CN112235515B - LED light source image detection method and device with stroboscopic suppression function - Google Patents

LED light source image detection method and device with stroboscopic suppression function Download PDF

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CN112235515B
CN112235515B CN202011096818.XA CN202011096818A CN112235515B CN 112235515 B CN112235515 B CN 112235515B CN 202011096818 A CN202011096818 A CN 202011096818A CN 112235515 B CN112235515 B CN 112235515B
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exposure time
light source
image sensor
led light
stroboscopic
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CN112235515A (en
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孟德远
胡庭波
安向京
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Changsha Xingshen Intelligent Technology Co Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/70—Circuitry for compensating brightness variation in the scene
    • H04N23/73—Circuitry for compensating brightness variation in the scene by influencing the exposure time
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/70—Circuitry for compensating brightness variation in the scene
    • H04N23/741—Circuitry for compensating brightness variation in the scene by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/50—Control of the SSIS exposure
    • H04N25/53—Control of the integration time
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/50—Control of the SSIS exposure
    • H04N25/57—Control of the dynamic range
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection

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Abstract

The invention discloses a method and a device for detecting an LED light source image with a stroboscopic suppression function, wherein the method comprises the following steps: s1, determining an optimal exposure time for a target image sensor, so that an LED stroboscopic effect does not exist when the target image sensor collects an image of an LED light source to be detected according to the optimal exposure time; s2, according to the determined optimal exposure time, reducing and adjusting the light inlet quantity of the target image sensor so as to reduce the light inlet quantity of the target image sensor until no overexposure occurs, and determining the adjusted light inlet quantity; and S3, controlling the target image sensor to collect the image of the LED light source to be detected according to the optimal exposure time determined in the step S1 and the light incoming amount adjusted in the step S2 for detection. The invention can inhibit the LED stroboscopic effect when detecting the LED light source and simultaneously avoid the overexposure phenomenon.

Description

LED light source image detection method and device with stroboscopic suppression function
Technical Field
The invention relates to the technical field of LED light source detection, in particular to an LED light source image detection method and device with a stroboscopic suppression function.
Background
The LED as a diode device can only pass direct current, when the mains supply is connected, the mains supply alternating current must be converted into direct current by using a power supply, and the response time of the light emitting brightness of the LED to the current is very short, and the light emitting brightness changes along with the change of the current, that is, the amount of current passing through the LED is proportional to the light emitting brightness, and how much light is emitted according to the amount of current passing through the LED, so that the LED flickers are only related to the frequency and ripple of the output current of the driving power supply. The stroboscopic effect of the LED light source is that the light emitted by the light source exhibits a certain frequency and period change with time, and the light also changes with time between different brightness and colors.
Because the LED lamp is driven in an alternating current manner, the flashing frequency of the LED is generally 100Hz (2 times of mains power frequency), that is, the pulse period is about 10 milliseconds, the LED can be turned on and off once within the 10 millisecond period, and for energy saving and service life prolonging, the duty ratio is usually set to not more than 50%, so that when an image of the LED lamp is collected by the camera, if the exposure time of the camera is short (for example, 3 milliseconds), it is possible that the exposure time of the camera is just in the LED turn-off period, so that the image collected by the image sensor is an image with the LED turned off at this time, if the image is collected by the LED array, the image shot by the camera also presents a state of being partly on and partly off, so that the LED lamp cannot be detected from the image.
