KR102108537B1 - Method for adjusting contrast of thermal image and apparatus for using the same - Google Patents

Abstract

The present invention relates to a thermal image contrast ratio adjustment method and a thermal image processing apparatus using the same, using an average minimum value and an average maximum value of continuously input image frames for a predetermined period, as an average minimum value and an average maximum value of all image frames. After updating, by using this to adjust the contrast ratio of the image frame input during the next predetermined section, the user does not feel a large change in brightness of the image even if there is a hot or cold object than the average value, and also, the average minimum value of the histogram of the image and By performing the process of updating the average maximum value while the non-uniformity correction process is being performed, the user does not notice much about this, and thus can be more easily performed during object detection and tracking.

Description

A method for adjusting the contrast ratio of a thermal image and a thermal image processing apparatus using the same {METHOD FOR ADJUSTING CONTRAST OF THERMAL IMAGE AND APPARATUS FOR USING THE SAME}

The present invention relates to a thermal image contrast ratio adjustment method and a thermal image processing apparatus using the same, using an average minimum value and an average maximum value of continuously input image frames for a predetermined period, as an average minimum value and an average maximum value of all image frames. After updating, the present invention relates to a thermal image contrast ratio adjusting method and a thermal image processing apparatus using the thermal image contrast ratio that can adjust the contrast ratio of the input image frame during the next predetermined period.

The contents described in this section merely provide background information for the present embodiment, and do not constitute a prior art.

A camera using a sensor such as a general Charge Coupled Device (CCD) / Complementary Metal-Oxide Semiconductor (CMOS) displays an image based on the reflectance of the subject according to the wavelength when the light source (Source) is radiated to the subject. On the other hand, the thermal imaging camera (Thermal Camera) has a structure that displays the thermal energy emitted by the subject itself as an image. Therefore, there is an advantage in that it is possible to acquire an image even at night when there is no light since no light source is required.

Such thermal imaging cameras are used in various fields. As a representative example, medical / quarantine fields, such as screening high temperature patients by measuring the temperature of immigrants remotely at an airport, ride the temperature of a transformer mounted on a pole on a ground or vehicle There are industrial fields such as determining whether to overheat by measuring long distances while moving, and fields for military / security such as detecting and detecting enemy or abnormal objects in the dark without light.

However, the method using the thermal image sensor to date has a lower resolution than the CCD / CMOS sensor, and there are many non-uniformity between pixels. In addition, because the temperature distribution between the background and the target is large, the dynamic range of the image is wide, resulting in artifacts or unnaturalness when displaying the image. Therefore, in a system using a thermal image sensor, a technique for adjusting the contrast ratio to increase the visibility of the original image is a very important technique that determines the performance of the entire system. In order to adjust the contrast ratio of the thermal image, there are conventional histogram equalization, contrast stretching, and plateau equalization methods, but the conventional method only considers global information of the current frame. The contrast ratio is improved for each frame. This is a problem that it is difficult to apply a real-time system, and there is a problem that, due to excessive enhancement of contrast ratio, artifacts increase and noise amplification increases.

Korean Registered Patent No. 10-1041136, announced on June 14, 2011 (Name: Thermal image processing method)

The present invention has been proposed to solve the above-described conventional problems, and in particular, by updating the average minimum value and average maximum value of all image frames by using the average minimum value and average maximum value of continuously input image frames for a certain period. Thereafter, an object of the present invention is to provide a thermal image contrast ratio adjusting method and a thermal image processing apparatus using the thermal image contrast ratio that can adjust the contrast ratio of the input image frame during the next predetermined period.

However, the object of the present invention is not limited to the above object, and other objects not mentioned will be clearly understood from the following description.

The thermal image processing apparatus according to an embodiment of the present invention for achieving the above object is based on the histogram minimum and maximum values of each image frame continuously input for a certain period, and the image frame input during the predetermined period. A histogram processing unit that calculates an average minimum value and an average maximum value, and then updates the average minimum value and average maximum value of the calculated image frame to a histogram average minimum value and average maximum value of the image; And a contrast ratio processing unit that adjusts the contrast ratio of the input image frame during the next predetermined period by using the histogram average minimum and average maximum values of the image updated through the histogram processing unit.

In this case, a non-uniformity correction unit performing non-uniformity correction on an image frame continuously input for a predetermined period may be further included.

In addition, the histogram processing unit may update the histogram average minimum value and average maximum value of the image while non-uniformity correction is performed on the image frame input during the next predetermined period through the non-uniformity correction unit.

