A method and device for dynamic infrared image detail enhancement

Abstract

The present invention discloses a method and device for dynamic infrared image detail enhancement. The method comprises: calculating attribute values of all frame images in an infrared image sequence, the attribute values including window width and window level values, defining the attribute values of the first frame image in the infrared image sequence as initial attribute values; and correcting the attribute values of the frame images based on the difference between the attribute values of the frame images and the initial attribute values. By adopting the technical solution of the present invention, the window width and window level values of other frames in the infrared image sequence are corrected based on the difference between the window width and window level values of the other frames and the window width and window level values of the first frame infrared image. This can solve the problem of overexposure caused by large changes in the infrared image scene and achieve the effect of enhancing the details of the infrared image sequence.

Description

Technical Field

[0001] The present invention relates to the field of infrared image processing, and in particular to a method and device for dynamic infrared image detail enhancement. Background Art

[0002] Infrared target detection technology mainly uses the difference in infrared radiation between the background and the target to detect the target. An important measurement indicator of infrared target detection technology is the ability to detect small and weak targets. When the distance between the target to be detected and the detector is far, the spectral energy of the target is transmitted through the atmosphere. Under the influence of atmospheric disturbances, optical scattering and diffraction, the spectral irradiance of the target that can be received by the detector target surface is very small, resulting in a very low signal-to-noise ratio of the target. At the same time, the area of the distant target in the infrared image is very small, and the grayscale value is very different from the surrounding imaging pixels. Even using manual detection methods based on contrast adjustment and histogram equalization, it is difficult to extract distant and small targets from the background. In addition, the detection accuracy manually achieved by the annotator will affect the accuracy of a series of subsequent technologies. Histogram equalization is limited to the overall grayscale distribution of the image and cannot achieve the effect of enhancing specific details. Summary of the Invention

[0003] The present invention provides a method and device for dynamic infrared image detail enhancement, which are used to at least solve the problem in the prior art that detail enhancement of infrared images cannot be achieved.

[0004] A first embodiment of the present invention provides a method for enhancing details of a dynamic infrared image, comprising:

[0005] Calculating attribute values of all frame images in the infrared image sequence, the attribute values including window width and window level, and defining the attribute value of the first frame image in the infrared image sequence as an initial attribute value;

[0006] The attribute value of the frame image is corrected based on the difference between the attribute value of the frame image and the initial attribute value.

[0007] According to some embodiments of the present invention, the method further comprises: performing a secondary adjustment on the attribute value of the frame image based on the corrected attribute value and according to an adjustment strategy;

[0008] The adjustment strategies include:

[0009] When the corrected attribute value satisfies: and , adjusting the corrected attribute value to a preset attribute value;

[0010] When the corrected attribute value satisfies: and when l<Max, the window width value in the modified attribute value is adjusted to w=2(Max-l);

[0011] When the corrected attribute value satisfies: When l>Min, the window width value in the modified attribute value is adjusted to w=2(l-Min);

[0012] Where w represents the window width, l represents the window level, Max represents the maximum grayscale value of the infrared image sequence, and Min represents the minimum grayscale value of the infrared image sequence.

[0013] According to some embodiments of the present invention, the secondary adjustment of the attribute value of the frame image based on the corrected attribute value and according to the adjustment strategy includes:

[0014] Based on the corrected attribute value, grayscale stretching is performed on the frame image;

[0015] Displaying the frame image after grayscale stretching;

[0016] A secondary adjustment of the attribute value is completed on the displayed frame image.

[0017] According to some embodiments of the present invention, grayscale stretching is performed on the frame image based on the following formula:

[0018]

[0019] Among them, Ho represents the grayscale value after stretching, Hi represents the original grayscale value, A and B represent the end values of the grayscale stretching range, and A<B.

[0020] According to some embodiments of the present invention, the range of the grayscale stretching [A, B] is [0, 255].

[0021] According to some embodiments of the present invention, including:

[0022] a calculation unit, configured to calculate attribute values of all frame images in an infrared image sequence, wherein the attribute values include a window width value and a window level value, and define the attribute value of the first frame image in the infrared image sequence as an initial attribute value;

[0023] The first correction unit is configured to correct the attribute value of the frame image based on a difference between the attribute value of the frame image and the initial attribute value.

[0024] According to some embodiments of the present invention, the apparatus further comprises a second correction unit configured to perform a second adjustment on the attribute value of the frame image based on the corrected attribute value and in accordance with an adjustment strategy;

[0025] The adjustment strategies include:

[0026] When the corrected attribute value satisfies: and , updating the corrected attribute value to the preset attribute value;

[0027] When the corrected attribute value satisfies: When l<Max, the window level value does not change, and the window width value is adjusted to w=2(Max-l);

[0028] When the corrected attribute value satisfies: And l≥Max, or And when l≤Min, the window width value and the window level value are no longer adjusted;

[0029] When the corrected attribute value satisfies: When l>Min, the window level value does not change, and the window width value is adjusted to w=2(l-Min);

[0030] Where w represents the window width, l represents the window level, Max represents the maximum grayscale value of the infrared image sequence, and Min represents the minimum grayscale value of the infrared image sequence.

