Method and apparatus for determining the speed of travel of a long rod having a surface texture

Abstract

The invention relates to a method and an apparatus for determining the running speed of a long rod having a surface texture. The apparatus comprises a sensor assembly which generates a signal in response to the movement of the surface texture of the long rod. A computing unit is employed to collect the signal and to calculate the running speed of the rod in the direction of the sensor measurement.

Description

Background Technology

[0001] a. Technical Field

[0002] This description generally relates to determining the travel speed and length of a long bar with surface texture. Specifically, it pertains to methods and apparatus for determining the speed and length of reinforcing metal bars (also known as reinforcing bars or shaped bars). Reinforcing bars are bars with numerous surface textures. However, the methods and apparatus of this invention are applicable to bars with surface textures.

[0003] b. Background Technology

[0004] The following background description is provided for the purpose of providing context only. Therefore, any viewpoint in this background description, whether express or implied, shall not be considered as existing technology for this purpose, unless it is inconsistent with the conditions of existing technology.

[0005] Reinforcing metal bars (steel bars), typically made of steel or stainless steel, are widely used in construction projects. The typical manufacturing process is hot rolling, which involves heating a metal billet and then gradually reducing the cross-sectional area and shape of the bar through a series of rolling mills. Reinforcing bars are delivered by their actual or theoretical weight for a given length. Depending on the specifications, the difference between the actual and theoretical weight of a given length of reinforcing bar can be as large as 7%. This gives a significant advantage to manufacturers who can precisely control the weight per unit length (such as pounds per foot (lb) or kilograms per meter (Kg)). Therefore, the ability to accurately measure and verify the weight per unit length during manufacturing is invaluable. To achieve this, the movement of the reinforcing bar must be accurately measured, such as its speed of movement or the time required to move a unit length.

[0006] Furthermore, the ability to measure the speed of bar movement can be used as a tool to monitor the condition of manufacturing equipment. For example, when rolling steel bars, the rolls wear down slowly. As a result, the passage through the steel formed by the forming rolls (called the die in the rolling industry) changes, leading to a change in the speed of the steel bar movement.

[0007] Several known methods exist for determining the speed and length of reinforcing bars. One method involves using two metal detectors installed at a known separation distance (called the span, such as 20m). The time difference between the detection of metal by the two metal detectors, combined with the known separation distance, can be used by those skilled in the art to calculate the moving speed. However, the drawbacks are obvious. This method provides at most two readings per bar (front and end). This is sufficient for reinforcing bars of finite length. However, many reinforcing bars today are produced in coils with minimal waste and much higher moving speeds (up to 90 meters per second). Coils can be hundreds or even thousands of meters long. Furthermore, the speed of hot-rolled reinforcing bars cannot be precisely controlled. The reinforcing bars can move laterally and can even bend slightly within the span when there is no proper tension (especially for smaller dimensions, such as 10mm or less).

[0008] Another known method involves measuring the moving speed and / or length using speed measuring devices such as roll encoders or laser Doppler velocimeters (LDVs) and integrating the measurements over time. The advantages of online instantaneous measurement for real-time process control are obvious. However, there are issues associated with the speed measuring devices. LDVs are accurate to within + / -0.2% and require no calibration for smooth surface applications. However, when used on non-smooth surfaces such as the ribbed surfaces of reinforcing bars (which can vary between rolling mills) or when iron oxide flakes are present on the bar surface, there is a lot of noise. Even if some assumptions and compensations can be made to the LDV data to produce speed readings, it must be constantly calibrated once the forming rolls of the reinforcing bars change, especially from one manufacturer to another. Such calibration is relatively complex, involving actually extracting a reinforcing bar and manually measuring its length. Therefore, the measurement accuracy remains suboptimal.

[0009] Another known method involves using an encoder attached to the finishing roll. Ideally, one rotation of the finishing roll produces a section of steel bar with a length equal to the circumference of the finishing roll. Therefore, theoretically, measuring devices such as encoders attached to the finishing roll can be used to measure the amount of rotation of the finishing roll to measure both length (revolutions) and speed (revolutions per second). However, bar rolling involves a substantial 3D material flow; even with a textured roll surface, there is substantial slippage of hot metal relative to the finishing roll. Furthermore, the effective diameter of the finishing roll used to calculate its circumference depends on many factors, including metal temperature, rotational speed, rolling force, etc. The roll can also wear uniformly or non-uniformly, introducing additional variations during production. Therefore, measurements may be inaccurate. Because a 100% slip-free contact between the hot-rolled bar and the measuring roll cannot be guaranteed, measuring rolls with encoders are not practically feasible for hot rolling. The measuring roll can also wear over time.

