CN116429020A - Multi-projector monocular 3D structured light system and 3D depth measurement method - Google Patents
Multi-projector monocular 3D structured light system and 3D depth measurement method Download PDFInfo
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- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
- G01B11/254—Projection of a pattern, viewing through a pattern, e.g. moiré
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- G—PHYSICS
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- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/22—Measuring arrangements characterised by the use of optical techniques for measuring depth
Abstract
The invention provides a multi-projector monocular 3D structured light system and a 3D depth measurement method, the multi-projector monocular 3D structured light system comprises: a first projector configured to project first structured light into a field of view; a second projector configured to project a second structured light into the field of view; and an IR camera configured to collect information of the first structured light or information of the second structured light; wherein the optical center of the first projector, the optical center of the second projector, and the optical center of the IR camera are disposed on the same plane, and a first distance between the optical center of the first projector and the optical center of the IR camera is smaller than a second distance between the optical center of the second projector and the optical center of the IR camera.
Description
Technical Field
Embodiments of the present disclosure relate to 3D measurement systems, and in particular, to a multi-projector monocular 3D structured light system and a 3D depth measurement method.
Background
Structured light is a set of system structures consisting of a projector and an IR camera. The specific light information (generally infrared light invisible to human eyes, which is specifically coded) is projected by a projector and then collected by an IR camera after being on the surface and the background of an object.
When the projector works, the projector projects light with a certain structure, such as stripe light with light and shade, if the light is projected on a plane, the light is reflected back to be the same thick stripe as the original stripe, if the light is projected on an irregular object (such as a human face), the stripe changes when the light is reflected back from the irregular object, and the information of the position, the depth and the like of the object can be determined according to the change of a light signal caused by the object, so that the whole three-dimensional space is restored.
In face recognition applications (e.g., smart device unlocking, face-brushing payment, attendance checking, etc.), structured light is mainly used to obtain depth information of a face, so as to be used for organism detection and assist in face recognition.
Disclosure of Invention
At least one embodiment of the present disclosure provides a multi-projector monocular 3D structured light system, comprising:
a first projector configured to project first structured light into a field of view;
a second projector configured to project a second structured light into the field of view; and
an IR camera configured to collect information of the first structured light or information of the second structured light;
wherein the optical center of the first projector, the optical center of the second projector, and the optical center of the IR camera are disposed on the same plane, and a first distance between the optical center of the first projector and the optical center of the IR camera is smaller than a second distance between the optical center of the second projector and the optical center of the IR camera.
In one embodiment of the present disclosure, the optical center of the first projector, the optical center of the second projector, and the optical center of the IR camera are disposed on a straight line, and the first projector and the second projector are disposed on the same side of the IR camera.
In one embodiment of the present disclosure, the optical center of the first projector, the optical center of the second projector, and the optical center of the IR camera are disposed on a straight line, and the first projector and the second projector are disposed on both sides of the IR camera, respectively.
In one embodiment of the present disclosure, a first projector projects first structured light in odd frames, and an IR camera collects information of the first structured light to obtain a first image;
the second projector projects second structured light in even frames, and the IR camera collects information of the second structured light to obtain a second image; and
and the IR camera fuses the first image and the second image to obtain a measurement result.
In one embodiment of the present disclosure, the IR camera takes the depth of the second image as a measurement in case the depth difference of the first image and the second image is equal to or less than a first threshold.
In one embodiment of the present disclosure, the IR camera takes the depth of the first image as a measurement in case the depth difference of the first image and the second image is equal to or greater than a first threshold value, or in case no depth information is contained in the second image.
In one embodiment of the present disclosure, the IR camera determines a range of values of the measurement result from the depth information in the first image, searches for the depth information of the second image within the range of values as the measurement result.
In one embodiment of the present disclosure, the first projector and the second projector are the same or different.
In one embodiment of the present disclosure, the power of the first projector and the second projector are adjustable, and the density and brightness of the first structured light projected by the first projector and the second structured light projected by the second projector are adjustable.
