CN210469533U - Ambient light adjusting device, image sensor, and electronic device - Google Patents
Ambient light adjusting device, image sensor, and electronic device Download PDFInfo
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- CN210469533U CN210469533U CN201921881996.6U CN201921881996U CN210469533U CN 210469533 U CN210469533 U CN 210469533U CN 201921881996 U CN201921881996 U CN 201921881996U CN 210469533 U CN210469533 U CN 210469533U
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Abstract
The application relates to an ambient light adjusting device, image sensor and electron device, the module includes: an ambient light detection unit for detecting an intensity value of ambient light; adjusting means for adjusting the intensity of light received by the image sensor; and the controller is respectively connected with the ambient light detection unit and the adjusting device and is used for controlling the adjusting device to adjust the intensity of the light received by the image sensor based on the intensity value. The controller controls the adjusting device to adjust the intensity of the light received by the image sensor based on the intensity value, so that the situation that the image sensor cannot work normally due to overhigh intensity of the light received by the image sensor, which causes overlarge noise in a detected target signal, is avoided, and meanwhile, the situation that the image sensor cannot work normally due to overhigh intensity of ambient light is also avoided.
Description
Technical Field
The present disclosure relates to the field of image sensor technologies, and in particular, to an ambient light adjusting device, an ambient light adjusting method, an image sensor, and an electronic device.
Background
With the increasing development of semiconductor imaging technology, semiconductor image sensors are widely used in various electronic devices such as digital cameras, mobile phones, medical imaging devices, security inspection devices, and distance measuring cameras due to their advantages of small size, low energy consumption, high sensitivity, and the like.
However, in an image sensor of a device for measuring depth or distance information, such as a conventional Time of Flight (TOF) system or a laser radar ranging system, a laser emitter is required to illuminate infrared laser, if ambient light is too strong, noise in a detected target signal is too large, which results in inaccurate measurement result of the target signal, and may cause the image sensor to fail to work normally under the condition of high ambient light intensity, which results in a limitation of an application range of the image sensor.
SUMMERY OF THE UTILITY MODEL
In view of the above, it is necessary to provide an ambient light adjusting device, an image sensor, and an electronic device capable of automatically adjusting the intensity of received light, in order to solve the technical problem of the background art that the ambient light adversely affects the measurement accuracy and the application range of the image sensor.
An aspect of the present application provides an ambient light adjusting device, including:
an ambient light detection unit for detecting an intensity value of ambient light;
adjusting means for adjusting the intensity of light received by the image sensor; and
and the controller is respectively connected with the ambient light detection unit and the adjusting device and is used for controlling the adjusting device to adjust the intensity of the light received by the image sensor based on the intensity value.
In the ambient light adjusting apparatus in the above embodiment, since the ambient light detecting unit for detecting the intensity value of the ambient light is provided, and the controller controls the adjusting apparatus to adjust the intensity of light received by the image sensor based on the intensity value, it is avoided that the intensity of light received by the image sensor is too high, so that the noise in the detected target signal is too large, which results in an inaccurate measurement result, and meanwhile, the situation that the image sensor cannot work normally due to too high intensity of ambient light is also avoided.
In one embodiment, the image sensor comprises:
the first single photon avalanche diode array is used for detecting the intensity of the light received by the image sensor; and
and the first time digital converter is connected with the controller and used for calculating the number of times that the first single photon avalanche diode array is triggered so as to obtain the intensity of the light received by the image sensor.
In one embodiment, the ambient light detection unit comprises at least one of a photodiode or an ambient light sensor.
In one embodiment, the ambient light detection unit is disposed outside the image sensor.
In one embodiment, the ambient light detection unit comprises:
the second single photon avalanche diode array is used for detecting the intensity of the ambient light; and
and the second time digital converter is connected with the controller and used for calculating the number of times the second single photon avalanche diode array is triggered so as to obtain the intensity of the ambient light.
In one embodiment, the first single photon avalanche diode array comprises at least two sub-signal regions, and output signals of the single photon avalanche diodes in the sub-signal regions are mutually superposed.
In one embodiment, the controller is configured to control the adjusting device to reduce the intensity of light received by the image sensor and/or reduce the bias voltage for operating the image sensor when the detected intensity value is greater than or equal to a preset threshold value.
In one embodiment, the adjusting device comprises:
and the light chopper is provided with a diaphragm and is used for moving along with the motor so as to change the cross section area of the diaphragm and further adjust the intensity of light received by the image sensor.
In one embodiment, the adjusting device comprises:
and the at least two attenuation sheets are respectively connected with the motor, and the intensity of light received by the image sensor is adjusted by changing the number, the model or the position of the attenuation sheets covering the upper surface of the image sensor.
