thermal detector according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

An infrared thermal detector used in thermal imaging equipment has a structure in which a plurality of detection elements are connected in a two-dimensional array such as an image sensor, and the detection elements convert an optical signal including infrared rays into an electrical signal and output the electrical signal. The output of this infrared thermal detector depends on the intensity of the infrared light, ie the temperature emitted by the object. The signal obtained by each detection element may be referred to as "thermal data".

In order to determine whether there are defective pixels, the reactivity R for the infrared thermal detector may be used, and the reactivity R may be expressed as follows.

Here, (x, y) represents the position of each pixel (detection element), V represents the output of each pixel, and t represents the temperature. In particular, V _H represents the output at high temperature (H), and V _C represents the output at low temperature (C).

Based on the response R of any pixel of the infrared thermal detector calculated based on Equation 1 above, it may be determined whether the pixel is a bad pixel.

E.g,

In this case, it is determined that the pixel is a bad pixel due to disconnection. In addition, when the reactivity of the pixel is significantly smaller than the reference value T (

Or if the responsiveness of the pixel is significantly greater than the reference value (

), It is determined that the detection element is a bad pixel.

In order to obtain the reactivity of each pixel, a temperature source capable of producing high temperature (H) and low temperature (C) is required, and a black body is generally used. Blackbody is a special equipment that can generate the desired temperature source and can be used to calibrate the infrared thermal detector, but it is inconvenient to carry and is used only in the process of manufacturing thermal equipment.

However, devices that may be impacted from the outside, such as sights and portable observation mirrors used in the military, may generate additional bad pixels due to external impacts during the operation of the equipment even if bad pixels are extracted in the manufacturing process. Therefore, there is a need for a function that allows a user to correct defective pixels without using special equipment in an operating environment.

The main reason for the generation of defective pixels is that the IR thermal detector has an irregular response due to temperature change. Therefore, in order to effectively extract the defective pixels, the IR thermal detector has to use the reactivity.

In an exemplary embodiment of the present invention, a defective pixel is accurately detected and corrected by calculating a reactivity of an infrared thermal detector without special equipment in an environment where a user operates the thermal imaging equipment.

To this end, in the embodiment of the present invention, in calculating the reactivity of the infrared thermal detector, two temperature sources, that is, a reference temperature source and an additional temperature source, are used. Reactivity is calculated using thermal image data for the additional temperature source (named "additional temperature source thermal image" for convenience of explanation)) and thermal image data for the additional temperature source.

Infrared thermal detector may have uneven output of infrared thermal detector because the response of each pixel is different according to the change of ambient temperature. Correct it. In order to perform non-uniformity correction, a uniform temperature source must be supplied in front of the infrared thermal detector. To do this, portable thermal equipment such as sights and observation mirrors with infrared thermal detectors cover the front of the lens with a palm or use a shutter embedded in the thermal equipment. Human palms that can be used for non-uniformity correction have a constant temperature by body temperature. In addition, the shutter has a constant temperature by conduction of heat generated therein while the thermal imaging device is driven. Therefore, a temperature source (such as a human palm or a shutter) used to perform non-uniformity correction can be used as one temperature source necessary for calculating the reactivity of the infrared thermal detector.

In an embodiment of the present invention, a temperature source used to perform non-uniformity correction is used as a reference temperature source, but is not necessarily limited thereto. Uniform thermal data (which may be thermal data used for non-uniformity correction) acquired through the infrared thermal detector while the infrared thermal detector is covered using a human palm or shutter, which is a temperature source used to perform non-uniformity correction, Used as reference temperature source thermal image data. The means for screening the infrared thermal detector may be referred to as a blocking member, and the blocking member may include other means besides a palm or a shutter.

Since the environmental temperature at which the thermal imaging equipment to which the infrared thermal detector is applied is different from the human body temperature or the internal temperature of the thermal imaging equipment, the scene includes a temperature source different from the reference temperature source. In an embodiment of the present invention, the thermal image data included in the background information is used as an additional temperature source. The thermal image data obtained through the infrared thermal detector with the background as a detection object while the infrared thermal detector is not covered by a palm or a shutter is used as the additional temperature source thermal image data.

In an embodiment of the present invention, thermal image data for calculating reactivity is obtained using thermal image data accumulated during a set time.

The formula for accumulating thermal data in time is as follows.

