Optical image capture unit for a sewer inspection system

Abstract

Optical image capture unit (10) for inspecting sewer pipes and which can be coupled to a sewer inspection system, comprising: a housing (12, 14) which can be coupled to the sewer inspection system; an image sensor (20) arranged in the housing for capturing image information of an image of an object displayed on the image sensor, a lens (16) arranged in or on the housing for generating the image of the object on the image sensor (20), a lens (18) arranged between the objective (16) and the image sensor (20), the imaging properties of which can be changed by means of an input signal (19) in order to focus the image of the object produced by the objective onto the image sensor (20); and a control unit (22) arranged in the housing (12, 14) which is designed to generate the input signal (19) based on the image information.

Description

[0001] The invention relates to an optical image capture unit for inspecting sewers or sewer pipes and a sewer inspection system comprising an optical image capture unit.

[0002] Sewer inspection systems are used for the inspection, in particular the optical inspection, of sewers, sewer pipes, lines and / or shafts, etc., for example sewer shafts or pipes. For optical inspection, an optical image capture unit is inserted into the object to be inspected, for example a sewer, in order to visually examine it for damage or blockages, for example. The optical image capture unit can be coupled to a push rod, for example, and can be inserted or pushed into the object to be inspected using the push rod. Alternatively, the optical image capture unit can also be arranged on an inspection carriage equipped with a drive, whereby the inspection carriage moves past the object to be inspected and, as it moves away, the object can be examined with the optical image capture unit.

[0003] During inspection, the optical image capture unit is typically positioned at varying distances from the object (object distance). Furthermore, the image information captured by the optical image capture unit during inspection is displayed to an operator or user via a control unit, such as a screen. It is important that the optical image capture unit focuses on the object to be inspected so that the image information displayed to the operator is sharply displayed. Focusing by the optical image capture unit can be performed manually or automatically.

[0004] In conventional optical image capture units, the focusing mechanism, for example, mechanically or micromechanically driven focusing devices, has proven to be error-prone. Causes of errors can include, in particular, vibrations of the optical image capture unit and / or temperature fluctuations. Furthermore, the focusing in conventional optical image capture units is often very sluggish and slow, making visual inspection of the object to be inspected difficult.

[0005] Furthermore, DE 20 2014 103 294 U1 relates to a focusing system for a pipe inspection system, comprising a distance measuring device for measuring a distance to an object, a control device operatively coupled to the distance measuring device, and an optical lens operatively coupled to the control device and designed as a liquid lens, wherein the control device is adapted to adjust the focal length of the liquid lens based on the distance data received from the distance measuring device.

[0006] US 2018 / 0 372 985 A1 relates to a vision system arranged to compensate for optical drift that may occur in certain variable lens arrangements.

[0007] Therefore, it is an object of the present invention to provide an optical image acquisition unit for a sewer inspection system which overcomes the aforementioned problems.

[0008] This object is achieved by the subject matter of the independent claims. Preferred embodiments are defined in the dependent claims.

[0009] One aspect relates to an optical image capture unit for inspecting sewer pipes and which can be coupled to a sewer inspection system, comprising: a housing which can be coupled to the sewer inspection system; an image sensor arranged in the housing for capturing image information of an image of an object displayed on the image sensor, a lens arranged on or in the housing for generating the image of the object on the image sensor, and a lens arranged between the objective lens and the image sensor, the imaging properties of which can be changed by means of an input signal in order to focus the image of the object produced by the objective lens onto the image sensor.

[0010] Advantageously, by providing a lens whose imaging properties can be changed using the input signal, mechanical focusing, which generally requires a relative movement of the lens with respect to the objective, can be dispensed with. In other words, the proposed invention enables focusing of the optical image capture unit without the use of mechanical focusing. This makes it possible to provide an optical image capture unit that is insensitive to environmental influences, such as vibrations and / or temperature fluctuations. Furthermore, the use of a lens whose imaging properties can be changed using the input signal enables rapid focusing.

[0011] Preferably, the input signal can be controlled such that the image of the object generated on the image sensor is focused as a function of the object distance, ie the distance of the object from the optical image capture unit.

