CN115480258A - A detection device and method - Google Patents

Abstract

The application provides a detection device and a detection method using the detection device, wherein the detection device comprises a light source module used for emitting detection light to an object to be detected; the photosensitive module receives the emitted light to process the pixels; the processing module can process the reflected light to obtain the distance of the object to be measured; the control module is used for controlling the light source module and the receiving module; the control module controls the light source module to emit detection light with first power and first exposure duration; the control module controls the light source module to emit the detection light with the second power and the first exposure duration, and the detection device and the detection method can simultaneously meet detection requirements in different distance ranges and different scenes.

Description

A detection device and method

technical field

The present application relates to the field of detection technology, in particular to a detection device and method.

Background technique

Time-of-Flight (TOF) technology was developed as a method of measuring distances to objects in a scene. This TOF technology can be applied in various fields, such as the automotive industry, man-machine interface, games, robotics and security, etc. Generally speaking, TOF technology works by illuminating a scene with modulated light from a light source and observing the reflected light reflected by objects in the scene. In the existing detection system, in order to ensure that the detection process can obtain higher detection efficiency and also ensure that the detection system has a wider field of view, an array type receiving module is currently used more, and the array type receiving module can have There are tens of thousands of pixel units, and each pixel unit can be a charge-coupled semiconductor CCD or a complementary metal-oxide-semiconductor CMOS type diode, and it is not limited here that only these two types of diodes form an array receiving module.

In order to obtain the distance information, in TOF detection, the delay information of the emitted light and the returned light is obtained indirectly first, and then the delayed phase or phase offset is obtained, and then the phase offset is converted into the final result information. The method converts the distance information of the detected object into the return light and the phase offset of the emitted light instead of directly giving the distance result. This scheme is called indirect time-of-flight ranging (ITOF). In actual use, the complementary phase can be used to receive the return optical signal, and then obtain the distance information. This method is called a two-phase scheme, and there is also a scheme that uses four phases of 0°, 90°, 180° and 270° to obtain the target distance. , of course, there are also literatures that try 3-phase or even 5-phase schemes to obtain the distance of the detected object, and obtain phase-shifted electrical signals, which need to be processed by a processing unit to obtain the final distance information.

During the detection process, the light received by the photosensitive module includes the reflected light of the detection light and the ambient light. Therefore, the ambient light needs to be detected separately to eliminate the influence of the ambient light. However, the prior art is usually interfered by the detection light during the actual detection process, and cannot accurately detect the ambient light energy, resulting in poor accuracy of the obtained measurement distance. Moreover, during the detection process, the total number of integrated electrons = the number of signal photoelectrons + the number of ambient photoelectrons. When the integration mode is used, the ambient light will occupy a large amount of integration capacitance, leaving a limited margin for integration capacitance for signal light. In addition, the different distances of the object to be measured during the detection process will lead to changes in the target reflectivity of the object to be measured and the efficiency of receiving the echo light of the object to be measured. There is a 50-fold difference in the distance of the object to be measured, and there is a 2,500-fold change in the echo light receiving efficiency according to the inverse square law. When the object to be measured is 0.05m, the target reflectance of the object to be measured is 0.1, and when the object to be measured is 0.05m, the target reflectance of the object to be measured is 0.8, that is to say, the target reflectance at the two distances is 8 times different. Considering the difference between receiving light efficiency and reflectivity, the dynamic range that needs to be detected is 20,000 times when the object to be measured is 0.05m~2.5m.

To sum up, there is an urgent need for a detection method and detection device to meet the detection requirements of high dynamic range under ambient light conditions.

Contents of the invention

The purpose of the present application is to provide a detection device to solve the technical problem that the existing detection device cannot satisfy multi-distance detection at the same time, aiming at the deficiencies in the above-mentioned prior art.

In order to achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

In the first aspect, the embodiment of the present application provides a detection device, which is characterized by comprising:

A light source module, configured to emit detection light to the object to be measured;

a photosensitive module, which receives and emits light and processes the pixels;

A processing module, which can process the reflected light to obtain the distance of the object to be measured;

The control module is used to control the light source module and the receiving module;

The control module controls the light source module to emit detection light with a first power and a first exposure duration;

The control module controls the light source module to emit detection light with the second power and the first exposure time.

Optionally, the control module controls the light source module to emit detection light with a first power and a second exposure duration;

The control module controls the light source module to emit detection light with a second power and a second exposure time.