Adopt the LED lamp usually like electronic road sign, traffic signal etc. tail lamp, detect time measuring to LED lamps such as this type of electronic road sign, traffic signal etc. tail lamp at present, all directly use ordinary camera to take a candid photograph according to fixed exposure time usually, very easily have above-mentioned LED stroboscopic effect, the existence of LED stroboscopic effect can lead to the unable normal detection electronic road sign of system and traffic signal lamp, can't distinguish turn signal lamp and tail lamp etc. leads to serious traffic accident even. The light sensing capability of the image sensor is certain, namely the exposure amount is limited, if the problem of the stroboscopic effect is solved by simply dynamically increasing and adjusting the exposure time, if the exposure time is too long, the problem of overexposure exists, if stroboscopic is to be eliminated, the exposure time of a conventional common camera needs to be set to be at least more than 7ms, and under the exposure time, part of traffic lights can cause higher brightness due to large duty ratio of the LED bright period, and in addition, the superposition of ambient light during outdoor work, especially under the condition of sufficient sunlight at noon, the overexposure of the camera is easily caused, and the problems of motion blur effect and the like can be caused by long-time exposure. Therefore, it is desirable to provide a method for detecting an image of an LED light source, which can prevent the occurrence of overexposure while suppressing the stroboscopic phenomenon of the LED.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: aiming at the technical problems in the prior art, the invention provides the LED light source image detection method and the LED light source image detection device which are simple in implementation method, can inhibit the LED stroboscopic effect when detecting the LED light source and simultaneously avoid the overexposure phenomenon.
In order to solve the technical problems, the technical scheme provided by the invention is as follows:
an LED light source image detection method with a strobe suppression function comprises the following steps:
s1, determining an optimal exposure time for a target image sensor, so that an LED stroboscopic effect does not exist when the target image sensor collects an image of an LED light source to be detected according to the optimal exposure time;
s2, reducing and adjusting the light inlet quantity of the target image sensor according to the determined optimal exposure time so as to reduce the light inlet quantity of the target image sensor until no over-exposure occurs, and determining the adjusted light inlet quantity;
and S3, controlling the target image sensor to collect the image of the LED light source to be detected according to the optimal exposure time determined in the step S1 and the light inlet quantity adjusted in the step S2 for detection.
Further, when the optimal exposure time is determined in step S1, an initial exposure time is determined according to the flicker parameter of the LED light source to be detected, and the exposure time of the target image sensor is continuously adjusted from the initial exposure time until the condition that there is no LED stroboscopic effect and the stroboscopic performance parameter meets the preset condition when the target image sensor acquires the image of the LED light source to be detected is met, so as to obtain the optimal exposure time output.
Further, the step of continuously adjusting the exposure time of the destination image sensor from the initial exposure time in step S1 includes: the method comprises the steps of continuously increasing and adjusting exposure time, obtaining an image of an LED light source to be detected, collected by a target image sensor, after adjustment every time, judging whether a stroboscopic effect exists, continuously reducing and adjusting the exposure time when the number of times that the stroboscopic effect does not continuously exist is judged to reach a preset value, calculating current LED stroboscopic performance parameters after adjustment every time until the LED stroboscopic performance parameters are judged to accord with preset conditions, and obtaining optimal exposure time output.
Further, a first step length is used when the exposure time is increased and adjusted, and a second step length is used when the exposure time is decreased and adjusted, wherein the first step length is greater than or equal to the second step length.
Further, the initial exposure time is calculated according to the flicker frequency and/or the flicker index of the LED light source to be detected.
Further, the specific step of step S1 is:
s101, defining a parameter for representing the frequency of occurrence of stroboscopic effect as stroboscopic frequency M f The parameter for representing the times of no stroboscopic effect is normal times M c And configuring the number of strobes M f Normal times M c Determining an initial exposure time according to the flicker parameter of the LED light source to be detected;
s102, acquiring an image of the LED light source to be detected, acquired by the target image sensor according to the current exposure time, judging whether the acquired image has an LED stroboscopic effect or not, and if not, increasing the normal times M c Step S103 is entered; otherwise, increasing and adjusting the stroboscopic times M f And increasing the value for adjusting the current exposure time, and returning to the step S102;
s103, judging whether the normal times M are met or not c Is greater than a preset threshold and the number of stroboscopic events M f If the value is the initial value, the value for adjusting the current exposure time is reduced, the step S102 is returned to be executed, otherwise, the step S104 is shifted to;
s104, judging whether the current LED stroboscopic performance parameters meet preset conditions, if so, determining the optimal exposure time output according to the current exposure time, otherwise, controlling and adjusting the acquisition conditions of the LED light source, and returning to the step S102.
Further, in step S2, a dimmer having a specific light transmittance is configured on the target image sensor to reduce the amount of light entering until no overexposure occurs.