[0031] According to some embodiments of the present invention, the secondary adjustment of the attribute value of the frame image based on the corrected attribute value and according to the adjustment strategy includes:

[0032] Based on the corrected attribute value, grayscale stretching is performed on the frame image;

[0033] Displaying the frame image after grayscale stretching;

[0034] A secondary adjustment of the attribute value is completed on the displayed frame image.

[0035] According to some embodiments of the present invention, grayscale stretching is performed on the frame image based on the following formula:

[0036]

[0037] Wherein, Ho represents the grayscale value after stretching, Hi represents the original grayscale value of the infrared image, A and B represent the end values of the grayscale stretching range, and A<B.

[0038] According to some embodiments of the present invention, the range of the grayscale stretching [A, B] is [0, 255].

[0039] By adopting the technical solution in the embodiment of the present invention, the window width values and window position values of the other frames of the infrared image sequence are corrected based on the difference between the window width values, window position values of the other frames of the infrared image and the window width values, window position values of the first frame of the infrared image, so as to solve the overexposure problem caused by large changes in the infrared image scene and achieve the effect of detail enhancement of the infrared image sequence.

[0040] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Various other advantages and benefits will become apparent to those skilled in the art by reading the detailed description of the embodiments below. The accompanying drawings are only for the purpose of illustrating preferred embodiments and are not to be considered as limiting the present invention. In the accompanying drawings:

[0042] Figure 1 1 is a flow chart of a method for dynamic infrared image detail enhancement in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0044] A first embodiment of the present invention provides a method for enhancing details of a dynamic infrared image, comprising:

[0045] Calculate the attribute values of all frame images in the infrared image sequence, wherein the attribute values at least include a window width value and a window level value, and define the attribute value of the first frame image in the infrared image sequence as an initial attribute value.

[0046] Based on the difference between the attribute value of the other frame image and the initial attribute value, the attribute value of the other frame image is corrected.

[0047] It can be understood that when correcting the attribute values of other frame images, the attribute values of other frame images are subtracted from the initial attribute values of the first frame image, and the obtained difference is superimposed on the attribute values of other frame images as the new attribute values of other frame images.

[0048] By adopting the technical solution in the embodiment of the present invention, the window width values and window position values of the other frames of the infrared image sequence are corrected based on the difference between the window width values, window position values of the other frames of the infrared image and the window width values, window position values of the first frame of the infrared image, so as to solve the overexposure problem caused by large changes in the infrared image scene and achieve the effect of detail enhancement of the infrared image sequence.

[0049] Based on the above embodiment, various modified embodiments are further proposed. It should be noted that, in order to simplify the description, only the differences from the above embodiment are described in each modified embodiment.

[0050] According to some embodiments of the present invention, the method further includes: performing a secondary adjustment on the attribute value of the frame image based on the corrected attribute value and according to an adjustment strategy.

[0051] The adjustment strategies include:

[0052] When the corrected attribute value satisfies: and When the modified attribute value is updated to the preset attribute value, or the attribute value is recalculated and updated through external operation input.

[0053] When the corrected attribute value satisfies: When l<Max, the window level value does not change, and the window width value is adjusted to w=2(Max-l).

[0054] When the corrected attribute value satisfies: And l≥Max, or And l≤Mi n , the window width value and the window level value are no longer adjusted.

[0055] When the corrected attribute value satisfies: When l>Min, the window level value does not change, and the window width value is adjusted to w=2(l-Min).

[0056] Wherein, w represents the window width, l represents the window level, Max is the maximum value among the grayscale values of each frame in the infrared image sequence, and Min is the minimum value among the grayscale values of each frame in the infrared image sequence.

[0057] According to some embodiments of the present invention, the secondary adjustment of the attribute value of the frame image based on the corrected attribute value and according to the adjustment strategy includes:

[0058] Based on the corrected attribute values, the frame image is grayscale stretched using a linear mapping grayscale stretching method, converting the 16-bit original infrared image data into an 8-bit grayscale image that can be directly displayed on a display.

[0059] The infrared image after grayscale stretching is displayed on a monitor.

[0060] A secondary adjustment of the attribute value of the infrared image displayed on the monitor is performed. For example, according to the adjustment strategy, the attribute value is dynamically adjusted on the monitor using an external operation such as a mouse.