[0012] Furthermore, the objective and the lens can be arranged relative to one another such that the optical axis of the objective and the optical axis of the lens are substantially parallel to one another and preferably lie on top of one another. Furthermore, the image sensor can be designed, for example, as a CCD sensor (charge-coupled device), wherein the image sensor is arranged relative to the lens and the objective such that the sensor surface of the image sensor is substantially perpendicular to the optical axis of the lens. Furthermore, the sensor surface of the image sensor points towards the lens, and the optical axis of the lens preferably runs through the center or centroid of the sensor surface of the image sensor.

[0013] Furthermore, due to the coupling configuration of the optical image capture unit to the sewer inspection system, the optical image capture unit can be connected to a voltage source of the sewer inspection system, which voltage source supplies the electrical components of the optical image capture unit with the necessary operating voltage. Furthermore, the optical image capture unit can be coupled to the sewer inspection system in such a way that the image information can be output to an operating unit of the sewer inspection system. For example, the optical image capture unit can be configured to output the image information to the operating unit as a video signal or video stream. To view the video signal or video stream, the operating unit can have a corresponding display, for example a screen.

[0014] Furthermore, it can be provided to control the input signal by means of the control unit in order to focus the optical image capture unit on the object (manual focusing by an operator).

[0015] Preferably, the objective lens, the lens, and the image sensor can be positionally fixed with respect to one another. In other words, the objective lens, the lens, and the image sensor are rigidly positioned relative to one another. This advantageously eliminates the need for mechanical components for focusing. Preferably, the objective lens and the lens can be designed as a single assembly that is or can be permanently connected to the image sensor. This enables a compact design of the objective lens, the lens, and the image sensor to form a camera module, which simplifies the assembly and maintenance of the optical image capture unit. Furthermore, the high level of integration enables a space-saving implementation of the camera module, enabling small optical image capture units so that even pipes or ducts with small diameters can be inspected.

[0016] The optical image capture unit has a control unit arranged in the housing, which is designed to generate the input signal based on the image information. Advantageously, the provision of the control unit enables autofocus control of the optical image capture unit, which ensures automatic focusing of the optical image capture unit on the object to be inspected. Furthermore, the provision of the control unit in the optical image capture unit enables the optical image capture unit to have all the necessary components for focusing the optical image capture unit.

[0017] In particular, the lens, the image sensor, and the control unit form a control loop to adjust the imaging properties of the lens to changing object distances. Preferably, the control unit can adjust the input signal of the lens based on a contrast measurement of the image information so that the image of the object is focused on the image sensor.

[0018] Furthermore, it can be provided that the optical image capture unit can be adjusted, for example by an operator, to determine whether the focusing should be automatic or manual. For example, the operator can use the control unit to select between manual or automatic focusing. In the case of manual focusing, the operator can further control the input signal and thus influence the imaging properties of the lens.

[0019] Preferably, the lens curvature and / or the material properties of the lens can be adjusted using the input signal, thereby allowing the imaging properties of the lens to be adjusted. The imaging properties preferably relate to the focal length of the lens. This means that the focal length of the lens can be changed by changing the input signal, for example, by changing an electrical voltage applied to the lens.

[0020] The optical image capture unit is preferably designed such that the housing encloses the objective, the lens, and the image sensor in a dust- and liquid-tight manner. Furthermore, it can be provided that the housing also encloses the control unit in a dust- and liquid-tight manner. In particular, the housing can have a receiving space in which the objective, the lens, the image sensor, and the control unit can be arranged. Due to the dust- and liquid-tight design of the housing, the optical image capture unit can be designed to be particularly resistant to environmental influences and, for example, be protected from the ingress of dirty water. Furthermore, an image information processing unit can be arranged in the housing, which processes the image information from the image sensor and outputs it to the sewer inspection system as a video signal and / or video stream.

[0021] Preferably, the housing may comprise a first housing element and a second housing element, which are connectable to one another and which, in the connected state, enclose the objective, the lens, and the image sensor. Furthermore, the optical image capture unit may comprise a support element, which is connectable to the first housing element or the second housing element, and wherein the image sensor is arranged on the support element.