An aspect of the present application provides an image sensor, including the ambient light adjusting apparatus according to any one of the embodiments of the present application, configured to adjust an intensity of light received by the image sensor according to an intensity value of ambient light detected by the ambient light detecting unit.
In the image sensor in the above embodiment, since the ambient light detection unit for detecting the intensity value of the ambient light is provided, and the controller controls the adjustment device to adjust the intensity of light received by the image sensor based on the intensity value, it is avoided that the intensity of light received by the image sensor is too high, so that the noise in the detected target signal is too large, which results in inaccurate measurement result, and meanwhile, the situation that the image sensor cannot work normally due to too high intensity of ambient light is also avoided.
An aspect of the present application provides an electronic device, including the image sensor ambient light adjusting apparatus according to any one of the embodiments of the present application, configured to adjust the intensity of light received by the image sensor according to the intensity value of ambient light detected by the ambient light detecting unit.
In the electronic device in the above embodiment, because the ambient light detection unit for detecting the intensity value of the ambient light is arranged, and the controller controls the adjustment device to adjust the intensity of light received by the image sensor based on the intensity value, it is avoided that the intensity of light received by the electronic device is too high, so that the noise in the detected target signal is too large, which results in inaccurate measurement results, and meanwhile, the electronic device is also avoided from being incapable of working normally due to too high intensity of ambient light.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments are briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain drawings of other embodiments based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an ambient light adjusting device according to an embodiment of the present disclosure.
Fig. 2 is a schematic structural diagram of an ambient light adjusting device according to another embodiment of the present disclosure.
Fig. 3 is a schematic structural diagram of a shutter according to an embodiment of the present application.
Fig. 4 is a schematic structural diagram of an electronic device provided in an embodiment of the present application.
Fig. 5 is a flowchart of an ambient light adjusting method according to an embodiment of the present application.
Fig. 6 is a flowchart of an ambient light adjusting method according to another embodiment of the present application.
Fig. 7 is a statistical histogram of the number of times the SPAD array is triggered by incident light with an ambient light intensity value of 10kLux in one embodiment of the present application.
FIG. 8 is a simulation of the signal of FIG. 7 after being corrected by Coates.
Fig. 9 is a simulation diagram obtained by performing matched filtering on the signals in fig. 8.
Fig. 10 is a statistical histogram of the number of times the SPAD array is triggered by incident light with an ambient light intensity value of 100kLux in an embodiment of the present application.
Fig. 11 is a statistical histogram of incident light signals obtained by the image sensor adjusted by the ambient light adjusting device in the embodiment of the present application in the same situation as in fig. 10.
FIG. 12 is a simulation of the signal of FIG. 10 after being corrected by Coates.
Fig. 13 is a simulation diagram obtained by performing matched filtering on the signals in fig. 12.
FIG. 14 is a simulation of the signal of FIG. 11 after being corrected by Coates.
Fig. 15 is a simulation diagram obtained by performing matched filtering on the signals in fig. 14.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are illustrated in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
Where the terms "comprising," "having," and "including" are used herein, another element may be added unless an explicit limitation is used, such as "only," "consisting of … …," etc. Unless mentioned to the contrary, terms in the singular may include the plural and are not to be construed as being one in number.
In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
As shown in fig. 1, an ambient light adjusting apparatus applied to an image sensor provided in an embodiment of the present application includes: an ambient light detection unit 10 for detecting an intensity value of ambient light; adjusting means 20 for adjusting the intensity of light received by the image sensor; and a controller 30, respectively connected to the ambient light detection unit 10 and the adjustment device 20, for controlling the adjustment device to adjust the intensity of the light received by the image sensor based on the intensity value.
The ambient light detection unit 10 is generally a semiconductor device, and is mainly used for collecting an optical signal, converting the collected optical signal into an electrical signal, and indirectly determining the intensity value of the detection light according to the electrical signal.
The adjusting device 20 may include at least one of an optical element such as a shutter or an attenuation sheet, and is configured to adjust the intensity of the light received by the image sensor so that the intensity of the light received by the image sensor falls within a preferred operating range of the image sensor.
