CN112135012B - Image acquisition device and image acquisition method - Google Patents

Image acquisition device and image acquisition method Download PDF

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CN112135012B
CN112135012B CN201910553965.6A CN201910553965A CN112135012B CN 112135012 B CN112135012 B CN 112135012B CN 201910553965 A CN201910553965 A CN 201910553965A CN 112135012 B CN112135012 B CN 112135012B
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light
image
filtering
red
signal
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CN112135012A (en
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高浩然
范沣曦
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Hangzhou Hikvision Digital Technology Co Ltd
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Hangzhou Hikvision Digital 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
    • H04N23/50—Constructional details
    • H04N23/55—Optical parts specially adapted for electronic image sensors; Mounting thereof
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/50—Constructional details
    • H04N23/54—Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/64—Circuits for processing colour signals
    • H04N9/73—Colour balance circuits, e.g. white balance circuits or colour temperature control

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Abstract

According to the image acquisition device and the image acquisition method provided by the embodiment of the invention, the optical filtering device blocks infrared light in optical signals and at least part of red visible light with a preset waveband from passing through, so that the optical signals after being filtered are transmitted to the image sensor, and the preset waveband is matched with the red visible light emission waveband of a traffic signal lamp; the image sensor senses the filtered light signal and generates an image signal through exposure. In this embodiment, the filter device can block infrared light and part of red visible light from passing through, and can reduce the passing rate of the red visible light in unit time, so that the red visible light reaching the image sensor can be reduced in the same exposure time period, the saturation time of the red visible light can be prolonged, and the problem of red light color cast can be avoided.

Description

Image acquisition device and image acquisition method
Technical Field
The embodiment of the invention relates to the technical field of intelligent traffic, in particular to an image acquisition device and an image acquisition method.
Background
The electronic police is a modern traffic law enforcement system which utilizes a high-definition camera to automatically record traffic violations such as red light running, reverse running, overspeed running and the like of a motor vehicle by capturing traffic roads and vehicles.
In the traffic field, because the brightness of the traffic signal lamp is high, the phenomenon of color cast and overexposure of the red traffic signal lamp often occurs through the image captured by the camera. Illustratively, a red traffic light in a snapshot is biased yellow and even overexposed to white. If the captured image is taken as the evidence of traffic violation, the evidence of traffic violation may be ambiguous.
Disclosure of Invention
The embodiment of the invention provides an image acquisition device and an image acquisition method, which are used for solving the problem of color cast and overexposure of a red traffic signal lamp in an image captured in the traffic field.
In a first aspect, an embodiment of the present invention provides an image capturing apparatus, including: the image sensor is positioned on the light-emitting side of the light filtering device;
the filtering device is used for blocking infrared light in the optical signal and at least part of red visible light with a preset waveband from passing through, so that the filtered optical signal is transmitted to the image sensor, and the preset waveband is matched with a red visible light emission waveband of the traffic signal lamp;
the image sensor is used for sensing the filtered optical signal and generating an image signal through exposure.
Optionally, the image capturing device further includes: the controller is connected with the filtering device;
the controller is used for controlling the filtering device to filter light in a day filtering mode or a night filtering mode; wherein, the light signal passing rate in the day filtering mode is greater than the light signal passing rate in the night filtering mode.
Optionally, the controller is specifically configured to control the filtering device to filter light in the night filtering mode when it is determined that the current time belongs to the time period corresponding to the night filtering mode;
the controller is further specifically configured to control the filtering device to filter light in the daytime filtering mode when it is determined that the current time belongs to a time period corresponding to the daytime filtering mode.
Optionally, the image acquisition device further comprises a photosensitive device, and the controller is further connected with the photosensitive device;
the photosensitive device is used for sensing the brightness of the current environment;
the controller is specifically configured to control the filtering device to filter light in the daytime filtering mode when the brightness of the current environment is higher than or equal to a preset brightness;
the controller is further specifically configured to control the filtering device to filter light in the night filtering mode when the brightness of the current environment is lower than the preset brightness.
Optionally, the image capturing device further includes: a processor connected with the image sensor;
the processor is used for performing red correction on the image signal generated by the image sensor to obtain a corrected image signal;
wherein, the red correction adopts at least one of the following correction modes: automatic white balance AWB correction, RGB color correction, hue saturation correction.