[0010] Methods and devices that can provide near-online results without the need for calibration are worth exploring.

[0011] The foregoing discussion is intended to be illustrative of the art only and should not be construed as a denial of the scope of the claims. Summary of the Invention

[0012] This invention is based on the analysis of signals from the surface texture of a long bar (such as a reinforcing bar), and includes the following steps in the method: (1) positioning a first non-contact sensor S1 at a predetermined position along the reinforcing bar path to measure signals and / or signal characteristics sensed by the surface texture of the bar (such as the ribs of the reinforcing bar); (2) positioning a second non-contact sensor S2 at a second predetermined position along the reinforcing bar path to measure signals and / or signal characteristics sensed by the surface texture of the bar; (3) setting a predetermined interval distance between sensors S1 and S2, denoted as δ, preferably a small distance, such as less than 50 mm, to limit the amount of change in the state of the reinforcing bar between the two sensors, so that the signals from the two sensors have a large reproducibility, but with a time delay; (4) collecting analog or digital signals from the two sensors at a computing unit for comparison to extract the time delay of the same signals and / or signal characteristics sensed by the surface texture between the two sensors, denoted as Δt; and (5) calculating the moving speed by v(t) = δ / Δt and by... Calculate the length, where t o The time at which the length calculation begins.

[0013] Note that the measured velocity and length will be the velocity components of the object's motion in the direction defined by the vector from the orientation of sensor S1 to the orientation of sensor S2, or in the direction of the predetermined measurement interval distance δ. In the above description, the two sensors S1 and S2 are placed along the path of the reinforcing bar, but are separate. That is, it is designed to measure the velocity of the reinforcing bar traveling along its path.

[0014] The foregoing and other aspects, features, details, utility, and advantages of this description will become apparent from reading the following description and claims, as well as from reviewing the accompanying drawings. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a system for manufacturing long bars such as steel bars, including one embodiment of a device for determining the travel speed of a long bar with a textured surface.

[0016] Figure 2 This is a flowchart of one embodiment of a method for determining the travel speed of a long bar.

[0017] Figure 3 This is a schematic diagram of one embodiment of a method for determining the length of a long bar.

[0018] Figure 4 This is an illustrative view of typical reinforcing bars.

[0019] Figure 5 This is an illustrative example of the steps in one embodiment of a method for image matching to determine the length of a long bar, and in particular, a reinforcing bar.

[0020] Figure 6 An embodiment of a device for determining the travel speed of a long bar with a textured surface. Detailed Implementation

[0021] Now for reference Figure 1 In the manufacture of long bars such as steel bars, a block of metal 200 is typically heated to a high temperature, such as 900°C or higher, and rolled by a series of rolling mills collectively referred to as rolling mill 310 / 310' to shape the metal into a desired cross-sectional geometry, such as round or square. Rolling mill 310 / 310' consists of two rolls rotating respectively relative to axes 312 / 312' in the directions indicated by arrows 314 / 314'. The gap between the two rolls determines the degree of reduction in the cross-section of the metal block. To balance the deformation of the metal material, the rotational speed of 310 / 310' should be set such that the volume of input metal per unit time equals the volume of output metal per unit time. This is well known to those skilled in the art of rolling. In most rolling systems, the rolls have smooth or relatively smooth surfaces, resulting in rolled bars without noticeable surface texture. Figure 1 In this process, the metal 220 exiting from the rolling mill 310 / 310' has a substantially smooth surface. Note that the output metal 220 is smaller in cross-sectional dimensions than the input metal 200.

[0022] To produce reinforcing bars, a pair of textured rolls, 320 / 320', are used as a finishing mill to deform hot-rolled bars into reinforcing bars 240. For typical reinforcing bars, the surface texture may include ribs 242 and manufacturer marking 244. There are no specifications for this texture, but there are requirements for the height of the ribs and the constant cross-sectional area along the length of the reinforcing bar. Therefore, different manufacturers may have different texture designs and different patterns for the ribs 242. The manufacturer marking 244 is naturally different, as it is the manufacturer's identifier. A physical reinforcing bar, such as... Figure 4 As shown.