Further, before configuring the dimmer, the method further comprises an optimal dimmer determining step, and the specific steps comprise: and respectively acquiring images acquired when the target image sensor is respectively configured with the light-reducing sheets with different transmittances according to the optimal exposure time, and comparing the images, and determining the optimal light-reducing sheet as the optimal light-reducing sheet according to the image quality comparison result.
An LED light source image detection device with a stroboscopic suppression function comprises an image sensor, an exposure time determining module, a light inlet quantity adjusting module and an LED light source detection control module which are connected with one another, wherein the LED light source detection control module is connected with the image sensor;
the exposure time determining module is used for determining a target exposure time for the target image sensor, so that an LED stroboscopic effect does not exist when the target image sensor collects an image of the LED light source to be detected according to the target exposure time;
the light inlet quantity adjusting module is used for reducing and adjusting the light inlet quantity of the target image sensor according to the determined target exposure time so as to reduce the light inlet quantity of the target image sensor until no overexposure occurs and determining the adjusted light inlet quantity;
the LED light source detection control module is used for controlling the image sensor to collect the image of the LED light source to be detected according to the optimal exposure time determined by the exposure time determination module and the light inlet quantity adjusted by the light inlet quantity adjustment module for detection.
Further, the light-entering amount adjusting module is a dimmer with specified light transmittance.
Compared with the prior art, the invention has the advantages that:
1. the invention firstly determines a corresponding optimal exposure time for the LED light source to be detected, so that the LED stroboscopic effect does not exist when the target image sensor collects the image of the LED light source to be detected, then reduces the light input quantity of the image sensor according to the optimal exposure time to avoid the overexposure of the image sensor, finally controls the image sensor to detect the LED light source to be detected according to the optimal exposure time, can realize the self-adaptive image detection of the LED light source by combining the exposure time and the adjustment of the light input quantity, compared with the traditional method which directly uses the fixed or dynamically adjusted exposure time to detect various LED lamps, can adaptively determine the corresponding optimal exposure time according to the characteristics of different LED light source types, ensure that the image sensor can realize the LED stroboscopic effect inhibition when detecting various LED light sources, and simultaneously avoid the generation of problems of motion blur effect and the like caused by the overexposure, thereby improving the image detection performance of the LED light source.
2. When the optimal exposure time is determined, the exposure time is properly prolonged by continuously increasing and adjusting on the basis of the initial exposure time, so that the exposure time is longer than the LED driving period, and when the stroboscopic effect does not occur for a plurality of times continuously, the exposure time is continuously reduced and adjusted, so that the optimal exposure time can be determined, and the effects of reducing the exposure time as much as possible and inhibiting the stroboscopic effect can be achieved.
3. The invention further arranges the dimmer in front of the image sensor, which can reduce the light input quantity of the image sensor, ensure the sampling time and reduce the input signal intensity to inhibit the image overexposure, thereby combining the optimal exposure time, and conveniently achieving the effect of inhibiting the stroboscopic effect and avoiding the overexposure problem.
4. According to the invention, the image sensor can work in all weather by fixing the exposure time and the gain, and different cameras do not need to be arranged in the daytime and at night, so that the detection implementation cost is further reduced.
Drawings
Fig. 1 is a schematic flow chart of an LED light source image detection method with a strobe suppression function according to this embodiment.
Fig. 2 is a flowchart illustrating the detailed steps of determining the optimal exposure time in an embodiment of the present invention.
Fig. 3 is a schematic diagram of the arrangement of a dimmer in the image sensor in the present embodiment.
Detailed Description
The invention is further described below with reference to the drawings and specific preferred embodiments of the description, without thereby limiting the scope of protection of the invention.
As shown in fig. 1, the steps of the LED light source image detection method with strobe suppression function in this embodiment include:
s1, determining an optimal exposure time for a target image sensor, so that an LED stroboscopic effect does not exist when the target image sensor collects an image of an LED light source to be detected according to the target exposure time;
s2, reducing and adjusting the light inlet quantity of the target image sensor according to the determined optimal exposure time so as to reduce the light inlet quantity of the target image sensor until no over-exposure occurs, and determining the adjusted light inlet quantity;
and S3, controlling the target image sensor to collect the image of the LED light source to be detected according to the target exposure time determined in the step S1 and the light inlet quantity adjusted in the step S2 for detection.