Optionally, the wavelength range of the optical signal that can be passed by the optical filtering device is 400nm to 630nm, wherein the passing rate of the optical signal in the range of 610nm to 630nm is smaller than the passing rate of the optical signal in the range of 400nm to 610 nm.
Optionally, the filtering device is electrochromic glass, and the electrochromic glass is electrically connected to the controller.
In a second aspect, an embodiment of the present invention provides an image capturing method, which is applied to an image capturing device, where the image capturing device includes a filtering device and an image sensor, and the method includes:
the filtering device is used for blocking infrared light in the light signal and at least part of red visible light with a preset waveband from passing through, so that the filtered light signal is transmitted to the image sensor, and the preset waveband is matched with a red visible light emission waveband of a traffic signal lamp;
the filtered optical signal is sensed by the image sensor and an image signal is generated by exposure.
Optionally, before the infrared light in the light signal and at least part of the red visible light in the preset wavelength band are blocked by the filtering device, the method further includes:
controlling the filtering device to filter light in a day filtering mode or a night filtering mode; wherein, the light signal passing rate in the day filtering mode is greater than the light signal passing rate in the night filtering mode.
Optionally, the controlling the filtering device to filter light in a day filtering mode or a night filtering mode includes:
when the current time is determined to belong to the time period corresponding to the night filtering mode, controlling the filtering device to filter light by adopting the night filtering mode;
and when the current time is determined to belong to the time period corresponding to the daytime filtering mode, controlling the filtering device to filter light by adopting the daytime filtering mode.
Optionally, the image sensor further includes a photosensitive device, and the method further includes:
sensing the brightness of the current environment through the photosensitive device;
the control the filtering device adopts a day filtering mode or a night filtering mode to filter light, and comprises:
when the brightness of the current environment is higher than or equal to the preset brightness, controlling the light filtering device to filter light in the daytime light filtering mode;
and when the brightness of the current environment is lower than the preset brightness, controlling the filtering device to filter light in the night filtering mode.
Optionally, after the sensing the filtered optical signal by the image sensor and generating an image signal by exposure, the method further includes:
performing red correction on the image signal generated by the image sensor to obtain a corrected image signal;
wherein, the red correction adopts at least one of the following correction modes: automatic white balance AWB correction, RGB color correction, hue saturation correction.
Optionally, the wavelength range of the optical signal that can be passed by the optical filtering device is 400nm to 630nm, wherein the passing rate of the optical signal in the range of 610nm to 630nm is smaller than the passing rate of the optical signal in the range of 400nm to 610 nm.
Optionally, the filtering device is electrochromic glass.
According to the image acquisition device and the image acquisition method provided by the embodiment of the invention, the optical filtering device blocks infrared light in optical signals and at least part of red visible light with a preset waveband from passing through, so that the optical signals after being filtered are transmitted to the image sensor, and the preset waveband is matched with the red visible light emission waveband of a traffic signal lamp; the image sensor senses the filtered light signal and generates an image signal through exposure. In this embodiment, the filter device can block infrared light and part of red visible light from passing through, and can reduce the passing rate of the red visible light in unit time, so that the red visible light reaching the image sensor can be reduced in the same exposure time period, the saturation time of the red visible light can be prolonged, and the problem of red light color cast can be avoided. In addition, compared with the prior art that the color of the traffic signal lamp is corrected by adopting an image processing technology, the color cast and overexposure problem of the red traffic signal lamp can be solved only by changing the filtering device from hardware, so that the complicated image processing steps are avoided, and the traffic signal lamp cannot be deformed or distorted.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic diagram of an application scenario in which an embodiment of the present invention is applicable;
FIG. 2 is a schematic diagram of an image acquisition principle provided by an embodiment of the present invention;
fig. 3 is a schematic structural diagram of an image capturing device according to an embodiment of the present invention;
FIG. 4 is a graph illustrating the relationship between the wavelength at which a filter device can pass and the transmittance of the filter device in an embodiment of the present invention;
fig. 5 is a schematic structural diagram of an image capturing device according to another embodiment of the present invention;
FIG. 6 is a schematic diagram illustrating a relationship between a wavelength of light that can pass through the filter device in the daytime filtering mode and a passing rate of the light;
FIG. 7 is a schematic diagram illustrating a relationship between a wavelength of light that can pass through the filter device in the night filtering mode and a transmittance of the light;
fig. 8 is a schematic structural diagram of an image capturing device according to another embodiment of the present invention;
fig. 9 is a schematic flowchart of an image acquisition method according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
In order to facilitate understanding of the technical solution of the present invention, an application scenario and an image acquisition principle to which the embodiment of the present invention is applied are described below with reference to fig. 1 and 2.