[0023] Return to reference Figure 1A non-contact device 100 is positioned after the rolling mill to measure the moving speed of the reinforcing bar 240 along its direction of movement indicated by arrow 210. The device 100 comprises a sensing unit 110 and a processing or computing unit 120. In the sensing unit 110, two sensors S1 and S2 are installed to detect the surface texture information of the reinforcing bar 240 as it moves along direction 210 using two non-contact sensing beams 111 and 112, respectively. The non-contact sensing beams 111 and 112 can be electromagnetic and / or mechanical waves or energy, provided the beams are sufficiently sensitive and capable of withstanding interference from texture movement in the intended application. Electromagnetic sensing devices include, but are not limited to, detecting physical quantities such as ultraviolet radiation, visible light, infrared radiation, microwave radiation, UHF, VHF, eddy currents, magnetic flux leakage, etc., and / or the interference they cause. Mechanical sensing devices include, but are not limited to, detecting physical quantities such as sound waves, ultrasonic waves, vibrations, etc., and / or the interference they cause. The two sensing beams are positioned at a fixed interval 114 (denoted as δ). The movement of surface textures can interfere with the non-contact sensing beam and generate corresponding signals through two sensors S1 and S2.

[0024] The signals generated by the two sensors are collected by the computing unit 120, which can plot the signal data relative to time. For example... Figure 1 Two curves 121 and 122, plotted relative to time within the plotting unit 120, can be used to illustrate the concept, where curve 121 represents the signal generated by sensor S1 and curve 122 represents the signal generated by sensor S2. If the two curves 121 and 122 are collected synchronously in time, then we can expect the two curves to have high similarity when δ is small, but with displacement on the time axis. Based on the similarity, features of curves 121 and 122 can be identified and matched, and the time difference or time delay 124, denoted as Δt, from a specific feature of curve 121 to a feature of curve 122 can be obtained. Those skilled in the art will understand that, for ease of description, the “features” shown in curves 121 and 122 are obviously similar in this case; but as an example, the features carried in the signal, i.e., curves 121 and 122, can be derived through signal processing. In addition, it will be understood that curves 121 and 122 are merely exemplary, and the representation of the signal from the sensor can be in various forms, including, for example, an image (2D) or a data cloud (3D), without loss of generality.

[0025] Using the information δ and Δt, calculation unit 120 can generate the traveling speed of the reinforcing bar 240 through v(t) = δ / Δt and through Generate a 240mm long reinforcing bar. Figure 2 This description is used to determine the value of rebar 240 at a given time t. i speed of travel v i =v(t) iAn embodiment of the method. Figure 3 This describes an embodiment of a method for determining the length of the reinforcing bar 240 using a determined travel speed.

[0026] refer to Figure 2 The method for determining the travel speed of the rebar 240 can begin with the steps of acquiring or collecting signals from sensors S1 and S2 and identifying common features in the signals. Feature recognition can be any known technique, such as pattern matching, fitting, etc. Some matching techniques can lead to subdivision (such as subpixel accuracy in the case of images) accuracy, and thus reduce the requirement for scanning rate. Those skilled in the art should be familiar with various subdivision methods. Features can be direct signal characteristics and / or derived signal characteristics. Derived signal characteristics can be parameters or a set of parameters extracted through signal processing (such as signal segmentation, Fourier series decomposition, wavelet analysis, principal component analysis, etc.). The texture patterns on certain long bars, such as rebar 240, are repetitive, leading to potential ambiguity between curves 121 and 122 for multiple matching features. Therefore, the theoretical travel speed v o The texture pattern pitch p can be used as a reference. o This can be an estimate or derived from the rotational speed and diameter of the finished rolling mill rolls. p should be a design value and known. Use v. o And p, the calculation unit 120 can adjust the scan rate during the collection of sensing signals to avoid ambiguity; or, match a set of features with a relative spatial relationship between two sets of curves; or, select the one closest to v in the program. o Matching features.