Here, I (n; x, y) represents the result of accumulating the output for each pixel (x, y) for n frames, and V represents thermal data coming into the current input as the output of the pixel. In addition, a represents a weight for the input, which is a coefficient for suppressing unnecessary input. Meanwhile, when acquiring reference temperature source thermal image data, the cumulative result may be used during the setting frame based on Equation 2 above.

Based on Equation 2, the thermal image data acquired through the infrared thermal detector is accumulated in time with the background as a detection object, thereby obtaining additional temperature source thermal image data.

In the exemplary embodiment of the present invention, the reference temperature source thermal image data is selectively based on Equation 2, and data obtained by temporally accumulating thermal data acquired through the infrared thermal detector while covering the infrared thermal detector using a human palm or a shutter. May be used as reference temperature source thermal image data.

In an exemplary embodiment of the present invention, the reactivity of each pixel is obtained by using the reference temperature source thermal image data and the additional temperature source thermal image data acquired for each pixel. In an embodiment of the present invention, the reactivity of each pixel of the infrared thermal detector, which is used for determining a bad pixel, may be calculated according to the following equation.

Here, I _R represents reference temperature source thermal image data, and I _S represents additional temperature source thermal image data.

The reactivity R (x, y) of an arbitrary pixel (x, y) according to an exemplary embodiment of the present invention is based on the reference temperature source thermal image data I _R (x, y) and the additional temperature source thermal image data I for the pixel. Calculated based on the difference of _S (x, y)). Since the absolute value is taken in the calculation result, the order in which the reference temperature source thermal image data and the additional temperature source thermal image data are input in the reactivity calculation is not significant.

On the other hand, since the background information includes various temperature sources, when a temperature source similar to the reference temperature source is included, a problem may occur when determining a bad pixel thereafter. Since the responsiveness determines that the pixel having a sharp difference from the surrounding pixels is a bad pixel, when using background information without motion, the normal pixel may be misjudged in a portion having an edge or a rough texture. . Accordingly, in an exemplary embodiment of the present invention, thermal data is obtained while moving thermal equipment so that various temperature sources can be evenly mixed. However, the present invention is not necessarily limited thereto.

In detail, FIG. 1 is an image of a reactivity calculated using reference temperature source thermal image data obtained by using a palm and additional temperature source image data, which is thermal image data (temporal accumulated thermal image data) acquired outdoors in the background.

As shown in (a) of FIG. 1, strong edge components are generated by various objects when there is no movement of the thermal equipment, whereas when there is movement of the thermal equipment as shown in FIG. Thermal image data may become information that is easy to detect a bad pixel because the edge portion is blurred.

Therefore, in the embodiment of the present invention, the additional temperature source thermal image data is obtained while the thermal image equipment is moved. To this end, a method of controlling a separate button on the thermal device may be used, or a motion sensor or a motion determination algorithm in an image may be used. For example, the additional temperature source thermal data may be acquired when a separate button is operated, or the additional temperature source thermal data may be obtained when the thermal equipment is determined to be moved using a motion sensor or a motion determination algorithm. can do.

Meanwhile, in the exemplary embodiment of the present invention, reference temperature source thermal image data is obtained by using a temperature source used to perform non-uniformity correction as a reference temperature source, but a temperature source (for example, a palm or a shutter for performing non-uniformity correction) is obtained. Etc.), the reference temperature source thermal image data can be obtained using the background information. In this case, the obtained background information should have a temperature source different from the background information of the additional temperature source. For example, using the thermal image data acquired through the infrared thermal detector as a reference temperature source thermal image data using the first background (for example, indoor) as a detection target, and detecting the second background (for example, outdoor). The thermal image data obtained through the infrared thermal detector as an object is used as the additional temperature source thermal image data. In this case, the reference temperature source thermal data may be obtained by moving the thermal equipment as well as the additional temperature source thermal data.

In an embodiment of the present invention, the reference temperature source thermal image data and the additional temperature source thermal image data may be analyzed to extract defective pixels when the temperature difference is greater than or equal to a threshold value.

As described above, the defective pixel is extracted using the reactivity calculated based on the reference temperature source thermal image data and the additional temperature source thermal image data obtained through various methods. For example, when the difference between the average value of the reference temperature source thermal image data for each pixel and the average value of the additional temperature source thermal image data for each pixel is greater than or equal to a set value, the bad pixel processing method according to an exemplary embodiment of the present disclosure may be performed.

On the other hand, the conventional method using a black body was a method of extracting a pixel having a special response by using a distribution of reactivity for all the pixels because a temperature source having a uniform output is used.

