Signal transmission quality evaluation system for Cameralink protocol

Abstract

The invention provides a signal transmission quality evaluation system for a Cameralink protocol. The signal transmission quality evaluation system comprises a signal processing module, an offset resolving module, an offset adjusting module, an image matching module and a quality evaluation module, the signal processing module performs frequency multiplication operation on the clock signal; the offset resolving module obtains initial delay time; the offset adjusting module adjusts delay time, the frequency multiplication clock signal / data signal is subjected to corresponding time delay in each adjustment, the data signal is resampled based on the delayed signal, and a grayscale image is obtained; the image matching module judges whether the delay time exceeds the range or not according to whether the grayscale image is consistent with the reference image or not, and sends the delay time which does not exceed the range to the quality evaluation module; the quality evaluation module obtains a delay time range and evaluates the signal transmission quality; according to the scheme, the anti-interference capability of the cable in the signal transmission process can be effectively evaluated, and test personnel can be assisted to carry out rapid model selection and performance test.

Description

Technical Field

[0001] The present invention relates to the field of signal transmission quality assessment, and in particular to a signal transmission quality assessment system for a Cameralink protocol. Background Art

[0002] CameraLink cables are commonly used for image transmission. Cameras and controllers connected via CameraLink cables transmit data based on the CameraLink protocol, enabling the transmission of both signals and image data. During signal transmission, CameraLink cables simultaneously transmit data signals and clock signals. The data signal is used to transmit the grayscale data of the camera image to the controller, while the clock signal is used to adjust the frequency at which the controller acquires grayscale data. Therefore, the quality of data signal transmission in the link between the camera, the CameraLink cable, and the control board directly impacts image transmission reliability. Therefore, before the transmission link is put into operation, it is necessary to test the performance of each component and cable to ensure that it meets the requirements.

[0003] Existing CameraLink cable performance testing solutions often only test the electrical characteristics of the cable. When the cable can complete signal transmission, it is considered qualified. However, during the use of CameraLink cables, the transmission signal is inevitably subject to external interference, resulting in poor signal transmission stability, inaccurate image data sampling, data loss and other problems. For example: Figure 1a As shown, the data of the third bit should be sampled normally, but, as Figure 1b As shown in the figure, signal fluctuations cause signal delay, resulting in the incorrect capture of the second bit of data. This results in garbled images (grayscale value calculation errors), affecting subsequent image processing. Therefore, it is crucial to evaluate the data transmission stability and interference resistance of cables before they are put into use. Summary of the Invention

[0004] To address the aforementioned technical issues, the present invention provides a signal transmission quality assessment system for the CameraLink protocol. This solution can effectively evaluate the anti-interference and fault tolerance capabilities of CameraLink cables during signal transmission, assisting testers in rapid selection and performance testing, thereby improving detection speed and efficiency and reducing industrial production and operation and maintenance costs.

[0005] The technical solution is as follows:

[0006] A signal transmission quality evaluation system for the CameraLink protocol includes a camera and a controller connected via a CameraLink cable;

[0007] The controller includes a signal processing module, an offset solving module, an offset adjusting module, an image matching module and a quality assessment module connected in sequence;

[0008] The signal processing module receives the clock signal and performs a frequency multiplication operation on the clock signal to obtain a frequency multiplied clock signal, and then sends the clock signal and the frequency multiplied clock signal to the offset calculation module; the clock signal includes two clock differential signals;

[0009] The offset calculation module obtains an initial delay time based on the received clock signal and the multiplied clock signal; the initial delay time is: the time required to delay the multiplied clock signal / clock differential signal so that the time difference between the rising edge of the multiplied clock signal and the rising edge of one of the clock differential signals reaches half a bit time;

[0010] The offset adjustment module adjusts the delay time multiple times, and each time the frequency-multiplied clock signal / data signal is delayed accordingly and the data signal is resampled based on the delayed signal, a grayscale image is obtained based on the sampled data, and the grayscale image is sent to the image matching module;