Optionally, the control module controls the light source module to emit probe light with a first power and a third exposure duration; the control module controls the light source module to emit probe light with a second power and a third exposure duration.

Optionally, the first power is greater than the second power.

Optionally, the control module controls the light source module not to emit detection light; the durations of not emitting detection light are respectively the first exposure duration, the second exposure duration, and the third exposure duration.

Optionally, the first exposure duration is longer than the second exposure duration, and the second exposure duration is longer than the third exposure duration.

Optionally, the time periods for not emitting the detection light are respectively located after the time periods for emitting the detection light, and are the same as the corresponding exposure time for emitting the detection light.

In the second aspect, the embodiment of the present application provides a detection method, which is applied to the detection device described in the first aspect above, and the detection method includes:

The control module controls the light source module to emit detection light to the object to be measured with the first exposure time and the first transmission power; the control module can also control the light source module to emit detection light to the object to be measured with the first exposure time and the second transmission power Light.

Optionally, the control module controls the light source module to emit detection light to the object under test with the third exposure time and the first transmission power; the control module can also control the light source module to use the third exposure time and the second The transmitting power transmits the detection light to the object to be measured.

The beneficial effect of this application is:

A detection device and method provided in an embodiment of the present application, the detection device includes: a light source module, configured to emit detection light to an object to be measured;

a photosensitive module, which receives and emits light and processes the pixels;

A processing module, which can process the reflected light to obtain the distance of the object to be measured;

The control module is used to control the light source module and the receiving module;

The control module controls the light source module to emit detection light with a first power and a first exposure duration;

The control module controls the light source module to emit detection light with the second power and the first exposure time. In this mode, the detection device can simultaneously meet detection requirements at different distances and in different scenarios.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, so It should be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

FIG. 1 is a schematic diagram of functional modules of a detection device provided in an embodiment of the present application;

FIG. 2 is a schematic diagram of a TOF ranging principle provided in an embodiment of the present application;

Fig. 3 illustrates a schematic diagram of setting multiple subframes with different phase delays and different exposure durations;

FIG. 4 is a new frame structure provided by the embodiment of the present application;

FIG. 5 is another new frame structure provided by the embodiment of the present application;

Fig. 6 shows the implementation steps of the present invention.

detailed description

In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments It is a part of the embodiments of this application, not all of them. The components of the embodiments of the application generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations.

Accordingly, the following detailed description of the embodiments of the application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the application. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this application.

It should be noted that like numerals and letters denote similar items in the following figures, therefore, once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

FIG. 1 is a schematic diagram of functional modules of a detection device provided by an embodiment of the present application. As shown in Figure 1, the detection device includes: a light source 110, a processing module 120, a photosensitive module 130, and a detected object 140, wherein the light source 110 can be configured as a unit emitting continuous light or an array type light source system, which can be a semiconductor laser, It can also be an LED or other pulse-modulated light source. When a semiconductor laser is used as a light source, a vertical-cavity surface-emitting laser (VCSEL) or an edge-emitting semiconductor laser (EEL) can be used. Here, it is only for exemplary illustration and not specifically limited, and the waveform of the light output by the light source 110 is also not limited, and may be a square wave, a triangular wave, or a sine wave. The photosensitive module 130 includes a photoelectric conversion module, which has a photoelectric conversion function and can be realized by a photodiode (Photo-Diode, PD), which can be specifically a photosensitive coupling device (Charge-coupled Device, CCD), a complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor) , CMOS), and its type is not specifically limited here.

The processing module 120 may include a control module, which can control the light source to emit light for different times, or control the light source module not to emit light, control the emission power of the light source, and control the exposure time. Of course, the control module can also It exists independently of the processing module, and this embodiment is only for illustration and does not make specific limitations. The processing module 120 can enable the photosensitive module 130 to obtain different phase delay correspondences when the phase difference delay with the light source 110 is respectively 0°, 180°, 90° and 270° when the light source 110 emits light. The light reflected by the detected object 140, the reflected light forms incident light at the photosensitive module 130, and then undergoes photoelectric conversion by the receiving part to generate different information. The phase scheme realizes the information acquisition of the object to be detected. There are also documents disclosing 0°, 120° and 240° three-phase acquisition of target information, and even some documents disclose a five-phase difference delay scheme. The present invention is not specifically limited. The target information may be image information of the target, or distance information, contour information, etc. of the target.