[0061] According to some embodiments of the present invention, grayscale stretching is performed on the infrared image based on the grayscale value mapping relationship shown in the following formula 1:

[0062]

[0063] Wherein, Ho represents the grayscale value after stretching, Hi represents the original grayscale value of the infrared image, A and B represent the end values of the grayscale stretching range, and A<B.

[0064] According to some embodiments of the present invention, since the color channels displayed by the display are all 8 bits, the range of grayscale stretching [A, B] is set to [0, 255].

[0065] A second embodiment of the present invention provides a device for enhancing details of dynamic infrared images, comprising:

[0066] The calculation unit is used to calculate the attribute values of all frame images in the infrared image sequence, wherein the attribute values include window width value and window level value, and define the attribute value of the first frame image in the infrared image sequence as the initial attribute value.

[0067] For example, the calculation unit may be a window width filter.

[0068] The first correction unit is configured to correct the attribute value of the frame image based on a difference between the attribute value of the frame image and the initial attribute value.

[0069] It can be understood that when correcting the attribute values of other frame images, the attribute values of other frame images are subtracted from the initial attribute values of the first frame image, and the obtained difference is superimposed on the attribute values of other frame images as the new attribute values of other frame images.

[0070] By adopting the technical solution in the embodiment of the present invention, the window width values and window position values of the other frames of the infrared image sequence are corrected based on the difference between the window width values, window position values of the other frames of the infrared image and the window width values, window position values of the first frame of the infrared image, so as to solve the overexposure problem caused by large changes in the infrared image scene and achieve the effect of detail enhancement of the infrared image sequence.

[0071] According to some embodiments of the present invention, the apparatus further includes a second correction unit configured to perform a second adjustment on the attribute value of the frame image based on the corrected attribute value and according to an adjustment strategy.

[0072] The adjustment strategies include:

[0073] When the corrected attribute value satisfies: and When the modified attribute value is updated to the preset attribute value.

[0074] When the corrected attribute value satisfies: When l<Max, the window level value does not change, and the window width value is adjusted to w=2(Max-l).

[0075] When the corrected attribute value satisfies: And l≥Max, or And when l≤Min, the window width value and the window level value are no longer adjusted.

[0076] When the corrected attribute value satisfies: When l>Min, the window level value does not change, and the window width value is adjusted to w=2(l-Min).

[0077] Wherein, w represents the window width, 1 represents the window level, Max is the maximum value among the grayscale values of each frame in the infrared image sequence, and Min is the minimum value among the grayscale values of each frame in the infrared image sequence.

[0078] According to some embodiments of the present invention, the secondary adjustment of the attribute value of the frame image based on the corrected attribute value and according to the adjustment strategy includes:

[0079] Based on the corrected attribute value, an image grayscale stretching visualization algorithm is used to perform a grayscale stretching operation on the frame image.

[0080] The frame image after grayscale stretching is displayed.

[0081] A secondary adjustment of the attribute value is performed on the displayed frame image. For example, the attribute value is adjusted on the display using a mouse or the like according to the adjustment strategy.

[0082] According to some embodiments of the present invention, grayscale stretching is performed on the frame image based on the following formula 1:

[0083]

[0084] Wherein, Ho represents the grayscale value after stretching, Hi represents the original grayscale value of the infrared image, A and B represent the end values of the grayscale stretching range, and A<B.

[0085] According to some embodiments of the present invention, since the color channels displayed by the display are all 8 bits, the range of grayscale stretching [A, B] is set to [0, 255].

[0086] The following describes a method for detail enhancement of dynamic infrared images in detail using a specific embodiment. It should be understood that the following description is merely illustrative and does not limit the present invention. Any similar structures and variations thereof employing the present invention should be included within the scope of protection of the present invention.

[0087] refer to Figure 1In this embodiment, a window width filter first reads a 16-bit infrared image sequence and selects the first frame of the infrared image sequence for operation. The window width filter determines the grayscale interval of interest for the first frame, calculates the grayscale distribution of the infrared image, and thus calculates the window width and window level values of the first frame, which are used as the initial window width and initial window level values. Based on the initial window width and initial window level values, a grayscale stretching operation is performed on the first frame of the image, and the 16-bit raw infrared image data is converted into an 8-bit grayscale image that can be directly displayed on a display according to Formula 1 described below.

[0088]

[0089] Then, according to the adjustment strategy, the window width and window level of the infrared image are adjusted for the second time using the external mouse operation as input.

[0090] Before switching to the second frame image, the window width and window level filter calculates the window width and window level of the second frame image, and subtracts them from the initial window width and window level to obtain a correction value, which is then superimposed on the window width and window level of the second frame image as the new window width and window level of the image.

[0091] The second frame of infrared image is grayscale stretched according to Formula 1 based on the corrected new window width value and window level value, and is displayed on the monitor after stretching.

