Knitting machine with monitoring device and method for monitoring needles during knitting machine operation.

Abstract

In order to monitor needles (3) during the operation of a knitting machine, the knitting machine is provided with a monitoring device having a camera (4), a light source (5) and a control unit (11) having a camera control. The light source (5) and the camera (4) are arranged relative to one another such that light rays (6) incident on at least one needle (3) are emitted from the light source (5), and light rays (7) reflected from the needles (3) are detected by the camera (4). The camera (4) has a surface camera element. Images of an image area (9), which corresponds to at least one needle (3) or at least one part of the needle (3), are acquired, wherein the image data are measured brightness values of the reflected light rays (7). The frame rate fK, i.e. the number of images per unit time, and the intensity of the reflected light rays (7) of the light source (5) are selected to be high enough that, in at least two consecutive images, all of the needles (3) of the image area (9), which comprises at least five needles (3), are imaged from the image data with a minimum separation. From the image data, the position of each needle (3) is identified on the image, and from the positions of the needles (3), a defective needle (3) is identified.

Description

1 / 15 Knitting machine with monitoring device and method for monitoring needles during knitting machine operation.

[001] The invention relates to a knitting machine with a monitoring device and a method for monitoring needles during the operation of the knitting machine according to the generic terms of the independent claims.

[002] A method for optical quality control of needles in automatic knitting machines is known from document DE 40 14 661 A1. To detect gross defects, an image of the needle zone to be monitored is displayed on a semiconductor array server synchronized with the needle frequency. Analog brightness signals from discrete pixels are digitized and compared with reference data.

[003] In the method described in document DE 199 24 924 A1 for needle verification with a light scanning system, the light reflected by the needles of a first optical waveguide reaches a second optical waveguide. Intact and correctly positioned needles generate a basic signal sequence in a receiver. During operation, a signal sequence is recorded and compared with the basic signal sequence.

[004] US patent 2022 / 0349097 A1 discloses the use of a camera module to monitor a knitting machine based on the surface of the knitted fabric, where the camera module compares images of the same vertical line.

[005] Document DE 102 23 754 A1 describes how to detect defects in a knitted fabric by comparing recorded information, for example, by a camera on an illuminated fabric web with stored information. Petition 870260048135, dated 05 / 20 / 2026, page 6 / 13 2 / 15

[006] A camera with area-scanning camera elements for monitoring a moving web is known in DE 10 2015 119 444 B4.

[007] In many methods of monitoring the needles of a knitting machine, reference data are recorded in advance and used to detect defects during operation.

[008] The object of the invention is to develop a knitting machine with a monitoring device and a method for monitoring needles during the operation of the knitting machine, in which direct monitoring of the needles is possible without comparison with reference information.

[009] The object is resolved by the independent claims.

[0010] A knitting machine according to the invention comprises a monitoring device for monitoring needles during the operation of the knitting machine. The monitoring device is provided with a camera, a light source, and a control unit with a camera control. The light source and the camera are arranged relative to each other so that the light beams incident on at least one needle are emitted by the light source and the light beams reflected by the needles are captured by the camera.

[0011] The camera has an area scanning camera element. The camera control is incorporated to capture images of an image area corresponding to at least one needle or at least part of a needle. The image data consists of brightness values ​​measured from the reflected light beams.

[0012] The camera has a high frame rate and the light beams reflected from the light source have such high intensity that, in at least two consecutive images, all needles in the image area of ​​the image data are captured with a minimum distance.

[0013] The image area comprises at least five needles. Petition 870240095061, dated 06 / 11 / 2024, p. 9 / 39 3 / 15 The control unit is incorporated to identify the position of each needle in the image from the image data and to identify a defective needle from the needle positions.

[0014] The monitoring device allows the generation of at least two consecutive images in which all needles in the image data area are distinctly imaged. The generation of such images makes it possible to recognize and verify the positions and therefore the distances between all visible needles. No reference information is required for this.