Specifically, the ambient light adjusting device 100 may be disposed outside or inside the image sensor or the electronic component for detecting the intensity value of the ambient light, and controlling the adjusting device to adjust the intensity value of the light received by the image sensor or the electronic component based on the detected intensity value of the ambient light. For example, when the intensity value of the ambient light detected by the ambient light detecting unit 10, acquired by the controller 30, is greater than or equal to a preset threshold value, which indicates that the intensity value of the ambient light has exceeded the preferred operating range of the image sensor, the controller 30 may control the adjusting device to weaken the intensity of the light received by the image sensor; when the intensity value of the ambient light detected by the ambient light detecting unit 10, which is obtained by the controller 30, is less than or equal to the preset threshold, which indicates that the intensity value of the ambient light is lower than the requirement of the preferred operating range section of the image sensor or the electronic component for the intensity of the ambient light, the controller 30 may control the adjusting device 20 to increase the intensity value of the light received by the image sensor or the electronic component, for example, increase the area of the received light or decrease the refractive index of the incident light, so that the intensity value of the light received by the image sensor meets the requirement of the preferred operating range section.
In the above-mentioned embodiment of the ambient light adjusting apparatus, since the ambient light detecting unit for detecting the intensity value of the ambient light is provided, the controller controls the adjusting apparatus to adjust the intensity of the light received by the image sensor based on the detected intensity value, so that the intensity value of the light received by the image sensor meets the requirement of the image sensor in a better working state. The method and the device avoid the inaccuracy of the measurement result caused by the overlarge noise in the detected target signal due to the overlarge intensity of the light received by the image sensor, and also avoid the condition that the image sensor cannot work normally due to the overlarge intensity of the ambient light.
Further, in an embodiment of the present application, there is provided an image sensor to which the ambient light adjusting apparatus illustrated in fig. 1 is applied, including: a first single photon avalanche diode array (not shown) for detecting the intensity of light received by the image sensor; and a first time-to-digital converter (not shown) connected to a controller (not shown) for calculating the number of times the first single photon avalanche diode array is triggered to obtain the intensity of light received by the image sensor.
Further, in the Ambient Light adjusting apparatus provided in an embodiment of the present application, the Ambient Light detecting unit may include at least one of a Photodiode (PD) or an Ambient Light Sensor (ALS), and in this embodiment, the photodiode and/or the Ambient Light Sensor are preferably disposed outside the image Sensor and connected to the controller, so as to better collect and convert the Light signal into an electrical signal, so as to improve the accuracy of detecting the Ambient Light intensity value. In the embodiment, the excellent photoelectric conversion characteristics of the photodiode and/or the ambient light sensor are utilized, the intensity of the detected ambient light is indirectly measured by converting the collected ambient light into an electric signal, and the measuring method is simple and has high precision.
As shown in fig. 2, in the ambient light adjusting apparatus provided in an embodiment of the present application, the ambient light detecting unit 10 may include a second Single Photon Avalanche Diode (SPAD) array 11 and a second Time To Digital Converter (TDC) 12, where the second SPAD array 11 and the second Time to digital converter 12 are communicatively connected to calculate the number of times the second SPAD array 11 is triggered; the second time digitizer 12 is connected to the controller 30 for transmitting the acquired number of times the second SPAD array 11 is triggered to the controller 30. In this embodiment, it is preferable that the second single photon avalanche diode array includes single photon avalanche diodes arranged in an array. The SPAD is a binary device, a PN junction is biased under the bias voltage close to avalanche, a small number of carriers excited by a weak optical signal pass through a field area close to the avalanche, the number of the carriers is multiplied due to impact ionization, and therefore a larger electric signal is obtained. Therefore, the SPAD has only two states of 'output signal' and 'no output signal', and the second time digitizer 12 is adopted in the embodiment to record the number of times the SPAD array 11 is triggered so as to indirectly measure the intensity of the incident light. The single photon avalanche diode has extremely high sensitivity to light, and the ambient light detection unit 10 including the second single photon avalanche diode array 11 can be provided inside or outside the image sensor. In the embodiment, the excellent photoelectric conversion characteristic of the single photon avalanche diode is utilized, the single photon avalanche diode is combined with the time digital converter, the total number of times of triggering the single photon avalanche diode array is recorded through the time digital converter, the intensity of the detected ambient light is indirectly measured, and the measuring method is simple and high in precision.
Further, in the ambient light adjusting device in the above embodiment, the first single photon avalanche diode array includes at least two sub-signal regions, and output signals of the single photon avalanche diodes in the sub-signal regions are superimposed on each other. For example, if the original image sensor used an 80 × 60 SPAD array, and every 4 SPAD subunits could be bound together, there would be 40 × 30 signals output. The output signals of the SPADs in each 4 SPAD subunits are superposed with each other to form the output signal of the subsignal area. By dividing the first single photon avalanche diode array into a plurality of sub-signal regions and superposing the output signals of the single photon avalanche diodes in each sub-signal region, the intensity of the signal collected in each sub-signal region is improved, and the quality of the image acquired by the image sensor adopting the ambient light adjusting device in the embodiment is improved.
