Assembly for non-uniformity correction and thermal imaging camera having same

Abstract

The present invention relates to an assembly for non-uniformity correction and a thermal imaging camera having same, the assembly comprising: a frame of a predetermined size, having, at the center thereof, an optical hole through which infrared light is incident; a rotating body installed on the frame to rotate in place and having driven gear teeth formed on the circumferential surface thereof; a plurality of filters, each of which is mounted in one of a plurality of holes arranged at regular intervals along the edge of the rotating body, is the same size as or smaller than the optical hole, and is mounted so as to transmit infrared light in a different wavelength range; a plurality of one-point correcting plates arranged between the filters at the same intervals, each of the correcting plates being positioned adjacent to the associated filter thereof in the clockwise or counterclockwise direction and blocking the wavelength range of the infrared light transmitted by the adjacent associated filter; and a power unit comprising a power source, which is operated by applying power to rotate the rotating body, and a driving gear, which is mounted to rotate in place by means of the power source and installed to be engaged with the driven gear teeth.

Description

Non-uniformity correction assembly and thermal imaging camera equipped therewith

[0001] The present invention relates to a thermal imaging camera, and more particularly, to an assembly for non-uniformity correction that blocks infrared rays incident on a thermal imaging detector by wavelength and can block them in a short period of time for non-uniformity correction, and a thermal imaging camera equipped with the same.

[0002] Thermal imaging cameras, also known as infrared cameras, are typically designed to detect infrared radiation and output images. In other words, thermal imaging cameras are devices that detect temperature differences caused by radiant energy emitted from the surface of an object and output the shape of the object in a visually recognizable manner. Examples of thermal imaging cameras include remotely measuring the body temperature of travelers entering and leaving the country at airports to screen for patients with high fevers; industrial applications such as remotely measuring the temperature of transformers mounted on utility poles while moving on the ground or in vehicles to determine whether they are overheated; and military and security applications such as detecting and detecting enemies or abnormal objects in the dark. These thermal imaging cameras may be equipped with a thermal detector that detects infrared radiation, or the radiant heat emitted from the surface of an object.

[0003] Here, the thermal image detector includes pixel detectors that detect infrared radiation on a pixel-by-pixel basis, and a thermal image is reconstructed based on the information detected from each pixel detector. Each pixel detector should detect the same information regarding the temperature of the surface of the same object. However, sensitivity errors may exist between each pixel detector, and if the sensitivity error between pixel detectors is large, an accurate thermal image of the object may not be output. In other words, a non-uniform thermal image that does not accurately correspond to the shape of the object is obtained.

[0004] Therefore, when the user of the thermal imaging camera deems it necessary, the sensitivity error between each pixel detector is automatically compensated for at regular intervals. This compensation for the sensitivity error between each pixel detector is called non-uniform compensation.

[0005] In addition, the sensitivity error of the pixel detector of the thermal imaging camera can be compensated by adjusting the signal level of the output of each pixel detector to the same level using an image composed by detecting a thermal image of an object with a uniform temperature distribution. For example, in Korean Patent Registration No. 10-1797132 (announced on November 13, 2017), a method is proposed to compensate for the sensitivity error of the pixel detector by using a shutter to block temperature information input to the thermal detector, i.e., infrared rays incident on the thermal detector.

[0006] However, there is a problem that it is difficult to manufacture in a compact form because many parts are required for shutter installation and a large space is required for these parts to be installed, and the current consumption of the motor for opening and closing the shutter is large, so the overall size increases and the weight increases.

[0007] The purpose of the present invention, which was devised to solve the above-mentioned problem, is to provide a non-uniformity correction assembly and a thermal imaging camera equipped with the same, which comprises a rotating body equipped with a wavelength-specific correction filter such as a long wavelength and a medium wavelength between a thermal optical system and a thermal imaging detector, thereby rotating the rotating body with a small power, and having a simple structure so as to reduce weight and enable compact manufacturing.