In one embodiment of the present disclosure, the multi-projector monocular 3D structured light system further includes a third projector configured to project third structured light into the field of view of the IR camera, the optical center of the third projector and the optical center of the first projector, the optical center of the second projector, and the optical center of the IR camera being on the same plane, the third distance of the optical center of the third projector from the optical center of the IR camera being different from both the first distance and the second distance.
In one embodiment of the present disclosure, the third projector is the same as or different from the first projector and the second projector, and the third structured light projected by the third projector is the same as or different from the first structured light projected by the first projector and the second structured light projected by the second projector.
In the multi-projector monocular 3D structure light system provided by the embodiment of the disclosure, the multi-projector monocular 3D structure light system can have high measurement precision in different depth ranges by arranging the first projector and the second projector with different base lines. By making the base lines of the first projector and the second projector different, the structured light projected by different projectors is selected in different measuring ranges, thereby realizing high-precision measurement of depth. The power of the first projector and the second projector can be adjusted, the density and the brightness of the projected first structure light and second structure light can be adjusted, and the multi-projector monocular 3D structure light system can be suitable for indoor environment or outdoor environment and outdoor environment without illumination intensity.
At least one embodiment of the present disclosure further provides a 3D depth measurement method, applicable to the above multi-projector monocular 3D structured light system, the 3D depth measurement method including:
the first projector projects first structure light in odd frames, and information of the first structure light is acquired through the IR camera to form a first image;
the second projector projects second structure light in even frames, and information of the second structure light is acquired through the IR camera to form a second image; and
and merging the depth information of the first image and the depth information of the second image to determine a depth measurement result.
In one disclosed embodiment, fusing depth information of a first image and depth information of a second image, determining a depth measurement includes:
taking the depth of the second image as a measurement result in the case that the depth difference between the first image and the second image is small;
taking the depth of the first image as a measurement result when the depth difference between the first image and the second image is larger than a first threshold value; and
in case the second image does not comprise depth information, the depth of the first image is taken as a measurement result.
In one embodiment of the present disclosure, the first projector and the second projector are the same or different.
In one embodiment of the present disclosure, the power of the first projector and the second projector is adjustable, and in response to measuring an ambient light intensity greater than a first light intensity threshold, it is determined that the multi-projector monocular 3D structured light system is operating in an outdoor environment, increasing the power of the first projector and the second projector.
In one embodiment of the present disclosure, the power of the first projector and the second projector is adjustable, and in response to measuring an ambient light intensity that is less than a second light intensity threshold, it is determined that the multi-projector monocular 3D structured light system is operating in an indoor environment, reducing the power of the first projector and the second projector.
In one embodiment of the present disclosure, the multi-projector monocular 3D structured light system further comprises a third projector, the method further comprising: the distance between the optical center of the third projector and the optical center of the IR camera is set to be different from the first distance and the second distance.
In the 3D depth measurement method according to the embodiment of the disclosure, the depth of the measured object is obtained by utilizing the structure optical modules with different base line lengths, and the depth of the measured object can be measured in a large range with high precision by fusing images generated by the different structure optical modules by utilizing the characteristics of measurement of the structure optical modules with different base line lengths. Meanwhile, the power of the first projector and the power of the second projector can be adjusted, so that the multi-projector monocular 3D structure light system can obtain more accurate measurement results in different illumination environments.
At least one embodiment of the present disclosure also provides an electronic device including the above multi-projector monocular 3D structured light system.
In one embodiment of the disclosure, the electronic device is a mobile phone, an attendance machine, an access control or a face brushing payment device.
Drawings
Fig. 1 schematically shows a schematic diagram of a measuring profile of a structured light device.
Fig. 2 schematically shows the depth z versus the corresponding parallax d for different baseline lengths for a given reference plane distance, a given focal length.
Fig. 3 schematically shows the depth differences of 1 pixel parallax for structured light devices of different baseline lengths at different distances.