[0027] If the calculation unit 120 fails to identify a common feature, making the effective speed undeterminable or unavailable (n / a), then the calculation unit 120 can be configured to output "invalid" or the previous speed, causing v to... i =v i-1 This is because if the time interval between two measurements remains sufficiently small, the velocity of objects of considerable weight and / or continuous motion (such as steel bars) will not change abruptly. If the calculation unit 120 can identify a common feature, it will determine the time delay 124(Δt) based on the time difference between the time when the feature appears in the signal from sensor S1 and the time when the feature appears in the signal from sensor S2. We will verify the required time delay accuracy. Assuming the expected measurement accuracy is ±μ, set at ±0.1% or ±0.001, relative to the target's maximum moving speed v... α The predetermined interval distance and measurement time delay can be precisely designed. As an example, without loss of generality, δ = 10 mm and v... α=100m / s. As per the aforementioned requirements, the measured speed reading will be between 99.9 and 100.1 m / s. That is, the measurement time delay should be between 0.0000999 and 0.0001001 seconds, with a difference of 0.0000002 seconds. This time difference determines the response time of sensors 111 and 112, typically defined as a time constant or scan rate (or sampling rate). Note that this sampling rate may differ from the measurement rate, as a single measurement can be based on collecting a set of high scan rate signals (high-speed scanning does not require continuity). A reasonable measurement rate generated by the computing unit 120, or the speed reading rate output from the computing unit 120, will be at least twice per revolution of the finished roll to capture changes caused by the roll. As an example, the diameter D of the finished roll is set to 225 mm, and its circumference is approximately 706 mm. In extreme cases, let v... α =100m / s, and the roller rotates approximately 0.007 seconds per revolution. To complete two measurements per revolution, the measurement rate is approximately 280Hz.

[0028] Once the time delay 124(Δt) is determined, the calculation unit 120 determines the travel speed based on the time delay 124(Δt) and the fixed interval distance 114 (denoted as δ). The interval distance δ can be measured directly by the instrument after the sensor is installed, or calibrated under known conditions after the device 100 is assembled. In a typical implementation, δ can be fixed and measured according to specific circumstances, and can also be post-calibrated after the measuring device is assembled, provided that an accurately known object is available. Therefore, the assumption that δ is constant is acceptable. Then, we can express the requirement for the accuracy of the time delay measurement as follows: seconds. The sensor's time constant should be within... Seconds or less, and the sensor's scan rate should be able to Hz or faster. The measurement rate should be in Hz or higher. Or even faster, measured in Hz.

[0029] refer to Figure 3 This illustrates a method for discretely determining the speed and length of the reinforcing bar 240. This method can begin with a step detecting the start or end of the reinforcing bar 240. (Reference) Figure 1 A metal detector 130 with a fast response time, preferably identical to the metal detectors of sensors S1 and S2, can be integrated to detect the front and rear ends of the rebar, and a start time t is defined. o and end time t e . t o and t e It can also be defined by digital inputs such as digital on / off signals sent from the rolling control unit. Another possibility is to use sensors S1 and S2 as metal detectors, determining t by processing signals 121 and 122. oand t e Refer again Figure 3 In this method, you can continue to use, such as Figure 2 The method described outlines the steps for determining the travel speed of the reinforcing bar and subsequently using that speed to determine its length. Because the speed v(t) can be measured at discrete moments, the length measurement can be converted into a discrete form, such as L. i =∑ i＝0 v i / ρ i , where v i =v(t) i ), and ρ i For time t i The measurement rate is i = 0, 1, 2, 3, ... If the measurement rate is constant, then L i =∑ i＝0 v i / ρ. Or, it can be L. i =∑ i＝0 v i ·(t i -t i-1 When i > 0, the length of the rolled steel bar can be calculated as follows: or

[0030] Once the end of the bar is reached, this method can terminate by reporting the length of the reinforcing bar 240 and other statistics associated with various measurements (travel speed, length) obtained through the calculation unit 120. The calculation unit 120 can be configured to transmit results via a number of standard output formats, such as speed readings and / or from t o The length of the integral, and these standard output formats include, but are not limited to, screen displays for visual observation, analog signal channels with defined protocols, and / or digital signal channels with defined protocols. The display can be a monitor, television, flat panel, color, or monochrome. Analog channels can be based on current or voltage. Digital channels can be parallel ports, serial ports, network communication, wired or wireless, etc.

[0031] Now for reference Figure 5 In a specific embodiment of the device for determining the speed of a long bar, sensors S1 and S2 include two imaging devices capable of acquiring images at very high frequencies. In this embodiment, the imaging devices can be linear, also known as line scanning, or area-based, also known as surface scanning. Theoretically, the additional dimension of the data (2D image) provides better stability and accuracy for feature recognition than a one-dimensional signal. Images can be decomposed into many features. The ability to achieve sub-pixel accuracy in pattern and / or feature matching also reduces the requirement for high scanning frequencies. (Reference) Figure 5In this embodiment, based on any illumination that can produce an image with surface texture information, such as, but not limited to, reflected illumination (bright or dark field, or cloudy, etc., surface texture) or backlighting (surface texture on edges), the image will be generated from the imaging sensor S. i1 and S i2 Simultaneous images were captured, denoted as images 1021 and 1022. Note that S represents the direction of the rebar's movement. i1 Placed in S i2 The computing unit 120 processes the image to identify blocks of the same features / patterns, such as dashed rectangles 1023. Once identified, the same features / patterns are arranged by shifting the image 1022, as shown in 1022'. The shift will produce a pixel offset 1024. The number of pixels in the offset 1024 multiplied by the reciprocal of the scan rate will result in a time delay Δt.