[0022] Advantageously, a compact design of the optical image capture unit can be realized, which is also modular in design and thus enables a high level of ease of maintenance of the optical image capture unit.

[0023] In particular, the first housing half and the second housing half can be screwed or screwable together. Furthermore, the support element can be connectable, for example, screwable, to the first housing element or to the second housing element. Furthermore, the lens and the objective can also be arranged on the support element or supported by the support element. In particular, the support element can have a flat support section having a first side on which the image sensor is arranged.

[0024] Furthermore, the optical image capture unit can be designed such that the control unit is arranged on the support element. In particular, the support section can have a second side on which the control unit is arranged or fastened. The control unit and the image sensor can be arranged opposite one another with respect to the support section. Preferably, the support element is made of an aluminum alloy and has an anodized surface, which is thus preferably also electrically insulating. Advantageously, the support element is thus electrically insulating and cannot enable an electrical connection between the control unit and the image sensor.

[0025] The optical image capture unit can preferably be designed to transmit the image information from the image sensor to an operating unit of the sewer inspection system. For example, the optical image capture unit can be electrically connected to the operating unit. Furthermore, the optical image capture unit can have a quick-coupling mechanism, for example a bayonet lock, to couple the optical image capture unit to a coupling element, wherein the coupling element connects the optical image capture unit to the sewer inspection system and / or the operating unit. Furthermore, the coupling element can be designed to transmit the image information from the optical image capture unit to the sewer inspection system or to the operating unit. Furthermore, the coupling element can be designed to transmit control commands regardingto transmit the input signal from the control unit to the optical image capture unit, and to electrically connect the optical image capture unit to a power supply. For example, the coupling element can have one or more electrical conductors with which the aforementioned functions can be implemented.

[0026] Furthermore, the optical image capture unit can have a support housing on which the housing is pivotably mounted, wherein the optical image capture unit can be coupled to the sewer inspection system by means of the support housing. Furthermore, it is possible to control the pivoting of the housing relative to the support housing using the control unit of the sewer inspection system. By pivoting the optical image capture unit, it is possible, for example, to precisely inspect the inner walls of the pipe or shaft to be inspected. In particular, pivoting the optical image capture unit enables pivoting of the field of view of the optical image capture unit. The optical image capture unit can preferably be designed as a circular or pan-and-tilt camera.

[0027] Another aspect relates to a sewer inspection system comprising: a control unit; and an optical image capture unit according to one of the preceding claims, which can be coupled to the operating unit.

[0028] Preferably, the optical image capture unit can be coupled to the sewer inspection system by means of a coupling element (see above). A push rod, for example, can be provided as the coupling element, which is connected to the optical image capture unit in order to connect the optical image capture unit to the sewer inspection system or to the operating unit. Furthermore, the push rod enables the optical image capture unit to be inserted into the object to be inspected, for example, a sewer or sewer pipe, and to be withdrawn from the object to be inspected.

[0029] Alternatively, the coupling element can be designed as a connecting cable that electrically connects the sewer inspection system or the control unit to the optical image capture unit. Furthermore, the optical image capture unit can be arranged on a carriage equipped with a drive, which can be moved within the object to be inspected via appropriate control commands. Furthermore, the sewer inspection system can be designed as mentioned above.

[0030] An embodiment of the invention is described in more detail below with reference to the accompanying figures. It is understood that the present invention is not limited to this embodiment, and that individual features of the embodiment can be combined to form further embodiments within the scope of the appended claims.

[0031] They show: Fig. 1 is an exploded perspective view of an optical image capture unit; Fig. 2 a cross-sectional view through the optical image capture unit; Fig. 3 a block diagram of the control of the optical image acquisition unit; Fig. 4 a perspective view of an optical image capture unit designed as a swivel head.

