METHOD FOR PRODUCEING A COMPOSITE CIRCLE OR RING PICTURE

Description

[0001] The invention relates to a method for generating a composite circular image or ring image on a screen using image data from a rotating camera and a deletion system for this purpose.

[0002] To monitor a large room thermographically from its center, a fisheye lens with a field of view of at least 180° would be advantageous for an infrared camera. However, such a lens is unsuitable for use with an infrared camera for capturing thermographic images because it produces strong distortions at the edges of the image, leading to temperature measurement errors.

[0003] A room to be monitored by a camera, as described in the invention, could be, for example, a storage facility, a production facility, or the like, both outdoors and indoors. For fire detection or early fire detection, such rooms predominantly include automatic extinguishing systems with at least one camera, which is generally mounted above, for example on a ceiling or a mast or the like, and is panned over the area to be monitored.If a fire source, smoldering ember, or an area with an unusually high temperature for the monitored material—indicating a developing fire, possibly even in a deeper area below the thermographically monitored surface—is detected, the control system directs a fire extinguisher cannon toward this source of fire and opens a valve, releasing the extinguishing agent at a relatively high pressure and in a relatively large quantity. Due to inaccuracies in detecting the source of the fire and in the aiming of the fire extinguisher cannon, the cannon is often swiveled vertically and / or horizontally to extinguish the fire.

[0004] EP 3 013 044 A1 discloses a surveillance system with PTZ cameras. A circular panoramic image of the area around each camera is generated from multiple images taken by the cameras. The disclosure further details how overlapping panoramic images can be combined.

[0005] US patent 2013 / 0 021 433 A1 discloses a method for displaying images from a movable surveillance camera on a monitor. Furthermore, WO 97 / 25 628 A1 discloses a camera system for the optical monitoring of large areas. Finally, DE 20 2010 000 060 U1 describes a fire suppression system for combating fires, comprising an infrared camera.

[0006] The invention is based on the objective of creating a method of the type mentioned above that provides a continuous informative display of the monitored space on a screen. According to the invention, this objective is achieved by the features of the independent claim.

[0007] The dependent claims represent advantageous embodiments of the invention.

[0008] In a method for generating a composite circular image or ring image on a screen using image data from a rotating camera with a specific orientation to the axis of rotation, the image data is processed by an image processing device, wherein the camera provides a rectangular image bounded lengthwise by a start line and an end line, and the image is modified in such a way that that, when the camera is oriented in such a way that the starting line intersects the axis of rotation, the starting line forms the center of a circular image and the ending line forms the outer radius of a circular segment image, wherein several circular segment images are successively combined to form a circular image, or that, when the camera is oriented in such a way that the starting line is offset by a positive angle to the axis of rotation, the starting line forms the inner radius and the ending line forms the outer radius of a circular sector image, wherein several circular sector images are successively combined to form an annular image, wherein the image processing device aligns at least one generated circular image concentrically with at least one generated annular image and displays successively combined images captured by the cameras on the screen.

[0009] Naturally, digital cameras are used in conjunction with the method according to the invention, which also send digital images, i.e., image data, to the computer's image processing unit for further processing and analysis. The computer can be a desktop computer, a virtual machine, a tablet computer, a laptop, or the like.

[0010] The circular or annular image can encompass any angle and, to the expert's knowledge, can be any size smaller than 360°. In particular, the circular or annular images can be adapted to an object being monitored, for example, a corner of a building or storage area. Then, for instance, the camera can oscillate through an angle of less than 360°, and a corresponding circular or annular image is assembled and displayed.

[0011] The camera used in the invention can be an infrared camera (IR camera) or a video camera, the images of which are analyzed on the image processing device with regard to features that indicate smoke or fire.

[0012] The resulting circular or ring-shaped image is relatively clear and allows observation of a relatively large space without the distortions caused by the lens, whereby the usual distortions become more pronounced the wider the image is.

[0013] To obtain detailed and informative images of a relatively large area being monitored by the camera, both in the center (below the camera's axis of rotation) and at a distance, the image processing unit combines at least one generated circular image with at least one generated annular image. These images are concentrically aligned and captured sequentially by the camera. Naturally, due to the potential need to pan the camera, the circular image is displayed with a slight time delay compared to the annular image, whose inner diameter can seamlessly connect to the outer diameter of the circular image. Multiple annular images can, of course, be combined.

[0014] Of course, circular and ring-shaped images smaller than 360° can also be generated and displayed here, with the size being determined by rotating the camera or during image generation, particularly to exclude, for example, a corner of a building or a sector that should not be observed.