[0008] In order to achieve the above-described object, the assembly for non-uniformity correction according to the present invention may include a frame of a predetermined size having an optical hole through which infrared rays are incident at the center; a rotating body installed in the frame so as to rotate in place and having driven gear teeth machined on a circumferential surface; each filter mounted in a plurality of holes machined at equal intervals along the periphery of the rotating body, each filter having a size equal to or smaller than the optical hole but having a different wavelength range of infrared rays transmitted therethrough; a plurality of one-point correction plates positioned at equal intervals between the filters, one of which is positioned clockwise or counterclockwise adjacent to each associated filter, and which block a wavelength range of infrared rays transmitted by the adjacent associated filter; and a power unit including a power source that is operated by applying power to rotate the rotating body, and a driving gear that is installed so as to rotate in place by the power source and is meshed with the driven gear teeth.

[0009] Therefore, when the driving gear and the driven gear teeth are meshed and operated by the power source and the rotating body rotates clockwise or counterclockwise by a certain angle, the optical hole and the filter can be positioned on the same center line for infrared transmission, or the optical hole and the one-point compensation plate can be positioned on the same center line for infrared blocking.

[0010] Here, the filter may include a first filter that transmits infrared rays of the entire wavelength, a second filter that transmits infrared rays of a long wavelength, and a third filter that transmits infrared rays of a medium wavelength.

[0011] Additionally, the one-point compensation plate may include a first one-point compensation plate adjacent to the first filter and blocking the wavelength of the first filter, a second one-point compensation plate adjacent to the second filter and blocking the wavelength of the second filter, and a third one-point compensation plate adjacent to the third filter and blocking the wavelength of the third filter.

[0012] And it may further include a gap adjusting unit installed between the rotating body and the frame to induce smooth rotation of the rotating body.

[0013] Here, the gap adjustment unit may include gap adjustment protrusions fixedly protruding at a constant interval along the periphery of the rotating body, and a ball screw mounted on the tip of the gap adjustment protrusions and in contact with the surface of the frame. At this time, while the rotating body rotates, the ball screw may contact the surface of the frame and perform rolling motion.

[0014] And the ball screw can be mounted so as to be elastically pushed outward on the spacing adjustment lugs so as to maintain surface contact with the frame.

[0015] Meanwhile, a thermal imaging camera equipped with an assembly for non-uniformity correction according to the present invention may include a thermal optical system into which infrared rays are incident from the front; a thermal detector for detecting temperature information by incident infrared rays emitted from the thermal optical system; an assembly for non-uniformity correction according to any one of claims 1 to 3 disposed between the thermal optical system and the thermal detector; and a case in which the thermal optical system, the thermal detector, and the assembly for non-uniformity correction are built.

[0016] As described above, according to the present invention, by rotating the rotating body to transmit and block infrared rays through a plurality of filters and a single-point correction plate, the opening and closing time is shortened compared to the conventional shutter opening and closing method, the number of parts is reduced, so that the manufacturing cost is lowered, the size is reduced, and the weight is reduced, so that miniaturization is realized.

[0017] In addition, by blocking ultraviolet rays incident on the thermal image detector by wavelength band, including long wavelengths and medium wavelengths, it has the effect of generating a more precise non-uniformity correction image.

[0018] And, due to the elastic mounting of the ball screw, it has the effect of absorbing external forces including vibration.

[0019] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0020] FIG. 1 is a schematic internal perspective view of a thermal imaging camera having a non-uniformity correction assembly for a thermal detector installed therein according to a preferred embodiment of the present invention.

[0021] Figure 2 is a perspective view illustrating the non-uniform compensation assembly illustrated in Figure 1.

[0022] Figure 3 is a perspective view schematically illustrating the fixed frame illustrated in Figure 1.

[0023] Fig. 4 is a perspective view showing the rotating body illustrated in Fig. 2.

[0024] Figures 5 to 7 are state diagrams of use of the non-uniform assembly shown in Figure 2.