Fig. 4 schematically shows measurement results of a face at the same location using a structured light device without a baseline length.
FIG. 5 schematically illustrates a structural schematic of a multi-projector monocular 3D structured light system according to an embodiment of the present disclosure;
fig. 6 schematically illustrates a structure of a multi-projector monocular 3D structured light system and FOV distribution schematic according to an embodiment of the present disclosure.
Detailed Description
The present disclosure is further described in detail below with reference to the drawings and examples. The features and advantages of the present disclosure will become more apparent from the description.
The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are illustrated in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
In addition, technical features described below in the different embodiments of the present disclosure may be combined with each other as long as they do not collide with each other.
Monocular structured light refers to structured light comprising only one camera, typically comprising a structured light projector for projecting structured light, an IR camera for acquiring 3D images, and an RGB camera for acquiring 2D RGB images. Monocular structured light is commonly used in Face recognition applications, such as iphone's Face-ID, face-swipe payment devices, etc.
When the structured light equipment leaves the factory, the device related to the structured light needs to be calibrated in the factory, such as an internal reference and an external reference of a camera, an IR diagram of a reference distance (hereinafter referred to as a reference diagram, generally a plan view about 50cm from the camera) and the like. In the using process of the device, an IR camera collects an image containing infrared light, and the depth of each pixel point in the current image is calculated by using relevant parameters calibrated by the camera and a reference image and matching with a corresponding depth calculation algorithm. The monocular structured light has high close-range precision, the farther the distance is, the worse the precision is, and the main factors of the precision are: baseline size, projector density, camera parameters, algorithm scheme, etc.
Fig. 1 shows a schematic diagram of a measuring profile of a structured light device. As shown in fig. 1, the center of the projected light of the IR projector is P, the optical center of the IR camera is C, and the distance from P to C is b, which is referred to as the baseline length. When the structured light device is in operation, the IR projector of the distance IR camera projects structured light (e.g. stripe light, light spots, etc. with alternating light and dark) onto the object, the IR camera receives structured light reflected back by objects of different distances (as imaging point K1 in fig. 1), and for the same ray PO emitted by the IR projector, passes through the R point on the reference plane and the imaging point R1 on the sensor CCD of the IR camera. For point R1 and point K1, the imaging point is actually a projection point of the same ray at different distances, the difference in the positions of the set of matching points is taken as the parallax d, and the distance of O from the camera plane is called the depth z.
In fig. 1, Δ RKC is similar to Δr1k1c, and therefore:
meanwhile, Δ OKR is similar to Δocp, and therefore:
R1K1 is the parallax d, i.e. the pixel offset in the current camera image and the reference plane image. Thus, the depth formula is expressed as:
wherein b represents the baseline length, the distance between the IR projector and the IR camera;
f represents a focal length;
z0 represents the distance of the reference plane; and
d represents parallax.
When calculating the depth, the algorithm searches the offset of the current point in the reference plane graph, and substitutes the offset into the formula to calculate the depth of the current point.
Fig. 2 shows the depth z versus the corresponding parallax d for different baseline lengths for a given reference plane distance, a given focal length. In FIG. 2, the reference plane is 500mm away, the focal length is 1000mm, and the baseline lengths are 60mm and 100mm, respectively. In fig. 2, the abscissa is the parallax d, in pixel, and the ordinate is the distance z, in mm. As can be seen from fig. 2, at close distances, the parallax produced by the small baseline length structured light device is smaller than the parallax produced by the large baseline length structured light device, i.e. the larger the baseline, the smaller the ranging range. Meanwhile, as can be seen from fig. 2, in the same parallax range (-90, 100), the measurable range of the structured light apparatus having a base line length of 60mm is 200 mm+2000 mm, and the measurable range of the structured light apparatus having a base line length of 100mm is 300 mm+900 mm.