[0015] To avoid unwanted distortions of the constantly refreshing image displayed on the screen in real time, a section of the rectangular image extending from the start line to the end line is selected and processed by the image processing unit to create a circular segment or circular sector image. A section of the image with a width of, for example, 40 thermal pixels can be extracted relatively precisely from the center of the image, as this is where the least distortion is present. A relatively narrow strip of the image is selected for processing and analysis because, with increasing image width, the fisheye effect becomes more pronounced, making it impossible to stitch images together without distortion.In this process, the individual images, especially IR thermal images, are not strung together one after the other, but rather small sections of the IR thermal image are captured along with the camera's position during rotation and strung together.

[0016] In this configuration, the height of the image forms a radius for circular segment images or a width for circular sector images. The rectangular image captured and processed by the camera is converted into a thermographic circular or annular image, whereby the lower row of pixels, referred to here as the starting row, becomes a central pixel in a circular image and a small diameter of the annular image in an annular image.

[0017] The image processing unit conveniently converts the image into a thermographic image and evaluates it according to temperature thresholds stored in a memory device. It is not necessary to display all details of the thermographic image continuously. The display of specific hotspots—that is, heat points with a temperature above stored threshold temperatures—against a uniform background is very clear. In this case, the individual circular segment or sector image is only indicated in real time, and the detailed view appears after a corresponding command is entered into the image processing unit. For example, if an operator taps on a touchscreen at the location of a displayed hotspot, the detailed image is shown, and the cause of the hotspot becomes apparent.Limit temperatures can be stored, for example, for pre-alarms and / or alarms, which can be displayed in different ways.

[0018] Preferably, the image processing unit calculates polar coordinates of thermal pixels when converting the image into a thermographic image. These polar coordinates can be used, for example, to control a fire extinguisher. The polar coordinates can be easily determined if the camera's position in the monitored area and its rotational orientation are available to a computer controller that includes the image processing unit. Data from a stepper motor or a position sensor can be used to evaluate the rotational orientation of the camera, which may be rotating continuously or oscillating.

[0019] The method is used, for example, in a fire suppression system with at least one extinguishing agent monitor, which is rotatable about a mounting axis and pivotable about a swivel axis by means of at least one motor and is connected to an extinguishing agent line for supply, at least one camera which is rotatable about at least one mounting axis by means of at least one motor, an electronic control unit which includes at least one storage device in which at least basic geometric data of the relevant area and / or data of the extinguishing agent monitor are stored in a readable manner, and a computer module for data processing as well as an image processing device operating according to the previously described method, an input device connected to the control unit for data input and / or for controlling the extinguishing agent monitor and the camera and a screen connected to the control unit for displaying images of the camera processed by the image processing device.

[0020] The image processed by the image processing unit is displayed on the screen as a circular image, an annular image, or a combination of both with at least one concentrically aligned annular image. In the case of thermal analysis, areas with temperatures exceeding stored limits are displayed as a pre-alarm or alarm. An alarm indicates a fire, and the extinguishing agent dispenser can be positioned based on the data received by the control unit so that the extinguishing agent is directed at the fire. Accuracy is increased if a laser connected to the control unit, capable of distance measurement, is assigned to the camera and / or the extinguishing agent dispenser.

[0021] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations. The scope of the invention is defined solely by the claims.

[0022] The invention will be explained in more detail below using exemplary embodiments with reference to the associated drawing.

[0023] It shows: Fig. 1 a schematic representation of an arrangement for carrying out the method according to the invention, Fig. 2 a schematic representation of a composite camera image, Fig. 3 a representation of a camera image, Fig. 4 a partial representation of a camera image section according to Fig. 3 , Fig. 5 a schematic representation of the transformed camera image section according to Fig. 4 Fig. 6 a schematic representation of a generated circular image, Fig. 7 a second schematic representation of the arrangement according to Fig. 1Fig. 8 a schematic representation of a generated annular image, Fig. 9 a schematic representation of a circular image composed of several annular images and a circular image, Fig. 10 a third schematic representation of the arrangement according to Fig. 1 , Fig. 11 a fourth schematic representation of the arrangement according to Fig. 1 , Fig. 12 a representation of a thermo-circular diagram and Fig. 13 a schematic representation of a room to be monitored with a fire extinguishing system according to the invention.

