CN217155312U - Structured light projector and non-contact three-dimensional image acquisition system with same - Google Patents
Structured light projector and non-contact three-dimensional image acquisition system with same Download PDFInfo
- Publication number
- CN217155312U CN217155312U CN202220767379.9U CN202220767379U CN217155312U CN 217155312 U CN217155312 U CN 217155312U CN 202220767379 U CN202220767379 U CN 202220767379U CN 217155312 U CN217155312 U CN 217155312U
- Authority
- CN
- China
- Prior art keywords
- plane
- optical axis
- lens
- pattern
- structured light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Length Measuring Devices By Optical Means (AREA)
Abstract
The utility model provides a structured light projector and non-contact three-dimensional image acquisition system who has it. The structured light projector includes a light source disposed in front of the light source for projecting a pattern on the pattern generating device onto a projection plane, a pattern generating device disposed on a light transmission path between the pattern generating device and the projection plane, and a condensing lens disposed on the light transmission path between the pattern generating device and the projection plane, wherein an image point formed on the projection plane by a point on the pattern generating device closer to the condensing lens is farther from the condensing lens. Therefore, the image plane formed by the refraction of the pattern on the pattern generating device by the convergent lens can be superposed with the surface of the measured object as much as possible, and the projected pattern is clear as much as possible. The out-of-focus of the structured light can be avoided, and a high-precision three-dimensional reconstruction scene can be performed. This arrangement is particularly advantageous for scenes where the structured light projector cannot project vertically due to device interference or the like.
Description
Technical Field
The utility model relates to a three-dimensional imaging's technical field specifically relates to a structured light projector and non-contact three-dimensional image acquisition system who has this structured light projector.
Background
Recently, accurate three-dimensional object reconstruction or three-dimensional scene reconstruction is required in many fields. For this reason, 3D sensing techniques using structured light have been introduced, thereby enabling more accurate three-dimensional object reconstruction or three-dimensional scene reconstruction.
In application, the projection direction of the projected structured light forms a certain angle with the surface of an object to be measured, so that the projected structured light pattern can generate deformation along with the convex-concave change of the surface of the object. The camera collects the deformed structured light pattern on the surface of the object. The software algorithm calculates the curved surface or curvature of the object according to the deformation of the structured light pattern.
In order to achieve high 3D scanning accuracy, it is necessary that the pattern of the projected structured light on the surface of the scanned object is sharp, or that the depth of field of the projected structured light is large enough. However, the projection direction of the structured light forms a certain angle with the surface of the measured object, and the farthest end and the nearest end of the measured object are positioned at two sides of the projection image plane, so that the structured light is out of focus, the projection pattern is blurred, and the method cannot be used for high-precision three-dimensional reconstruction scenes. This problem is particularly pronounced when the object distance is small or the projection direction of the structured light is significantly non-perpendicular to the surface of the object to be measured.
SUMMERY OF THE UTILITY MODEL
In order to at least partially solve the problems in the prior art, the present invention provides a structured light projector. The structured light projector includes a light source disposed in front of the light source for projecting a pattern on the pattern generating device onto a projection plane, a pattern generating device disposed in front of the light source, and a condensing lens disposed on a light transmission path between the pattern generating device and the projection plane, wherein a projection point formed on the projection plane by a point on the pattern generating device closer to the condensing lens is farther from the condensing lens.
By placing the pattern generating device at an angle to the optical axis of the converging lens, rather than vertically, the projection point formed on the projection plane by a point on the pattern generating device that is closer to the converging lens is farther from the converging lens. Therefore, the image plane formed by the refraction of the pattern on the pattern generating device by the convergent lens can be superposed with the surface of the measured object as much as possible, and the projected pattern is clear as much as possible. Thus, the out-of-focus of the structured light can be avoided, and a high-precision three-dimensional reconstruction scene can be performed. This arrangement is particularly advantageous for scenes where the structured light projector cannot project vertically due to device interference or the like. For the image acquisition device for acquiring the image of the surface of the measured object, the depth of field of the lens can be set to be smaller, and the aperture is enlarged, so that the requirements on exposure time and light supplement quantity are lower.
Illustratively, the pattern generating device is located at a first non-zero included angle α between a pattern generating plane and a lens plane, a second non-zero included angle β between a projection plane and the lens plane, and an intersection line of the pattern generating plane and the projection plane is located on the lens plane, wherein the lens plane is a plane passing through an optical center of the converging lens and perpendicular to an optical axis thereof.