[0011] The image matching module determines whether the received grayscale image is consistent with the reference image. If they are consistent, it is considered that the adjusted delay time does not exceed the adjustable range, and the current delay time is sent to the quality assessment module. If they are inconsistent, it is considered that the adjusted delay time exceeds the adjustable range, and the offset adjustment module performs reverse adjustment. When the reverse adjusted delay time also exceeds the adjustable range, the adjustment is stopped;

[0012] The quality evaluation module obtains a delay time range based on the received delay time; and evaluates the signal transmission quality based on the size of the delay time range.

[0013] Furthermore, there are two ways to obtain the initial delay time:

[0014] Method 1:

[0015] Delay one of the clock differential signals

[0016] The clock differential signal after delay is recorded as signal n, and the clock differential signal without delay is recorded as signal p;

[0017] With the delay resolution Δt as the adjustment step, the signal n and the signal p are adjusted synchronously multiple times to increase the current delay time;

[0018] During the delay process, when the rising edge of the multiplier clock signal can sample both the low level and the high level at the same time, the adjustment is stopped;

[0019] The total time that signal p is delayed is recorded as the initial delay time;

[0020] Method 2:

[0021] The clock signal includes two clock differential signals, one of which is delayed Delay the multiplied clock signal by 1 bit time;

[0022] Then, the clock signal is kept unchanged, and the delay resolution Δt is used as the adjustment step, and the multiplied clock signal is adjusted multiple times to shorten the current delay time;

[0023] During the delay time adjustment process, when the level sampled by the rising edge of the multiplier clock signal jumps, the adjustment is stopped, and the delay time of the multiplier clock signal at this time is recorded as time R;

[0024] but:

[0025] Preferably, the image matching module determines whether the received image is consistent with the reference image in the following manner:

[0026] The image matching module performs a pixel-by-pixel grayscale comparison on the received image and the reference image. If the grayscale values of all pixels are consistent, the two images are considered to be consistent, the data signal acquisition is accurate, and the adjusted delay time does not exceed the adjustable range. Otherwise, the two images are considered to be inconsistent, the data signal acquisition is incorrect, and the adjusted delay time exceeds the adjustable range.

[0027] Furthermore, the image is a test image pre-stored in the camera, or a target image captured by the camera under normal signal transmission conditions;

[0028] The grayscale value of any pixel in the image is different from the grayscale values of each pixel in its eight neighborhoods, and the grayscale values of each pixel in the eight neighborhoods are different from each other.

[0029] The present invention also discloses a method for performing signal transmission quality assessment using the above-mentioned signal transmission quality assessment system, wherein the camera and the controller are connected via a Cameralink cable;

[0030] The controller includes a signal processing module, an offset solving module, an offset adjusting module, an image matching module and a quality assessment module connected in sequence;

[0031] The method comprises the following steps:

[0032] 1) The signal processing module receives a clock signal and performs a frequency multiplication operation on the clock signal to obtain a frequency multiplied clock signal, and then sends the clock signal and the frequency multiplied clock signal to the offset calculation module; the clock signal includes two clock differential signals;

[0033] The offset calculation module calculates an initial delay time based on the received clock signal and the multiplied clock signal; the initial delay time is the time required to delay the multiplied clock signal / clock differential signal so that the time difference between the rising edge of the multiplied clock signal and the rising edge of one of the clock differential signals reaches half a bit time;

[0034] 2) The offset adjustment module adjusts the delay time and, based on the adjusted delay time, delays the frequency-multiplied clock signal / data signal accordingly, resamples the data signal using the delayed signal, obtains a grayscale image based on the sampled data, and then sends the grayscale image to the image matching module;

[0035] 3) The image matching module compares the received grayscale image with the reference image to see if they are consistent:

[0036] If they are consistent, it is considered that the currently adjusted delay time does not exceed the adjustable range, and the current delay time is sent to the quality assessment module, and then step 2) is continued based on the current time value;

[0037] If they are inconsistent, it is considered that the currently adjusted delay time has exceeded the adjustable range; based on the initial delay time, step 2 is executed again), the offset adjustment module performs reverse adjustment, and when the time value after reverse adjustment also exceeds the adjustable range, the adjustment is stopped and step 4 is executed;

[0038] 4) The quality assessment module obtains a delay time range based on the received delay time; if the delay time range is greater than a preset interval, the signal transmission quality is considered qualified, otherwise, it is unqualified.