Fig. 1 is a schematic view of an application scenario applicable to the embodiment of the present invention. The application scene of the embodiment is an image acquisition scene in the intelligent transportation field. As shown in fig. 1, in the field of intelligent transportation, an image acquisition device is arranged in an intersection area or an important road section to be monitored, and is used for capturing vehicles running on the monitored road section so as to record traffic violation behaviors of the vehicles. The captured image will serve as evidence of traffic violation. Wherein, the traffic violation behaviors that the image capturing device can be used to capture include, but are not limited to, the following: running red light, running in reverse direction, running at overspeed, running without marking, running in overload, running without fastening safety belt, etc.
Fig. 1 illustrates a scene requiring monitoring of red light running, and as shown in fig. 1, an image capturing device is generally disposed above an intersection area where traffic lights are installed. The image acquisition device can acquire the images of the traffic signal lamps and the vehicles at the intersection. If the image acquisition device captures an image of the vehicle A driving at the intersection with the red traffic signal lamp, the image can be used as an evidence that the vehicle A runs the red traffic signal lamp.
Fig. 2 is a schematic diagram of an image acquisition principle provided in an embodiment of the present invention. As shown in fig. 2, the image pickup apparatus includes: a lens 10, a filter 20 and an image sensor 30. The lens 10 is used for collecting optical signals within a view angle range. Referring to fig. 2, a light signal in the environment is reflected by a target object (e.g., a vehicle in a road), the reflected light signal enters the lens 10, and the lens 10 collects the reflected light signal and transmits the collected light signal to the optical filtering device 20. Due to the presence of visible and infrared light in the environment, both visible and infrared light is present in the optical signal reaching the filter means 20. In order to avoid the influence of infrared light on the imaging quality, the filtering device 20 is usually used to filter the infrared light in the optical signal, so that only visible light is transmitted to the image sensor 30. The image sensor 30 senses a visible light signal, generates and outputs an image signal through exposure.
In practical application, in order to ensure the quality of a snapshot image, the brightness of the whole image of the image can be adjusted and controlled when the image acquisition device performs snapshot. Illustratively, when the ambient light brightness is not enough, methods such as prolonging the exposure time or artificially supplementing light are adopted to allow more light signals to enter the lens, so that the overall brightness of the image is improved.
Although the brightness control mode ensures the overall brightness of the image, the phenomenon that the red traffic light is color-cast often occurs when the image is captured by the mode because the brightness of the traffic light is high. Illustratively, a red traffic light in a snapshot is biased yellow and even overexposed to white. If the captured image is taken as the evidence of traffic violation, the evidence of traffic violation may be ambiguous.
Therefore, in the prior art, for the image captured by the image capturing device, an image processing technology is also needed to correct the color of the traffic signal in the image. Specifically, the edge of the traffic signal lamp in the image acquired by the image acquisition device is detected to obtain the edge information of the traffic signal lamp. Then, the traffic signal lamp area is segmented in the image according to the edge information, and color enhancement correction is carried out on the segmented traffic signal lamp area. After the method obtains the edge information of the traffic signal lamp, the image is required to be scanned in a column or a row, and the image segmentation of the traffic signal lamp area can be completed through mapping from line to surface, so that the steps are complicated, and the situations of signal lamp deformation and color distortion are easy to occur.
In order to solve the color cast problem of the traffic signal lamp, an embodiment of the present invention provides an image capturing device, which improves a filtering device from a hardware perspective, so that the filtering device can block a part of red visible light corresponding to a light-emitting waveband of red visible light of the traffic signal lamp from passing through while blocking infrared light from passing through, thereby prolonging a saturation time of an image sensor sensing the red visible light within an exposure time period, and avoiding the color cast overexposure problem of the red traffic signal lamp. In addition, compared with the prior art that the color of the traffic signal lamp is corrected by adopting an image processing technology, the color cast and overexposure problem of the red traffic signal lamp can be solved only by changing the filtering device from hardware, so that the complicated image processing steps are avoided, and the traffic signal lamp cannot be deformed or distorted.