[0032] Fig. 1 shows a possible embodiment of an optical image capture unit 10. The optical image capture unit 10 has a housing consisting of a first housing element 12 and a second housing element 14, which can be connected to one another, for example by screwing. When the first housing element 12 and the second housing element 14 are connected, the housing encloses a recording space in which an objective 16, a lens 18, an image recorder 20, and a control unit 22 are arranged. The image recorder 20 is designed to capture an image of an object located outside the housing, projected onto the image recorder 20, and to convert it into image information. The image of the object on the image recorder 20 is generated by means of the objective 16. Furthermore, the lens 18 is arranged between the objective 16 and the image recorder 20.In particular, the optical axis of the objective 16 and the lens 18 can run substantially parallel to one another and preferably lie one above the other. Furthermore, the lens 18 is designed to have a variable imaging property that can be changed or controlled by an input signal 19 applied to the lens 18. In particular, the lens 18 is designed such that the focal length of the lens 18 can be adjusted by means of the input signal 19. Thus, by appropriately controlling the control unit 22, which controls the input signal 19, the imaging property of the lens 18 can be adjusted such that the image of the object generated on the image sensor 20 is focused.

[0033] The image sensor 20 can be configured, for example, as a CCD sensor, wherein the sensor surface 21 of the image sensor 20 extends substantially perpendicular to the optical axis of the lens 18 and / or perpendicular to the optical axis of the objective 16. Furthermore, the optical axis of the lens 18 and / or the optical axis of the objective 16 extends through the center or center of gravity of the sensor surface 21 of the image sensor 20.

[0034] The housing or the first housing element 12 and the second housing element 14 can be made, for example, of a stainless steel or aluminum alloy.

[0035] Furthermore, the first housing element 12 can have an optical window 26, which lies on the optical axis of the lens 16. Thus, the lens 16 can capture the object located outside the housing through the first housing element 12.

[0036] Furthermore, the objective 16, the lens 18, and the image sensor 20 are arranged in the housing in a positionally fixed manner relative to one another. In other words, the focusing of the image on the image sensor 20 is performed by the lens 18 without any further mechanical focusing steps.

[0037] Furthermore, a support element 24 is arranged in the housing, which is designed to accommodate the image sensor 20 and the control unit 22. In particular, the support element 24 has a support section 28, which is essentially flat. The image sensor 20 is arranged on a first side of the support section 28 when the optical image acquisition unit 10 is assembled. The sensor surface 21 of the image sensor 20 runs essentially parallel to the support section 28. The control unit 22 is also arranged on a second side of the support section 28, so that the image sensor 20 and the control unit 22 are arranged opposite one another with respect to the support section 28. Furthermore, the lens 18 and the objective 16 can be designed as a unit, which is connected to the image sensor 20 and is thus also arranged on the support section 28.Thus, a very compact design of all essential components of the optical image capture unit 10 can be realized.

[0038] Furthermore, the support element 24 can be connected to the first housing element 12 or the second housing element 14. For this purpose, the support element 24 can have a plurality of projections 30, which extend from the support section 28 in the direction of the first housing element 12 (as shown) or in the direction of the second housing element 14. Furthermore, it is provided that the support element 24 is screwed to the first housing element 12 or the second housing element 14 by means of the projections 30.

[0039] Fig. 2 shows the composite optical image capture unit 10 in a cross-sectional view, wherein the reference numerals used correspond to the corresponding ones in Fig. 1. Furthermore, Fig. 3 shows a block diagram of a control circuit of the optical image capture unit 10. The image of an object is projected onto the image sensor 20 by means of the objective 16 and the lens 18. The image sensor 10 generates image information from the projected image, which is transmitted to an image processing unit 36. The image processing unit 36 ​​can be integrated together with the control unit 22. Furthermore, the image processing unit 36 ​​is designed to transmit the image information from the image sensor 20 to a sewer inspection system (not shown) that can be coupled to the optical image capture unit 10. The transmission can take place, for example, as a video signal (analog) or as a video stream.