[0025] Hereinafter, with reference to the attached drawings, preferred embodiments are described in detail so that those skilled in the art can easily practice the present invention. Furthermore, among the components mentioned in the various embodiments, similar and related components may be replaced, exchanged, or added to each embodiment. However, when describing the operating principles of preferred embodiments of the present invention in detail, if a specific description of a related known function or component is judged to unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

[0026]

[0027] <Composition>

[0028] Hereinafter, a non-uniformity correction assembly for a thermal image detector and a thermal imaging camera equipped therewith according to a preferred embodiment of the present invention will be described.

[0029] As shown in FIGS. 1 and 2, the thermal imaging camera comprises a thermal optical system (100), a thermal detector (200), and an assembly for non-uniformity correction (300).

[0030] A thermal imaging optical system (100) can receive radiant energy, i.e., infrared radiation, emitted from the surface of an external object. This thermal imaging optical system (100) can have multiple lenses arranged on the same optical axis and positioned at a constant distance from each other. By adjusting the spacing between these lenses, the field of view magnification can be appropriately changed. This thermal imaging optical system (100) can be similar to or identical to a conventional system.

[0031] A thermal imaging detector (200) can detect information about the temperature of an object through infrared rays incident along the optical axis from the surface of the object and passing through a thermal imaging optical system (100). To this end, the thermal imaging detector (200) may be equipped with a plurality of pixel detectors arranged in a matrix. This thermal imaging detector (200) may be similar to or identical to a conventional one.

[0032] The assembly (300) for non-uniformity correction is placed between the thermal imaging optical system (100) and the thermal image detector (200), and can block temperature information that passes through the thermal imaging optical system (100) and is input to the thermal image detector (200), i.e., infrared rays incident on the thermal image detector (200), thereby generating a reference image for non-uniformity correction. To this end, the assembly (300) for non-uniformity correction can include a frame (310), a rotating body (320), a power unit (330), and a gap adjustment unit (340).

[0033] First, the frame (310) may include a fixed frame (311) and a central frame (312), as shown in FIGS. 1 to 3.

[0034] The fixed frame (311) is arranged between the thermal imaging optical system (100) and the thermal imaging detector (200), and the non-uniformity correction assembly (300) can be fixed to a case (not shown) that accommodates not only the thermal imaging optical system (100) but also the thermal imaging detector (200). In addition, a power unit (330) and a rotating body (320) can be installed at appropriate locations on the fixed frame (311). In addition, the case is manufactured to have an internal space, and the thermal imaging optical system (100), the thermal imaging detector (200), and the non-uniformity correction assembly (300) can be built into the case. Of course, all components constituting the thermal imaging camera can be mounted on the case.

[0035] The central frame (312) may be positioned at the center of the fixed frame (311) and may have an optical hole (313) machined at the center. At this time, the optical hole (313) may be machined to have the same central axis as the optical axis of the thermal imaging optical system (100) and the thermal imaging detector (200). A number of holes may be machined around the central frame (312), thereby reducing the weight of the fixed frame (311). As another example, the central frame (312) and the holes may be excluded, and the optical hole (313) may be directly machined at the center of the flat fixed frame (311).

[0036] Meanwhile, the rotating body (320) may be installed to block infrared rays incident on the thermal imaging detector (200) in all or multiple wavelength bands while rotating in place. For example, the rotating body (320) may be installed to rotate in place on one side of the fixed frame (311). To this end, a rotating shaft (not shown) protruding and fixed on one side of the fixed frame (311) may be inserted into a rotating shaft hole (322) machined in the center of the rotating body (320) and mounted.

[0037] In addition, the rotating body (320) may have a certain area and may have one or more holes formed along the periphery at a certain angle with respect to the center of the rotating body (320), and an infrared transmission filter may be installed in each hole. These filters may be formed to have the same center line as the optical axis so that infrared rays incident through the thermal imaging optical system (100) are transmitted while the rotating body (320) rotates. In addition, the rotating body (320) may have one-point correction plates installed between the filters at a certain angle with respect to the center of the rotating body (320). At this time, the filter and the one-point correction plate may have a diameter equal to or smaller than the optical hole (313).