Illustratively, the projection distance along the optical axis of the converging lens of the pattern generation plane to the lens plane
Where f is the focal length of the converging lens and v is the projection distance along the optical axis of the converging lens from the projection plane to the lens plane.
Illustratively, the first included angle
Illustratively, the pattern generating unit includes one or more of a grating and a diffractive optical element.
Illustratively, the pattern includes a plurality of bands that are alternating light and dark.
Illustratively, the pattern includes a plurality of stripes with alternating light and dark, and a plurality of points having brightness differences with the stripe are disposed in each of the plurality of stripes.
Illustratively, the plurality of stripes include a plurality of first stripes distant from an intersection line of the pattern generation plane and the projection plane with respect to the optical axis and a plurality of second stripes close to the intersection line with respect to the optical axis, wherein the first stripes farther from the optical axis are wider; and/or the second band being narrower the further away from the optical axis.
In the case where a plurality of points having brightness differences from the strip in which they are located are provided in each of the plurality of strips, illustratively, the size of the point on the first strip that is farther from the optical axis is larger; and/or, illustratively, the size of the dots on the second strip that are farther from the optical axis is smaller.
Illustratively, the pattern includes a plurality of light and dark stripes, the plurality of stripes include a plurality of first stripes far from the intersection line with respect to the optical axis and a plurality of second stripes near the intersection line with respect to the optical axis, a boundary is formed between any two adjacent stripes, and a symbol distance between the No. 0 boundary and the No. n boundary
Wherein n is an integer, the optical axis of the convergent lens passes through the No. 0 boundary line, the No. 1 boundary line, the No. 2 boundary line and the No. 3 boundary line … are sequentially formed among the plurality of first strips along the direction far from the optical axis, and the No. 1 boundary line, the No. 2 boundary line and the No. 3 boundary line … are sequentially formed among the plurality of second strips along the direction far from the optical axis;
d 1 from boundary line 0 to boundary line 1Symbolic distance of line of marks, D 1 The projection width of a first strip between the No. 0 boundary and the No. 1 boundary on the projection plane;
u is the distance from the generating plane to the lens plane along the optical axis pattern of the converging lens; and is
v is the distance from the projection plane to the lens plane along the optical axis of the converging lens.
Illustratively, the pattern comprises a plurality of alternating light and dark stripes, wherein the plurality of stripes are parallel to the intersecting lines; and/or the wider the strip the further away from the intersection.
Illustratively, the pattern comprises a plurality of light and dark stripes, wherein a plurality of points having brightness difference with the stripe are arranged in each of the plurality of stripes, and the size of the points on the stripes farther away from the intersection line is larger.
Illustratively, the ratio between the size of each of the plurality of points and the width of the strip is in the range of 1/3 to 2/3.
Illustratively, the distance between the center of each of the plurality of points to the two lines of demarcation that form the strip at which the point is located is equal.
Illustratively, the plurality of points within each of the plurality of strips are arranged in a line along the direction of extent of the strip.
Illustratively, each of the plurality of points is circular or polygonal.
According to the utility model discloses an on the other hand still provides a non-contact three-dimensional image acquisition system, include: a structured light projector as described above; and the image acquisition device is aligned to the projection plane and is used for acquiring the image of the three-dimensional target placed on the projection plane.
A series of concepts in a simplified form are introduced in the disclosure, which will be described in further detail in the detailed description section. The summary of the invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
The advantages and features of the present invention are described in detail below with reference to the accompanying drawings.
Drawings
The following drawings of the present invention are used herein as part of the present invention for understanding the present invention. There are shown in the drawings, embodiments and descriptions thereof, which are used to explain the principles of the invention. In the drawings, there is shown in the drawings,
fig. 1 is an optical path diagram of a structured light projector according to an exemplary embodiment of the present invention;
fig. 2 is a simplified optical path diagram of a structured light projector according to an exemplary embodiment of the present invention;
fig. 3 is a schematic diagram of a pattern generation unit of a structured light projector according to an exemplary embodiment of the present invention;
fig. 4 is a schematic illustration of a projection formed by a structured light projector on a projection plane according to an exemplary embodiment of the present invention; and
fig. 5 is a schematic diagram of a three-dimensional image acquisition system according to another exemplary embodiment of the present invention.