[0015] In one embodiment, the camera is configured to operate at a frame rate fK that is greater than the maximum possible needle rate fN, that is, the number of needles per unit of time that the needles pass through the camera.

[0016] By adapting the camera's frame rate to the highest possible needle rate of the knitting machine, the monitoring device can be used independently of the knitting machine's operating mode.

[0017] In one embodiment, camera control is incorporated to combine pixels of the area-scanning camera element to read image data from the image area.

[0018] This increases reading speed.

[0019] In one embodiment, the camera control is incorporated to select a selection field of pixels selected for the image area for reading image data.

[0020] This also increases reading speed.

[0021] In one mode, the camera control is incorporated to move the selection field for fine adjustment of the image area.

[0022] As an electronic adjustment, moving the selection field is a much simpler adjustment than mechanical adjustment, for example, by adjusting adjustment screws. Moving the selection field using the unit Petition 870240095061, dated 06 / 11 / 2024, page 10 / 39 4 / 15 control allows for automated adjustment.

[0023] In one embodiment, the camera and light source are arranged so that the image area captures at least five needles projected onto the reversal point area.

[0024] This allows for a smaller image area height and therefore faster reading and evaluation of the image data.

[0025] In one embodiment, the distance from the camera to the needles is 5 cm to 40 cm and / or the distance from the light source to the needles is 5 cm to 40 cm.

[0026] It is advantageous for the operation of the knitting cylinder and the camera mounting to position the camera at a distance of at least 5 cm or more from the needles.

[0027] In one embodiment, the light source is configured to emit light beams that strike the needles as a converging beam.

[0028] Due to the converging beam, the intensity of the light beams incident on the camera's area scanning element is higher for a good needle and lower for a broken needle due to the rough, cracked surface.

[0029] In one embodiment, the control unit is incorporated to determine, from the image data of a plurality of images, a median value for the distances between the imaged needles and, from the median values ​​of the images, a floating average value as a standard distance and to compare each individual distance determined between two needles with the standard distance to detect a defective or missing needle.

[0030] The formation of median values ​​and an updated standard distance allow for the quick and reliable detection of a defective or missing needle.

[0031] The methods according to the invention have corresponding characteristics and advantages. Petition 870240095061, dated 06 / 11 / 2024, page 11 / 39 5 / 15

[0032] Other features and advantages are described in the following description.

[0033] The invention is explained further below with reference to examples shown schematically in the drawing. It is shown:

[0034] Figure 1 is a schematic view of a circular knitting machine with a monitoring device;

[0035] Figure 2 is a simplified view of a row of needles, with a labeled image area;

[0036] Figure 3 is a block diagram of the monitoring device;

[0037] Figures 4 a, b, c are successive images with image data from an image area with five needles in the area of ​​needle ascent or descent;

[0038] Figure 5 is an image of an image area with seven needles in the reversal point area.

[0039] Figure 1 shows a circular knitting machine 1 with a knitting cylinder 2 and stitch-forming needles 3. For clarity, the yarn feed is not shown in Figure 1.

[0040] The circular knitting machine 1 has a monitoring device equipped with a camera 4 and a light source 5. The light source 5 and the camera 4 are arranged together so that the light beams 6 incident on the needles 3 are emitted by the light source 5 and the light beams 7 reflected by the needles 3 are captured by the camera 4. The angle between the incident and reflected light beams 6, 7 is approximately 60°. The camera 4 is positioned approximately at the height of the needles 3 and the light source 5 above it. The camera 4 and the light source 5 are fixed to a common support 8 on the circular knitting machine 1.

[0041] The distance from camera 4 to needles 3 and / or the distance from the light source to needles 3 is 5 cm to 40 cm.

[0042] Figure 2 shows a simplified row of needles 3, by Petition 870240095061, dated 06 / 11 / 2024, page 12 / 39 6 / 15 in the middle of which an image area 9 with five needles 3 is marked. Also marked is an area 10 within the image area 9 below the needle heads 3a, which can be masked using a digital mask, for example.