In the embodiment, a corresponding optimal exposure time is determined for the LED light source to be detected, so that the LED stroboscopic effect does not exist when the target image sensor collects the image of the LED light source to be detected based on the optimal exposure time, then the light input quantity of the image sensor is reduced according to the optimal exposure time to avoid the overexposure of the image sensor, and finally the image sensor is controlled to detect the LED light source to be detected according to the optimal exposure time and the adjusted light input quantity, so that the self-adaptive image detection of the LED light source can be realized by combining the exposure time and the adjustment of the light input quantity, compared with the traditional method that the fixed or dynamically adjusted exposure time is directly used for detecting various LED lamps, the corresponding optimal exposure time can be determined in a self-adaptive manner according to the characteristics of different LED light source types, so that the image sensor can realize the suppression of the LED stroboscopic effect when detecting various LED light sources, and simultaneously avoid the generation of the problems of motion blur effect and the like caused by the overexposure, thereby improving the image detection performance of the LED light source.
Because in an exposure period, the luminous flux of the LED in the projection area of the image is composed of light emitted by the LED and ambient light, for the same LED luminous flux, the same is achieved in daytime and at night, the luminous flux ratio of the ambient light to the light emitted by the LED is relatively small, after the optimal exposure time is determined according to different LED light sources, the image sensor fixedly uses the optimal exposure time to acquire the LED light source image, through the modes of fixed exposure time and fixed gain, the image sensor can work in all weather, different cameras do not need to be respectively arranged in daytime and at night, and therefore the detection implementation cost is reduced.
In this embodiment, when the optimal exposure time is determined in step S1, an initial exposure time is determined according to the flashing parameters of the LED light source to be detected, and the exposure time of the target image sensor is continuously adjusted from the initial exposure time until the condition that the LED stroboscopic effect does not exist and the stroboscopic performance parameters meet the preset conditions when the target image sensor collects the image of the LED light source to be detected is met, so as to obtain the optimal exposure time output. Through the continuous adjustment, the minimum exposure time for restraining the stroboscopic effect can be obtained.
In this embodiment, the exposure time of the target image sensor is continuously adjusted from the initial exposure time: the method comprises the steps of continuously increasing and adjusting exposure time, obtaining an image of an LED light source to be detected collected by a target image sensor after adjustment every time, judging whether a stroboscopic effect exists, continuously reducing and adjusting the exposure time when the image collected by the target image sensor is judged to be free of the stroboscopic effect, calculating current LED stroboscopic performance parameters after adjustment every time until the LED stroboscopic performance parameters are judged to meet preset conditions, and outputting optimal exposure time.
When the optimal exposure time is determined, the exposure time is continuously increased and adjusted on the basis of the initial exposure time, namely, the exposure time is properly prolonged, so that the exposure time is longer than the LED driving period, namely, an image with a bright lamp can be captured each time, and when the stroboscopic effect does not occur for a plurality of times continuously, the exposure time is continuously reduced and adjusted, so that the optimal exposure time can be determined, and the effects of reducing the exposure time as much as possible and inhibiting the stroboscopic effect can be achieved.
In this embodiment, the initial exposure time is specifically calculated according to parameters such as a flicker frequency and a flicker index of the LED light source to be measured, and if the initial exposure time is specifically calculated according to the following formula:
Figure BDA0002724031850000051
wherein f is the theoretical flicker frequency of the LED light source, and FI is the theoretical flicker index of the LED light source.
It is understood that, besides the above-mentioned manners, other manners or parameters may be adopted to determine the initial exposure time, such as setting a fixed initial exposure time according to experience, or determining the initial exposure time according to the comprehensive index size of parameters such as flicker frequency and flicker index, where the initial exposure time may be set slightly smaller in practice, so as to ensure that the optimal exposure time can be found by adjustment.