In addition, the histogram processing unit calculates the minimum and maximum values of each histogram for the image frames during the predetermined period in which the non-uniformity is corrected through the non-uniformity correction unit, and based on this, the average minimum value of the image frames input during the predetermined period. And an average maximum value.

A method for adjusting the contrast ratio of a thermal image according to an exemplary embodiment of the present invention for achieving the above object includes: calculating the minimum and maximum histogram values of each image frame continuously input for a predetermined period; Calculating an average minimum value and an average maximum value of the image frames input during the predetermined period, based on the minimum and maximum histogram values of each of the image frames; Updating the average minimum value and the average maximum value of the calculated image frame to an average minimum value and an average maximum value of the histogram of the image; And adjusting the contrast ratio of the input image frame during the next predetermined period by using the histogram average minimum and average maximum values of the updated image.

At this time, the step of updating the histogram average minimum value and average maximum value of the image may be performed while the non-uniformity correction process is performed on the image frame.

In addition, prior to the step of calculating the minimum and maximum values of the histogram, if there is a histogram average minimum and average maximum value of the image, the histogram average minimum value and average maximum value are continuously input for the predetermined period using the histogram average minimum value and average maximum value. And adjusting the contrast ratio of the image frame.

In addition, the present invention can provide a computer-readable recording medium recording a program for executing a thermal image contrast ratio adjustment method according to an embodiment of the present invention as described above.

According to the thermal image contrast ratio adjustment method of the present invention and the thermal image processing apparatus using the same, the image frame inputted in the next predetermined section is adjusted by using the histogram average minimum and average maximum values of the updated image before non-uniformity correction is performed. By doing so, the user does not feel a large change in the brightness of the image even if there is a hot or cold object than the average value. In addition, by performing the process of updating the histogram average minimum value and average maximum value of the image while the non-uniformity correction process is performed, the user does not notice much about this, so that it can be more easily performed during object detection and tracking.

In addition, various effects other than the above-described effects may be directly or implicitly disclosed in a detailed description according to an embodiment of the present invention to be described later.

1 is a diagram schematically illustrating an operation process of a thermal image processing apparatus according to an embodiment of the present invention.
2 is a block diagram showing a main configuration of a thermal image processing apparatus according to an embodiment of the present invention.
3 is a flowchart illustrating a method of adjusting a contrast ratio of a thermal image according to an embodiment of the present invention.
4 to 5 are exemplary views for explaining a video image contrast ratio adjustment method according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail preferred embodiments that can be easily carried out by the person of ordinary skill in the art. However, in the detailed description of the operating principle for the preferred embodiment of the present invention, if it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. This is to more clearly communicate the core of the present invention by omitting unnecessary description. In addition, the present invention can be applied to various changes and can have various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description, but this is not intended to limit the present invention to specific embodiments. It should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In addition, terms including ordinal numbers such as first and second are used to describe various components, and are used only to distinguish one component from other components, and to limit the components It is not used. For example, the second component may be referred to as a first component without departing from the scope of the present invention, and similarly, the first component may also be referred to as a second component.

In addition, when referring to a component being "connected" or "connected" to another component, it means that it can be connected or connected logically or physically. In other words, it may be understood that a component may be directly connected to or connected to other components, but other components may exist in the middle and may be connected or connected indirectly.

In addition, the terms used herein are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In addition, terms such as "comprises" or "have" described herein are intended to designate the existence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, or one or more thereof. It should be understood that the above or other features or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Now, a method for adjusting a contrast ratio of a thermal image according to an embodiment of the present invention and a thermal image processing apparatus using the same will be described in detail with reference to the drawings. At this time, the same reference numerals are used for parts having similar functions and actions throughout the drawings, and duplicate descriptions thereof will be omitted.

1 is a diagram schematically illustrating an operation process of a thermal image processing apparatus according to an embodiment of the present invention.

Referring to FIG. 1, when the image frame is continuously input, the thermal image processing apparatus 100 of the present invention adjusts a contrast ratio for the image frame and outputs an image in which the contrast ratio is adjusted.

At this time, the thermal image processing apparatus 100 may exist in an independent form to receive a thermal image photographed through an external thermal image camera, and exists as a component in the thermal image camera device and is photographed through a thermal image sensor. It can receive and receive a thermal image. For example, the thermal imaging camera may be an infrared camera that senses infrared rays to form an image.