Wherein the figures include the following reference numerals:
10. a structured light projector; 11. a light source; 12. a pattern generation unit; 122. a first strip, 123, a second strip; 124. point; 13. a converging lens; 14. an object to be measured; 141 and 142, projection strips; 30. an image acquisition device; 40. a finger.
Detailed Description
In the following description, numerous details are provided to provide a thorough understanding of the present invention. One skilled in the art, however, will understand that the following description illustrates only a preferred embodiment of the invention and that the invention may be practiced without one or more of these details. In addition, some technical features that are well known in the art are not described in detail in order to avoid obscuring the present invention.
In accordance with one aspect of the present invention, a structured light projector 10 is provided. The structured light projector 10 may include a light source 11, a pattern generation unit 12, and a condensing lens 13.
The light source 11 may be a point light source, and may for example comprise a single light emitting element. The light source 11 may be a surface light source, and may include a plurality of light emitting elements arranged in an array, for example. The light emitting elements may be Light Emitting Diodes (LEDs).
The pattern generating unit 12 is disposed in front of the light source 11. The pattern generating unit 12 has a pattern, and after the light emitted from the light source 11 is irradiated onto the pattern generating unit 12, one part is blocked and the other part is emitted through the pattern generating unit 12, so that a projection with a desired pattern is formed on the surface of the object to be measured. As shown in fig. 1, the light source 11 may project the pattern on the pattern generating unit 12 onto the surface of the object to be measured 14. Illustratively, the pattern generation unit 12 may include a grating. The grating typically comprises a substrate on which the pattern is formed. Such as by spraying, printing, photolithography, or any other suitable means of forming the pattern on the substrate. The substrate may be a film, or may be made of other materials, such as glass, plastic, etc. Illustratively, the pattern generation unit 12 may include a Diffractive Optical Element (DOE), and the structured light projected to the projection plane may be patterned by the design of the diffractive unit structure of the DOE. The condensing lens 13 is disposed on the optical transmission path between the pattern generating unit 12 and the projection plane. The projection plane is the surface of the object 14 to be measured. The light passing through the pattern generating unit 12 is converged by the converging lens 13 and then reaches the projection plane. The condensing lens 13 may include various types of convex lenses, and of course, the condensing lens 13 may include other types of lenses as long as the condensing lens 13 has a condensing effect on light as a whole. Fig. 1 shows a schematic diagram in which light passing through two points m and n on the pattern generating unit 12 is refracted by the condensing lens 13 and projected onto the surface of the object to be measured 14. In order to be able to project the point converged by the converging lens 13 exactly on the surface of the object to be measured 14, i.e. to converge into two points M and N on the surface of the object to be measured 14, the inventors propose that the pattern generating unit 12 may be placed obliquely with respect to the converging lens 13. By placing the pattern generating device 12 at an angle to the optical axis of the condenser lens 13, rather than vertically, the projection point formed on the projection plane CE by a point on the pattern generating device 12 that is closer to the condenser lens 13 is farther from the condenser lens 13. Thus, the image plane formed by the refraction of the pattern on the pattern generating unit 12 by the converging lens 13 can be superposed with the surface of the object to be measured 14 as much as possible, and the projected pattern can be as clear as possible. Thus, the out-of-focus of the structured light can be avoided, and a high-precision three-dimensional reconstruction scene can be performed. This arrangement is particularly advantageous for scenes where the structured light projector cannot project vertically due to device interference or the like. For the image acquisition device for acquiring the image on the surface of the object to be detected 14, the depth of field of the lens can be set to be smaller, the aperture is enlarged, so that the requirements on exposure time and light supplement quantity are lower, correspondingly, the acquisition time of the image acquisition device can be reduced, and the brightness of a light supplement lamp can be reduced.