FIG. 2 is a schematic diagram of a principle of TOF ranging provided by an embodiment of the present application. As shown in FIG. 2 , 201 is a detection light emitted by a light source. The receiving end uses demodulated signals with a certain phase difference (that is, a certain time delay) to receive the reflected light signal. In Figure 2, the phase difference between 202 and 201 is 0°, the phase difference between 203 and 201 is 180°, and 204 The phase difference with 201 is 90°, and the phase difference between 205 and 201 is 270°. According to the four-phase ranging principle, the distance of the object to be measured can be obtained, and the specific process is shown in the following formula (1) - formula (8):

The actual distance obtained after considering the inherent delay

其中固有延迟td偏差可以通过算法矫正回来。

Among them, the inherent delay td deviation can be corrected by the algorithm.

Figure 3 shows a schematic diagram of multiple subframes with different phase delays and different exposure durations, for example, when the frame rate is 15FPS, 30FPS or 60FPS, that is to say, each second can contain 15, 30 or 60 subframes, and the Nth The frame and the N+1th frame are exposed according to the four phase information of different lengths to obtain the distance of different detection targets, and by setting in this way, the distance information of the detected object can be obtained in the same way, such as the four-phase algorithm.

However, in scenarios with different detection distances as described above, the long and short exposure methods cannot meet the requirements of all detection distances. For example, in the scene where the object to be measured is 0.05m to 2.5m, the object to be detected with a short distance appears in the long exposure frame Overexposure phenomenon, the object to be measured at a close distance cannot be obtained. For example, in the case of a reflectance of 0.8 and a peak power of 54W, the long exposure frame will appear overexposure, and the distance of the object to be measured cannot be obtained; in the case of a reflectance of 0.8 , reduce the peak power to 3.5W, and the range of the long exposure frame can be measured is 0.45m ~ 1.35m. In the short exposure frame, when the peak power is 54W, the distance of the object to be measured can be obtained from 0.2m to 1.25m, and when the peak power is 3.5W, the distance to the object to be measured can be obtained from 0.05m to 0.3m. From the analysis of the above examples, it can be seen that long and short exposures cannot meet the requirements of the distance range of all objects to be measured. So a new frame rate structure is needed to solve this problem.

FIG. 4 is a new frame structure provided by the embodiment of the present application. In the frame structure shown in Figure 4, the exposure time is divided into three types: long, medium and short. For example, the duration of the long exposure may be 4750 μs, the duration of the medium exposure may be 500 μs, and the duration of the short exposure may be 125 μs. The light source has two emission powers for each exposure length, high power and low power. The high power can be tens of W, such as 54W, and the low power can be several W, such as 3.5W. The data in this embodiment are all for illustrative purposes, and do not mean to be limited to these specific values. In each exposure time length, a four-phase method can be used to obtain the distance of the object to be measured. For the frame structure shown in Figure 4, if there are two TAP structures at 0° and 180°, the corresponding received charge can be obtained in the same time; the same principle can obtain the corresponding received charge in the same time at 90° and 270° under the two TAP structures. received charge. FIG. 4 shows the four phases in different subframes for illustration purposes only. The detection requirements of different distances can be met by adopting the frame structure shown in FIG. 4 . For example, under the frame structure shown in Figure 4, the reflectivity is 0.8 under the medium exposure time length, the range of detection is 0.4m-2.5m when the transmission power is 54W, and the detection range is 0.1m-2.5m when the transmission power is 3.5W. 0.6m. It can make up for the detection distance requirements that cannot be covered in the long and short exposure frame structure.

FIG. 5 is another new frame structure provided by the embodiment of the present application. The frame structure shown in Figure 4 solves the scene requirements of different detection distances, but the ambient light has a great impact on the detection accuracy, and it is necessary to eliminate the impact of the ambient light on the detection accuracy as much as possible. In the frame structure shown in Figure 5, in the frame structure of long and short exposures, in each case of high emission power and low emission power, sub-frames that do not emit probe light of the same duration are arranged behind each case, and sub-frames that do not emit probe light In the sub-frames, the receiving end only receives the ambient light, and in the sub-frames with emitted light, a signal common to the detection light and the ambient light is obtained. The echo signal with only ambient light is subtracted from the echo signal in the photon frame with emitted detection photons, so that the influence of ambient light on the detection result can be eliminated. In Fig. 5, the long-exposure high-power and low-power emission frames followed by the non-emission of probe light are the same as the long-exposure duration, that is to say, if the long-exposure duration is 4750 μs, then the long-exposure high-power and The duration of non-emitting probe light following the low-power emission frame is also 4750 μs; similarly, the duration of non-emission of detection light following the high-power and low-power emission frames of medium exposure is the same as the duration of medium exposure, that is to say, if medium exposure If the duration is 500μs, then the duration of non-emission of probe light following the high-power and low-power emission frames of medium exposure is also 500μs; similarly, the non-emission of detection light immediately following the high-power and low-power emission frames of short exposure The duration of the short exposure is the same as that of the short exposure, that is, if the duration of the short exposure is 125 μs, then the duration of not emitting the probe light immediately following the high-power and low-power emission frames of the short exposure is also 125 μs.