In a specific application embodiment, when judging whether the stroboscopic performance parameter meets the preset condition, specifically judging whether parameters such as the stroboscopic percentage and the like reach a preset threshold value, wherein a specific calculation formula of the stroboscopic percentage is as follows:
Figure BDA0002724031850000052
wherein M is c The number of stroboscopic effects is not present for detecting the image captured by the image sensor of interest.
The stroboscopic performance parameters may also be the flicker index FI:
Figure BDA0002724031850000053
where a1 and a2 are areas above and below the average value of the optical signal output in one period, respectively.
Or percent scintillation PF:
Figure BDA0002724031850000061
wherein, y max And y min Respectively a maximum light output and a minimum light output within one period.
Besides the above parameters, it is of course possible to use other strobe performance parameters, or to use a combination of multiple strobe performance parameters to make the determination together to further improve the accuracy.
In this embodiment, the first step length is used for increasing and adjusting the exposure time, the second step length is used for decreasing and adjusting the exposure time, and the first step length and the second step length may be the same, that is, the same step length is used for increasing and decreasing the exposure time, for example, the adjustment of the target image sensor may be determined according to the type of the LED light source to be measuredMinimum time scale T of exposure time i Using the minimum time scale T i The most adjusted step size, i.e. the exposure time increases or decreases by T per adjustment i 。
The first step length and the second step length can be set to be different so as to adjust the exposure time by adopting the variable step length, the first step length can be preferably set to be larger than the second step length, namely, on the basis of the initial exposure time, the exposure time is increased according to the slightly larger step length so as to quickly determine the search area of the optimal exposure time, and then the exposure time is reduced according to the slightly smaller step length, so that the efficiency of searching the optimal exposure time can be further improved, and the search precision of the optimal exposure time is improved.
In this embodiment, the specific steps of step S1 are as follows:
s101, defining a parameter for representing the frequency of occurrence of stroboscopic effect as stroboscopic frequency M f The parameter for representing the times of no stroboscopic effect is normal times M c And configuring the frequency of stroboflash M f Normal times M c Determining an initial exposure time according to the flicker parameter of the LED light source to be detected;
s102, acquiring an image of the LED light source to be detected acquired by the target image sensor according to the current exposure time, judging whether the acquired image has an LED stroboscopic effect or not, and if not, increasing the normal times M c Step S103 is entered; otherwise, increasing and adjusting the stroboscopic frequency M f And increasing the value for adjusting the current exposure time, and returning to the step S102;
s103, judging whether the normal times M are met c Is greater than a predetermined threshold and the number of stroboscopic cycles M f If the value is the initial value, the value for adjusting the current exposure time is reduced, the step S102 is returned to be executed, otherwise, the step S104 is shifted to;
s104, judging whether the current LED stroboscopic performance parameters meet preset conditions, if so, determining the optimal exposure time output according to the current exposure time, otherwise, controlling and adjusting the acquisition conditions of the LED light source, and returning to the step S102.
In the step S104, when it is determined that the current LED stroboscopic performance parameter meets the preset condition, the current exposure time is taken as the optimal exposure time; preferably, in order to further improve the fault tolerance, a preset margin value may be added to the current optimal exposure time to obtain a final optimal exposure time.
Through the steps, after multiple judgment and adjustment, the optimal exposure time suitable for the LED light source to be detected can be efficiently determined.
In step S2, the light-reducing sheet with a specific light transmittance is disposed on the target image sensor to reduce the amount of light entering the target image sensor until no overexposure occurs. By arranging the dimmer in front of the image sensor, as shown in fig. 3, the light incoming quantity of the image sensor can be reduced, the sampling time is ensured, and meanwhile, the intensity of an input signal is reduced to inhibit the image overexposure, so that the effect of inhibiting the stroboscopic effect and avoiding the overexposure problem can be conveniently achieved by combining and using the optimal exposure time.