In fig. 3, the abscissa z represents distance in mm, and the ordinate represents error in mm. Fig. 3 shows the depth differences of 1 pixel parallax at different distances for different baseline lengths of the structured light device, from which it can be seen that at 600mm, the error for 60mm baseline structured light is 5.9mm and the error for 100mm baseline structured light is 3.6mm, the single pixel parallax accuracy for structured light devices of greater baseline length (100 mm) is higher with higher accuracy, and the single pixel parallax accuracy for structured light devices of smaller baseline length (60 mm) is lower with greater visible baseline and smaller same distance error.
Taking a face at a distance of 800mm as an example, measurement is performed by using structured light devices with different base line lengths, respectively. Fig. 4 shows the measurement results of a face measurement at the same location using a structured light device without a baseline length. The position of the face shown in fig. 4 is at 80mm, and the baseline lengths of the adopted structured light devices are 60mm and 100mm, respectively, where (a) in fig. 4 shows a face depth point cloud detected by the structured light device with the baseline length of 100mm, and (b) in fig. 4 shows a face depth point cloud detected by the structured light device with the baseline length of 60 mm. As can be seen from fig. 4, the face detected by the structured light device having a baseline length of 100mm is more detailed, e.g., the bridge of the nose is closer to the actual height, and the overall face detail is higher.
Based on this, at least one embodiment of the present disclosure provides a multi-projector monocular 3D structured light system having a larger viewing angle and having a relatively higher accuracy, for the problem of small viewing angle of a large baseline length structured light device and low accuracy of a small baseline length structured light device.
At least one embodiment of the present disclosure provides a multi-projector monocular 3D structured light system, the multi-projector monocular 3D structured light system comprising: a first projector configured to project first structured light into a field of view; a second projector configured to project a second structured light into the field of view; and an IR camera configured to collect information of the first structured light or information of the second structured light; wherein the optical center of the first projector, the optical center of the second projector, and the optical center of the IR camera are disposed on a straight line, and a first distance between the optical center of the first projector and the optical center of the IR camera is smaller than a second distance between the optical center of the second projector and the optical center of the IR camera.
Fig. 5 shows a schematic structural diagram of a multi-projector monocular 3D structured light system according to one embodiment of the present disclosure. The multi-projector monocular 3D structured light system includes; a first projector 01, a second projector 02 and an IR camera 00. The optical center of the first projector 01, the optical center of the second projector 02, and the optical center of the IR camera 00 are located on the same straight line. The first distance between the optical center of the IR camera 00 and the optical center of the first projector 01 is the first baseline 03 of the first projector 01, the first projector 01 and the IR camera 00 forming a first structured light module of the first baseline 03. The second distance between the optical center of the IR camera 00 and the optical center of the second projector 02 is the second baseline 04 of the second projector 02, the second projector 02 and the IR camera 00 forming a second structured light module of the second baseline 04. The first distance is less than the second distance. The first projector 01 is configured to project first structured light into a field of view of an IR camera, the IR camera being configured to collect the first structured light within the field of view. The second projector 02 is configured to project second mechanism light into a field of view of an IR camera configured to collect second structured light within the field of view.
The structure of the multi-projector monocular 3D structured light system according to the embodiment of the present disclosure is described in fig. 5 taking an example in which the first projector 01 and the second projector 02 are disposed at one side of the IR camera, but the structure of the multi-projector monocular 3D structured light system according to the embodiment of the present disclosure is not limited thereto. In some embodiments of the present disclosure, the first projector 01 and the second projector 02 may be disposed at both sides of the IR camera, respectively, and the optical center of the first projector 01, the optical center of the second projector 02, and the optical center of the IR camera are located on a straight line, and a distance between the optical center of the first projector 01 and the optical center of the IR camera is smaller than a distance between the optical center of the second projector 02 and the optical center of the IR camera.