Fig. 6 has shown the method step of the realization of the present invention, and S601 control module controls light source 110 to emit light with high power, can be square wave, triangular wave or sine wave etc. here are not specifically limited, and control exposure time (execute long, medium, respectively Short three exposure time lengths) the field of view is illuminated under the action of the emitted light, and the object 140 to be detected reflects the emitted light, thereby forming a reflected light echo.

S602 The control module controls the light source 110 not to emit light, and controls the exposure time (long, medium and short exposure time respectively) to reflect the ambient light from the object 140 to be detected, thereby forming a reflected light echo of the ambient light.

S603 The control module controls the light source 110 to emit light at low power, which can be a square wave, a triangle wave or a sine wave, etc. There is no specific limitation here, and the exposure time is controlled (the long, medium and short exposure durations are respectively executed) under the action of the emitted light The field of view is illuminated, and the detected object 140 reflects the emitted light, thereby forming a reflected light echo.

S604 The control module controls the light source 110 not to emit light, and controls the exposure time (long, medium and short exposure time respectively) to reflect the ambient light from the object 140 to be detected, thereby forming a reflected light echo of the ambient light.

The S605 control module eliminates the influence of ambient light on detection according to the echo signal of the signal and the echo signal of ambient light.

It should be noted that for the steps shown in FIG. 6 , the long, medium and short exposures are performed sequentially, as shown in the frame structure shown in FIG. 5 .

It should be noted that in this article, relative terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these No such actual relationship or order exists between entities or operations. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, there may be various modifications and changes in the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the protection scope of this application. It should be noted that like numerals and letters denote similar items in the following figures, therefore, once an item is defined in one figure, it does not require further definition and explanation in subsequent figures. The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, there may be various modifications and changes in the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims (10)

1. A detection device, characterized in that it comprises: A light source module, configured to emit detection light to the object to be measured; a photosensitive module, which receives and emits light and processes the pixels; A processing module, which can process the reflected light to obtain the distance of the object to be measured; The control module is used to control the light source module and the receiving module; The control module controls the light source module to emit detection light with a first power and a first exposure duration; The control module controls the light source module to emit detection light with the second power and the first exposure time. 2. The detection device according to claim 1, wherein the control module controls the light source module to emit detection light with a first power and a second exposure duration; The control module controls the light source module to emit detection light with a second power and a second exposure time. 3. The detection device according to claim 1, wherein the control module controls the light source module to emit detection light with a first power and a third exposure duration; The control module controls the light source module to emit detection light with a second power and a third exposure time. 4. The detection device of claim 1, wherein the first power is greater than the second power. 5. The detection device according to claim 1, wherein the control module controls the light source module not to emit detection light; the duration of the non-emission of detection light is the first exposure duration and the second exposure duration respectively. duration, the third exposure duration. 6 . The detection device according to claim 5 , wherein the first exposure duration is longer than the second exposure duration, and the second exposure duration is longer than the third exposure duration. 7 . The detecting device according to claim 5 , wherein the duration of not emitting detection light is respectively located after the duration of emitting detection light, and is the same as the corresponding exposure duration of emitting detection light. 7 . 8. A detection method using the detection device according to claim 1, characterized in that it comprises: the control module controls the light source module to emit detection light to the object to be measured with the first exposure time and the first transmission power; the control module can also The light source module is controlled to emit detection light to the object to be measured with the first exposure duration and the second emission power. 9. The detection method according to claim 8, wherein the control module controls the light source module to emit detection light to the object to be measured with the second exposure duration and the first transmission power; the control module can also control The light source module emits detection light to the object to be measured with a second exposure time and a second emission power. 10. The detection method according to claim 8, wherein the control module controls the light source module to emit detection light to the object to be measured with the third exposure time and the first emission power; the control module can also control The light source module emits detection light to the object to be measured with a third exposure duration and a second emission power.

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