[0043] As shown in the block diagram of Figure 3, the monitoring device comprises a control unit 11 with a camera control unit, the control unit 11 being connected to the camera 4. The camera control unit is integrated into the control unit 11.

[0044] Alternatively, the camera control unit is located inside camera 4.

[0045] The camera control unit includes, for example, a frame capture plate. Control unit 11 is equipped with a microprocessor. The camera control unit incorporates a digital mask to mask any pixels that may be outside the path traversed by the needle heads 3a. In this example, the pixels in area 10 are masked.

[0046] Alternatively, control unit 11 is incorporated as a hardware unit with the camera control unit.

[0047] A power supply 12 is connected to control unit 11 and light source 5.

[0048] The control unit 11 comprises a switch 13 for generating a stop signal, the switch being connected to a machine control unit 14. When the switch 13 is activated by the control unit 11, a stop signal is sent to the machine control 14 and the circular knitting machine 1 is stopped.

[0049] Alternatively, control unit 11 is connected to the machine control system via a bus system, for example, a CAN bus or an Ethernet bus, through which a stop signal is sent. Petition 870240095061, dated 06 / 11 / 2024, page 13 / 39 7 / 15

[0050] A display device 15 is connected to the control unit 11, for example, to display images selected by the control unit 11. Since the images are not perceptible at the fK frame rate of the camera 4, only selected images, for example, images selected every 1 / 30th of a second, are displayed. The display device 15 also displays a distance determined by the control unit 11, for example, a number of needles 3, between a specific needle 3 and a specific position on the knitting cylinder 2. The specific needle 3 is, for example, a needle 3 determined to be defective or missing. The specific position is, for example, a repair position.

[0051] Camera 4 has an area scanning camera element. The camera control unit is incorporated to capture an image of an image area 9 with at least five needles 3 activated.

[0052] Alternatively, image area 9 comprises 3 to 20 needles.

[0053] The image data of an image are the brightness values ​​of the beams 7 reflected in the needles 3, which are measured per pixel of the area scanning camera element.

[0054] Figures 4a, 4b, 4c show three successive images of image area 9 shown schematically in Figure 2.

[0055] Camera 4 has a high frame rate fK and the reflected light beams 7 from the light source 5 have such a high intensity that in the three consecutive images of Figures 4a, 4b, 4c all the needles 3 of the image area 9 of the image data are captured with a minimum distance.

[0056] In this example, camera control is incorporated to capture images of an image area with representations of at least five 3a needle heads. Petition 870240095061, dated 06 / 11 / 2024, page 14 / 39 8 / 15

[0057] In the images of Figures 4a, 4b, 4c, the five needles 3 are recognizable as representations of needle heads 3a, that is, as bright points corresponding to the needle heads. The representations of needle heads 3a go from the lower left to the upper right.

[0058] A minimum distance between representations, for example, between the right flank of a bright spot and the right flank of the next bright spot, is given if the spacing between representations is at least three times greater than the width of the representations. The minimum distance ensures sufficient distance between representations to be able to recognize a missing or broken needle 3.

[0059] For example, image area 9 comprises 256 pixels in the row and 200 pixels in the column. The spacing between representations is approximately 50 pixels. The extent of a representation is approximately 10 pixels and the distance between the edges of the representations is approximately 40 pixels. The spacing between representations is approximately five times greater than the width of the representations. The distance between representations corresponds to the distance between the needles 3.

[0060] The minimum distance is 20 to 50 pixels, for example, with a representation width of 5 to 15 pixels.

[0061] The different representations of the needle heads 3a of the five needles 3 show that throughout the three images, Figures 4 a, b, c, the representations move to the lower left corner.

[0062] Light source 5 has an optical system, through which a point of light is generated by the optical system, which essentially illuminates only the needles 3 of the image area 9. In this example, the point of light illuminates essentially the needle heads 3a of the needles 3. The point of light is, for example, round and has a diameter of, for example Petition 870240095061, dated 06 / 11 / 2024, p. 15 / 39 9 / 15 example, 5 mm.