Further, in the ambient light adjusting device in the above embodiment, the adjusting device may include a shutter 21 as shown in fig. 3, the shutter 21 is provided with an aperture 211, and the intensity of the incident light may be increased or decreased by adjusting the size of the cross-sectional area of the aperture 211. In this embodiment, the diaphragm 211 may be connected to a dc servo motor (not shown), and the dc servo motor is controlled to operate to drive the diaphragm 211 to increase or decrease the cross-sectional area of the diaphragm, so as to adjust the intensity of light received by the image sensor. In other embodiments of the present application, the attenuation rate of the shutters may also be varied, for example, the shutters may be made using liquid crystal or phase change material. When the intensity value of the light detected by the ambient light detection unit is greater than or equal to a preset threshold value, the controller can control the direct current servo motor to act so as to drive the diaphragm to reduce the cross-sectional area of the diaphragm, so that the intensity of the incident light is reduced; on the contrary, the direct current servo motor can be controlled to move in the opposite direction to drive the diaphragm to increase the cross-sectional area of the diaphragm so as to improve the intensity of incident light.
Further, in the ambient light adjusting device in the above embodiment, the adjusting device may include at least two attenuation sheets, the types of the attenuation sheets may be the same or different, and the intensity of the light received by the image sensor is adjusted by increasing or decreasing the number of the attenuation sheets covering the upper surface of the image sensor, and/or changing the types of the attenuation sheets covering the upper surface of the image sensor, and/or changing the positions of the attenuation sheets covering the upper surface of the image sensor. For example, a plurality of different attenuation sheets can be arranged, and the number of the attenuation sheets used can be adjusted; the relative rotation of the two polarized attenuators can be set to change the position of the attenuator; or the type of the attenuation sheet used can be adjusted.
Specifically, the attenuation sheet may be an optical element having a strong reflection and/or refraction property with respect to incident light, and by increasing the number of attenuation sheets used, the intensity of light received by the image sensor may be effectively reduced, and conversely, the intensity of light received by the image sensor may be increased. In this embodiment, for example, the attenuation sheet may be connected to the dc servo motor, and the intensity of light received by the image sensor is controlled and reduced by controlling the dc servo motor to drive the attenuation sheet to cover the upper surface of the image sensor; or the attenuation sheet is driven to move away from the upper surface covering the image sensor by controlling the action of the direct current servo motor so as to increase the intensity of light received by the image sensor.
Specifically, in the ambient light adjusting apparatus in the above embodiment, for example, when the ambient light detecting unit detects the intensity of the incident light by using the SPAD array and the time-to-digital converter together, first, in the case where there is no laser emission signal irradiation, and the ambient light intensity value is 10kLux, the time-to-digital converter records the number of times that the SPAD array is triggered by the ambient light, and repeats the measurement for a plurality of times, so as to obtain the statistical histogram that the SPAD array is triggered by the ambient light, and further determine the intensity of the ambient light. The cross-sectional area value of the aperture required to be used by the ambient light adjusting device in the application under different ambient light intensity values can be formulated according to the requirement of the better working state of the SPAD array on the incident light intensity, and/or the type of attenuation sheet used and the corresponding quantity value, and/or the bias voltage value for the operation of the SPAD array, the specific ambient light intensity value and the cross-sectional area value of the aperture to be used, and/or the type and the corresponding numerical value of the attenuation sheet to be used can be established, and/or a comparison table of the bias voltage value of the SPAD array operation, and the controller is arranged to control the adjusting device according to the specific value of the comparison table, control the cross-sectional area of the aperture of the light shield in the adjusting device and/or the number of the attenuators according to the specific light intensity value detected by the ambient light detection unit, and/or control the bias voltage value of the SPAD array operation.
In the above-mentioned embodiment of the ambient light adjusting apparatus, because the ambient light detecting unit for detecting the intensity value of the ambient light is provided, the controller controls the adjusting apparatus to adjust the intensity of the light received by the image sensor based on the intensity value, so that the intensity of the light received by the image sensor meets the requirement of the preferable working range of the image sensor, the situation that the image sensor cannot work normally due to the fact that the intensity of the light received by the image sensor is too high and the noise in the detected target signal is too large is avoided, and meanwhile, the situation that the image sensor cannot work normally due to the fact that the intensity of the ambient light is too high is also avoided.