[0038] In addition, the rotating body (320) may have a driven gear (321) machined on the side surface, which is a circumferential surface, and a rotating shaft hole (322) in the center.

[0039] Here, the driven gear (321) can be arranged to mesh with the driven gear (321) described later. Therefore, when the driven gear (321) rotates, the rotating body (320) can rotate via the driven gear (321).

[0040] A plurality of filters may be provided, each categorized by wavelength band of the infrared rays to be transmitted. For example, the filters may include a first filter (323), a second filter (324), and a third filter (325), each of which is installed in holes machined at a certain angle. Here, the first filter (323), the second filter (324), and the third filter (325) may transmit the entire wavelength, long wavelength, and medium wavelength of infrared rays. Of course, in addition, more or fewer filters may be provided for each wavelength band, including short wavelengths, as needed, and the first filter (323), the second filter (324), and the third filter (325) may be changed to transmit a wavelength range other than the above-mentioned wavelength range or a more detailed range of wavelengths.

[0041] To explain further, the first filter (323) may be a window filter and a filter that transmits the entire infrared wavelength. To distinguish this, the first filter (323) may be a sky blue film.

[0042] In addition, the second filter (324) may be a long-wavelength filter, and may be a filter that transmits long-wavelength (LWIR; Longwave Length Infra Red) in the range of approximately 8 to 14 ㎛. To distinguish this, the second filter (324) may be a blue film.

[0043] And the third filter (325) is a medium wavelength filter, and may be a filter that transmits short wavelengths (MWIR (Middle Length Infra Red)) in the range of approximately 3 to 5㎛. To distinguish this, the third filter (325) may be a pink film.

[0044] As shown in FIGS. 2 and 4, the one-point compensation plates can be arranged at a certain angle with respect to the center of the rotating body (320) between the filters. The one-point compensation plate can be processed so that a groove, instead of a hole, is processed on one surface of the rotating body (320) so that the rotation angle of the rotating body (320) can be checked to be accurate while being visually distinguished. At this time, the groove can be the same size as or smaller than the size of the optical hole (313). In addition, the one-point compensation plate can be prepared so that the groove is excluded and a width is secured to the extent that the optical hole (313) can be blocked.

[0045] In addition, one 1-point correction plate is provided corresponding to each filter, and for example, a first 1-point correction plate (326) corresponding to the first filter (323), a second 1-point correction plate (327) corresponding to the second filter (324), and a third 1-point correction plate (328) corresponding to the third filter (325) may be provided.

[0046] To explain in more detail, the first 1-point correction plate (326) may be adjacent to the first filter (323) and positioned between the first filter (323) and the second filter (324), the second 1-point correction plate (327) may be adjacent to the second filter (324) and positioned between the second filter (324) and the third filter (325), and the third 1-point correction plate (326) may be adjacent to the third filter (325) and positioned between the third filter (325) and the first filter (323). In Fig. 2, the colors of the first 1-point correction plate (326) and the first filter (323) are expressed to correspond to each other. The colors of the second 1-point correction plate (327) and the second filter (324), and the colors of the third 1-point correction plate (328) and the third filter (325) are also expressed to correspond to each other.

[0047] Meanwhile, the power unit (330) may be installed to rotate the rotating body (320) in place. To this end, the power unit (330) may include a power source (331) and a driving gear (332).

[0048] Here, the power source (331) operates by receiving external power and can be installed near the rotating body (320) in the fixed frame (311). This power source (331) can be, for example, a stepper motor capable of forward and reverse rotation to which an external wire (343) is connected, or a device capable of rotating the driving gear (332) in place in forward and reverse rotation.

[0049] And the driving gear (332) can be installed so as to be connected to the power source (331) and rotate in place, and to mesh with the driven gear teeth (321) machined on the circumference of the rotating body (320). This driving gear (332) can be manufactured separately and installed on the rotational axis of the power source (331).