Further, the thermal image processing apparatus 100 may receive and input an image frame transmitted from a separate external device in real time through a communication network (not shown). At this time, the thermal image processing apparatus 100 may include, for example, wireless communication methods such as WLAN (Wireless LAN), Wi-Fi, Wibro, Wimax, HSDPA (High Speed Downlink Packet Access) or Ethernet. (Ethernet), xDSL (ADSL, VDSL), HFC (Hybrid Fiber Coaxial Cable), FTTC (Fiber to The Curb), FTTH (Fiber To The Home), etc. I can receive it. In addition, it is also possible to receive an image frame through a communication network (not shown) according to all other well-known or future types of communication methods.

When such an image frame is received, the thermal image processing apparatus 100 calculates a histogram minimum value and a maximum value of each image frame during a predetermined period, calculates an average minimum value and an average maximum value of the input image frame during a predetermined period, and then The calculated histogram average minimum value and average maximum value are updated to the image histogram average minimum value and average maximum value. And, by adjusting the contrast ratio of the image frame input for the next predetermined period using the histogram average minimum value and average maximum value, and outputting an image frame with the contrast ratio adjusted, an image with improved visibility is provided.

The processor mounted in the thermal image processing apparatus 100 may process program instructions for executing the method according to the present invention. In one implementation, this processor may be a single-threaded processor, and in other implementations, the processor may be a multithreaded processor. Furthermore, the processor can process instructions stored on the storage device 400.

 The main configuration and operation method of the thermal image processing apparatus 100 will be described in more detail with reference to FIG. 2.

2 is a block diagram showing a main configuration of a thermal image processing apparatus according to an embodiment of the present invention.

Prior to description with reference to FIG. 2, the thermal image processing apparatus 100 of the present invention will be described as an example of a device embedded in a module format in a thermal image camera system, but is not limited thereto.

Referring to FIG. 2, the thermal image processing apparatus 100 according to an embodiment of the present invention includes an ADC processing unit 10, a pixel correction processing unit 20, a non-uniformity correction unit 30, a histogram processing unit 40, and a contrast ratio processing unit ( 50).

In more detail for each component, the ADC processing unit 10 first converts the analog image signal output from the thermal image sensor into a digital image signal. At this time, the ADC processor 10 may convert an analog input video signal to a 14-bit or 16-bit digital video signal and output the converted video signal.

The pixel correction processing unit 20 performs a pre-processing process before processing the contrast ratio correction, and in particular, may perform a role of correcting a defective pixel existing in a frame.

The non-uniformity correction unit 30 serves to correct a fixed-type noise pattern (non-uniformity of the image) generated due to the inherent characteristics of the detection sensor. More specifically, a detection sensor capable of detecting a thermal image, such as an infrared detection sensor, does not properly detect an image when a certain period of time passes. In other words, a detection sensor is provided for each pixel, and there are tens of thousands to millions. Each of the detection sensors is provided, but due to a change in the temperature of the sensor itself or the surrounding conditions, the offset of the sensor is changed or a non-uniform correction state occurs. The non-uniformity correction state has a noise form of the final output image. The non-uniformity correction unit 30 serves to correct the image non-uniformity, and the non-uniformity correction is generally performed periodically.

Here, the non-uniformity correction unit 30 may perform non-uniformity correction through various known methods. For example, the non-uniformity correction unit 30 may process the non-uniformity correction using a macroblock-based repetitive padding method, that is, a method of defining values of luminance information and chromaticity information belonging to an area outside the object information. have. Also, the non-uniformity correction unit 30 may process non-uniformity correction based on image processing. That is, non-uniformity correction may be processed according to an algorithm using image registration between adjacent frames. In addition, the image may be output in a freezing state in which the image is stopped for a few seconds while the non-uniformity correction is performed through the non-uniformity correction unit 30.

The histogram processing unit 40 generates a histogram for each image frame subjected to non-uniformity correction processing through the non-uniformity correction unit 30, and calculates a minimum and maximum histogram value for each image frame using the generated histogram. Then, after calculating the average minimum value and the average maximum value of the input image frame for a predetermined period, and updating the average minimum value and average maximum value of the calculated image frame to the histogram average minimum value and average maximum value of the image, updated The histogram average minimum value and average maximum value of the image are transmitted to the contrast ratio processor 50.

At this time, the histogram processing unit 40 according to an embodiment of the present invention updates the average minimum value and average maximum value of the image frames input during the predetermined period to the histogram average minimum value and average maximum value of the image during the next predetermined period The update is performed while the non-uniformity correction process for the frame is being performed.