In this embodiment, before configuring the dimmer sheet, the method further includes a step of determining an optimal dimmer sheet, and the specific steps include: and respectively acquiring images acquired when the target image sensor is respectively configured with the light-reducing sheets with different transmittances according to the optimal exposure time, and comparing the images, and determining the optimal light-reducing sheet as the optimal light-reducing sheet according to the image quality comparison result. Let the maximum light-incoming quantity of the camera not over-exposed be Q, the light-incoming quantity per unit exposure time be Qi, the exposure time be Te, and the light transmittance of the dimmer be R (R is less than 1), then Qi × Te is inevitably greater than Q.
In a specific application embodiment, when determining an optimal dimmer, the optimal dimmer is determined by directly facing the LED light source to be measured so that the number of pixels in a projection area of the LED light source in an image is greater than a preset Value (e.g., 50 × 50), collecting the image after a neutral dimmer is additionally installed in front of a lens, where the reference transmittance of the neutral dimmer may be 0.01%, 0.1%, 0.3%, 1%, 2%, 3%, 5%, 10%, 25%, 30%, 40%, 50%, and the like, matting the light source projection area in the image collected by each dimmer, converting the light source projection area from an RGB color model into an HSV (Hue, Saturation) color model, counting a V (brightness) component mean Value of each matting area, selecting an image with the V component mean Value between preset intervals, comparing S (Saturation) values of the selected images, and selecting the dimmer corresponding to the image with the largest S Value as the selected dimmer.
In a specific application embodiment, the method of the present invention is used to determine the optimal exposure time, as shown in fig. 2, and the detailed steps of configuring the dimmer sheet are as follows:
the method comprises the following steps: determining the minimum time scale T of the target image sensor for adjusting the exposure time according to the type of the LED light source to be detected i And as a step size for the exposure time adjustment.
Step two: calculating an initial exposure time T according to equation (1) s And exposing time T of the image sensor c Set to the initial exposure time T s The digital gain is 1.
Step three: setting initial value of parameter, specifically setting stroboscopic frequency M f 0, number of normalizations M c Is 0.
Step four: the camera is over against the LED light source, a sequence image is collected at the maximum frame rate, and whether the sequence image has the LED stroboscopic effect or not is judged; and if no stroboscopic effect exists, jumping to the step five, otherwise, jumping to the step six.
Step five: m c And increased by 1. If M is c Greater than a preset threshold and M f Equal to 0, i.e. no stroboscopic effect for a predetermined number of times, so that the exposure time T of the image sensor is c Reduction of T i Then jumping to the third step; otherwise, calculating the strobe percentage according to equation (2), if M p If the value is larger than the preset value (such as 0.999), the step seven is skipped, otherwise, the image acquisition condition is adjusted, such as the light source acquisition time or the acquisition scene is changed, and the step four is skipped.
Step six: m f And increased by 1. Let the exposure time T of the image sensor c Increase of T i And then jumping to the fourth step.
Step seven: obtaining the final exposure time T of the image sensor c For the current image sensor exposure time T c Adding T i I.e. at the current exposure time T c On the basis of the above-mentioned formula, T is added i Is obtainedThe final optimal exposure time.
Step eight: and using the optimal exposure time obtained in the step seven as the exposure time of the image sensor, enabling the number of pixels of a projection area of the LED light source in the image to be larger than a preset value by facing the LED light source, and collecting the image after a neutral dimmer is additionally arranged in front of the lens.
Step nine: and (3) matting and selecting the light source projection area in the image acquired by each dimmer, converting the light source projection area from an RGB color model into an HSV color model, counting the V component mean value of each matting and selecting the image with the V component mean value in a preset interval (such as [100-150 ]).
Step ten: and comparing the S values of the selected images in the ninth step, selecting the light-reducing sheet corresponding to the image with the maximum S value as the selected light-reducing sheet, and detecting the LED light source to be detected by using the current image sensor.