Further, in an ambient light adjusting device provided in an embodiment of the present application, the controller is configured to:
calculating the time-varying estimation of the incident light intensity by the output signal of the first single-photon avalanche diode array through a Coates correction algorithm
Wherein N is the total number of times the first single photon avalanche diode array is triggered, NkRepresenting the number of firings of said first single photon avalanche diode array within a kth time stamp.
Based on an estimation of the variation of the incident light intensity values with timeAcquiring a distance value d between a target object and the image sensor:
where Δ t is the accuracy of the timestamp and c is the speed of light.
Further, in the ambient light adjusting apparatus provided in an embodiment of the present application, the controller is configured to calculate an estimate of a temporal change in incident light intensity from the output signals of the first single photon avalanche diode array by a Coates correction algorithmThen, estimating the time variation of the incident light intensity valueObtaining through matched filtering
Based onAcquiring a distance value d between a target object and the image sensor, wherein Δ t is the precision of the timestamp, c is the speed of light, and d is:
in an embodiment of the present application, an image sensor includes any one of the ambient light adjusting devices described in the embodiments of the present application, and is configured to adjust the intensity of light received by the image sensor according to the intensity value of the ambient light detected by the ambient light detecting unit, so that the intensity value of light received by the image sensor meets the requirement of a better operating state of the image sensor.
In an embodiment of the present application, an electronic device includes any one of the ambient light adjusting devices described in the embodiments of the present application, and is configured to adjust an intensity of light received by the image sensor according to an intensity value of ambient light detected by the ambient light detecting unit, so that the intensity value of light received by the electronic device meets a requirement of a better operating state of the electronic device, and a laser emitter configured to emit a laser signal.
Specifically, in an embodiment of the present application, as shown in fig. 4, the electronic device may be a laser radar 200, and the signal power emitted by the laser 40 may be appropriately adjusted according to the intensity of the ambient light detected by an ambient light detection unit (not shown) in the ambient light adjustment device 100, so as to achieve an appropriate signal-to-noise ratio, and avoid increasing the power consumption of the product due to blindly increasing the signal power.
The controller in the embodiment of the application can comprise at least one of a single chip microcomputer, a vehicle-mounted PLC, an ARM, a DSP, a programmable logic controller and the like.
In an embodiment of the present application, there is provided an ambient light adjusting method, applicable to an image sensor, as shown in fig. 5, including:
step 202: an intensity value of the ambient light is detected based on an ambient light detection unit.
An ambient light detection unit may be provided inside or outside the image sensor to detect the intensity value of the ambient light, and the ambient light detection unit may be provided in connection with the controller. The environment light detection unit can adopt a semiconductor device and is mainly used for collecting light signals, converting the collected light signals into electric signals and transmitting the electric signals to the controller, and then indirectly judging the intensity value of the detection light according to the electric signals.
Step 204: and controlling the adjusting device to adjust the intensity of the light received by the image sensor based on the intensity value received by the controller.
Specifically, the adjusting device may be configured to include a shutter as shown in fig. 3, and when the intensity value of the light detected by the ambient light detecting unit is greater than or equal to a preset threshold, the controller may control the dc servo motor to operate to drive the aperture to reduce the cross-sectional area of the aperture, so as to reduce the intensity of the incident light; on the contrary, the direct current servo motor can be controlled to move in the opposite direction to drive the diaphragm to increase the cross-sectional area of the diaphragm so as to improve the intensity of incident light.
Further, the ambient light adjusting method in the above embodiment includes: a first single photon avalanche diode array (not shown) for detecting the intensity of light received by the image sensor; and a first time-to-digital converter (not shown) connected to a controller (not shown) for calculating the number of times the first single photon avalanche diode array is triggered to obtain the intensity of light received by the image sensor.
Further, in the ambient light adjusting method in the above embodiment, the adjusting device may further include at least two attenuation sheets, and the intensity of light received by the image sensor is adjusted by increasing or decreasing the number of the attenuation sheets covering the upper surface of the image sensor.
Specifically, in the ambient light adjusting method in the above embodiment, the attenuation sheet may be an optical element having a strong reflection and/or refraction performance for the incident light, and by increasing the number of the attenuation sheets used, the intensity of the light received by the image sensor may be effectively reduced, and conversely, the intensity of the light received by the image sensor may be increased. In this embodiment, for example, the attenuation sheet may be connected to the dc servo motor, and the dc servo motor is controlled to drive the attenuation sheet to cover the upper surface of the image sensor to reduce the intensity of light received by the image sensor; or the attenuation sheet is driven to move away from the upper surface covering the image sensor by controlling the action of the direct current servo motor so as to increase the intensity of light received by the image sensor.