[0039] The technical solution of the present invention has the following characteristics:

[0040] ①Effective evaluation of the cable's anti-interference capability:

[0041] In this solution, the signal delay time range (adjustable time range) is used to characterize the fluctuation range of accurate signal transmission, reflecting the anti-interference ability during signal transmission. The larger the delay time range, the stronger the anti-interference ability during signal transmission and the higher the fault tolerance rate.

[0042] For example, the delay time range (adjustable time range) obtained by the quality assessment module is [Q-k1×Δt, Q+k2×Δt], where Δt is the controller's delay resolution (which can be found in the user manual of the controller chip) and is the minimum step size for delay time adjustment.

[0043] When k1 and k2 are both greater than the preset values (such as k=4), it means that the cable can accurately transmit data within a larger time fluctuation range during signal transmission (ensuring the correctness of the grayscale data obtained by sampling), has a higher fault tolerance rate, and is more likely to meet the requirements of use in complex environments. That is, when signal transmission is unstable, the probability of signal sampling errors is lower, and it is more suitable for signal transmission in complex environments.

[0044] The larger the adjustable time range, the higher the cable's ability to resist electromagnetic interference and the cable's signal transmission quality meets standards, making it suitable for use in complex industrial environments. This solution helps testers quickly select and perform performance testing on CameraLink cables, improving the reliability of subsequent image data transmission.

[0045] ②Easy to implement:

[0046] This solution can complete testing without disassembling the link or introducing other detection tools, improving detection speed and efficiency and reducing industrial production and operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1a This is a schematic diagram of data collection under normal circumstances;

[0048] Figure 1b This is a schematic diagram of data collection when signal delay occurs;

[0049] Figure 2 It is the system structure diagram;

[0050] Figure 3 Schematic diagram of the process of obtaining the initial delay time using method 1;

[0051] Figure 4 This is a schematic diagram of the process of obtaining the initial delay time using method 2. DETAILED DESCRIPTION

[0052] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] To facilitate understanding, the following explanation is provided: a CameraLink cable simultaneously transmits four image data signals (square wave signals) and one clock signal; the four image data signals are used to transmit the grayscale data of the camera image to the controller; the clock signal is used to generate a multiplied clock signal, and the rising edge of the multiplied clock signal is used to control the sampling time of the data signal, that is, the data signal is sampled at every rising edge of the multiplied clock signal;

[0054] More specifically, when transmitting images, the CameraLink protocol encodes the grayscale value of each pixel in the image based on four image data signals (square wave signals), with high and low levels representing 1 and 0. The data signal is sampled at each rising edge of the multiplied clock signal. The sampled high and low levels are converted to digital signals 0 and 1, and then converted to binary to obtain grayscale data, which is then analyzed to produce a grayscale image.

[0055] The details of this design are as follows:

[0056] A signal transmission quality evaluation system for the CameraLink protocol includes a camera and a controller connected via a CameraLink cable;

[0057] The controller includes a signal processing module, an offset calculation module, an offset adjustment module, an image matching module and a quality assessment module connected in sequence;

[0058] The signal processing module receives the clock signal and performs a frequency multiplication operation (7 times) on the clock signal to obtain a frequency-multiplied clock signal, and then sends the clock signal and the frequency-multiplied clock signal to the offset calculation module; the clock signal includes two clock differential signals;

[0059] The offset calculation module calculates the initial delay time based on the received clock signal and the multiplied clock signal. The initial delay time is the delay time required for the multiplied clock signal / clock differential signal to reach half the bit time when the time difference between the rising edge of the multiplied clock signal and the rising edge of one of the clock differential signals is greater than one-half the bit time.