The embodiment also provides an LED light source image detection device with a strobe suppression function, which comprises an image sensor, and further comprises an exposure time determination module, a light intake amount adjustment module and an LED light source detection control module which are connected with each other, wherein the LED light source detection control module is connected with the image sensor;
the exposure time determining module is used for determining a target exposure time for the target image sensor, so that an LED stroboscopic effect does not exist when the target image sensor collects an image of the LED light source to be detected according to the target exposure time;
the light inlet quantity adjusting module is used for reducing and adjusting the light inlet quantity of the target image sensor according to the determined target exposure time so as to reduce the light inlet quantity of the target image sensor until no overexposure occurs and determining the adjusted light inlet quantity;
the LED light source detection control module is used for controlling the image sensor to collect the image of the LED light source to be detected according to the optimal exposure time determined by the exposure time determination module and the light inlet quantity adjusted by the light inlet quantity adjusting module for detection.
In this embodiment, when the exposure time determining module determines the optimal exposure time, an initial exposure time is determined according to the flicker parameter of the LED light source to be detected, and the exposure time of the target image sensor is continuously adjusted from the initial exposure time until the condition that the LED stroboscopic effect does not exist and the stroboscopic performance parameter meets the preset condition when the target image sensor acquires the image of the LED light source to be detected is met, so as to obtain the optimal exposure time output.
In this embodiment, the light incident amount adjusting module is a dimmer having a predetermined transmittance.
The LED light source image detection apparatus with strobe suppression function in this embodiment corresponds to the LED light source image detection method with strobe suppression function one to one, and is not described herein again.
The foregoing is considered as illustrative of the preferred embodiments of the invention and is not to be construed as limiting the invention in any way. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention should fall within the protection scope of the technical scheme of the present invention, unless the technical spirit of the present invention departs from the content of the technical scheme of the present invention.

Claims (7)

1. An LED light source image detection method with a strobe suppression function is characterized by comprising the following steps:
s1, determining an optimal exposure time for the target image sensor, so that the target image sensor does not have the LED stroboscopic effect when acquiring the image of the LED light source to be detected according to the optimal exposure time;
s2, reducing the light inlet quantity of the target image sensor according to the determined optimal exposure time so as to reduce the light inlet quantity of the target image sensor until no overexposure occurs, and determining the adjusted light inlet quantity;
s3, the control target image sensor collects the image of the LED light source to be detected according to the optimal exposure time determined in the step S1 and the light inlet quantity adjusted in the step S2 for detection;
when the optimal exposure time is determined in the step S1, specifically, an initial exposure time is determined according to the flicker parameter of the LED light source to be detected, and the exposure time of the target image sensor is continuously adjusted from the initial exposure time until the condition that the LED stroboscopic effect does not exist and the stroboscopic performance parameter meets the preset condition when the target image sensor acquires the image of the LED light source to be detected is met, so as to obtain the optimal exposure time output;
the specific steps of step S1 include:
s101, determining the minimum time scale of the target image sensor for adjusting the exposure time according to the type of the LED light source to be detectedTiAnd used as the step length of exposure time adjustment; defining the parameter for characterizing the number of stroboscopic effects occurring as the number of stroboscopic effectsM f The parameter for representing the frequency of no stroboscopic effect is normal frequencyM c And configuring the number of strobesM f Number of times of normalityM c Determining an initial exposure time according to the flicker parameter of the LED light source to be detected;
s102, acquiring an image of the LED light source to be detected acquired by the target image sensor according to the current exposure time, judging whether the acquired image has an LED stroboscopic effect or not, and if not, increasing the normal timesM c Step S103 is entered; otherwise, increasing and adjusting the stroboscopic timesM f And let the exposure time of the image sensorT c Increase ofTiReturning to step S102;
s103, judging whether the normal times are met or notM c Is greater than a predetermined threshold and the number of stroboscopic cyclesM f Is an initial value, if yes, the exposure time of the image sensor is madeT c Reduction ofTiResetting the initial value of the parameter, returning to the step S102, otherwise, turning to the step S104;
s104, judging whether the current LED stroboscopic performance parameters meet preset conditions, if so, determining the optimal exposure time output according to the current exposure time, wherein the optimal exposure time is the current exposure timeT c Is increased on the basis ofTiOtherwise, controlling and adjusting the acquisition condition of the LED light source, and returning to the step S102.