For example, when the thermal image processing apparatus 100 of the present invention is embedded in a thermal imaging camera that generates 100 frames per second, 100 frames may be received for a certain period (1 second). Then, the histogram processing unit 40 calculates the minimum and maximum histogram values in each image frame of the 100 frames. Then, the histogram processing unit 40 calculates an average minimum value and an average maximum value of the image frames input during the predetermined period, based on the minimum and maximum histogram values of each of the image frames. That is, the minimum and maximum histogram values of frames 1 to 100 are calculated, and the average minimum and average maximum values of the image frame for 1 second can be calculated using the histogram.

Thereafter, the histogram processing unit 40 sets the average minimum value and average maximum value of the image frames in the predetermined period to the average minimum value of the histogram of the image while the non-uniformity correction is performed for the input image frames continuously for the next predetermined period (eg, 1 second). And the average maximum value.

The contrast ratio processing unit 50 may serve to adjust the contrast ratio of the image frame input during the next predetermined period by using the average minimum and maximum histogram values of the image updated through the histogram processing unit 40. In addition, when the contrast ratio processing unit 50 of the present invention has a histogram average minimum value and average maximum value of the image before updating, the contrast ratio of the continuously input image frames during the predetermined period may be adjusted.

The main configuration and operation method of the thermal image processing apparatus 100 according to an embodiment of the present invention has been described above. However, not all of the components illustrated through FIG. 2 are essential components, and the thermal image processing apparatus 100 may be implemented by more components than the components illustrated, and thermal images may be generated by using fewer components. The processing device 100 may be implemented. For example, a storage unit for storing various information calculated by the histogram processing unit 40 of the present invention may be further included, and in addition, various components for thermal image processing may be further included.

In addition, each element constituting the thermal image processing apparatus 100 according to an embodiment of the present invention is arranged according to the flow of the sequence in which the thermal image processing is performed, but it should be noted that the present invention is not limited thereto.

Although the specification and drawings describe exemplary device configurations, the functional operations and subject implementations described herein may be implemented with other types of digital electronic circuits, or the structures disclosed herein and their structural equivalents. It may be implemented in the included computer software, firmware or hardware, or a combination of one or more of them. Implementations of the subject matter described herein are one or more computer program products, that is, one for computer program instructions encoded on a tangible program storage medium to control or thereby execute the operation of a device according to the present invention. It can be implemented as the above modules. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of materials affecting a machine-readable propagated signal, or a combination of one or more of these.

Hereinafter, a method for adjusting the contrast ratio of a thermal image according to an embodiment of the present invention will be described.

3 is a flowchart for explaining a method of adjusting a thermal image contrast ratio according to an embodiment of the present invention, and FIGS. 4 to 5 are exemplary views for explaining a method for adjusting the image image contrast ratio according to an embodiment of the present invention.

First, referring to FIG. 3, in the thermal image contrast ratio adjusting method according to an embodiment of the present invention, when the thermal image processing apparatus 100 first receives an image frame continuously input for a certain period, it is continuously performed for the predetermined period. The histogram minimum and maximum values of each input video frame are calculated (S101). For example, when the thermal image processing apparatus 100 of the present invention is built in a thermal imaging camera that generates 100 frames per second, 100 frames may be received for a certain period (1 second). Then, the histogram minimum and maximum values are calculated in each image frame of 100 frames.

Then, the thermal image processing apparatus 100 calculates an average minimum value and an average maximum value of the image frames input during the predetermined period based on the histogram minimum and maximum values of each of the image frames. That is, the minimum and maximum histogram values of frames 1 to 100 are calculated, and the average minimum and average maximum values of the image frame for 1 second can be calculated using the histogram.

Thereafter, the thermal image processing apparatus 100 displays a histogram of the average minimum value and average maximum value of the image frames in the predetermined period while the non-uniformity correction is performed for the image frames continuously input for the next predetermined period (eg, 1 second). It is updated to the average minimum value and the average maximum value (S105).

Then, using the histogram average minimum value and average maximum value of the updated image, it is used to adjust the contrast ratio for the image frame input in the next predetermined section (S107).