[0060] The offset adjustment module adjusts the delay time multiple times, and each time the offset adjustment module delays the multiplied clock signal / data signal by a corresponding time, resamples the data signal based on the delayed signal, obtains a grayscale image based on the sampled data, and sends the grayscale image to the image matching module;

[0061] For example, after delaying the multiplied clock signal accordingly, the non-delayed data signal is sampled based on each rising edge of the delayed multiplied clock signal to obtain the rising / falling edge information of the data signal, convert it into digital signals 0 and 1, and then obtain grayscale data through binary conversion;

[0062] Alternatively, the data signal may be delayed accordingly, and then the delayed data signal may be sampled based on each rising edge of the non-delayed frequency-multiplied clock signal.

[0063] The image matching module determines whether the received grayscale image is consistent with the reference image. If they are consistent (the data signal acquisition is correct and the image grayscale values are consistent), the adjusted delay time is considered to be within the adjustable range, and the current delay time is sent to the quality assessment module. If they are inconsistent (the data signal acquisition is incorrect and the image grayscale values are inconsistent), the adjusted delay time is considered to be beyond the adjustable range, and the offset adjustment module performs reverse adjustment. When the reverse-adjusted delay time also exceeds the adjustable range, the adjustment stops;

[0064] The quality evaluation module obtains a delay time range based on the received delay time; and evaluates the signal transmission quality based on the size of the delay time range.

[0065] For example, the offset adjustment module may adjust the delay time multiple times by: first gradually increasing the delay time and then gradually decreasing the delay time according to a preset step size; or first gradually decreasing the delay time and then gradually increasing the delay time according to a preset step size. This embodiment does not impose any specific restrictions on the adjustment method, and adjustment may be performed without step size, as long as the delay time can be changed.

[0066] In more detail, the specific steps of the quality assessment module are as follows:

[0067] The delay time range (adjustable time range) obtained by the quality assessment module is [Q-k1×Δt, Q+k2×Δt], where Δt is the controller's delay resolution (which can be found in the user manual of the controller chip) and is the minimum step size for delay time adjustment.

[0068] Then: The signal transmission quality is evaluated based on the time range as follows:

[0069] The preset threshold range is [Qk×Δt, Q+k×Δt], where k is a coefficient, which is set according to actual usage requirements. The larger the value, the higher the quality requirement for the cable. It is usually set to 3 to 6. In this embodiment, k is set to 3.

[0070] When k1 and k2 are both greater than k, the cable can accurately transmit grayscale data (the sampling data is correct), meet the use requirements, and the transmission quality is qualified; otherwise, it does not meet the use requirements and is unqualified.

[0071] For ease of understanding, the general understanding of delay resolution and bit time is explained:

[0072] Bit time refers to the time required to send 1 bit.

[0073] Delay resolution: This refers to the delay accuracy of the logic elements within a controller (e.g., FPGA controller chip, Zynq chip, MPSoC chip). For example, if the controller's delay resolution is 1 nanosecond (ns), this means that the signal propagation time can be adjusted with an accuracy of 1ns during design. In other words, in this solution, the minimum delay adjustment step size of the offset adjustment module is the delay resolution, denoted as Δt.

[0074] The specific value of delay resolution is usually obtained from the user manual. For example:

[0075] The delay resolution of the ZYNQ chip is given by the formula Calculate, where f is the reference clock required by the system, the default value is 200 MHz, and the corresponding default value of the delay resolution is 78 ps.