The technical solution of the present invention will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.
Fig. 3 is a schematic structural diagram of an image capturing device according to an embodiment of the present invention. As shown in fig. 3, the image capturing apparatus of the present embodiment includes: a filter device 10 and an image sensor 20. The image sensor 20 is located on the light exit side of the filter device 10.
The optical filtering device 10 is used for blocking infrared light in the optical signal and at least a part of red visible light in a preset waveband from passing through, so that the filtered optical signal is transmitted to the image sensor 20. The preset wave band is matched with a red visible light emitting wave band of the traffic signal lamp.
The image sensor 20 is used for sensing the filtered light signal and generating an image signal through exposure.
In some embodiments, referring to fig. 3, the image capture device may further include a lens 30. At this time, the filter device 10 may be located between the lens 30 and the image sensor 20, and the image sensor 20 is located on the light emitting side of the filter device 10. Alternatively, the lens 30 is located between the filter device 10 and the image sensor 20, and the image sensor 20 is located on the light-emitting side of the lens 30. As an example, the filter device 10 may be a filter, such that the filter may be attached to a surface disposed on a light-emitting side of the lens 30 when the filter device 10 is located between the lens 30 and the image sensor 10, or attached to a surface disposed on a light-entering side of the lens 30 when the lens 30 is located between the filter device 10 and the image sensor 20.
The image acquisition device of the embodiment can be a video camera, a snapshot machine, an electronic eye, a panoramic detail camera and the like.
The image sensor 20 in this embodiment may adopt a global exposure mode or a rolling shutter exposure mode. The global exposure mode means that the exposure start time of each line of effective images is the same, and the exposure end time of each line of effective images is the same. In other words, the global exposure mode is an exposure mode in which all the lines of the effective image are exposed at the same time and the exposure is ended at the same time. The rolling shutter exposure mode means that the exposure time of different lines of effective images is not completely overlapped, that is, the exposure starting time of one line of effective images is later than the exposure starting time of the previous line of effective images, and the exposure ending time of one line of effective images is later than the exposure ending time of the previous line of effective images.
The embodiment of the present invention is different from the prior art in that the wavelength range of the optical signal that can be passed through the optical filter device 10 in the embodiment of the present application is different from the prior art. Fig. 4 is a schematic diagram of a relationship between a wavelength that a filter device can pass and a transmittance in an embodiment of the present invention. This is explained below with reference to fig. 4.
In the conventional image capturing apparatus, the filter 10 is used to prevent infrared light in the optical signal from passing through. It can be understood that because there are visible light and infrared light usually in the ambient light simultaneously, through adopting filter device to prevent that the infrared light passes through for only visible light transmits to image sensor, can avoid the influence of infrared light to imaging quality, makes the image of gathering be visible light luminance information, and the color is abundant.
Fig. 4 is a graph illustrating a relationship between a wavelength that a filter device can pass and a transmittance in the related art. As shown in the curve (r), the wavelength range of the light incident on the filter is 380nm-800 nm. The filter can pass visible light with wavelength in the range of 400nm-650nm and block infrared light in the range of 650nm-800 nm.
According to international regulations, the Light Emitting wavelength of a Light Emitting Diode (LED) lamp bead of a red traffic signal lamp is in the range of 620nm-625 nm. In the range of 620nm-625nm, the photosensitive response of the image sensor is R > G > B. Wherein R is red, G is green, and B is blue. Therefore, during a certain exposure period, the red color will quickly reach saturation, and at this time, the red light is in a normal color. As the exposure time is extended, the green and blue continue to integrate, followed by the saturation of the green, at which time the red light will be yellow. If the exposure time allows, the blue color will gradually reach saturation, and the red light will be overexposed to become white.
In the embodiment of the present invention, the filter 20 not only blocks infrared light from passing through, but also blocks a part of red visible light from passing through. The blocked part of the red visible light is red visible light of a light-emitting waveband corresponding to the red traffic signal lamp in the visible light, namely, red visible light with a wavelength of 620nm-625 nm. The transmittance of the red visible light with the wavelength of 620nm-625nm in the unit time can be reduced by blocking the red visible light with the wavelength of 620nm-625nm from passing through the part. Therefore, in the same exposure time period, the red visible light with the wavelength of 620nm-625nm reaching the image sensor is reduced, the saturation time of the red visible light is prolonged, and the problem of red light color cast is avoided.