[0092] Finally, according to the adjustment strategy, the window width and window level of the infrared image are adjusted again through external mouse operation to achieve interactive adjustment. The other frame images are then dynamically adjusted and grayscale stretched according to the above scheme to achieve detail enhancement of dynamic infrared images.

[0093] By adopting the technical solution in this embodiment, the method of image grayscale stretching based on the window width position utilizes the grayscale information of the infrared image and dynamically selects the appropriate grayscale visualization range, thereby avoiding the problem of loss of weak target information caused by directly adopting the histogram equalization algorithm. The adjustment algorithm used when adjusting the window width value and window position value of the infrared image sequence is interactively updated in real time during the image sequence processing process. Not only can the manual adjustment effect be updated in real time, but also weak targets can be effectively extracted from the image, thereby improving the efficiency and comparability of image detail enhancement. When switching between infrared image frames, a dynamic time domain update algorithm is used to dynamically adjust the window width position by utilizing the grayscale differences between each frame of infrared image, thereby solving the overexposure problem caused by large changes in the infrared image scene, greatly reducing the complexity of detail enhancement work during the infrared image data analysis process, and also increasing the efficiency of detail enhancement from a single infrared image to the entire sequence.

[0094] It should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations, and that the various embodiments may be freely combined. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0095] It should be noted that, in the description of this specification, well-known methods, structures and technologies are not shown in detail so as not to obscure the understanding of this specification.

Claims

1. A method for enhancing details of dynamic infrared images, characterized in that: include: Calculating attribute values of all frame images in the infrared image sequence, the attribute values including window width and window level, and defining the attribute value of the first frame image in the infrared image sequence as an initial attribute value; Correcting the attribute value of the frame image based on a difference between the attribute value of the frame image and the initial attribute value; Based on the corrected attribute value, according to the adjustment strategy, a second adjustment is performed on the attribute value of the frame image; The adjustment strategies include: When the corrected attribute value satisfies: ,and , adjusting the corrected attribute value to a preset attribute value; When the corrected attribute value satisfies: ,and When the window width in the modified attribute value is adjusted to ; When the corrected attribute value satisfies: ,and When the window width in the modified attribute value is adjusted to ; Where w represents the window width, l represents the window level, Max represents the maximum grayscale value of the infrared image sequence, and Min represents the minimum grayscale value of the infrared image sequence.

2. The method according to claim 1, wherein The second adjustment of the attribute value of the frame image based on the corrected attribute value according to the adjustment strategy includes: Based on the corrected attribute value, grayscale stretching is performed on the frame image; Displaying the frame image after grayscale stretching; A secondary adjustment of the attribute value is completed on the displayed frame image.

3. The method according to claim 2, wherein Grayscale stretching is performed on the frame image based on the following formula: Among them, Ho represents the grayscale value after stretching, Hi represents the original grayscale value, A and B represent the end values of the grayscale stretching range, and A<B.

4. The method according to claim 3, wherein The range of the grayscale stretching [A, B] is [0, 255].

5. A device for enhancing dynamic infrared image details, characterized in that: include: a calculation unit, configured to calculate attribute values of all frame images in an infrared image sequence, wherein the attribute values include a window width value and a window level value, and define the attribute value of the first frame image in the infrared image sequence as an initial attribute value; a first correction unit, configured to correct the attribute value of the frame image based on a difference between the attribute value of the frame image and the initial attribute value; a second correction unit, configured to perform a secondary adjustment on the attribute value of the frame image based on the corrected attribute value and according to an adjustment strategy; The adjustment strategies include: When the corrected attribute value satisfies: ,and , updating the corrected attribute value to the preset attribute value; When the corrected attribute value satisfies: ,and When the window level No change, the window width value is adjusted to ; When the corrected attribute value satisfies: ,and When, or ,and When , the window width value and the window level value are no longer adjusted; When the corrected attribute value satisfies: ,and When the window level No change, the window width value is adjusted to ; Where w represents the window width, l represents the window level, Max represents the maximum grayscale value of the infrared image sequence, and Min represents the minimum grayscale value of the infrared image sequence.

6. The device according to claim 5, characterized in that The second adjustment of the attribute value of the frame image based on the corrected attribute value according to the adjustment strategy includes: Based on the corrected attribute value, grayscale stretching is performed on the frame image; Displaying the frame image after grayscale stretching; A secondary adjustment of the attribute value is completed on the displayed frame image.

7. The device according to claim 6, characterized in that Grayscale stretching is performed on the frame image based on the following formula: Wherein, Ho represents the grayscale value after stretching, Hi represents the original grayscale value of the infrared image, A and B represent the end values of the grayscale stretching range, and A<B.

8. The device according to claim 7, characterized in that The range of the grayscale stretching [A, B] is [0, 255].

Images