Since the embodiment uses background information, as illustrated in FIG. 1, non-uniform thermal data may be received as an input. Therefore, since it is difficult to determine the presence or absence of defective pixels based on the distribution of all pixels, the defective pixels are determined using the surrounding pixels.

The hatched pixels around the bad pixels are peripheral pixels used for bad pixel extraction. The peripheral pixels are not limited to the range as illustrated in FIG. 2. In an exemplary embodiment of the present invention, in consideration of an increase in the amount of calculation, an example of using pixels positioned up, down, left, and right around a certain pixel as a peripheral pixel will be described.

According to an exemplary embodiment of the present invention, whether an arbitrary pixel is a bad pixel is determined based on whether an absolute value of the difference between the reactivity of an arbitrary pixel and the reactivity of an adjacent pixel exceeds a preset threshold. To this end, the following equation may be used.

Here, p represents the responsiveness of the current pixel to determine the bad pixel, p 'represents the responsiveness of the surrounding pixels. The reactivity is a reactivity calculated based on Equation 3 based on the reference temperature source thermal image data and the additional temperature source thermal image data.

map (x, y) is an array for recording the presence or absence of bad pixels, and can be designated to display 1 for bad pixels and 0 for normal pixels. Based on Equation 4, when the absolute value of the difference between the responsiveness of the current pixel and the responsiveness of the surrounding pixels is larger than the preset threshold T, the current pixel is determined to be a bad pixel, and map (x, y) is equal to "1". Has a value. If the absolute value of the difference between the responsiveness of the current pixel and the responsiveness of the surrounding pixels is less than or equal to the preset threshold T, the current pixel is determined to be a normal pixel, and map (x, y) has a value of "0".

Here, the threshold T may be a fixed value or may be an adaptively variable value. For example, the difference between the average value of the reference temperature source thermal image data for each pixel and the average value of the additional temperature source thermal image data for each pixel may be set as a threshold value T. In this case, the threshold may be adaptively set according to the operating environment.

As another example, the defective pixel may be determined using the average and the standard deviation of the surrounding pixels.

Here, the peripheral pixels may be pixels as shown in FIG. 3.

In order to determine a bad pixel, the following equation may be used.

Where m represents the average of the reactivity of the surrounding pixels, and σ represents the standard deviation of the reactivity of the surrounding pixels. α represents a constant for adjusting the sensitivity of the bad pixel judgment. For convenience of explanation

"Is called the setpoint based on the standard deviation.

Based on Equation 5, the absolute value of the difference between the average of the responsiveness of the current pixel and the responsiveness of the surrounding pixels is set based on the standard deviation of the responsiveness of the surrounding pixels.

Greater than), the current pixel is determined to be a bad pixel and map (x, y) has a value of "1". The absolute value of the difference between the average of the responsiveness of the current pixel and the responsiveness of the surrounding pixels is determined based on the standard deviation of the responsiveness of the surrounding pixels.

If less than or equal to), the current pixel is determined to be a normal pixel, and map (x, y) has a value of "0".

Here, the peripheral pixels represent pixels that came in ahead of the current pixel in a real-time processing system that processes data sequentially, as illustrated in FIG. 3, but is not limited thereto. As illustrated in FIG. The pixels may be positioned up, down, left, and right.

As described above, the defective pixels are extracted using the reactivity calculated based on the reference temperature source thermal image data and the additional temperature source thermal image data.

When the extraction of the defective pixels is completed, the positions of the defective pixels may be stored in a memory, and the incoming pixels may be replaced with the normal pixels by using normal pixels nearby. In general, the replacement of the bad pixel may be performed by using an average of surrounding normal pixels or by copying a representative value of the surroundings as it is.

As shown in FIG. 4, according to an exemplary embodiment of the present invention, thermal images of a reference temperature source are obtained for each pixel corresponding to the detection elements of the infrared thermal detector, and thermal data of an additional temperature source is obtained. (S100, S110). As described above, for example, thermal image data inputted to the infrared thermal detector while the infrared thermal detector is covered with a palm or a shutter is processed to obtain reference temperature source thermal data. The thermal image data acquired through the infrared thermal detector is accumulated in time with the background as a detection object to obtain additional temperature source thermal image data.

Next, the reactivity for each pixel is calculated based on the reference temperature source thermal image data and the additional temperature source thermal image data acquired for each pixel (S120). The reactivity for each pixel is an absolute value of the difference between the reference temperature source thermal image data and the additional temperature source thermal image data, based on Equation (3).