[0032] Now for reference Figure 6 In another embodiment of the device for determining the travel speed of a long bar, sensors S1 and S2 in sensor assembly 1010 are formed by an imaging device with multiple rows, such as a color line scan imaging device. The advantage of this implementation is that it offers chip-level synchronization (typically on the nanosecond scale) and sensor alignment accuracy (typically on the nanometer scale). For a color line scan imaging device, a typical implementation has three rows of imaging pixels, each covered by a color filter, typically RGB (red, green, and blue). Those skilled in the art will recognize the possibility of separating the signal beam (visible light beam) by different colors or different wavelengths, as long as the two selected wavelengths or wavelength spans are substantially separable in the spectrum.

[0033] In the illustrated embodiment, sensor assembly 1010 transmits radiation from two orientations to a juxtaposed imaging sensor. Radiation emanating from or reflected by the reinforcing bar 240 is transmitted as a beam 111 from a surface location on the reinforcing bar 240 and carries information about the surface texture of the reinforcing bar 240. The radiation contains at least a selected wavelength that matches the modulation capability of filter 1012a. When the surface location on the reinforcing bar 240 passes through the viewing window of filter 1012a, filter 1012a transmits a portion of the radiation, primarily having wavelengths within a first wavelength range. Similarly, radiation emanating from or reflected by the reinforcing bar 240 is transmitted as a beam 112 from a surface location on the reinforcing bar 240 and carries information about the surface texture of the reinforcing bar 240. The radiation contains at least a selected wavelength that matches the modulation capability of filter 1012b. When the surface location on the reinforcing bar 240 passes through the viewing window of filter 1012b, filter 1012b transmits a portion of the radiation, primarily having wavelengths within a second wavelength range. Filters 1012a and 1012b are configured such that the radiating portions passing through filter 1012a and having wavelengths within a first wavelength range and the radiating portions passing through filter 1012b and having wavelengths within a second wavelength range are different, but may partially overlap in some embodiments. The first wavelength range includes a first subset of wavelengths substantially excluded from the second wavelength range, and the second wavelength range includes a second subset of wavelengths substantially excluded from the first wavelength range. In one embodiment, "substantially excluded" means that the intensity of the first subset of wavelengths within the second radiating portion is less than or equal to 20% of the intensity of the second wavelength range within the second radiating portion, and "substantially excluded" means that the intensity of the second subset of wavelengths within the first radiating portion is less than or equal to 20% of the intensity of the first wavelength range within the first radiating portion. The radiation in beams 111 and 112 may be radiation emitted by the reinforcing bar 240 (e.g., due to heating) or radiation generated by a radiation source (e.g., a light source) and altered by it upon contact with the reinforcing bar 240. The radiation source can direct radiation to a surface location on the reinforcing bar 240. Alternatively, the reinforcing bar 240 can be backlit, meaning the radiation source directs radiation to the back of the surface location on the bar. In the latter case, beams 111 and 112 can be residual radiation from the background that is not blocked by the reinforcing bar 240. To separate the two beams 111 and 112 for the designed light propagation path, filters 1012a and 1012b are placed in a predetermined orientation, and specifically, filters 1012b are spaced a known distance from filters 1012a. Filters 1012a and 1012b respectively create radiation beams 111a and 112b, which contain only wavelengths selected from radiation beams 111 and 112, respectively.In one embodiment, filter 1012a transmits radiation with a wavelength associated with green, while filter 1012b transmits radiation with a wavelength associated with blue. However, it should be understood that this is merely illustrative and does not diminish the generality of the invention. A beam 111a containing a wavelength associated with green carries only a portion of the radiation from beam 111, while the wavelength associated with blue in beam 111 is substantially suppressed. Similarly, a beam 112a containing a wavelength associated with blue carries only a portion of the radiation from beam 112, while the wavelength associated with green in beam 112 is substantially suppressed.