[0024] A digital camera 2, configured as a video camera or infrared camera, is installed on the ceiling 27 of a room 1 to be monitored, or on a mast, support, or the like. Of course, room 1 could also be an outdoor storage area or any other suitable surface, such as a forest or similar. The camera 2 is mounted on a mounting axis 3 so that it can rotate about that axis. Thus, the mounting axis 3 represents a rotation axis 33. The camera 2 can rotate up to 360° by means of an associated motor 4, for example, by oscillating. The camera 2 has, for example, an image resolution of 640 x 480 pixels with a field of view of 90° x 67.5°. It is obvious to a person skilled in the art that cameras 2 with different resolutions and / or field of view can also be used.

[0025] The camera 2 and the motor 4 associated with the camera 2 are coupled to an electronic control unit 5, which in this case is designed as a tablet computer 6 with a touchscreen display 7. Of course, the control unit 5 can also comprise a stationary or virtual computer. The control unit 5 incorporates at least one storage device 8 for readable data storage, a computer module 9, and an image processing unit 10 for data processing.

[0026] The storage unit 8 of the electronic control 5 contains the basic geometric data of room 1, which are measured on-site as actual data. This basic geometric data of room 1 describes the floor area, i.e., the dimensions of the floor 34 and the height of room 1. Furthermore, the coordinates to which the rotation axis 33 of the camera 2 and a fire extinguisher 11 are attached are stored. In addition, manufacturer-determined standard launch curves, which describe the throw ranges of the extinguishing agent under a specific pressure and predefined fire extinguisher settings, as well as various software programs, can be stored.

[0027] The software and the image processing device 10 ensure the detection of a hotspot 23, i.e. a warm spot with an actual temperature above a limit temperature, which is stored for a pre-alarm and / or an alarm in the event of a fire.

[0028] To generate a representation of the monitored room 1 on the screen 7 that is easily perceptible to an observer or operating personnel, a circular image 12 or an annular image 13 or a circular image 12 consisting of at least one circular image 12 and / or at least one annular image 13 is generated by the image processing device 10, in which in particular the disadvantages of a rectangular image, which the camera 2 provides, for example, with a fisheye lens, are avoided.

[0029] The rectangular image from camera 2, at the given opening angle 20 of 90° x 67.5°, has an image resolution of 640 x 480 pixels and begins at the bottom with a start line 15 and ends at the top with an end line 16. Camera 2 is mounted on the mounting axis 3 or the rotation axis 33 such that, at the opening angle 20 of 90°, it is pivoted by 45° relative to the mounting axis 3, so that the start line 15 is aligned with the mounting axis 3 or intersects it at its extension, and a start corner pixel 17 is almost stationary. An end corner pixel 18 of the end line 16 describes a circular path 19 when camera 2 rotates.

[0030] Assigning the full resolution of camera 2 to the 360° circular path 19 results in: 360° circumference / 67.5° opening angle = 5.33 superimposed camera images Therefore:

[0031] 5.33 x 480 thermal pixels per 67.5° opening angle results in a circular resolution of approximately 2,558 thermal pixels for 360° resolution.

[0032] During a 360° rotation, a thermographic rectangular image 14 is created, bounded at the bottom by the start line 15 and at the top by the end line 16. This image has a height of 640 thermal pixels and a length of 2,558 thermal pixels. In the arrangement described above, the starting corner pixel 17 always points to virtually the same location below the mounting axis 3, which serves as the axis of rotation. To visually interpret this rectangular image 14, small sections of the IR thermal image 14 are captured along with the camera 2's position during its rotation and then strung together. The width of these sections varies. This depends on the processing speed of the computer module 9 of the controller 5, where these sections are joined, and on the rotational speed of the motor 4. The narrower the sections, the less distorted the overall image, but the more processing power the system requires.

[0033] To replicate a wide-angle lens of approximately 180° for an IR camera 2, a central section 21 of the image 14 is taken as a subsection with a width of, for example, 40 heat pixels, as precisely as possible from the center of the image, since there is the least image distortion in the center of the image, because the wider the image 14 is, the more the fisheye effect of a shot becomes and the sub-images can no longer be joined together without distortion.

[0034] The central section 21 of image 14 now represents, in effect, the image 14 that, in the arrangement described above, must be transformed into a thermographic circular image 12. The lower starting row 15 is converted into a central circular image center point 22, where the height of the central section 21 of the thermographic image 14 corresponds to the radius of a circular segment image 24. Each row of the central section 21 must be converted into a circular segment row. The closer one gets to the circular image center point 22, the fewer heat pixels fit into the respective row of the circular segment image 24. Therefore, heat pixel groups must be formed, consisting of several adjacent heat pixels. The closer one gets to the center, i.e., the circular image center point 22 of image 12, the more heat pixels a heat pixel group comprises.