[0050] Meanwhile, as shown in FIGS. 2 to 4, the gap adjustment unit (340) may be installed so that the gap with the fixed frame (311) is always maintained constant while the rotating body (320) rotates. To this end, the gap adjustment unit (340) may include a gap adjustment protrusion (341) and a ball screw (342).

[0051] The spacing adjustment protrusion (341) is positioned at a constant angle to the rear edge of the rotating body (320) and can be fixed by protruding toward the fixed frame (311). The protruding length of the spacing adjustment protrusion (341) can be set in consideration of the gap between the surface of the fixed frame (311) and the surface of the rotating body (320).

[0052] The ball screw (342) may be mounted on the tip of the spacing adjustment protrusion (341) and may be installed to make rolling motion by contacting one surface of the fixed frame (311). At this time, the ball screw (342) may be installed to be elastically pushed outward from the spacing adjustment protrusion (341) so that it may always make contact with one surface of the fixed frame (311). To this end, a spring may be built into the interior of the spacing adjustment protrusion (341), and the spring may be installed to push the ball screw (342). Accordingly, while the rotating body (320) rotates, the ball screw (342) makes rolling motion with respect to the fixed frame (311), thereby enabling smooth rotation of the rotating body (320), and the spacing adjustment protrusion (341) may maintain a constant gap between the rotating body (320) and the fixed frame (311). In addition, due to the elastic mounting of the ball screw (342), external force including vibrations may be absorbed.

[0053]

[0054] <Operation>

[0055] Hereinafter, the operation of the non-uniformity correction assembly according to the present invention will be described. Basically, as shown in FIG. 1, the non-uniformity correction assembly (300) is placed between the thermal optical system (100) and the thermal detector (200), and the rotating body (320) can rotate clockwise by the power source (331) and the driving gear (332).

[0056] For example, as shown in FIG. 5, infrared rays of the entire wavelength transmitted from the thermal imaging optical system (100) may pass through the first filter (323) and be incident on the thermal detector (200). Thereafter, in order to generate a reference image for non-uniformity correction for the infrared rays of the entire wavelength, the power source (331) is operated so that the driving gear (332) rotates in place, and the driven gear tooth (321) engaged with the driving gear (332) moves so that the rotating body (320) may rotate clockwise. Thereafter, when the center of the first 1-point correction plate (326) aligns with the center of the optical hole (313), the rotation of the rotating body (320) may be stopped. As a result, the infrared rays of the entire wavelength may be blocked, and a reference image for non-uniformity correction may be generated. When the following operation is performed, the rotor (320) may be rotated clockwise so that the second filter (324) or the third filter (325) is aligned with the optical hole (313), or may be rotated counterclockwise so that the first filter (323) is aligned with the optical hole (313) again.

[0057] As another example, as shown in FIG. 6, long-wave infrared rays transmitted through the thermal imaging optical system (100) may pass through the second filter (324) and be incident on the thermal detector (200). Thereafter, in order to generate a reference image for non-uniformity correction for the long-wave infrared rays, the power source (331) is operated to cause the driving gear (332) to rotate in place, and the driven gear teeth (321) engaged with the driving gear (332) move so that the rotating body (320) may rotate clockwise. Thereafter, when the center of the second one-point correction plate (327) aligns with the center of the optical hole (313), the rotation of the rotating body (320) may be stopped. As a result, the long-wave infrared rays may be blocked, and a reference image for non-uniformity correction may be generated. When the following operation is performed, the rotor (320) may be rotated clockwise so that the third filter (325) or the first filter (323) is aligned with the optical hole (313), or may be rotated counterclockwise so that the second filter (324) is aligned with the optical hole (313) again.