Furthermore, since the filter 20 only reduces the transmittance of the red visible light with the wavelength of 620nm to 625nm in the visible light, the transmittance of the light with other wavelengths in the visible light is ensured. That is to say, the passing rate of the green visible light within the range of about 550nm is not affected, so that most of the sensed brightness of the image sensor comes from green sensitization, and therefore, the overall brightness of the image can be ensured on the basis of avoiding the color cast of the red light.
In a possible implementation manner, considering that the traffic signal lamps are different in process or batch, the brightness or wavelength of the red traffic signal lamps is different, and therefore, the range of the red wavelength for reducing the passing rate is expanded from 620nm to 625nm to 610nm to 630nm, so as to be compatible with errors of different traffic signal lamps, and the image acquisition device of the embodiment can avoid the problem of color cast of the red lamps in any traffic signal lamp scene.
Fig. 4 is a graph illustrating a relationship between a wavelength of light that can pass through the filter device and a transmittance in the embodiment of the present invention. As shown by the curve (c), the wavelength range of the optical signal that can be passed by the optical filter in this embodiment is 400nm to 630nm, wherein the transmittance of the optical signal in the range of 610nm to 630nm is smaller than the transmittance of the optical signal in the range of 400nm to 610 nm. That is, the filter device in the present embodiment reduces the transmittance of red visible light in the range of 610nm to 630nm as compared with the prior art curve (r).
In one possible embodiment, the filter device may use a filter glass, and the color of the filter glass is set so that the wavelength and the transmittance of the optical signal that the filter glass can pass through are shown as a curve (c) in fig. 4.
In the image acquisition device provided by this embodiment, the filtering device is configured to block infrared light in the optical signal and at least part of red visible light in a preset wavelength band from passing through, so that the filtered optical signal is transmitted to the image sensor, where the preset wavelength band is matched with a red visible light emission wavelength band of a traffic signal lamp; the image sensor is used for sensing the filtered optical signal and generating an image signal through exposure. In this embodiment, the filter device can block infrared light and part of red visible light from passing through, and can reduce the passing rate of the red visible light in unit time, so that the red visible light reaching the image sensor can be reduced in the same exposure time period, the saturation time of the red visible light can be prolonged, and the problem of red light color cast can be avoided. In addition, compared with the prior art that the color of the traffic signal lamp is corrected by adopting an image processing technology, the color cast and overexposure problem of the red traffic signal lamp can be solved only by changing the filtering device from hardware, so that the complicated image processing steps are avoided, and the traffic signal lamp cannot be deformed or distorted.
Fig. 5 is a schematic structural diagram of an image capturing device according to another embodiment of the present invention. On the basis of the above embodiments, as shown in fig. 5, the image capturing apparatus of the present embodiment may further include a controller 40, and the controller 40 is connected to the filtering device 10.
The controller 40 is configured to control the filtering device to filter light in a day filtering mode or a night filtering mode. Wherein, the light signal passing rate in the day filtering mode is greater than the light signal passing rate in the night filtering mode.
The filter device 10 in this embodiment includes two operation modes, which are respectively: a day filter mode and a night filter mode.
Wherein the daytime filtering mode is suitable for filtering in a daytime environment. The brightness of the environment is high in daytime, the brightness of the traffic signal lamp is also high, and the contrast between the brightness of the traffic signal lamp and the brightness of the surrounding environment is not high. In order to avoid the red light color cast phenomenon, the filter device blocks part of the red visible light from passing through, and the red visible light sensed by the image sensor is reduced, so that more visible light in other bands needs to be sensed in the exposure time period, for example: visible light in the range of 400nm-610 nm. Therefore, the filter device needs to ensure the transmittance of visible light in the range of 400nm to 610 nm. Fig. 6 is a schematic diagram illustrating a relationship between a wavelength of light that can pass through the filtering device in the daytime filtering mode and a passing rate of the light. As shown in fig. 6, in accordance with the curve of fig. 4, that is, visible light in the range of 400nm to 610nm can pass through the filter 10, and only part of red visible light in the range of 610nm to 630nm can pass through the filter.