As can be seen from fig. 5 and 6, since the first projector 01 is relatively close to the IR camera, the range of coincidence of the first structured light projected by the first projector 01 with the field of view (FOV) of the IR camera is relatively large, which is suitable for depth calculation in a large viewing angle, whereas the second projector 02 is relatively far from the IR camera, the range of coincidence of the second structured light projected by the second projector 02 with the FOV of the field of view of the IR camera is relatively small, which is suitable for depth calculation in a small viewing angle but at a relatively far distance. The accuracy is higher at relatively large distances due to the relatively large length of the second baseline of the second projector 02.
When the multi-projector monocular 3D structured light system according to the embodiment of the present disclosure is operated, the first projector 01 and the second projector 02 alternately operate, the IR camera collects information of first structured light projected by the first projector 01 in an odd frame, obtains a first image, the IR camera collects information of second structured light projected by the second projector 02 in an even frame, obtains a second image, and the IR camera fuses the first image and the second image to obtain a measurement result.
In one embodiment of the present disclosure, if the depth difference between the first image and the second image is equal to or less than the first threshold, i.e., the depth difference between the first image and the second image is small, the depth of the second image is taken as the measurement result. In one embodiment of the present disclosure, if the depth difference of the first image and the second image is greater than a first threshold, the depth of the first image is taken as the measurement result. In one embodiment of the present disclosure, if depth information is not included in the second image, the depth of the first image is taken as a measurement result.
The first image is obtained by the IR camera 00 under the condition that the first projector 01 projects the first structured light, the length of the first base line 03 is smaller, the first image has the characteristics of large visual angle and low precision, the second image is obtained by the IR camera 00 under the condition that the second projector 02 projects the second structured light, the length of the second base line 04 is larger, and the second image has the characteristics of small visual angle and high precision.
In the case where the difference in depth information between the first image and the second image is small, that is, in the two curves shown in fig. 2, the distance between the two curves is relatively short, it can be determined that the distance between the measured object and the imaging plane of the IR camera is at a relatively moderate position, that is, in the region where the two curves are relatively short in fig. 2, at this time, since the second image has the characteristic of high accuracy, the second image is used as the measurement result.
In the case where the difference in depth information of the first image and the second image is large, that is, in the two curves shown in fig. 2, the distance between the two curves is large, it can be determined that the distance of the object to be measured with respect to the imaging plane of the IR camera is large, as shown in the upper right part of fig. 2. At this time, since the first image is suitable for determining depth information within a larger angle of view, the first image is employed as a measurement result.
Under the condition that the first image contains depth information and the second image does not contain depth information, the included angle of the measured object relative to the imaging plane of the IR camera can be determined to be larger, so that the second image does not contain depth information. At this time, since the first graph is suitable for determining depth information within a larger angle of view, the first image is employed as a measurement result.
Since the first image has a larger measurement range and the second image has a higher measurement accuracy, in another embodiment of the present disclosure, a value range of the measurement result is determined according to the depth information in the first image, and the depth information of the second image is searched in the value range as the measurement result. For example, the distance from the measured object to the IR camera is determined to be about 50cm based on the depth information in the first image, only the depth information in a range centering around 50cm, for example, the depth information in a range of 47cm to 53cm is searched in the second image, and the depth information of the measured object is rapidly determined.
In one embodiment of the present disclosure, the first projector and the second projector are the same. The first projector and the second projector are identical in power, and the first projector and the second projector are identical in structure, density, brightness, power and the like of the first structure light projected by the first projector and the second structure light projected by the second projector.
In another embodiment of the present disclosure, the first projector and the second projector are different. To achieve a 3D effect of a higher accuracy over a longer distance, the second projector has a higher power than the first projector, and the second projector projects a second structured light having a higher density than the first structured light projected by the first projector, and the second projector projects a second structured light having a higher brightness than the first structured light projected by the first projector.