[0076] In specific implementation, there are two ways to obtain the initial delay time:

[0077] Method 1:

[0078] Delay one of the clock differential signals ( Figure 3 Step 2 in the previous step);

[0079] The clock differential signal after delay is recorded as signal n, and the clock differential signal without delay is recorded as signal p;

[0080] With the delay resolution Δt as the adjustment step, the signal n and the signal p are adjusted synchronously multiple times to increase the current delay time ( Figure 3 Step 3 in the previous step);

[0081] During the delay process, when the rising edge of the multiplier clock signal can sample both the low level and the high level at the same time, the adjustment is stopped ( Figure 3 That is, when the rising edge of the multiplier clock signal can simultaneously sample the low level of signal n and the high level of signal p, or the low level of signal p and the high level of signal n, the adjustment is stopped;

[0082] The total time that signal p is delayed is recorded as the initial delay time (F_delay);

[0083] Method 2:

[0084] Delay one of the clock differential signals Delay the multiplied clock signal by 1 bit time ( Figure 4 Step 2 in the previous step);

[0085] Then keep the clock signal unchanged, use the delay resolution Δt as the adjustment step, and adjust the multiplied clock signal multiple times to shorten the current delay time ( Figure 4 Step 3 in the previous step);

[0086] For example, the delay time after the first adjustment is shortened to 1 bit time - Δt, and the delay time after the second adjustment is shortened to 1 bit time - 2×Δt...

[0087] During the delay time adjustment process, when the level sampled by the rising edge of the multiplier clock signal changes (from high level to low level), the adjustment is stopped, and the delay time of the multiplier clock signal at this time is recorded as time R ( Figure 4 -step4);

[0088] but:

[0089] Specifically, the image matching module determines whether the received image is consistent with the reference image as follows:

[0090] The image matching module performs a pixel-by-pixel grayscale comparison between the received image and the reference image. If the grayscale values of all pixels are consistent, the two images are considered to be consistent, the data signal acquisition is accurate, and the adjusted delay time does not exceed the adjustable range. Otherwise, the two images are considered to be inconsistent, the data signal acquisition is incorrect, and the adjusted delay time exceeds the adjustable range.

[0091] The image is a test image pre-stored in the camera (such as a gradient image of oblique stripes), or a target image captured by the camera under normal signal transmission conditions;

[0092] The grayscale value of any pixel in the image is different from the grayscale values of each pixel in its eight neighborhoods, and the grayscale values of each pixel in the eight neighborhoods are different from each other.

[0093] In this embodiment, a test image pre-stored in the camera is selected, that is, each time the offset adjustment module adjusts the delay time, the frequency-multiplied clock signal / data signal is delayed accordingly and based on the delayed signal, the grayscale value of each pixel in the test image is retransmitted, and the data signal (grayscale value) is resampled. A grayscale image is obtained based on the sampled data (a grayscale image is formed based on the grayscale value of each pixel in the test image parsed based on the current sampling data (0 / 1)), and the grayscale image is sent to the image matching module.

[0094] Currently, CameraLink cables have three usage modes: Base, Medium, and Full. Each mode has different data transmission capabilities and requires different cable counts. This solution does not restrict the usage mode of CameraLink cables; signal transmission quality can be evaluated based on this solution for all modes.

[0095] Take CameraLink Full mode as an example:

[0096] In Full mode, the CameraLink interface includes 12 pairs of data lines and 3 pairs of clock lines, supporting higher data rates and higher image resolutions. Specifically, CameraLink Full mode synchronously transmits three groups of signals, each of which includes four data signals and one clock signal.

[0097] The controller includes a signal processing module, an offset solving module, an offset adjusting module, an image matching module and a quality assessment module connected in sequence;

[0098] The signal processing module synchronously receives the clock signals from the three groups of signals and performs frequency multiplication on the clock signals respectively to obtain three groups of frequency multiplied clock signals and then sends the three groups of clock signals and the frequency multiplied clock signals to the offset calculation module;

[0099] The offset calculation module calculates the initial delay time corresponding to each of the three received clock signals and the multiplied clock signal. The initial delay time is the delay required for the multiplied clock signal / clock differential signal to reach half the bit time when the time difference between the rising edge of the multiplied clock signal and the rising edge of one of the clock differential signals is 1 / 2 bit time.