The defective pixel is extracted using the pixel-by-pixel reactivity (S130). At the time of extracting the defective pixels, the absolute value of the difference between the reactivity of the current pixel and the reactivity of the neighboring pixel for determining whether the defective pixel is determined according to the first determination method is compared, and the current value is obtained when the absolute value of the difference is larger than the threshold value. It is determined that the pixel is a bad pixel. Alternatively, according to the second determination method, the absolute value of the difference between the average of the responsiveness of the current pixel and the responsiveness of the neighboring pixels may be set based on the standard deviation of the responsiveness of the peripheral pixels (

), And the absolute value of the difference is based on the standard deviation of the

If greater than), it is determined that the current pixel is a bad pixel.

A process is performed on the pixel determined to be a bad pixel (S140). For example, the defective pixels may be replaced by the surrounding normal pixels for data received through the infrared thermal detector. For example, the value of the bad pixel may be replaced with the average value of the normal pixels in the periphery of the bad pixel, or the representative value of the normal pixels in the periphery.

As shown in FIG. 5, the bad pixel processing apparatus 100 according to an exemplary embodiment of the present invention includes a processor 110, a memory 120, and an input / output unit 130.

The processor 110 may be configured to implement the methods described with reference to FIGS. 1 through 4 above. For example, the processor 110 may acquire thermal image data for a reference temperature source and acquire thermal image data for an additional temperature source for each pixel corresponding to the detection elements of the infrared thermal detector. A reactivity calculation processor configured to calculate reactivity for each pixel based on reference temperature source thermal image data and additional temperature source thermal image data acquired for each pixel; a bad pixel extraction processor configured to extract bad pixels using pixel reactivity; It may include a bad pixel processing unit configured to perform a process for the pixel.

The memory 120 is connected to the processor 110 and stores various information related to the operation of the processor 110. The memory 120 may store instructions for execution in the processor 110 or temporarily load the instructions from a storage device (not shown). The processor 110 may execute instructions stored or loaded in the memory 120. The processor 110 and the memory 120 may be connected to each other through a bus (not shown), and an input / output interface (not shown) may also be connected to the bus. In addition, the memory 120 may be configured to store a result (eg, map (x, y)) of determining whether the pixel is a bad pixel.

The input / output unit 130 is configured to provide data output from the infrared thermal detector to the processor 110, and is configured to output a processing result of the processor 110. The input / output unit 130 may be configured to process an analog signal output from the infrared thermal detector and provide data corresponding to the digital signal to the processor 110.

In addition, the input / output unit 130 may be configured to provide an input signal to the processor 110 according to an operation of a separate button installed in the thermal imaging apparatus to which the bad pixel processing apparatus according to the embodiment of the present invention is applied. In addition, the input / output unit 130 may include a motion sensor or may be configured to provide a signal from the motion sensor to the processor 110. In this case, when the signal according to the operation of the button provided through the input / output unit 130 or a signal from the motion sensor is input, the processor 110 determines that the device to which the infrared thermal detector is applied is moved based on the corresponding signal. Can be configured to perform bad pixel extraction and processing as described above.

The above-described embodiments of the present invention are not implemented only through an apparatus (object) and a method, but a program capable of executing a function corresponding to the configuration of the method according to an embodiment of the present invention or a computer on which the program is recorded. It can also be implemented through a recording medium that can be read, such an implementation can be easily implemented by those skilled in the art from the description of the embodiments described above.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims

A method of processing a bad pixel of an infrared thermal detector,

Obtaining, by the device, reference temperature source thermal image data for each pixel corresponding to the detection elements constituting the infrared thermal detector;

Acquiring, by the device, additional temperature source thermal image data for each pixel;

Calculating, by the device, reactivity for each pixel based on reference temperature source thermal image data and additional temperature source thermal image data acquired for each pixel; And

Extracting, by the device, a bad pixel based on the reactivity of each pixel

Processing method comprising a.
The method of claim 1,

Calculating the reactivity for each pixel,

And calculating the reactivity based on the absolute value of the pixel-to-pixel difference between the reference temperature source thermal image data and the additional temperature source thermal image data.
The method of claim 1,

The reference temperature source thermal image data is thermal image data obtained through the infrared thermal detector while the infrared thermal detector is covered with a blocking member including a palm or a shutter.