[0034] Radiation beams 111a and 112b are spaced a distance 114 apart and, at any given time, represent information related to the surface texture at different locations on the rebar 240. However, the rebar 240 is expected to move during production, causing the same surface location on the rebar 240 to first generate radiation beam 111 / 111a, and then, after moving a certain distance, generate radiation beam 112 / 112a. (See again...) Figure 6The apparatus further includes means 1014 for combining the first portion of radiation 111a and the second portion of radiation 112a into a combined radiation beam 1016, such as a reflective surface 1014a and a beam splitter 1014b. Those skilled in the art will understand that the combined radiation beam 1016 should be a single beam that is substantially a superimposed beam of beams 111a and 112a. For illustrative purposes, the combined radiation beam 1016 is drawn at small intervals to show the content from each of the beams 111a and 112a. The reflective surface 1014a bends the path of beam 111a toward beam 112a. The bending angle may be 180° minus 2α, where α is the angle between the reflective surface 1014a and the beam 111a. The beam splitter 1014b is positioned such that both beams 111a and 112a illuminate substantially the same point on the beam splitter 1014b. Those skilled in the art will understand that as long as the reflecting surface 1014a and the beam splitter 1014b are parallel to each other, the two detection beams 111a and 112a will be combined into a single beam 1016. However, the best and easiest implementation is to keep the α of both at a 45-degree angle to the detection beams 111a and 112a. For a given spacing distance 114, this will result in a minimum envelope of the combining device 1014. In fact, in one embodiment, the combining device may include a laterally displaced beam splitter, which is typically used to split a beam into two parallel beams; the present invention applies this in reverse. After beams 111a and 112a illuminate the beam splitter 1014b, a portion of each of beams 111a and 112a is combined into a combined radiating beam 1016. Those skilled in the art will understand that another portion of beams 111a and 112a will form another discarded beam 1016'. The portion of beams 111a and 112a combined into the detection beam 1016 depends on the optical characteristics of the beam splitter 1014b. A 50-50 beam splitter will result in 50% of beam 111a and 50% of beam 112a being combined into beam 1016. A 40-60 beam splitter will result in 40% of beam 111a and 60% of beam 112a being combined into beam 1016. Designers can select the appropriate beam splitting characteristics based on the optical characteristics of other components, such as the wavelength intensity content of beams 111 and 112, and the pixel imaging sensitivity of the line scan imaging device to different wavelengths. Although in the illustrated embodiment beam 111a illuminates the reflective surface 1014a, those skilled in the art will also understand that the use of reflective surface 1014a and beam splitter 1014b can be conveniently reversed, such that the detection beam 112a is bent by reflective surface 1014a toward the path of detection beam 111a, and beams 111a and 112a are combined at beam splitter 1014b.

[0035] The combined detection beam 1016 is sent to the line scan imaging apparatus 1018. Apparatus 1018 includes at least two pixel rows 1018G and 1018B that are mediated and receive radiation of different wavelength ranges. For example, apparatus 1018 may include a color line scan imaging apparatus having three pixel rows that receive radiation with wavelengths corresponding to red, green, and blue light. The two pixel rows 1018G and 1018B in apparatus 1018 serve as... Figure 5 The imaging sensor S referenced in the text i1 and S i2 The first pixel row 1018G is configured to receive at least a portion of a first wavelength subset belonging to the radiation beam 111a in the combined radiation beam 1016 based on the matching optical characteristics between pixel row 1018G and filter 1012a, but is not configured to receive radiation from a second wavelength subset belonging to the radiation beam 112a in the combined radiation beam 1016. The second pixel row 1018B is configured to receive at least a portion of a second wavelength subset belonging to the radiation beam 112a in the combined radiation beam 1016 based on the matching optical characteristics between pixel row 1018B and filter 1012b, but is not configured to receive radiation from a first wavelength subset belonging to the radiation beam 111a in the combined radiation beam 1016. Those skilled in the art will recognize that another implementation is to make the optical characteristics of filter 1012a complementary to those of pixel row 1018B, rather than matching those of pixel row 1018G. In this case, beam 111a will contain not only the wavelengths to be received by pixel row 1018G, but also wavelengths other than those that can be received by pixel row 1018B. Similarly, filter 1012b may complement the optical characteristics of pixel row 1018G, rather than matching them to the optical characteristics of pixel row 1018B. Note that the number of pixels in each pixel row 1018G, 1018B can be any natural number. Typical numbers include 512, 1024, 2048, etc. Nevertheless, the number of pixels in each row can be 1 or any natural number. In the case where the number of pixels in each row is 1, the output will not be an image, but rather... Figure 1 Signals 121 and 122 in the diagram represent the intensity of the radiation beams 111a and 112a over time, respectively.