Referring to FIG. 4 as an example, an average minimum value and an average maximum value of the image frame for the first section 500 are calculated using the image frame of the first section 500 after the non-uniformity correction (NUC) process is completed. Then, the thermal image processing apparatus 100 updates the average minimum value and the average maximum value of the image frame for the first section 500 to the histogram average minimum value and average maximum value of the image. During the non-uniformity correction process of the image frame for the second section 520, an update process is performed. Then, the thermal image processing apparatus 100 adjusts the contrast ratio for the second section 520 after the non-uniformity correction process is completed, using the average minimum and maximum histogram values of the updated image. At the same time, the thermal image processing apparatus 100 calculates the average minimum value and average maximum value of the image frame for the second section 520, and inputs the average minimum value and average maximum value of the calculated image frame for the next predetermined period. The histogram average minimum value and average maximum value of the image are updated to be used to adjust the contrast ratio of the image frame. At this time, similarly, processing is performed while non-uniformity correction is performed on the input image frame of the next section.

That is, as shown in FIG. 5A, even when a dynamic region, which is a sudden change region of brightness, occurs while photographing an image using a thermal imaging camera, adjusts the contrast ratio before the non-uniformity correction process is performed. By outputting this, the user can check a clearer thermal image.

In other words, the present invention adjusts the contrast ratio using the histogram average minimum value and average maximum value of the updated image before the non-uniformity correction is performed on the input image frame in the next predetermined section, so that the user has a hot or cold object than the average value. Even if there is, you will not be able to notice the change in brightness of the image greatly. In addition, by performing the process of updating the histogram average minimum value and average maximum value of the image while the non-uniformity correction process is performed, the user does not notice much about this, so that it can be more easily performed during object detection and tracking.

The method for adjusting the contrast ratio of a thermal image according to an embodiment of the present invention has been described above.

The thermal image contrast ratio adjustment method for image recognition of the present invention as described above may be provided in the form of a computer readable medium suitable for storing computer program instructions and data. A program recorded in a recording medium for implementing a shadow removal method for image recognition according to an embodiment of the present invention includes calculating the minimum and maximum histogram values of each image frame continuously input for a predetermined period, and the image frame Calculating the average minimum value and the average maximum value of the image frames input during the predetermined period, based on the minimum and maximum values of each histogram, the average minimum value and average maximum value of the calculated image frame, and the average minimum value of the histogram of the image and Updating to the average maximum value and adjusting the contrast ratio of the input image frame during the next predetermined period using the histogram average minimum and average maximum values of the updated image may be performed.

At this time, the program recorded on the recording medium can be read, installed and executed on a computer to execute the above-described functions.

Here, in order for a computer to read a program recorded on a recording medium and execute functions implemented as a program, the above-described programs are C, C ++, which can be read by a computer's processor (CPU) through a computer's device interface, It may include code coded in a computer language such as JAVA or machine language.

Such code may include a function code related to a function defining functions described above, and the like, and control code related to an execution procedure necessary for a processor of a computer to execute the functions described above according to a predetermined procedure. In addition, the code may further include memory reference-related code as to which location (address address) of the computer's internal or external memory should be referred to additional information or media necessary for the computer's processor to perform the functions described above. . In addition, when the processor of the computer needs to communicate with any other computer or server in the remote in order to execute the above-described functions, the code indicates that the computer's processor is in remote using the computer's communication module. It may further include communication-related codes on how to communicate with other computers or servers, and what information or media should be transmitted / received during communication.

Such computer-readable media suitable for storing computer program instructions and data include, for example, recording media such as hard media, magnetic media such as floppy disks and magnetic tapes (Magnetic Media), and CD-ROM (Compact Disk Read Only Memory). , Optical Media such as DVD (Digital Video Disk), Magnetic-Optical Media such as Floptical Disk, and ROM (Read Only Memory), RAM (RAM) , Random Access Memory, Flash memory, EPROM (Erasable Programmable ROM), and semiconductor memory such as EEPROM (Electrically Erasable Programmable ROM). The processor and memory can be supplemented by, or incorporated into, special-purpose logic circuits.

The computer-readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs for implementing the present invention and related codes and code segments, etc., programmers in the technical field to which the present invention belongs, considering the system environment of a computer that reads a recording medium and executes the program It can be easily inferred or changed by.

This specification includes details of many specific implementations, but these should not be understood as limiting on the scope of any invention or claim, but rather as a description of features that may be specific to a particular embodiment of a particular invention. It should be understood. Certain features that are described in this specification in the context of separate embodiments may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented in multiple embodiments individually or in any suitable subcombination. Further, although features may operate in a particular combination and may be initially depicted as so claimed, one or more features from the claimed combination may in some cases be excluded from the combination, and the claimed combination subcombined. Or sub-combinations.