[0063] Alternatively, light source 5 has an optical system that generates an elliptical or rectangular point of light.

[0064] Light source 5 is a spotlight, in particular an LED spotlight with a power of at least 3 watts.

[0065] Alternatively, light source 5 is provided as an LED spotlight with a 12-watt output.

[0066] Alternatively, light source 5 is incorporated as a strobe light source.

[0067] The light source 5 is incorporated by its optics to emit the light beams 6 striking the needles 3 as a convergent beam. The convergent beam striking the needles 3 is reflected more strongly at the convex heads of the needles 3a than a parallel beam. Furthermore, the light beams 6 of a convergent beam are scattered more strongly on a rough fracture surface of a broken needle 3.

[0068] Alternatively, camera 4 is equipped with a telecentric lens.

[0069] The frame rate fK is the number of images at a time that camera 4 captures.

[0070] The camera control is incorporated to operate camera 4 at a frame rate fK that is greater than a needle rate fN of the circular knitting machine 1, i.e., greater than the number of needles 3 at a time that the needles 3 pass through camera 4.

[0071] If the circular knitting machine 1 has a speed of 1000 needles 3 per second, i.e. a needle rate fn of 1 kHz, a slightly higher frame rate fK of, for example, 1.1 kHz or, for example, 1.5 or, for example, 2 kHz is used.

[0072] The camera control is incorporated to set the camera's exposure time 4, that is, the time during which the element of Petition 870240095061, dated 06 / 11 / 2024, page 16 / 39 The 10 / 15 area scan of camera 4 measures the intensity of incident light as brightness values, for 2 to 15% of the frame spacing. In this example, the exposure time is set for 3 to 5% of the frame spacing. At a frame rate of 2 kHz, the frame spacing has a value of 0.5 ms.

[0073] Camera control is preferably incorporated to operate camera 4 at a frame rate f K that is greater than the maximum possible needle rate in the circular knitting machine 1.

[0074] Alternatively, the speed of circular knitting machine 1 is, for example, 6000 needles per second and the needle rate fn is 6 kHz. A frame rate of, for example, 7 kHz is used.

[0075] The area-scanning camera element of camera 4 is approximately 2500 x 2000 pixels.

[0076] To read the image data, i.e., the brightness values, from image area 9, the camera control unit is incorporated to combine pixels from the area scanning camera element. This process is called binning. In each case, 4 x 4 pixels are combined so that the pixels to be read are reduced to 600 x 500.

[0077] The camera control is incorporated to select a selection field of selected pixels for the image area 9. A selection field is called a region of interest (roi).

[0078] For example, the selection field has a size of 256 x 30 at 200 pixels. Camera control is incorporated to move image area 9 for fine adjustment of image area 9, i.e., for precise adjustment of image area 9 to needles 3. As a result, after mounting camera 4 and light source 5, image area 9 can be precisely adjusted to the five desired needles 3 of the knitting cylinder 2.

[0079] Alternatively, the scanning camera element of Petition 870240095061, dated 06 / 11 / 2024, page 17 / 39 The 11 / 15 camera area 4 is provided with 1300 x 1100 pixels, for example.

[0080] Alternatively, the area scanning camera element has 256 x 200 pixels.

[0081] Control unit 11 is incorporated to identify the position of each needle 3 in the image from the image data, i.e., the brightness values ​​of the pixels, and to identify a defective needle 3 from the positions of the needles 3.

[0082] Control unit 11 is incorporated to determine, from the image data of a plurality of images, a median value for the distances between the 3 photographed needles and, from the median values ​​of the images, a floating average value as a standard distance and to compare each individual distance determined between two needles 3 with the standard distance to detect a defective or missing needle 3.