2. The method as claimed in claim 1, wherein a first step is used for increasing the exposure time, and a second step is used for decreasing the exposure time, and the first step is greater than or equal to the second step.
3. The method for detecting the image of the LED light source with the strobe suppression function according to claim 1, wherein the initial exposure time is calculated according to a flashing frequency and/or a flashing index of the LED light source to be detected.
4. The method for detecting an image of an LED light source with a strobe suppression function as claimed in any one of claims 1 to 3, wherein the step S2 is specifically to configure a dimmer with a specified transmittance on the target image sensor to reduce the amount of incident light until no overexposure occurs.
5. The method for detecting the image of the LED light source with the strobe suppression function as claimed in claim 4, further comprising a step of determining an optimal dimmer before configuring the dimmer, wherein the specific steps include: and respectively acquiring images collected when the target image sensor is respectively configured with the light-reducing sheets with different transmittances according to the optimal exposure time, and comparing the images, and determining the optimal light-reducing sheet according to the image quality comparison result.
6. An LED light source image detection device with a stroboscopic suppression function comprises an image sensor, and is characterized by further comprising an exposure time determination module, a light inlet quantity adjustment module and an LED light source detection control module which are connected with each other, wherein the LED light source detection control module is connected with the image sensor;
the exposure time determining module is used for determining an optimal exposure time for the target image sensor, so that the target image sensor does not have the LED stroboscopic effect when acquiring the image of the LED light source to be detected according to the optimal exposure time;
the light inlet quantity adjusting module is used for reducing and adjusting the light inlet quantity of the target image sensor according to the determined optimal exposure time so as to reduce the light inlet quantity of the target image sensor until no overexposure occurs and determining the adjusted light inlet quantity;
the LED light source detection control module is used for controlling the image sensor to collect an image of the LED light source to be detected according to the optimal exposure time determined by the exposure time determination module and the light inlet quantity adjusted by the light inlet quantity adjustment module for detection;
when the exposure time determining module determines the optimal exposure time, an initial exposure time is determined according to the flicker parameter of the LED light source to be detected, the exposure time of the target image sensor is continuously adjusted from the initial exposure time until the condition that the LED stroboscopic effect does not exist when the target image sensor acquires the image of the LED light source to be detected and the stroboscopic performance parameter meets the preset condition is met, and the optimal exposure time output is obtained;
the exposure time determining module specifically includes:
a first unit for determining the minimum time scale of the target image sensor for adjusting the exposure time according to the type of the LED light source to be measuredTiAnd used as the step length of exposure time adjustment; defining the parameter for characterizing the number of stroboscopic effects occurring as the number of stroboscopic effectsM f The parameter for representing the frequency of no stroboscopic effect is normal frequencyM c And configuring the number of strobesM f Normal times of dayM c Determining an initial exposure time according to the flicker parameter of the LED light source to be detected;
a second unit for acquiring the image of the LED light source to be detected acquired by the target image sensor according to the current exposure time, judging whether the acquired image has LED stroboscopic effect, and if not, increasing the normal timesM c To the third unit; otherwise, increasing and adjusting the stroboscopic timesM f And let the exposure time of the image sensorT c Increase ofTiReturning to the second unit;
a third unit ofIn judging whether the normal times are satisfiedM c Is greater than a predetermined threshold and the number of stroboscopic cyclesM f Is an initial value, if yes, the exposure time of the image sensor is madeT c Reduction ofTiResetting the initial value of the parameter, returning to execute the second unit, and otherwise, switching to the fourth unit;
a fourth unit, configured to determine whether the current LED stroboscopic performance parameter meets a preset condition, and if so, determine the optimal exposure time output according to the current exposure time, where the optimal exposure time is the current exposure time
Figure 432141DEST_PATH_IMAGE001
Is increased on the basis of
Figure 83702DEST_PATH_IMAGE002
Otherwise, the acquisition condition of the LED light source is controlled and adjusted, and the signal returns to the second unit.
7. The LED light source image detecting device with a strobe suppression function as claimed in claim 6, wherein the light input amount adjusting module is a dimmer having a specified light transmittance.
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