[0100] The offset adjustment module adjusts the values of the three delay times synchronously multiple times. Each adjustment causes the multiplied clock signal / data signal to be delayed accordingly and re-collects data based on the delayed signal. After the collection is completed, the image is sent to the image matching module.

[0101] The synchronous adjustment is to first increase synchronously and then decrease synchronously, or first decrease synchronously and then increase synchronously;

[0102] The image matching module determines whether the adjusted delay time exceeds the adjustable range based on the consistency between the received image and the reference image, stores the time value that does not exceed the adjustable range and sends it to the quality assessment module. If it exceeds the range, reverse synchronous adjustment is performed. When the reverse synchronous adjustment also exceeds the range, the adjustment stops;

[0103] The quality assessment module obtains an adjustable time range of any group of signals based on the received values and assesses the signal transmission quality based on the time range.

[0104] In a specific implementation, the adjustable time range of any one group of signals (the first group of signals) is recorded as [Q1', Q2'], where Δt is the delay resolution of the controller (which can be found in the user manual of the control chip);

[0105] Then: The signal transmission quality is evaluated based on the time range as follows:

[0106] The threshold value of the adjustable time is preset to k×Δt, where k is a coefficient with a value of 3 to 6; in this embodiment, k is 4;

[0107] The differences between Q1', Q2' and the initial delay time corresponding to the first group of signals are calculated respectively. When the differences are all ≥ k × Δt, the transmission quality is qualified; otherwise, it is unqualified.

[0108] In addition, this embodiment also provides a method for performing signal transmission quality assessment using the above-mentioned signal transmission quality assessment system, wherein the camera and the controller are connected via a Cameralink cable;

[0109] The controller includes a signal processing module, an offset solving module, an offset adjusting module, an image matching module and a quality assessment module connected in sequence;

[0110] Specifically, the method includes the following steps:

[0111] 1) The signal processing module receives the clock signal and performs a frequency multiplication operation on the clock signal to obtain a frequency-multiplied clock signal, and then sends the clock signal and the frequency-multiplied clock signal to the offset calculation module; the clock signal includes two clock differential signals;

[0112] The offset calculation module calculates the initial delay time based on the received clock signal and the multiplied clock signal. The initial delay time is the delay time required for the multiplied clock signal / clock differential signal to reach half the bit time when the time difference between the rising edge of the multiplied clock signal and the rising edge of one of the clock differential signals is greater than one-half the bit time.

[0113] 2) The offset adjustment module adjusts the delay time and, based on the adjusted delay time, delays the frequency-multiplied clock signal / data signal accordingly. The delayed signal is used to resample the data signal (the data signal is sampled at each rising edge of the frequency-multiplied clock signal). A grayscale image is obtained based on the sampled data, and the grayscale image is then sent to the image matching module.

[0114] 3) The image matching module compares the received grayscale image with the reference image to see if they are consistent:

[0115] If they are consistent, it is considered that the currently adjusted delay time does not exceed the adjustable range, and the current delay time is sent to the quality assessment module, and then step 2) is continued based on the current time value;

[0116] If they are inconsistent, it is considered that the delay time has exceeded the adjustable range; based on the initial delay time, step 2 is executed again), and the offset adjustment module performs reverse adjustment. When the time value after reverse adjustment also exceeds the adjustable range, the adjustment is stopped and step 4 is executed;

[0117] 4) The quality assessment module obtains a delay time range based on the received delay time; if the delay time range is greater than a preset interval, the signal transmission quality is considered qualified, otherwise, it is unqualified.

[0118] The regulation includes first increasing (forward regulation) and then decreasing (reverse regulation), or first decreasing and then increasing.