The night filtering mode is suitable for filtering in a night environment. The ambient brightness decreases at night, and the traffic signal lamp brightness will be high, so that the contrast ratio of the traffic signal lamp brightness and the ambient brightness is high. If the wavelength-pass rate curve shown in fig. 6 is still used, the problem of color cast of the traffic signal lamp still occurs because more green visible light is sensed by the image sensor during the exposure period. For example: the periphery of a green light in the snapshot image has a halo, a yellow light is slightly red, and a red light is slightly yellow. Therefore, in the night environment, the passing rate of visible light in the range of 400nm to 610nm needs to be further reduced, the components of green visible light and blue visible light sensed by the image sensor are reduced, and the color cast problem of the traffic signal lamp is avoided.
Fig. 7 is a schematic diagram illustrating a relationship between a wavelength of light that can pass through the filter device in the night filter mode and a transmittance of the light. As shown in fig. 7, the transmittance of the optical signal in each wavelength band is further reduced on the basis of the curve shown in fig. 6. Illustratively, referring to fig. 7, the visible light transmittance in the range of 400nm to 610nm is reduced to about 50%, and the red visible light transmittance in the range of 610nm to 630nm is reduced to 50% or less.
In this embodiment, the controller may adopt a plurality of control strategies to switch and control the operating modes of the optical filtering device.
In one possible implementation, a time-division switching manner is adopted. Specifically, the time period corresponding to the daytime filter mode and the time period corresponding to the night filter mode may be preset according to the actual application scenario. Illustratively, the daytime filter mode corresponds to a time period of 7:00 to 19:00, and the nighttime filter mode corresponds to a time period of 19: 00-7: 00 of the next day.
Furthermore, clock control is carried out according to an internal timer of the image acquisition device, and time information of the current moment is acquired. And controlling according to the time information of the current moment and the preset switching time point. Illustratively, if the current time belongs to a time period corresponding to the night filtering mode, for example, the current time belongs to a range from 19:00 to 7:00 the next day, the filtering device is controlled to filter in the night filtering mode. And if the current time belongs to the time period corresponding to the daytime filtering mode, for example, the current time belongs to the range of 7:00 to 19:00, controlling the filtering device to filter in the daytime filtering mode.
In another possible embodiment, a photosensitive switching mode is used. For example, a photosensor is disposed in the image capturing device to sense the brightness of the current environment. And if the sensed brightness of the current environment is higher than or equal to the preset brightness, the controller controls the light filtering device to filter light in a daytime light filtering mode. And if the sensed brightness of the current environment is lower than the preset brightness, the controller controls the light filtering device to filter light in a night light filtering mode.
The photosensitive device may be any device capable of sensing ambient brightness. Illustratively, the photosensitive device may be a photoresistor, a photodiode, a phototransistor, or the like.
In the above embodiment, the filter device may be electrochromic glass. The optical property of the electrochromic glass generates a stable and reversible color change phenomenon under the action of an external electric field, and the electrochromic glass shows reversible changes of color and transparency in appearance.
Illustratively, the electrochromic glazing is electrically connected to the controller. After the electrochromic glass receives the switching control signal sent by the controller, the electric fields at the two ends of the electrochromic glass change to cause the color of the electrochromic glass to change, so that the wavelength transmittance curve corresponding to the electrochromic glass is switched between the graph 6 and the graph 7, and the switching between the day filtering mode and the night filtering mode is realized.
On the basis of the above embodiment, the filtering device blocks part of the red visible light in the 610nm-630nm range from passing through, so that the red visible light in the 610nm-630nm range sensed by the image sensor is reduced, and therefore, red distortion in the captured image can be caused. Meanwhile, because the red uptake in the whole image picture is insufficient, the whole picture tends to be bluish green. Therefore, on the basis of the above embodiment, the captured image signal may be further subjected to red color correction by an image processing technique to restore the red color in the image signal.
Fig. 8 is a schematic structural diagram of an image capturing device according to another embodiment of the present invention. On the basis of the foregoing embodiment, the image capturing apparatus of the present embodiment may further include: a processor 50. The processor 50 is connected to the image sensor 20.
The processor 50 is configured to perform red color correction on the image signal generated by the image sensor 20 to obtain a corrected image signal. Wherein, at least one of the following correction modes can be adopted for red correction: automatic White Balance (AWB) correction, RGB color correction, and hue saturation correction.