[0058] As another example, as shown in FIG. 7, the medium-wave infrared transmitted from the thermal imaging optical system (100) may pass through the third filter (325) and be incident on the thermal detector (200). Thereafter, in order to generate a reference image for non-uniformity correction for the medium-wave infrared, the power source (331) is operated so that the driving gear (332) rotates in place, and the driven gear tooth (321) engaged with the driving gear (332) rotates, thereby causing the rotating body (320) to rotate clockwise. Thereafter, when the center of the third one-point correction plate (328) aligns with the center of the optical hole (313), the rotation of the rotating body (320) may be stopped. As a result, the medium-wave infrared may be blocked, and a reference image for non-uniformity correction may be generated. When the following operation is performed, the rotor (320) may rotate clockwise so that the first filter (323) or the second filter (324) is aligned with the optical hole (313), or may rotate counterclockwise so that the third filter (325) is aligned with the optical hole (313) again.

[0059]

[0060] As described above, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without altering its technical spirit or essential characteristics. Therefore, the above-described embodiments should be understood as illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims below rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be construed as being included within the scope of the present invention.

Claims

1. A frame (310) of a certain size having an optical hole (313) in the center through which infrared rays are incident; A rotating body (320) installed to rotate in place on the above frame (310) and having a driven gear (321) machined on the circumference thereof; Each filter is mounted in a plurality of holes machined at equal intervals along the edge of the above-mentioned rotating body (320), and is mounted with a size equal to or smaller than the optical hole (313) but with different wavelength ranges of infrared rays transmitted; A plurality of one-point compensation plates positioned at equal intervals between the above filters, one for each associated filter positioned clockwise or counterclockwise, and blocking the wavelength range of infrared rays transmitted by the adjacent associated filters; and It includes a power unit (330) including a power source (331) that is operated by applying power to rotate the above-mentioned rotating body (320), and a driving gear (332) that is installed to rotate in place by the power source (331) and to mesh with the driven gear (321); An assembly for non-uniformity correction in which, when the driving gear (332) and the driven gear (321) are meshed and operated by the power source (331) and the rotating body (320) rotates clockwise or counterclockwise by a certain angle, the optical hole (313) and the filter are positioned on the same center line for infrared transmission, or the optical hole (313) and the one-point correction plate are positioned on the same center line for infrared blocking.

2. In claim 1, The above filter is an assembly for non-uniformity correction comprising a first filter (323) that transmits infrared rays of the entire wavelength, a second filter (324) that transmits infrared rays of a long wavelength, and a third filter (325) that transmits infrared rays of a medium wavelength.

3. In claim 2, The above 1-point correction plate is an assembly for non-uniformity correction, comprising a first 1-point correction plate (326) provided adjacent to the first filter (323), a second 1-point correction plate (327) provided adjacent to the second filter (324), and a third 1-point correction plate (328) provided adjacent to the third filter (325).

4. In claim 1, It further includes a gap adjustment unit (340) installed between the above-mentioned rotating body (320) and the frame (310) to induce smooth rotation of the rotating body (320); The above spacing adjustment unit (340) includes spacing adjustment protrusions (341) that are fixed and protrude at a constant interval along the edge of the rotating body (320), and a ball screw (342) that is mounted on the tip of the spacing adjustment protrusion (341) and comes into contact with the surface of the frame (310). An assembly for non-uniformity correction in which the ball screw (342) comes into contact with the surface of the frame (310) and performs a rolling motion while the above-mentioned rotating body (320) rotates.

5. In claim 4, The above ball screw (342) is an assembly for non-uniformity correction that is elastically pushed outward from a gap adjusting projection (341) so that surface contact with the frame (310) is maintained.

6. In the thermal imaging camera, A thermal imaging optical system (100) into which infrared rays are incident from the front; A thermal detector (200) that detects information about temperature by receiving infrared rays emitted from the above thermal optical system (100); An assembly (300) for non-uniformity correction according to any one of claims 1 to 3, which is placed between the thermal imaging optical system (100) and the thermal imaging detector (200); and A thermal imaging camera having an assembly for non-uniformity correction, comprising a case in which the above thermal optical system (100), thermal detector (200) and non-uniformity correction assembly (300) are built.

Images