[0036] Apparatus 1018 is configured to synchronously generate a multi-band image comprising a first band from a first pixel row 1018G and a second band from a second pixel row 1018B in response to a combined radiation beam 1016. In an embodiment employing a color line scan imaging apparatus, when one apparatus 1018 receives the combined radiation beam 1016, the apparatus 1018 generates a color image, from which signal images 1021 and 1022 (see also) can be obtained by extracting monochrome images from the individual color (e.g., green and blue) bands of the color image. Figure 5). Calculation unit 120 ( Figure 1 The calculation unit 120 can be configured (e.g., using appropriate programming instructions (i.e., software)) to process the multi-band images generated by the device 1018, performing several image processing actions and several calculation steps to determine the travel speed and length of the reinforcing bar 240. The calculation unit 120 can first extract a first monochrome image 1021 and a second monochrome image 1022 from the multi-band images generated by the device 1018, wherein the first monochrome image 1021 corresponds to the radiation received from the surface position of the reinforcing bar 240 when it passes through filter 1012a, and the second monochrome image 1022 corresponds to the radiation received from the surface position of the reinforcing bar 240 when it passes through filter 1012b. Then, the calculation unit 120 uses conventional pattern / feature matching techniques as described above to identify the location of corresponding surface positions in the first monochrome image 1021 and the second monochrome image 1022. (See again...) Figure 5 The calculation unit 120 then determines the pixel offset 124 between corresponding surface positions in the first monochrome image 1021 and the second monochrome image 1022 using the offset images 1021 and 1022'. The calculation unit 120 uses the pixel offset 124 to determine the time difference or time delay Δt between the appearances of the same surface positions at the observation windows of the filters 1012G and 1012B. The calculation unit 120 can use the methods described above... Figure 2-3 The method described herein uses a time difference Δt and an interval distance 114 to determine the travel speed of the reinforcing bar 240, and then determines the length of the reinforcing bar 240.

[0037] For convenience and usability of components, embodiments employing two filters 1012G, 1012B have been described and illustrated. These filters are configured to pass wavelengths corresponding to two different colors (green and blue) that match or complement the pixel rows in the color line scan imaging device 1018. However, those skilled in the art will understand that filters and imaging devices can be configured to pass through and receive any practically distinguishable wavelengths (e.g., two sets of wavelengths corresponding to different levels of blue), provided that the combination of the filter before the reflector / beam splitter and the filter in front of the pixel rows on the imaging device 1018 supports the reception of the selected wavelength by the pixel rows. Although the embodiments described and illustrated herein utilize radiation with wavelengths corresponding to green and blue, wavelengths corresponding to other colors, including red, may also be used (however, for applications involving high-temperature objects, such as steel reinforcement at 1000°C, avoiding red may be preferable). Those skilled in the art will also recognize that the use of color and / or wavelength filtering for separation can be considered a special case of using electromagnetic radiation with signal modulation / demodulation. That is, the disclosed embodiments of the invention are extendable to the use of any electromagnetic radiation with appropriate modulation / demodulation.

[0038] Those skilled in the art will also recognize that actual implementations of the device of the present invention may involve additional components, such as radiation sources (e.g., illumination), lenses, and other elements for focusing radiation, as well as mounting or support structures (fixtures) not shown or disclosed in this specification. Nevertheless, this should not preclude the present invention from using a focusing device to enhance the signal resolution capabilities associated with the detection sensor.

Claims

1. A device for determining the travel speed of a strip of bar with a textured surface, comprising: A first filter is configured to allow a first portion of radiation from the surface position on the long bar to pass through when a surface position of the long bar passes through the observation window of the first filter. The first portion of radiation has a wavelength primarily within a first wavelength range. A second filter is configured to allow a second portion of radiation from the surface position on the bar to pass through when the surface position on the bar passes through the observation window of the second filter. The second portion of radiation has wavelengths primarily within a second wavelength range, the first wavelength range including a first subset of wavelengths substantially excluded from the second wavelength range and the second wavelength range including a second subset of wavelengths substantially excluded from the first wavelength range, and the second filter is spaced apart from the first filter by a distance. A device for combining the first portion of radiation and the second portion of radiation into a combined radiation beam. A line scan imaging apparatus having a first pixel row and a second pixel row, the first pixel row being configured to receive a portion of the combined radiation beam corresponding to at least a subset of a first wavelength, and the second pixel row being configured to receive another portion of the combined radiation beam corresponding to at least a subset of a second wavelength, the line scan imaging apparatus being configured to synchronously generate a multi-band image including a first band from the first pixel row and a second band from the second pixel row; as well as The computing unit is configured as follows A first monochromatic image and a second monochromatic image are extracted from the multi-band image, wherein the first monochromatic image corresponds to the radiation received from the surface position of the bar when the surface position of the bar passes through the first filter, and the second monochromatic image corresponds to the radiation received from the surface position of the bar when the surface position of the bar passes through the second filter. The location of the surface position is identified in the first monochrome image and the second monochrome image, respectively. Determine the pixel offset between the positioning of the surface position in the first monochrome image and the second monochrome image. Determine the time difference in which the pixel offset is generated, and, The travel speed is determined based on the time difference, the pixel offset, and the distance.