The AWB correction is used for recovering the normal color in the captured image signal so as to solve the problem that the image signal is globally bluish-green. Illustratively, the bayer data corresponding to different color temperatures of the 24-color card corresponding to the filter device of the embodiment is captured, the gray area range corresponding to the filter device is calibrated, and the AWB correction is performed on the basis of the gray area range, so that the problem that the gray area cannot be found in the picture to cause the picture to be globally bluish-green is avoided.
The image picture after AWB correction can only ensure that the main body of the gray area does not deviate color, but can not solve the problem of red distortion. Therefore, further RGB color correction is required to restore the red color in the picture.
The RGB color correction process is as follows: and aiming at the first 18 colors of the 24 color card, determining a target color for each color, and obtaining the optimal solution of a 3 x 3 matrix by least square fitting by taking each color as a target, wherein the closer each color is to the target color, the better each color is. The matrix is left-multiplied over the RGB domain of the image to obtain a new color,the correction of the color is completed. The following formula is shown, wherein is matrix multiplication, (R)in，Gin，Bin) For the color before correction, (R)new，Gnew，Bnew) The corrected color.
Figure BDA0002106323460000121
After RGB color correction, for red that still cannot be corrected well, a hue saturation correction mode may be further adopted for correction.
The procedure of the hue saturation correction method is as follows: first, a gamut range (i.e., a range of HSV, where H is hue, S is saturation, and V is lightness) is predefined, and colors within the gamut range are considered as red. And calibrating the degree needing to be corrected by H and S, and finding corresponding output (H, S, V) as new red by a lookup table mode. The correction intensity in the color gamut range is gradually changed, and the correction intensity is sequentially enhanced from the edge to the center of the area, so that the problem of color jump of the flat area is prevented.
The three red correction methods may be combined according to actual conditions, and this embodiment is not particularly limited thereto.
Based on the above description of the image capturing apparatus, next, an image capturing method is explained with an image capturing apparatus provided based on the above-described embodiment shown in fig. 1 to 8. Fig. 9 is a schematic flowchart of an image acquisition method according to an embodiment of the present invention. As shown in fig. 9, the method of this embodiment includes:
s901: the filtering device is used for blocking infrared light in the light signal and at least part of red visible light with a preset waveband from passing through, so that the filtered light signal is transmitted to the image sensor, and the preset waveband is matched with a red visible light emission waveband of the traffic signal lamp.
S902: the filtered optical signal is sensed by the image sensor and an image signal is generated by exposure.
In a possible embodiment, before the filtering device blocks the infrared light and at least a part of the red visible light in the preset wavelength band from passing through, the method further includes:
controlling the filtering device to filter light in a day filtering mode or a night filtering mode; wherein, the light signal passing rate in the day filtering mode is greater than the light signal passing rate in the night filtering mode.
In a possible embodiment, the controlling the filtering device to filter light in a day filtering mode or a night filtering mode includes:
when the current time is determined to belong to the time period corresponding to the night filtering mode, controlling the filtering device to filter light by adopting the night filtering mode;
and when the current time is determined to belong to the time period corresponding to the daytime filtering mode, controlling the filtering device to filter light by adopting the daytime filtering mode.
In one possible embodiment, the image sensor further includes a photosensitive device, and the method further includes:
sensing the brightness of the current environment through the photosensitive device;
the control the filtering device adopts a day filtering mode or a night filtering mode to filter light, and comprises:
when the brightness of the current environment is higher than or equal to the preset brightness, controlling the light filtering device to filter light in the daytime light filtering mode;
and when the brightness of the current environment is lower than the preset brightness, controlling the filtering device to filter light in the night filtering mode.
In one possible embodiment, after the sensing the filtered light signal by the image sensor and generating an image signal by exposure, the method further includes:
performing red correction on the image signal generated by the image sensor to obtain a corrected image signal;
wherein, the red correction adopts at least one of the following correction modes: automatic white balance AWB correction, RGB color correction, hue saturation correction.
In one possible embodiment, the wavelength range of the optical signal that can be passed by the optical filter is 400nm to 630nm, wherein the light signal in the 610nm to 630nm range has a smaller transmittance than the light signal in the 400nm to 610nm range.
In one possible embodiment, the filter is electrochromic glass.
It should be noted that, since the present embodiment and the embodiment shown in fig. 1 to 8 may adopt the same inventive concept, for the explanation of the present embodiment, reference may be made to the explanation of the relevant contents in the embodiment shown in fig. 1 to 8, and the description thereof is omitted here.