[0035] Averaging the individual heat pixels within a heat pixel group smooths the maximum temperatures. Therefore, when combining a heat pixel group into a new heat pixel, the temperature value of the hottest heat pixel in the group is always used. Using the maximum value when combining a heat pixel group is particularly advantageous when the principle described above is used for fire monitoring and displaying a fire source, i.e., a hotspot.

[0036] Simultaneously, the polar coordinates of the heat pixels are calculated so that, in the event of a fire alarm, a fire extinguisher 11 can be immediately positioned on the source of the fire, the hotspot 23. Data from a position sensor 26 located on the mounting axis 3, which is present at the controller 5, can be determined and processed during the calculation of the polar coordinates. The alignment of the fire extinguisher 11 can be simplified to account for the trajectory of the extinguishing agent by a laser 24 assigned to the camera 2, which is designed for distance measurement and connected to the controller 5.

[0037] To display a circular image 12 on the screen 7, several circular segment images 24 are arranged in a row and overwritten as the camera 2 is continuously rotated.

[0038] If a camera 2 with a smaller opening angle 20 than 90° is chosen, for example, to monitor a partial area of ​​room 1, then the starting corner pixel 17 is not in line with the mounting axis 3 and describes a circular path that is concentric to the circular path 19 of the ending corner pixel 18.

[0039] Here too, a central section 21 is extracted from image 4 and transformed into a thermographic annular image 13, such that the lower starting line 15 is converted into an inner diameter 31 and the upper ending line 16 into an outer diameter 32 of a circular sector image 35, with the height of the central section 21 of the thermographic image 14 corresponding to the difference between the outer diameter 32 and the inner diameter 31 of the circular sector image 35. The circular sector images 35 generated by the rotation of the camera 2 are continuously assembled to form the annular image 13.

[0040] Of course, depending on the rotation angle of the camera 2 or controlled by the image processing unit 10, circular images 12 and / or ring images 13 or corresponding combinations with any angle less than 360° can also be generated and displayed.

[0041] To change the diameter or area to be monitored in room 1, a camera 2 with a smaller opening angle 20 than 90° is selected and aligned such that the starting corner pixel 17 is in line with the mounting axis 3 and the ending corner pixel 18 describes a circular path that is concentric to the circular path 19 and has a different diameter. As already described, a circular image 12 is generated and displayed.

[0042] If an area above the mounting location of camera 2 in room 1, for example a ceiling 27, is to be monitored, then a camera 2 with an opening angle 20 of 90° can be selected and aligned such that the starting corner pixel 17 is not in line with the mounting axis 3 and the ending corner pixel 18 describes a circular path that is concentric to the circular path 19 and has a different diameter. As already described, an annular image 12 is generated and displayed.

[0043] It is evident to the person skilled in the art that, by pivoting the camera 2 relative to the mounting axis 3, it is possible to successively generate, for example, a circular image 12 and several annular images 13 or several annular images 13 without a central circular image 12 with different diameters and to align them concentrically to each other in a common representation in order to be able to capture a relatively large space 1 both centrally and in peripheral edge areas.

[0044] Room 1, which is to be monitored, is, for example, a storage room for flammable materials such as tires, waste, but also motor vehicles, plastics, or the like. Room 1 can be defined by the dimensions of its floor area and its height in a known manner.

[0045] To monitor room 1 for the occurrence of a fire and, if necessary, to initiate automatic fire extinguishing, the extinguishing system is installed. This system essentially comprises camera 2, which is designed as a thermal imaging camera, and the extinguishing agent monitor 11, which can also be referred to as a fire monitor or fire monitor. Camera 2 and the extinguishing agent monitor 11 are mounted at specific positions on the ceiling 27 of room 1 such that the mounting axis 3 of camera 2 is aligned parallel to a mounting axis 28 of the extinguishing agent monitor 11.

[0046] The extinguishing agent monitor 11 is pivotable about two axes, as indicated by the arrows 29 associated with the extinguishing agent monitor 11, namely about its mounting axis 28 and an axis oriented at an angle to it. The extinguishing agent monitor 11 is connected to pipelines or hose lines for the extinguishing agent. Furthermore, the extinguishing agent monitor 11 is coupled to the electronic control unit 5, which, in a configuration as a tablet computer 6 with a touchscreen 30, serves both as an input unit and for displaying the generated circular images 12 and annular images 13.