[0040] Based on the image information, the control unit 22 is designed to control the input signal 19 of the lens 18 so that the image of the object is focused on the image sensor 20. For example, the control unit 22 can evaluate contrast information from the image information, by means of which the input signal 19 of the lens 18 is controlled. The input signal 19 can be, for example, an electrical voltage. A change in the input signal 19 causes a change in the imaging properties of the lens 18. In particular, the focal length of the lens 18 can be changed by means of the input signal 19. This is based on the fact that, for example, the curvature of the lens 18 or the material properties of the lens 18 can be changed by changing the input signal 19. The focusing of the optical image capture unit 10 is preferably carried out automatically by the control unit 22. Manual control of the focusing can also be provided.Preferably, an operator can choose between manual and automatic focusing.

[0041] Preferably, all essential control components of the optical image capture unit 10 are arranged in the housing. The optical image capture unit 10 can be coupled to the sewer inspection system via a coupling element (not shown).

[0042] Fig.4 shows the optical image capture unit 10 as a pan-head camera, wherein the housing consisting of the first housing element 12 and the second housing element 14 is pivotally mounted on a support housing 32. Furthermore, the support housing 32 has a quick-coupling mechanism 34, for example a bayonet lock, with which the optical image capture unit 10 can be coupled to a coupling element. Furthermore, the coupling element connects the optical image capture unit 10 to the sewer inspection system or the control unit. In particular, the sewer inspection system can have a control unit on which the image information recorded by the optical image capture unit 10 can be displayed. Furthermore, the control unit can pivot the housing in the support housing and / or manually control the focusing of the optical image capture unit 10. List of reference symbols 10 optical image capture unit 12 first housing element 14 second housing element 16 lens 18 lens 20 image sensors 21 Sensor area 22 Control unit 24 supporting element 26 optical window 28 supporting section 30 projections 32 carrier housings 34 Quick coupling mechanism 36 Image processing unit

Claims

[1] Optical image capture unit (10) for inspecting sewer pipes and which can be coupled to a sewer inspection system, comprising: a housing (12, 14) which can be coupled to the sewer inspection system; an image sensor (20) arranged in the housing for capturing image information of an image of an object displayed on the image sensor, a lens (16) arranged in or on the housing for generating the image of the object on the image sensor (20), a lens (18) arranged between the objective (16) and the image sensor (20), the imaging properties of which can be changed by means of an input signal (19) in order to focus the image of the object produced by the objective onto the image sensor (20); and a control unit (22) arranged in the housing (12, 14) which is designed to generate the input signal (19) based on the image information. [2] Optical image capture unit (10) according to claim 1, wherein the objective (16), the lens (18) and the image sensor (20) are positionally fixed with respect to one another. [3] Optical image capture unit (10) according to one of the preceding claims, wherein the lens curvature of the lens (18) and / or the material property of the lens (18) can be adjusted by means of the input signal (19), and wherein the imaging property preferably comprises the focal length of the lens (18). [4] Optical image capture unit (10) according to one of the preceding claims, wherein the housing (12, 14) encloses the objective (16), the lens (18) and the image sensor (20) in a dust- and liquid-tight manner. [5] Optical image capture unit (10) according to one of the preceding claims, wherein the housing (12, 14) has a first housing element (12) and a second housing element (14) which are connectable to one another and which, in the connected state, enclose the objective (16), the lens (18) and the image sensor (20), and wherein the optical image capture unit (10) has a support element (24) which is connectable (14) to the first housing element (12) or the second housing element, and wherein the image sensor (20) is arranged on the support element (24). [6] Optical image capture unit (10) according to claim 5, wherein the control unit (22) is arranged on the support element (24) and the support element (24) is preferably anodized. [7] Optical image capture unit (10) according to one of the preceding claims, which is further designed to transmit the image information of the image sensor (20) to an operating unit of the sewer inspection system. [8] Optical image capture unit (10) according to one of the preceding claims, further comprising a support housing (32), wherein the housing (12, 14) is pivotally mounted on the support housing (32) and wherein the support housing (32) is coupleable to the channel inspection system. [9] Sewer inspection system, comprising: a control unit; and an optical image capture unit (10) according to one of the preceding claims, which can be coupled to the operating unit.

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