[0083] During the operation of the circular knitting machine 1, the light source 5 and the camera 4 are arranged relative to each other to monitor the needles 3 by a monitoring device in such a way that the light beams 6 that strike at least five needles 3 are emitted by the light source 5 and the light beams 7 reflected by the needles 3 are captured by the camera 4 with an area scanning element. The images of an image area 9 are captured by the camera control, whereby the image area 9 corresponds to at least five needles 3. The image data are measured brightness values ​​of the light beams 7 reflected by the five needles 3.

[0084] In this example, the image data are the brightness values ​​of the light beams 7 reflected in the five needle heads 3a.

[0085] The images are recorded by camera 4 at a high frame rate and are recorded with such a high intensity of the light beams 6 emitted by the light source 5 and the light beams 7 reflected by the needle heads 3a of the needles 3, that in at least two images Petition 870240095061, dated 06 / 11 / 2024, page 18 / 39 12 / 15 consecutively all needles 3 are represented by their needle heads 3a of image area 9 of the image data with a minimum distance.

[0086] The light beams 6 that fall on the needles 3, specifically the needle heads 3a, are emitted as a convergent beam by the light source 5.

[0087] The camera control operates camera 4 at a frame rate fK that is higher than the maximum possible needle rate fN of the circular knitting machine 1 in which the needles 3 pass through camera 4. The frame rate fK is, for example, 2 kHz at a maximum needle rate fN of 1.5 kHz and 7 kHz at a maximum needle frequency fN of 6 kHz.

[0088] The camera control combines pixels from the area-scan camera element and / or selects a pixel selection field for the image area 9 to read the brightness from the image data of the image area 9. If necessary, the selection field is moved by the camera control for fine adjustment of the image area 9.

[0089] The control unit 11 identifies the position of each needle from the image data and defective needles 3 from the needle positions 3.

[0090] Control unit 11 determines, from image data from multiple images, a median value for the distances between needles 3 and, from the median values ​​of the images, a floating average value as the standard distance and compares each individual distance determined between two needles 3 with the standard distance to determine a defective or missing needle 3.

[0091] The position of a needle 3 in an image is determined by the control unit 11 as follows: The analog brightness values ​​of the pixels are converted by the camera 4 into values ​​from 0 to 255, i.e., digitized. A minimum brightness value is determined which indicates a needle 3 or a needle head 3a, for example, the Petition 870240095061, dated 06 / 11 / 2024, page 19 / 39 13 / 15 value 50. For evaluation, a value of 0 is determined column by column if the highest measured value in the column is below 50, or a value of 1 is determined if the highest measured value in the column is from 50 to 255. The position of the first needle 3 in the image is determined by the first determined value of 1, for example, moving from left to right in the image. If, for example, the image spans 10 pixels, the next 9 columns will also have the value 1. Then, between images, the column values ​​are 0 until the next column with the value 1, where the position of the second needle 3 is determined.

[0092] The distance between the first determined values ​​of columns 1 is evaluated by control unit 11 as the distance between needles 3. Control unit 11 determines a median value from the image data of several images for the determined distances between needles 3 shown in an image and from the median values ​​of the images a floating average value as the standard distance. For example, the last 50 images are taken into account. Alternatively, the last 20 to 100 images are taken into account.

[0093] To detect a defective or missing needle 3, the control unit 11 compares each individual distance determined between two needles 3 with the standard distance.

[0094] A defective or missing needle 3 is detected if the distance exceeds a limit value.

[0095] A defective needle 3 is, for example, a bent needle. 3. A missing needle 3 is, for example, a needle 3 whose head 3a is broken.

[0096] A first limit value for the distance is 1.2 times the standard distance. If the first limit value is exceeded, a defective needle 3 is detected.

[0097] A second limit value for the distance is 1.5 times the Petition 870240095061, dated 06 / 11 / 2024, page 20 / 39 14 / 15 standard distance. If the second limit value is exceeded, a missing needle 3 is detected.