[0047] If a hotspot 23 is displayed on the touchscreen 30 within the circular image 12 or ring image 13, then the image section containing the hotspot 23 can be displayed and a fire extinguisher 11 aligned by simply tapping the hotspot 23 on the touchscreen 30. Alternatively, instead of control via touchscreen 30, a joystick can also be provided as an input device on a computer with an associated screen.

[0048] The position of the fire source detected by camera 2 can be described with relatively little computational effort using the polar coordinates determined by the image processing unit 10 and, if necessary, the distance data determined by the laser 25. The extinguishing agent monitor 11 can then be tracked relatively accurately, since the two mounting axes 3 and 28 are aligned parallel to each other, so that deviations or errors due to the different mounting points are of minor significance. The error is usually so small that the extinguishing agent can be applied to the fire at this point. Reference sign

[0049] 1. Space 19. circular track 2. camera 20. Opening angle 3. Mounting axle of 2 21. Middle section 4. Motor 22. Center of the circular image 5. steering 23. Hotspot 6. Tablet computer 24. Circle segment image 7. Screen 25. Laser 8. Storage device 26. Position giver 9. Computer module 27. Ceiling 10. Image processing equipment 28. Mounting axle of 11 11. Fire extinguishing agent monitor 29. Arrows 12. Circular image 30. Touchscreen 13. circular ring pattern 31. inner diameter 14. Picture 32. outer diameter 15. Home bar 33. axis of rotation 16. End line 34. Floor 17. Starteck pixels 35. Circular sector image 18. Discovery pixels

Claims

1. A method for generating a composite circular image (12) or circular ring image (13) on a screen (7) with image data from a rotating camera (2) with a specific alignment to the axis of rotation (33), which are processed on an image-processing device (10), wherein the camera (2) provides a rectangular image (14) which is bounded on the longitudinal side by a start line (15) and an end line (16), and the image (14) is changed in such a way - that the start line (15) forms a circular image center point (22) and the end line (16) forms an outer radius of a circular segment image (24) when the camera (2) is aligned in such a way that the start line (15) intersects the axis of rotation (33), wherein a plurality of circular segment images (24) are temporally sequentially combined to produce a circular image (12), or - that the start line (15) forms an inner radius and the end line forms an outer radius of a circular sector image (35) when the camera (2) is aligned in such a way that the start line (15) is offset by a positive angle to the axis of rotation (33), wherein a plurality of circular sector images (35) are temporally sequentially combined to produce a circular ring image (13), - wherein the image-processing device (10) aligns at least one generated circular image (12) with at least one generated circular ring image (13) concentrically to one another and displays images (14), captured successively by means of the camera (2), in combined fashion on the screen (7).

2. The method according to claim 1, characterized in that a center portion (21) of the rectangular image (14) extending from the start line (15) to the end line (16) is selected and processed by the image-processing device (10) for processing to produce the circular segment image (24) or the circular sector image (35).

3. The method according to claim 1 or 2, characterized in that the height dimension of the image (14) forms a radius of the circular segment image (24) or a width of the circular sector image (35).

4. The method according to any one of claims 1 to 3, characterized in that the image-processing device (10) converts the image (14) into a thermographic image and evaluates it according to thermal limit values stored on a storage device (8).

5. The method according to any one of claims 1 to 4, characterized in that the image-processing device (10) calculates polar coordinates of thermal pixels when converting the image (14) into the circular segment image (24) or the circular sector image (35).

6. The method according to any one of claims 1 to 5, characterized in that the image-processing device (10) displays a plurality of generated circular ring images (13), concentrically aligned with one another and captured successively by means of the camera, in combined fashion on the screen (7).

7. The method according to any one of claims 1 to 6, characterized in that the camera (2) has an image resolution of 640 x 480 pixels with an opening angle (20) of 90° x 67.5°.

8. An extinguishing system with - at least one extinguishing agent sprayer (11) that is able to be rotated about a mounting axis (28) by means of at least one motor, is able to be pivoted about a pivot axis, and is connected to an extinguishing agent line in order to be supplied with extinguishing agent, - at least one camera (2) that is able to be rotated at least about a mounting axis (3) by means of at least one motor (4), - an electronic controller (5) that comprises at least one storage device (8) in which at least geometric basic data of the relevant area and / or data of the extinguishing agent sprayer (11) are stored so as to be capable of being read, and a computer module (9) for data processing, as well as an image-processing device (10) that operates according to the method according to claim 1, - an input device, connected to the controller (5), for inputting data and / or for controlling the extinguishing agent sprayer (11) and the camera (2), and - a screen (7) connected to the controller (5) for displaying circular images (12) and / or circular ring images (13) of the image-processing device (10).