Specifically, in the ambient light adjusting method in the above embodiment, for example, when the ambient light detecting unit detects the intensity of the incident light by using the SPAD array and the time-to-digital converter together, first, under the condition that no laser emission signal is irradiated, and under the condition that the ambient light intensity value is 10kLux, the time-to-digital converter records the number of times that the SPAD array is triggered by the ambient light, and repeats the measurement for multiple times, so as to obtain the statistical histogram that the SPAD array is triggered by the ambient light, and further determine the intensity of the ambient light. The cross-sectional area value of the aperture required to be used by the ambient light adjusting device in the application under different ambient light intensity values can be formulated according to the requirement of the better working state of the SPAD array on the incident light intensity, and/or the type of attenuation sheet used and the corresponding quantity value, and/or the bias voltage value for the operation of the SPAD array, the specific ambient light intensity value and the cross-sectional area value of the aperture to be used, and/or the type and the corresponding numerical value of the attenuation sheet to be used can be established, and/or a comparison table of the bias voltage value of the SPAD array operation, and the controller is arranged to control the adjusting device according to the specific value of the comparison table, control the cross-sectional area of the aperture of the light shield in the adjusting device and/or the number of the attenuators according to the specific light intensity value detected by the ambient light detection unit, and/or control the bias voltage value of the SPAD array operation.
In the above-described ambient light adjusting method in the embodiment, since the ambient light detecting unit for detecting the intensity value of the ambient light is provided, and the controller controls the adjusting device to adjust the intensity of light received by the image sensor based on the intensity value, the intensity of light received by the image sensor meets the requirement of the better working range of the image sensor, the situation that the image sensor cannot work normally due to the fact that the intensity of light received by the image sensor is too high and the noise in the detected target signal is too large is avoided, and meanwhile, the situation that the image sensor cannot work normally due to the fact that the intensity of ambient light is too high is also avoided.
In the ambient light adjusting method according to an embodiment of the present application, the ambient light detecting unit may include at least one of a photodiode or an ambient light sensor, and in this embodiment, the photodiode and/or the ambient light sensor are preferably disposed outside the image sensor and connected to the controller, so as to better collect and convert the light signal into an electrical signal, so as to improve the accuracy of detecting the ambient light intensity value. In the embodiment, the excellent photoelectric conversion characteristics of the photodiode and/or the ambient light sensor are utilized, the intensity of the detected ambient light is indirectly measured by converting the collected ambient light into an electric signal, and the measuring method is simple and has high precision.
Further, in the ambient light adjusting method in the above embodiment, the ambient light detecting unit may include a single photon avalanche diode array and a time-to-digital converter as shown in fig. 2. The embodiment utilizes the excellent photoelectric conversion characteristic of the single photon avalanche diode, combines the single photon avalanche diode with the time digital converter, records the total number of times of triggering the single photon avalanche diode array through the time digital converter to indirectly measure the intensity of the detected ambient light, and has simple measuring method and high precision.
In the above-described ambient light adjusting method in the embodiment, the ambient light detecting unit detects the intensity value of the ambient light, and then the controller receives the intensity value to control the adjusting device to adjust the intensity of the light received by the image sensor, so that the intensity value of the light received by the image sensor meets the requirement of a better working range interval on the intensity of the ambient light, thereby avoiding the inaccurate measurement result caused by the excessive noise in the detected target signal due to the excessive intensity of the received light, and simultaneously avoiding the occurrence of the situation that the target signal cannot be normally measured due to the excessive intensity of the ambient light.
Further, as shown in fig. 6, in an ambient light adjusting method provided in an embodiment of the present application, the controlling the adjusting device to adjust the intensity of the light received by the image sensor based on the controller receiving the intensity value further includes:
step 2041: when the detected intensity value is larger than or equal to a preset threshold value, the adjusting device is controlled to weaken the intensity of the light received by the image sensor and/or reduce the bias voltage for operating the image sensor.
Specifically, when the intensity value of the light detected by the ambient light detection unit is greater than or equal to a preset threshold value, the controller can control the direct current servo motor to act to drive the aperture to reduce the cross-sectional area of the aperture so as to reduce the intensity of the incident light; on the contrary, the direct current servo motor can be controlled to move in the opposite direction to drive the diaphragm to increase the cross-sectional area of the diaphragm so as to improve the intensity of incident light. Because the ambient light detection unit generally adopts semiconductor devices, the photosensitive sensitivity of some semiconductor devices can be improved by improving the amplitude of the bias voltage within a certain bias voltage range. Therefore, when the received intensity value is greater than or equal to the preset threshold value, the controller may control the adjusting device to weaken the intensity of light received by the image sensor and/or reduce the bias voltage for operating the image sensor, so as to reduce the intensity value of light received by the image sensor, so that the intensity value of light received by the image sensor meets the requirement of the preferred operating range interval on the ambient light intensity.