[0098] The position of a needle 3 in relation to the knitting cylinder 2 is, for example, during installation, determined by the control unit 11 in relation to a specific position on the knitting cylinder 2, for example, to a specific lock S on the knitting cylinder 2 or to a repair position such as needle number 3. When the circular knitting machine 1 is in operation, the needles 3 shown in the illustrations are counted backward from the maximum number of needles 3 on the knitting cylinder 2 with each revolution. The current distance, for example, to a repair point when a defective needle 3 has been detected, is also shown on the display device 15.

[0099] In an alternative embodiment, the position of a needle 3 in relation to the knitting cylinder 2 is determined by the control unit 11 by counting the needles 3 in relation to a position encoder 16 of the knitting cylinder 2.

[00100] Figure 5 shows an image of a second example that corresponds to the first example, except for the following characteristics. Camera 4 and light source 5 are arranged so that the image area 9 comprises seven needles 3 actuated in the area of ​​the reversal point.

[00101] A broken needle can be seen in the fifth position, originating from the left.

[00102] In this example, the minimum brightness value displayed by a needle 3 or a needle head 3a is determined as a value of 220, for example. The brightest pixel of the broken needle is below the minimum brightness value. The broken needle is ignored when the positions and distances are determined by the control unit 11. The distance between adjacent needles 3 is a factor of 1.5 greater than the standard distance determined from the median values. Petition 870240095061, dated 06 / 11 / 2024, page 21 / 39 15 / 15

[00103] Control unit 11 detects a defective needle 3 and sends a stop signal to the machine control 14 via switch 13. List of reference signs Circular knitting machine Knitting cylinder Needle 3rd Needle Head Camera Light source Beam of light Beam of light Support Image area Reach Control unit Power supply Switch Machine control Display device Position encoder S Blockade Petition 870240095061, dated 06 / 11 / 2024, page 22 / 39

Claims

1 / 5 CLAIMS 1. Knitting machine with a monitoring device for monitoring needles (3) during the operation of the knitting machine, wherein the monitoring device is provided with a camera (4), with a light source (5) and with a control unit (11) with a camera control, wherein the light source (5) and the camera (4) are arranged relative to each other so that the light beams (6) incident on at least one needle (3) are emitted by the light source (5) and the light beams (7) reflected by the needles (3) are captured by the camera (4), wherein the camera (4) comprises an area scanning camera element, and wherein the camera control is incorporated to capture images of an image area (9) corresponding to at least one needle (3) or at least part of the needle (3), wherein the image data are measured brightness values ​​of the reflected light beams (7), characterized in that the camera (4) has a high frame rate fK, that is,number of images per time, and the reflected light beams (7) from the light source (5) have such a high intensity that in at least two consecutive images all the needles (3) of the image area (9) of the image data are captured with a minimum distance, wherein the image area (9) comprises at least five needles (3), and the control unit (11) is incorporated to identify the position of each needle (3) in the image from the image data and to identify a defective needle (3) from the positions of the needles (3).

2. Knitting machine with monitoring device, according to claim 1, characterized in that the camera control is incorporated to operate the camera (4) at a rate of Petition 870240095061, dated 06 / 11 / 2024, page 23 / 39 2 / 5 frames k which is greater than a maximum possible needle rate ín , i.e., the number of needles (3) per time that the needles (3) pass through the camera (4).

3. Knitting machine with a monitoring device, according to either of claims 1 or 2, characterized in that the camera control is incorporated to combine pixels of the area scanning camera element to read the image data from the image area (9).

4. Knitting machine according to any one of claims 1 to 3, characterized in that the camera control is incorporated to select a selection field of selected pixels for the image area (9) for reading the image data.

5. Knitting machine, according to claim 4, characterized in that the camera control is incorporated to move the selection field for fine adjustment of the image area (9).

6. Knitting machine with monitoring device, according to any one of claims 1 to 5, characterized in that the camera (4) and the light source (5) are arranged so that the image area (9) captures at least five needles (3) ejected in the area of ​​the reversal stitch.