[0119] For example, taking Δt=78ps, increasing and then decreasing as an example, the specific steps are as follows:

[0120] 1) The signal processing module receives the clock signal and performs a frequency multiplication operation on the clock signal to obtain a frequency-multiplied clock signal, and then sends the clock signal and the frequency-multiplied clock signal to the offset calculation module; the clock signal includes two clock differential signals;

[0121] The offset calculation module calculates the initial delay time based on the received clock signal and the multiplied clock signal; in this embodiment, the initial delay time is 500 ps;

[0122] 2) The offset adjustment module increases the delay time with a step size of Δt. That is, the delay time is adjusted to 500ps + 78ps, delaying the multiplied clock signal / data signal by 500ps + 78ps. The data signal is resampled based on the delayed signal, and a grayscale image is obtained based on the sampled data. The grayscale image is then sent to the image matching module.

[0123] 3) The image matching module compares the received grayscale image with the reference image to see if they are consistent:

[0124] If they match, the currently adjusted delay time is considered within the adjustable range. The current delay time is sent to the quality assessment module, and step 2) is continued based on the current time value. That is, when step 2) is performed for the second time, the delay time is adjusted to 500 ps + 2 × 78 ps; when step 2) is performed for the third time, the delay time is adjusted to 500 ps + 3 × 78 ps; and so on.

[0125] If they are inconsistent, it is considered that the currently adjusted delay time has exceeded the adjustable range. Based on the initial delay time, step 2) is executed again to perform reverse adjustment. That is, in the first reverse adjustment, the delay time is adjusted to 500ps-78ps. In the second reverse adjustment, the delay time is adjusted to 500ps-2×78ps. ... When the reduced time value also exceeds the adjustable range, the adjustment is stopped and step 4) is executed.

[0126] 4) The quality assessment module obtains a delay time range (e.g., [500ps-3×78ps, 500ps+4×78ps]) based on the received delay time; if the delay time range is greater than the preset interval, the signal transmission quality is considered qualified, otherwise, it is unqualified.

[0127] In this solution, the adjustable signal time range represents the fluctuation range for accurate signal transmission, reflecting the signal's anti-interference capability during transmission. Furthermore, this solution can complete testing without disassembling the link or introducing other testing tools, improving testing speed and efficiency while reducing industrial production and maintenance costs.

[0128] The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. The foregoing descriptions are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been chosen and described in order to explain the specific principles of the invention and their practical application, thereby enabling others skilled in the art to make and utilize the various exemplary embodiments of the invention and various alternatives and modifications thereof. The scope of the invention is intended to be defined by the appended claims and their equivalents.

Claims

1. A signal transmission quality assessment system for the CameraLink protocol, comprising a camera and a controller connected via a CameraLink cable; Its characteristics are: The controller includes a signal processing module, an offset solving module, an offset adjusting module, an image matching module and a quality assessment module connected in sequence; The signal processing module receives the clock signal and performs a frequency multiplication operation on the clock signal to obtain a frequency multiplied clock signal, and then sends the clock signal and the frequency multiplied clock signal to the offset calculation module; the clock signal includes two clock differential signals; The offset calculation module obtains an initial delay time based on the received clock signal and the multiplied clock signal; The initial delay time is: the time required to delay the multiplied clock signal / clock differential signal when the time difference between the rising edge of the multiplied clock signal and the rising edge of one of the clock differential signals reaches half a bit time; The offset adjustment module adjusts the delay time multiple times, and each time the frequency-multiplied clock signal / data signal is delayed accordingly and the data signal is resampled based on the delayed signal, a grayscale image is obtained based on the sampled data, and the grayscale image is sent to the image matching module; The image matching module determines whether the received grayscale image is consistent with the reference image. If they are consistent, it is considered that the adjusted delay time does not exceed the adjustable range, and the current delay time is sent to the quality assessment module. If they are inconsistent, it is considered that the adjusted delay time exceeds the adjustable range, and the offset adjustment module performs reverse adjustment. When the reverse adjusted delay time also exceeds the adjustable range, the adjustment is stopped; The quality evaluation module obtains a delay time range based on the received delay time; and evaluates the signal transmission quality based on the size of the delay time range.