An ambient light adjusting method provided in an embodiment of the present application further includes:
step 205: calculating the time-varying estimation of the incident light intensity by the output signal of the first single-photon avalanche diode array through a Coates correction algorithm
Wherein N is the total of said first single photon avalanche diode array triggeredNumber of times, NkRepresenting the number of firings of said first single photon avalanche diode array within a kth time stamp.
where Δ t is the accuracy of the timestamp and c is the speed of light.
Further, in the ambient light adjusting method in the above embodiment, after step 205, the method further includes:
step 206: estimating the variation of the incident light intensity value with timeObtaining an estimate after matched filtering
where Δ t is the accuracy of the timestamp and c is the speed of light.
Specifically, the ambient light adjusting method provided in this embodiment may be applied to a distance measurement chip, a depth imaging chip, a Time Of Flight (TOF) chip, and the like, for example, in the ambient light adjusting apparatus in this embodiment, a SPAD array and a Time-to-digital converter are adopted to cooperate together to detect the intensity Of the ambient light. Fig. 7 is a statistical histogram of the number of times the SPAD array acquired by the ambient light detection unit is triggered by incident light under the condition that the ambient light intensity value is 10kLux, fig. 8 is a simulation graph obtained by correcting the signals in fig. 7 by coats, and it can be found by comparing fig. 7 with fig. 8 that the waveform curve of the signals corrected by coats is smoother than that before the coats are corrected, and the characteristic value of the signals is more obvious. Fig. 9 is a simulation diagram obtained after the signal in fig. 8 is subjected to matched filtering, and it can be found by comparing fig. 8 with fig. 7 that the waveform curve of the signal subjected to matched filtering is smoother than that before the matched filtering, the eigenvalue of the signal is more obvious, and the noise signal in the acquired signal is well filtered out through the matched filtering. Therefore, the ambient light adjusting method adopting the Coates correction and matched filtering steps can well filter out noise signals in the collected incident light signals, can better extract target signals, and improves the accuracy of the measurement result of the image sensor or the electronic device adopting the ambient light adjusting method in the embodiment of the application.
Fig. 10 is a statistical histogram of the number of times the SPAD array acquired by the ambient light detection unit is triggered by incident light in the case where the ambient light intensity value is 100 kLux. Fig. 10 shows that the optical signal collected by the SPAD array at this time contains a large amount of noise signals, and the SPAD array is in an abnormal operating state. Fig. 11 is a statistical histogram of incident light signals obtained by the image sensor after being adjusted by the ambient light adjusting device in the embodiment of the present application under the same condition as that in fig. 10, and it can be found from fig. 11 that the ambient light adjusting device performs automatic attenuation adjustment on the collected ambient light, so that the incident light received by the image sensor meets the requirement of the image sensor on light intensity in a better working state. Fig. 12 is a simulation of the signal of fig. 10 after being corrected by coats, and comparing fig. 12 with fig. 10, it can be seen that the waveform curve of the signal after being corrected by coats is smoother than that before being corrected by coats, but still contains a large amount of noise signals. Fig. 13 is a simulation diagram of the signal in fig. 12 after being matched and filtered, and it can be found by comparing fig. 12 with fig. 13 that the waveform curve of the signal after being matched and filtered is smoother than that before being matched and filtered, but the image sensor still has difficulty in determining the position of the target signal. Fig. 14 is a simulation diagram of the signal of fig. 11 after being corrected by coats, and comparing fig. 14 with fig. 11, it can be seen that the waveform curve of the signal after being corrected by coats is smoother than before being corrected by coats, but still contains a large amount of noise signals. Fig. 15 is a simulation diagram obtained after the signal in fig. 14 is matched and filtered, and it can be found by comparing fig. 14 with fig. 15 that the waveform curve of the signal after being matched and filtered is smoother than that before being matched and the image sensor can accurately confirm the position of the target signal. Therefore, the image sensor adopting the environment adjusting method or device in the embodiment of the application can automatically adjust the ambient light when the ambient light exceeds the preset threshold value so as to meet the requirement of the image sensor on the incident light intensity in the better working state.
For the specific definition of the ambient light adjusting method in the above embodiments, reference may be made to the above definition of the ambient light adjusting device, which is not described herein again.