In one embodiment of the present disclosure, the power of the first projector and the second projector are adjustable, and the density and brightness of the first structured light projected by the first projector and the second structured light projected by the second projector are adjustable. By making the power of the first projector and the second projector adjustable, and the density and the brightness of the first structured light projected by the first projector and the second structured light projected by the second projector adjustable, the power of the first projector and the second projector can be set lower when the indoor environment is where the density and the brightness of the first structured light projected by the first projector and the second structured light projected by the second projector are lower, and the power of the first projector and the second projector is set higher when the outdoor environment is where the density and the brightness of the first structured light projected by the first projector and the second structured light projected by the second projector are higher. In the outdoor, due to the interference of infrared components in sunlight, the projector is required to project speckle with higher power, and the speckle signal-to-noise ratio is improved. Therefore, in an outdoor environment, in response to the measurement of larger ambient light intensity, the projector with larger available power and higher brightness can properly reduce the density of the first structure light and the second structure light, and the remote effect is sacrificed to improve the outdoor use effect even for achieving the purpose of higher signal-to-noise ratio.
In one embodiment of the present disclosure, the multi-projector monocular 3D structured light system further comprises a third projector configured to project third structured light into the field of view of the IR camera, the optical center of the third projector and the optical center of the first projector, the optical center of the second projector, and the optical center of the IR camera being on the same plane, the third distance of the optical center of the third projector from the optical center of the IR camera being different from both the first distance and the second distance. The third projector and the IR camera form a third structured light module, and the IR camera is further configured to collect information of the third structured light when the third projector projects the third structured light.
In the case where the multi-projector monocular 3D structured light system includes the third projector, by making the first distance, the second distance, and the third distance different from each other, high-precision measurement of depths within different measurement distances can be achieved in the case where each of the first baseline, the second baseline, and the third baseline is the same. The third projector may be the same as or different from the first projector and the second projector.
The third projector being identical to the first projector and the second projector means that the third projector is identical in power to the first projector and the second projector, and the third structured light projected by the third projector is identical in structure, density, and brightness to the first structured light projected by the first projector and the second structured light projected by the second projector.
The difference between the third projector and the first projector and the second projector means that the power of the third projector is different from that of the first projector and the second projector, and the third structured light projected by the third projector is different from that of the first structured light projected by the first projector and the second structured light projected by the second projector, and the density is different from that of the first structured light projected by the first projector and the second structured light projected by the second projector, and the brightness is different from each other.
In the multi-projector monocular 3D structure light system provided by the embodiment of the disclosure, the multi-projector monocular 3D structure light system can have high measurement precision in different depth ranges by arranging the first projector and the second projector with different base lines. By making the base lines of the first projector and the second projector different, the structured light projected by different projectors is selected in different measuring ranges, thereby realizing high-precision measurement of depth. The power of the first projector and the second projector can be adjusted, the density and the brightness of the projected first structure light and second structure light can be adjusted, and the multi-projector monocular 3D structure light system can be suitable for indoor environment or outdoor environment and outdoor environment without illumination intensity.
At least one embodiment of the present disclosure further provides a 3D depth measurement method, applicable to the above-mentioned multi-projector monocular 3D structured light system, the 3D depth measurement method including:
the first projector projects first structure light in odd frames, and information of the first structure light is acquired through the IR camera to form a first image;
the second projector projects second structure light in even frames, and information of the second structure light is acquired through the IR camera to form a second image; and
and merging the depth information of the first image and the depth information of the second image to determine a depth measurement result.
The first distance between the optical center of the first projector and the optical center of the IR camera is less than the second distance between the optical center of the second projector and the optical center of the IR camera. Therefore, the first structured light module formed by the first projector and the IR camera is suitable for measuring with a large visual angle and low precision, and the second structured light module formed by the second projector and the IR camera is suitable for measuring with a small visual angle and high precision.
In one embodiment of the present disclosure, fusing depth information of a first image and depth information of a second image, determining a depth measurement includes: in the case where the difference in depth between the first image and the second image is small, the depth of the second image is taken as the measurement result.
In one embodiment of the present disclosure, fusing depth information of a first image and depth information of a second image, determining a depth measurement includes: and taking the depth of the first image as a measurement result when the depth difference between the first image and the second image is larger than a first threshold value.