And the additional temperature source thermal image data is thermal image data obtained through the infrared thermal detector with a background as a detection object.
The method of claim 1,

The reference temperature source thermal image data is thermal image data obtained through the infrared thermal detector using a first background as a detection target,

And the additional temperature source thermal image data is thermal image data obtained through the infrared thermal detector using a second background different from the first background as a detection target.
The method of claim 3,

And at least one of the reference temperature source thermal image data and the additional temperature source thermal image data is thermal image data accumulated in time.
The method of claim 5,

The thermal data accumulated over time is,

Acquired based on the condition of, I (n; x, y) is the thermal image data accumulated for n frames of the output for each pixel (x, y), V denotes the output of the pixel, a is a weight Indication method.
The method of claim 1,

Extracting the bad pixel,

Calculating an absolute value of a difference between a responsiveness of a current pixel and a responsiveness of a neighboring pixel for determining whether a defective pixel is present;

Comparing the absolute value with a preset threshold; And

Determining that the current pixel is a bad pixel when the absolute value is greater than the threshold value

Including, the processing method.
The method of claim 7, wherein

And the threshold is set based on a difference between an average value of reference temperature source thermal image data for each pixel and an average value of additional temperature source thermal image data for each pixel.
The method of claim 1,

Extracting the bad pixel,

Obtaining an average of responsiveness with respect to neighboring pixels of the current pixel to determine whether the pixel is a bad pixel;

Calculating an absolute value of a difference between an average of the reactivity of the current pixel and the reactivity of the neighboring pixels;

Comparing the absolute value with a preset setting value; And

Determining that the current pixel is a bad pixel when the absolute value is greater than the set value.

Including, the processing method.
The method of claim 9,

And the set value is a value set based on a standard deviation of responsiveness of the peripheral pixels and a sensitivity for adjusting a sensitivity of bad pixel determination.
The method of claim 1,

After extracting the bad pixel,

Replacing the defective pixel by using the surrounding normal pixel

Processing method further comprising.
The method of claim 1,

The acquiring of the reference temperature source thermal image data and the acquiring of the additional temperature source thermal image data may include the reference temperature source thermal image data and the additional temperature source thermal image data, respectively, while the equipment to which the infrared thermal detector is applied moves. Acquisition method.
The method of claim 1,

The step of calculating the reactivity for each pixel and extracting the defective pixel are performed when a difference between the average value of the obtained reference temperature source thermal image data and the average value of the additional temperature source thermal image data is greater than or equal to a preset value. Way.
A device for processing defective pixels of an infrared thermal detector,

An input / output unit configured to receive data acquired for each pixel corresponding to the detection elements of the infrared thermal detector; And

A processor connected to the input / output unit and configured to process bad pixels of the infrared thermal detector based on the input data

Including;

The processor acquires reference temperature source thermal image data and additional temperature source thermal image data for each pixel based on the input data, calculates reactivity for each pixel based on the reference temperature source thermal image data and the additional temperature source thermal image data, And extract the defective pixel based on the star reactivity.
The method of claim 14,

And the processor is configured to calculate the reactivity based on an absolute value of a difference between the reference temperature source thermal image data and the additional temperature source thermal image data.
The method of claim 14,

The reference temperature source thermal image data is thermal image data obtained through the infrared thermal image detector while the infrared thermal image detector is covered with a palm or a shutter, and the additional temperature source thermal image data is a infrared ray thermal detector with a background as a detection object. Thermal data obtained through

The reference temperature source thermal image data is thermal image data obtained through the infrared thermal detector using a first background as a detection target, and the additional temperature source thermal image data is a detection target based on a second background different from the first background. And thermal image data obtained through the infrared thermal detector.
The method of claim 16,

At least one of the reference temperature source thermal image data and the additional temperature source thermal image data is thermal image data accumulated in time.

The thermal data accumulated over time is,

Acquired based on the condition of, I (n; x, y) is the thermal image data accumulated for n frames of the output for each pixel (x, y), V denotes the output of the pixel, a is a weight Indicating processing apparatus.
The method of claim 14,

The processor,

A first method of determining that the current pixel is a bad pixel when an absolute value of a difference between a responsiveness of a current pixel and a reactivity of a neighboring pixel for determining whether a bad pixel is greater than a preset threshold; and

A second pixel that determines that the current pixel is a bad pixel when an absolute value of a difference between an average of reactivity of the neighboring pixels of the current pixel and a current reactivity of the current pixel for determining whether the defective pixel is greater than a preset value; Way

And extract the defective pixel based on the method of one of the following.
The method of claim 14,

The apparatus may further include a memory configured to store the result of the bad pixel extraction by the processor for each pixel.

And the processor is configured to replace the defective pixel using a normal pixel around the pixel extracted as the defective pixel based on the extraction result stored in the memory.