In the ambient light adjusting method in the above embodiment, the ambient light detecting unit detects the intensity value of the ambient light, and then the controller receives the intensity value to control the adjusting device to adjust the intensity of the light received by the image sensor, so that the inaccuracy of the measurement result due to the excessive noise in the detected target signal caused by the excessively high intensity of the received light is avoided, and the occurrence of the situation that the target signal cannot be normally measured due to the excessively high intensity of the ambient light is also avoided. Because the single photon avalanche diode array is adopted in the ambient light detection unit to collect the optical signal, and the output signal of the ambient light detection unit is filtered by the Coates correction algorithm and the matched filter in sequence to further remove the noise signal in the collected signal, the characteristic value in the collected signal is effectively extracted, the accuracy of determining the characteristic signal is improved, and the accuracy and/or precision of the measured depth information is further improved.
It should be understood that although the various steps in the flowcharts of fig. 5-6 are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least some of the steps in fig. 5-6 may include multiple sub-steps or multiple stages that are not necessarily performed at the same time, but may be performed at different times, and the order of performance of the sub-steps or stages is not necessarily sequential, but may be performed in turn or alternating with other steps or at least some of the sub-steps or stages of other steps.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in the embodiments provided herein may include non-volatile and/or volatile memory, among others. Non-volatile memory can include read-only memory (ROM), Programmable ROM (PROM), Electrically Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus Direct RAM (RDRAM), direct bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (11)
1. An ambient light adjusting device used in an image sensor, comprising:
an ambient light detection unit for detecting an intensity value of ambient light;
adjusting means for adjusting the intensity of light received by the image sensor; and
and the controller is respectively connected with the ambient light detection unit and the adjusting device and is used for controlling the adjusting device to adjust the intensity of the light received by the image sensor based on the intensity.
2. The ambient light adjusting apparatus according to claim 1, wherein the image sensor includes:
the first single photon avalanche diode array is used for detecting the intensity of the light received by the image sensor; and
and the first time digital converter is connected with the controller and used for calculating the number of times that the first single photon avalanche diode array is triggered so as to obtain the intensity of the light received by the image sensor.
3. The ambient light adjustment device of claim 2, wherein the ambient light detection unit comprises at least one of a photodiode or an ambient light sensor.
4. The ambient light adjusting apparatus according to claim 3, wherein the ambient light detecting unit is disposed outside the image sensor.
5. The ambient light adjusting apparatus according to claim 2, wherein the ambient light detecting unit includes:
the second single photon avalanche diode array is used for detecting the intensity of the ambient light; and
and the second time digital converter is connected with the controller and used for calculating the number of times the second single photon avalanche diode array is triggered so as to obtain the intensity of the ambient light.
6. The ambient light adjusting apparatus according to claim 2, wherein the first single photon avalanche diode array comprises at least two independent sub-signal regions, and output signals of the single photon avalanche diodes in the sub-signal regions are superposed.
7. The ambient light adjusting apparatus according to claim 6, wherein the controller is configured to control the adjusting apparatus to reduce the intensity of light received by the image sensor and/or to reduce a bias voltage at which the image sensor operates when the detected intensity value is greater than or equal to a preset threshold value.
8. An ambient light adjusting device according to any one of claims 1-7, characterized in that the adjusting device comprises:
and the light chopper is provided with a diaphragm and is used for moving along with the motor so as to change the cross section area of the diaphragm and further adjust the intensity of light received by the image sensor.
9. An ambient light adjusting device according to any one of claims 1-7, characterized in that the adjusting device comprises:
and the at least two attenuation sheets are respectively connected with the motor, and the intensity of light received by the image sensor is adjusted by changing the number, the model or the position of the attenuation sheets covering the upper surface of the image sensor.
10. An image sensor comprising the ambient light adjusting device according to any one of claims 1 to 9, wherein the ambient light adjusting device adjusts the intensity of light received by the image sensor in accordance with the intensity value of the ambient light detected by the ambient light detecting unit.
11. An electronic device, comprising:
the ambient light adjusting device as defined in any one of claims 1 to 9; and
a laser emitter.
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CN115184956A (en) * | 2022-09-09 | 2022-10-14 | 荣耀终端有限公司 | TOF sensor system and electronic device |
CN117857910A (en) * | 2024-02-07 | 2024-04-09 | 荣耀终端有限公司 | Camera protection method, program and electronic device |
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CN115184956A (en) * | 2022-09-09 | 2022-10-14 | 荣耀终端有限公司 | TOF sensor system and electronic device |
CN115184956B (en) * | 2022-09-09 | 2023-01-13 | 荣耀终端有限公司 | TOF sensor system and electronic device |
CN117857910A (en) * | 2024-02-07 | 2024-04-09 | 荣耀终端有限公司 | Camera protection method, program and electronic device |
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