According to the image acquisition method provided by the embodiment of the invention, the filtering device is used for blocking infrared light in the optical signal and at least part of red visible light with a preset waveband from passing through, so that the filtered optical signal is transmitted to the image sensor, and the preset waveband is matched with the red visible light emission waveband of the traffic signal lamp; and sensing the filtered optical signal through an image sensor, and generating an image signal through exposure. In this embodiment, the filter device can block infrared light and part of red visible light from passing through, and can reduce the passing rate of the red visible light in unit time, so that the red visible light reaching the image sensor can be reduced in the same exposure time period, the saturation time of the red visible light can be prolonged, and the problem of red light color cast can be avoided. In addition, compared with the prior art that the color of the traffic signal lamp is corrected by adopting an image processing technology, the color cast and overexposure problem of the red traffic signal lamp can be solved only by changing the filtering device from hardware, so that the complicated image processing steps are avoided, and the traffic signal lamp cannot be deformed or distorted.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. An image acquisition apparatus, comprising: the image sensor is positioned on the light-emitting side of the light filtering device;
the light filtering device is used for blocking infrared light in the light signals and blocking at least part of red visible light with a preset waveband from passing through, so that the filtered light signals are transmitted to the image sensor, and the preset waveband is matched with a red visible light emission waveband of the traffic signal lamp;
the image sensor is used for sensing the filtered optical signal and generating an image signal through exposure.
2. The image capturing device of claim 1, further comprising: the controller is connected with the filtering device;
the controller is used for controlling the filtering device to filter light in a day filtering mode or a night filtering mode; wherein, the light signal passing rate in the day filtering mode is greater than the light signal passing rate in the night filtering mode.
3. The image capturing device according to claim 2,
the controller is specifically configured to control the filtering device to filter light using the night filtering mode when it is determined that the current time belongs to a time period corresponding to the night filtering mode;
the controller is further specifically configured to control the filtering device to filter light in the daytime filtering mode when it is determined that the current time belongs to a time period corresponding to the daytime filtering mode.
4. The image capturing device of claim 2, wherein the image capturing device further comprises a photosensitive device, and the controller is further connected to the photosensitive device;
the photosensitive device is used for sensing the brightness of the current environment;
the controller is specifically configured to control the filtering device to filter light in the daytime filtering mode when the brightness of the current environment is higher than or equal to a preset brightness;
the controller is further specifically configured to control the filtering device to filter light in the night filtering mode when the brightness of the current environment is lower than the preset brightness.
5. The image capturing device of claim 1, further comprising: a processor connected with the image sensor;
the processor is used for performing red correction on the image signal generated by the image sensor to obtain a corrected image signal;
wherein, the red correction adopts at least one of the following correction modes: automatic white balance AWB correction, RGB color correction, hue saturation correction.
6. The image capturing device as claimed in any one of claims 1 to 5, wherein the optical filter is capable of passing optical signals in a wavelength range of 400nm-630nm, and wherein the optical signal passing rate in the range of 610nm-630nm is less than the optical signal passing rate in the range of 400nm-610 nm.
7. The image capturing device as claimed in any one of claims 2 to 4, wherein the filter is an electrochromic glass, and the electrochromic glass is electrically connected to the controller.
8. An image acquisition method is applied to an image acquisition device, wherein the image acquisition device comprises a light filtering device and an image sensor, and the method comprises the following steps:
the filtering device is used for blocking infrared light in the optical signal and blocking at least part of red visible light with a preset waveband from passing through, so that the filtered optical signal is transmitted to the image sensor, and the preset waveband is matched with a red visible light emission waveband of a traffic signal lamp;
the filtered optical signal is sensed by the image sensor and an image signal is generated by exposure.
9. The method according to claim 8, wherein before the passing of the infrared light and at least a portion of the predetermined wavelength band of the red visible light in the light signal through the filter device, the method further comprises:
controlling the filtering device to filter light in a day filtering mode or a night filtering mode; wherein, the light signal passing rate in the day filtering mode is greater than the light signal passing rate in the night filtering mode.
10. The method of claim 8, wherein after sensing the filtered light signal by the image sensor and generating an image signal by exposure, further comprising:
performing red correction on the image signal generated by the image sensor to obtain a corrected image signal;
wherein, the red correction adopts at least one of the following correction modes: automatic white balance AWB correction, RGB color correction, hue saturation correction.
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