2. The device according to claim 1, wherein the line scan imaging device is a color line scan imaging device and the first wavelength range corresponds to a first color captured by the color line scan imaging device, and the second wavelength range corresponds to a second color captured by the color line scan imaging device.

3. The device according to claim 1, wherein the multi-band image is a color image comprising a first band of a first color and a second band of a second color.

4. The device of claim 1, wherein the radiation received from the surface location on the bar includes radiation emitted by the bar.

5. The device of claim 1, wherein the radiation received from the surface position on the bar includes radiation generated from a radiation source and altered by the bar after contact with it.

6. The device of claim 5, wherein the radiation generated from the radiation source and modified by the elongated bar is directed from the radiation source to the surface position on the elongated bar.

7. The device of claim 5, wherein the radiation generated from the radiation source and modified by the elongated bar is directed from the radiation source to the back side of the surface position on the elongated bar.

8. The device of claim 1, wherein the radiation received from the surface location on the long bar includes at least one of ultraviolet, visible, infrared and microwave radiation.

9. The device of claim 1, wherein the means for combining the first partial radiation and the second partial radiation comprises: A reflective surface configured to change the radiation direction of the first portion; as well as, A beam splitter is configured to receive the first and second portions of radiation, whose directions are altered by the reflective surface, and to output the combined radiation beam.

10. The device of claim 1, wherein the means for combining the first partial radiation and the second partial radiation comprises a lateral displacement beam splitter.

11. The device according to claim 1, wherein the line scan imaging device includes a focusing device.

12. The device of claim 1, wherein the first wavelength subset substantially excluded from the second wavelength range means that the intensity of the first wavelength subset within the second partial radiation is less than or equal to 20% of the intensity of the second wavelength range in the second partial radiation; and the second wavelength subset substantially excluded from the first wavelength range means that the intensity of the second wavelength subset within the first partial radiation is less than or equal to 20% of the intensity of the first wavelength range in the first partial radiation.

13. A method for determining the traveling speed of a long bar with a textured surface, comprising: Move one of the filter assembly and the bar relative to the other, the filter assembly comprising... A first filter is configured to allow a first portion of radiation from the surface position on the long bar to pass through when a surface position of the long bar passes through the observation window of the first filter. The first portion of radiation has a wavelength primarily within a first wavelength range. as well as, A second filter, spaced a distance from the first filter, is configured to allow a second portion of the radiation from the surface position on the bar to pass through when the observation window of the second filter is passed through the surface position on the bar. This second portion of radiation primarily has wavelengths within a second wavelength range. The first wavelength range includes a first wavelength subset that is substantially excluded from the second wavelength range, and the second wavelength range includes a second wavelength subset that is substantially excluded from the first wavelength range. The first part of radiation and the second part of radiation are combined into a combined radiation beam. The combined radiation beam is directed to a line scan imaging apparatus having a first pixel row and a second pixel row, the first pixel row being configured to receive a portion of the combined radiation beam corresponding to at least a subset of the first wavelength, and the second pixel row being configured to receive another portion of the combined radiation beam corresponding to at least a subset of the second wavelength, the line scan imaging apparatus being configured to simultaneously generate a multi-band image including a first band from the first pixel row and a second band from the second pixel row; A first monochromatic image and a second monochromatic image are extracted from the multi-band image, wherein the first monochromatic image corresponds to the radiation received from the surface position of the long bar when the surface position of the long bar passes through the first filter, and the second monochromatic image corresponds to the radiation received from the surface position of the long bar when the surface position of the long bar passes through the second filter; The location of the surface position is identified in the first monochrome image and the second monochrome image, respectively. Determine the pixel offset between the positioning of the surface position in the first monochrome image and the second monochrome image. Determine the time difference in which the pixel offset is generated, and, The travel speed is determined based on the time difference, the pixel offset, and the distance.

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