7. Knitting machine with monitoring device, according to any one of claims 1 to 6, characterized in that the distance from the camera (4) to the needles (3) is from 5 cm to 40 cm and / or the distance from the light source (5) to the needles (3) is from 5 cm to 40 cm.

8. Knitting machine with monitoring device, according to any one of claims 1 to 7, characterized in that the light source (5) is configured to emit the light beams (6) that fall on the needles (3) as a convergent beam.

9. Knitting machine with monitoring device, according to any one of claims 1 to 8, characterized by Petition 870240095061, dated 06 / 11 / 2024, page 24 / 39 3 / 5 fact that the control unit (11) is incorporated to determine from the image data of a plurality of images a median value for the distances between the imaged needles (3) and from the median values ​​of the images a floating average value as a standard distance and to compare each individual distance determined between two needles (3) with the standard distance to detect a defective or missing needle (3).

10. Method for monitoring needles (3) during the operation of a knitting machine with a monitoring device, wherein the monitoring device is provided with a camera (4), with a light source (5) and with a control unit (11) with a camera control, wherein the light source (5) and the camera (4) are arranged relative to each other so that the light beams (6) incident on at least one needle (3) are emitted by the light source (5) and the light beams (7) reflected by the needles (3) are captured by the camera (4), wherein the camera (4) comprises an area scanning camera element, and wherein images of an image area (9) are captured by the camera control, wherein the image area (9) corresponds to at least one needle (3) or at least part of a needle (3), wherein the image data are measured brightness values ​​of the light beams (7) reflected on at least one needle (3),characterized by the fact that the images are recorded by the camera (4) at a high frame rate fK and are recorded with such a high intensity of the light beams (6) emitted by the light source (5) and the light beams (7) reflected by the needles (3), that in at least two consecutive images all the needles (3) of the image area (9) of the image data are imaged with a minimum distance, wherein the image area (9) Petition 870240095061, of 06 / 11 / 2024, page 25 / 39 4 / 5 comprises at least five needles (3), and the control unit (11) identifies the position of each needle (3) from the image data and the defective needles (3) from the positions of the needles (3)., 11. Method for monitoring needles (3) during the operation of a knitting machine, according to claim 10, characterized in that the camera (4) is operated by camera control at a frame rate fK that is greater than a maximum possible rate fN at which the needles (3) pass through the camera (4).

12. Method for monitoring needles (3) during the operation of a knitting machine, according to any one of claims 10 or 11, characterized in that pixels of the area scanning camera element are combined by the camera control to read image data from the image area (9).

13. Method, according to any one of claims 10 to 12, characterized in that a selection field of pixels selected for the image area (9) is selected by the camera control for reading the image data.

14. Method according to claim 13, characterized in that the selection field is moved by the camera control for fine adjustment of the image area (9).

15. Method for monitoring needles (3) during the operation of a knitting machine, according to any one of claims 10 to 14, characterized in that the camera (4) and the light source (5) are arranged so that at least five ejected needles (3) are captured in the image area (9) in the vicinity of the reversal point.

16. Method for monitoring needles (3) during the operation of a knitting machine, according to any one of claims 10 to 15, characterized in that the distance from the camera (4) to the needle section is from 5 cm to 40 cm and / or the distance from the light source (5) to the needle section is from 5 cm to 40 cm.

17. Method for monitoring needles (3) during the operation of a knitting machine, according to any one of claims 10 to 16, characterized in that the light beams (6) incident on the needles (3) are emitted as a convergent beam by the light source (5).

18. Method for monitoring needles (3) during the operation of a knitting machine according to any one of claims 10 to 17, characterized in that a median value for the distances between the imaged needles (3) is determined by the control unit (11) from the image data of a plurality of images and from the median values ​​of the images a floating average value as a standard distance is determined and, to detect a defective or missing needle (3), each individual distance determined between two needles (3) is compared with the standard distance. Petition 870240095061, dated 06 / 11 / 2024, p. 27 / 39

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