Likewise, although the operations are depicted in the drawings in a particular order, it should not be understood that such operations should be performed in the particular order shown or in sequential order, or that all shown actions should be performed in order to obtain desirable results. In certain cases, multitasking and parallel processing may be advantageous. In addition, the separation of various system components of the above-described embodiments should not be understood as requiring such separation in all embodiments, and the described program components and systems will generally be integrated together into a single software product or packaged in multiple software products. You should understand that you can.

The present invention relates to a thermal image contrast ratio adjustment method and a thermal image processing apparatus using the same, using an average minimum value and an average maximum value of continuously input image frames for a predetermined period, as an average minimum value and an average maximum value of all image frames. After updating, the present invention relates to a thermal image contrast ratio adjusting method and a thermal image processing apparatus using the thermal image contrast ratio that can adjust the contrast ratio of the input image frame during the next predetermined period.

According to the present invention, by adjusting the contrast ratio using the histogram average minimum value and average maximum value of the updated image, before the non-uniformity correction is performed, the image frame that is input to the next predetermined section is adjusted even if the user has a hot or cold object than the average value. It is possible to output a superior thermal image because the brightness change of the image is not greatly felt. The thermal image contrast ratio adjustment method of the present invention and the thermal image processing apparatus using the same can be applied to various fields such as industrial, military / security applications, and in addition, the present invention is not only sufficient for commercial or commercial possibilities but also realistically implemented To the extent possible, there is industrial applicability.

10: ADC processing unit 20: pixel correction processing unit
30: non-uniformity correction unit 40: histogram processing unit
50; Contrast ratio processing unit

Claims (8)

◈ Claim 1 was abandoned when payment of the registration fee was set.◈ Periodically, after calculating the average minimum value and the average maximum value of the image frames input during the predetermined period, based on the histogram minimum and maximum values of each image frame continuously input for a certain period, and then the average minimum value of the calculated image frame And a histogram processing unit that updates the average maximum value to an average minimum value and an average maximum value of the image. And
A contrast ratio processing unit that adjusts the contrast ratio of the image frames input during the next predetermined period by using the average minimum and maximum histogram values of the image frames continuously input during the previous predetermined period updated through the histogram processing unit;
Thermal image processing apparatus comprising a. ◈ Claim 2 was abandoned when payment of the registration fee was set.◈ According to claim 1,
A non-uniformity correction unit that performs non-uniformity correction on an image frame continuously input for a predetermined period;
Thermal image processing apparatus further comprising a. ◈ Claim 3 was abandoned when payment of the set registration fee was made.◈ According to claim 2,
The histogram processing unit
Thermal image processing apparatus, characterized in that for the non-uniformity correction for the image frame input during the next predetermined period through the non-uniformity correction unit to update the histogram average minimum value and average maximum value of the image. ◈ Claim 4 was abandoned when payment of the set registration fee was made.◈ According to claim 2,
The histogram processing unit
Through the non-uniformity correction unit, the minimum and maximum values of each histogram are calculated for the image frames during the predetermined period in which the non-uniformity is corrected, and based on this, average minimum and average maximum values of the image frames input during the predetermined period are calculated. Thermal image processing apparatus, characterized in that. Periodically calculating a histogram minimum value and a maximum value of each of the image frames continuously input for a predetermined period;
Calculating an average minimum value and an average maximum value of the image frames input during the predetermined period, based on the minimum and maximum histogram values of each of the image frames;
Updating the average minimum value and the average maximum value of the calculated image frame to an average minimum value and an average maximum value of the histogram of the image; And
Adjusting the contrast ratio of the image frames input during the next predetermined period by using the histogram average minimum and average maximum values of the image frames continuously input during the updated previous predetermined period;
Thermal image contrast ratio adjustment method comprising a. The method of claim 5,
The step of updating the histogram average minimum value and average maximum value of the image is
A method of adjusting a contrast ratio of a thermal image, characterized in that it is performed while a non-uniformity correction process is performed on the image frame. The method of claim 5,
Before the step of calculating the minimum and maximum values of the histogram,
When the histogram average minimum value and average maximum value of the image are present,
Adjusting the contrast ratio of the image frames continuously input during the predetermined period using the average minimum value and the average maximum value of the histogram of the image;
Thermal image contrast ratio adjustment method characterized in that it further comprises. A computer-readable recording medium in which a program for executing the thermal image contrast ratio adjustment method according to any one of claims 5 to 7 is recorded.

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