In one embodiment of the present disclosure, fusing depth information of a first image and depth information of a second image, determining a depth measurement includes: in case the second image does not comprise depth information, the depth of the first image is taken as a measurement result.
In order to be able to quickly determine the depth of the object under test, in one embodiment of the present disclosure, a range of values of the measurement result is determined from the depth information in the first image, and the depth information of the second image is searched within the range of values.
In one embodiment of the present disclosure, the first projector and the second projector are the same. The first projector and the second projector are identical in power, and the first projector and the second projector are identical in structure, density, brightness, power and the like of the first structure light projected by the first projector and the second structure light projected by the second projector.
In another embodiment of the present disclosure, the first projector and the second projector are different. To achieve a 3D effect of a higher accuracy over a longer distance, the second projector has a higher power than the first projector, and the second projector projects a second structured light having a higher density than the first structured light projected by the first projector, and the second projector projects a second structured light having a higher brightness than the first structured light projected by the first projector.
In one embodiment of the present disclosure, the power of the first projector and the second projector is adjustable, and in response to measuring an ambient light intensity greater than a first light intensity threshold, it is determined that the multi-projector monocular 3D structured light system is operating in an outdoor environment, increasing the power of the first projector and the second projector.
In one embodiment of the present disclosure, the power of the first projector and the second projector is adjustable, and in response to measuring an ambient light intensity that is less than a second light intensity threshold, it is determined that the multi-projector monocular 3D structured light system is operating in an indoor environment, reducing the power of the first projector and the second projector.
In one embodiment of the present disclosure, the multi-projector monocular 3D structured light system further comprises a third projector, the method further comprising: the distance of the optical center of the third projector from the optical center of the IR camera is set to be different from the first distance and the second distance.
In the 3D depth measurement method according to the embodiment of the disclosure, the depth of the measured object is obtained by utilizing the structure optical modules with different base line lengths, and the depth of the measured object can be measured in a large range with high precision by fusing images generated by the different structure optical modules by utilizing the characteristics of measurement of the structure optical modules with different base line lengths. Meanwhile, the power of the first projector and the power of the second projector can be adjusted, so that the multi-projector monocular 3D structure light system can obtain more accurate measurement results in different illumination environments.
In the description of the present disclosure, it should be noted that the positional or positional relationship indicated by the terms such as "upper", "lower", "inner", "outer", "front", "rear", "left", "right", etc. are based on the positional or positional relationship in the operating state of the present disclosure, are merely for convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in the specific orientation, and thus should not be construed as limiting the present disclosure.
In the description of the present disclosure, it should be noted that the terms "mounted," "connected," and "connected" are to be construed broadly, unless otherwise specifically defined and limited. The specific meaning of the terms in this disclosure will be understood by those of ordinary skill in the art in the specific context.
The present disclosure has been described in connection with the preferred embodiments, but these embodiments are merely exemplary and serve only as illustrations. On this basis, many alternatives and modifications can be made to the present disclosure, which fall within the scope of the present disclosure.
Claims (19)
1. A multi-projector monocular 3D structured light system, comprising:
a first projector configured to project first structured light into a field of view;
a second projector configured to project a second structured light into the field of view; and
an IR camera configured to collect information of the first structured light or information of the second structured light;
wherein the optical center of the first projector, the optical center of the second projector, and the optical center of the IR camera are disposed on the same plane, and a first distance between the optical center of the first projector and the optical center of the IR camera is smaller than a second distance between the optical center of the second projector and the optical center of the IR camera.
2. The multi-projector monocular 3D structured light system of claim 1, wherein the optical center of the first projector, the optical center of the second projector, and the optical center of the IR camera are disposed on a straight line, and the first projector and the second projector are disposed on the same side of the IR camera.
3. The multi-projector monocular 3D structured light system of claim 1, wherein the optical center of the first projector, the optical center of the second projector, and the optical center of the IR camera are disposed on a straight line, and the first projector and the second projector are disposed on both sides of the IR camera, respectively.