2. The signal transmission quality assessment system according to claim 1, wherein: There are two ways to obtain the initial delay time: Method 1: Differentiate one of the clocks The clock differential signal after delay is recorded as signal n, and the clock differential signal without delay is recorded as signal p; With the delay resolution Δt as the adjustment step, the signal n and the signal p are adjusted synchronously multiple times to increase the current delay time; During the delay process, when the rising edge of the multiplier clock signal can sample both the low level and the high level at the same time, the adjustment is stopped; The total time that signal p is delayed is recorded as the initial delay time; Method 2: The clock signal includes two clock differential signals, one of which is a clock differential signal. Delay the multiplied clock signal by 1 bit time; Then, the clock signal is kept unchanged, and the delay resolution Δt is used as the adjustment step, and the multiplied clock signal is adjusted multiple times to shorten the current delay time; During the delay time adjustment process, when the level sampled by the rising edge of the multiplier clock signal jumps, the adjustment is stopped, and the delay time of the multiplier clock signal at this time is recorded as time R; but:

3. The signal transmission quality evaluation system according to claim 1, wherein: The image matching module determines whether the received image is consistent with the reference image as follows: The image matching module performs a pixel-by-pixel grayscale comparison on the received image and the reference image. If the grayscale values of all pixels are consistent, the two images are considered to be consistent, the data signal acquisition is accurate, and the adjusted delay time does not exceed the adjustable range. Otherwise, the two images are considered to be inconsistent, the data signal acquisition is incorrect, and the adjusted delay time exceeds the adjustable range.

4. The signal transmission quality evaluation system according to claim 1, wherein: The image is a test image pre-stored in the camera, or a target image captured by the camera under normal signal transmission conditions; The grayscale value of any pixel in the image is different from the grayscale values of each pixel in its eight neighborhoods, and the grayscale values of each pixel in the eight neighborhoods are different from each other.

5. A method for evaluating signal transmission quality using the signal transmission quality evaluation system according to any one of claims 1 to 4, wherein the camera and the controller are connected via a Cameralink cable; Its characteristics are: The controller includes a signal processing module, an offset solving module, an offset adjusting module, an image matching module and a quality assessment module connected in sequence; The method comprises the following steps: 1) The signal processing module receives a clock signal and performs a frequency multiplication operation on the clock signal to obtain a frequency multiplied clock signal, and then sends the clock signal and the frequency multiplied clock signal to the offset calculation module; the clock signal includes two clock differential signals; The offset calculation module calculates an initial delay time based on the received clock signal and the multiplied clock signal; the initial delay time is the time required to delay the multiplied clock signal / clock differential signal so that the time difference between the rising edge of the multiplied clock signal and the rising edge of one of the clock differential signals reaches half a bit time; 2) The offset adjustment module adjusts the delay time and, based on the adjusted delay time, delays the frequency-multiplied clock signal / data signal accordingly, resamples the data signal using the delayed signal, obtains a grayscale image based on the sampled data, and then sends the grayscale image to the image matching module; 3) The image matching module compares the received grayscale image with the reference image to see if they are consistent: If they are consistent, it is considered that the currently adjusted delay time does not exceed the adjustable range, and the current delay time is sent to the quality assessment module, and then step 2) is continued based on the current time value; If they are inconsistent, it is considered that the currently adjusted delay time has exceeded the adjustable range; based on the initial delay time, step 2 is executed again), the offset adjustment module performs reverse adjustment, and when the time value after reverse adjustment also exceeds the adjustable range, the adjustment is stopped and step 4 is executed; 4) The quality assessment module obtains a delay time range based on the received delay time; if the delay time range is greater than a preset interval, the signal transmission quality is considered qualified, otherwise, it is unqualified.

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