4. The multi-projector monocular 3D structured light system of claim 1, wherein the light source is a light source,
the method comprises the steps that a first projector projects first structural light in an odd frame, and an IR camera collects information of the first structural light to obtain a first image;
the second projector projects second structured light in even frames, and the IR camera collects information of the second structured light to obtain a second image; and
and the IR camera fuses the first image and the second image to obtain a measurement result.
5. The multi-projector monocular 3D structured light system of claim 4, wherein the IR camera takes the depth of the second image as a measurement if the difference in depth between the first image and the second image is equal to or less than a first threshold.
6. The multi-projector monocular 3D structured light system of claim 4, wherein the IR camera takes the depth of the first image as a measurement in the case where the depth difference between the first image and the second image is equal to or greater than a first threshold or in the case where no depth information is contained in the second image.
7. The multi-projector monocular 3D structured light system of claim 4, wherein the IR camera determines a range of values for the measurement result from the depth information in the first image, and searches for the depth information of the second image within the range of values as the measurement result.
8. The multi-projector monocular 3D structured light system of any one of claims 1 to 7, wherein the first projector and the second projector are the same or different.
9. The multi-projector monocular 3D structured light system of any one of claims 1 to 7, wherein the power of the first projector and the second projector are adjustable, and the density and brightness of the first structured light projected by the first projector and the second structured light projected by the second projector are adjustable.
10. The multi-projector monocular 3D structured light system of any one of claims 1 to 7, further comprising a third projector configured to project third structured light into the field of view of the IR camera, the optical center of the third projector and the optical center of the first projector, the optical center of the second projector, and the optical center of the IR camera being on the same plane, the third distance of the optical center of the third projector from the optical center of the IR camera being different from both the first distance and the second distance.
11. The multi-projector monocular 3D structured light system of claim 10, wherein the third projector is the same as or different from the first projector and the second projector, and the third structured light projected by the third projector is the same as or different from the first structured light projected by the first projector and the second structured light projected by the second projector.
12. A 3D depth measurement method suitable for use in the multi-projector monocular 3D structured light system of claim 1, the 3D depth measurement method comprising:
the first projector projects first structure light in odd frames, and information of the first structure light is acquired through the IR camera to form a first image;
the second projector projects second structure light in even frames, and information of the second structure light is acquired through the IR camera to form a second image; and
and merging the depth information of the first image and the depth information of the second image to determine a depth measurement result.
13. The 3D depth measurement method of claim 12, wherein fusing the depth information of the first image and the depth information of the second image, determining the depth measurement result comprises:
taking the depth of the second image as a measurement result in the case that the depth difference between the first image and the second image is small;
taking the depth of the first image as a measurement result when the depth difference between the first image and the second image is larger than a first threshold value; and
in case the second image does not comprise depth information, the depth of the first image is taken as a measurement result.
14. The 3D depth measurement method of claim 12 or 13, wherein the first projector and the second projector are the same or different.
15. The 3D depth measurement method of claim 12 or 13, wherein the power of the first projector and the second projector are adjustable, and wherein the multi-projector monocular 3D structured light system is determined to operate in an outdoor environment in response to measuring an ambient light intensity greater than a first light intensity threshold, and wherein the power of the first projector and the second projector is increased.
16. The 3D depth measurement method of claim 12 or 13, wherein the power of the first projector and the second projector are adjustable, and in response to measuring an ambient light intensity that is less than a second light intensity threshold, determining that the multi-projector monocular 3D structured light system is operating in an indoor environment, reducing the power of the first projector and the second projector.
17. The 3D depth measurement method of claim 12, wherein the multi-projector monocular 3D structured light system further comprises a third projector, the method further comprising: the distance between the optical center of the third projector and the optical center of the IR camera is set to be different from the first distance and the second distance.
18. An electronic device comprising the multi-projector monocular 3D structured light system of claim 1.
19. The electronic device of claim 18, wherein the electronic device is a cell phone, an attendance machine, a door access, or a face payment device.
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