Further, referring to the diagram shown in fig. 2, the plane in which the pattern generation unit 12 is located is simply referred to as the pattern generation plane AB, and it will be understood that, in the embodiment in which the image generation unit 12 includes a grating, the pattern generation unit 12 may be considered to be substantially planar with the pattern generation plane AB due to the thinner thickness of the grating; the plane where the convergent lens 13 is located is simply referred to as a lens plane MN, which is a plane passing through the optical center of the convergent lens 13 and perpendicular to the optical axis FF thereof; and the projection plane (i.e., the surface of the object to be measured 14) is denoted as CE. A first non-zero angle α is formed between the pattern generating plane AB and the lens plane MN, a second non-zero angle β is formed between the projection plane CE and the lens plane MN, and an intersection line (a straight line perpendicular to the paper surface at the point S in the drawing) of the pattern generating plane AB and the projection plane CE is located on the lens plane MN. In this way, it is ensured that the image plane of the projected pattern coincides as much as possible with the surface of the object to be measured 14, the definition of the projected pattern is further improved, and the accuracy of the three-dimensional reconstruction is further improved.
With continued reference to fig. 2, let the focal length of the condenser lens 13 be denoted as f, the projection distance of the projection plane CE to the lens plane MN along the optical axis FF of the condenser lens 13 be denoted as v, and the projection distance of the pattern generation plane AB to the lens plane MN along the optical axis FF of the condenser lens 13 be denoted as u.
According to the lens imaging formula:
it can be derived that:
thereby, the position of the pattern generation unit 12 along the optical axis FF with respect to the condensing lens 13 can be determined.
In addition, from fig. 2, the following relationship can be obtained: u cot α ═ v cot β
Based on this, the first included angle
Thereby, the inclination angle of the pattern generating unit 12 with respect to the condensing lens 13 can be determined.
Fig. 3 shows a schematic view of a pattern generation unit according to an exemplary embodiment of the present invention. Illustratively, the pattern on the pattern generating unit 12 includes a plurality of stripes that are alternately light and dark. In the illustrated embodiment, the plurality of strips are parallel to each other and arranged in series along the vertical direction. In other embodiments not shown, the plurality of strips may also be arranged in sequence along the horizontal direction, or in sequence along other directions. The dark band (black filled band) on the pattern generating unit 12 is an opaque band, for example, an opaque thin layer may be formed at the dark band. The bright band (no filled band) on the pattern generating unit 12 is a light transmittable band. Alternatively, the dark bands on the pattern generating unit 12 may also be stripes having a transmittance less than that of the light bands. The light emitted from the light source 11 may be transmitted through the bright band, or may be transmitted through both the bright band and the dark band, and then is converged by the converging lens 13 and projected onto the projection plane CE. This makes it possible to form a striped pattern of alternating light and dark on the projection plane CE. The stripe pattern is deformed according to the convex-concave change of the object surface, and the image acquisition device acquires the deformed stripe pattern on the surface of the object to be measured 14. The acquired deformed fringe pattern can be calculated by using a software algorithm, and then three-dimensional reconstruction can be performed to obtain the curvature or depth of the surface of the object to be measured 14. Therefore, the plurality of strips may be arranged in various directions as long as they can be projected onto the surface of the object to be measured 14. Illustratively, the width of the plurality of strips may be the same or different.
In one embodiment, the plurality of stripes may be parallel to an intersection of the pattern generation plane AB and the projection plane CE. Taking the illustrated embodiment as an example, the intersection of the pattern generation plane AB and the projection plane CE passes through the point S in fig. 2 and is perpendicular to the paper surface, and fig. 3 shows the pattern viewed from the left side perpendicular to the pattern generation unit 12 in fig. 2. Of course, the plurality of stripes may have other angles with respect to the intersection of the pattern generation plane AB and the projection plane CE.
In the case where the plurality of stripes form an angle greater than or equal to 0 and less than 90 degrees with respect to the intersection line of the pattern generating plane AB and the projection plane CE, the plurality of stripes 122 may include a plurality of first stripes 122 distant from the intersection line with respect to the optical axis FF and a plurality of second stripes 123 close to the intersection line with respect to the optical axis, as shown in fig. 3. Fig. 3 also shows a position where the optical axis FF is aligned on the pattern generation unit 12, that is, a position where the optical axis FF passes through. Below the optical axis FF is a first band 122, and above the optical axis FF is a second band 123. In the case where the plurality of stripes have an angle other than 90 degrees with respect to the intersection of the pattern generating plane AB and the projection plane CE, there may be the following: that is, a portion of the first band 122 near the optical axis FF is above the optical axis FF, and a portion of the second band 123 near the optical axis FF is below the optical axis FF. The positions of the first and second strips 122, 123 relative to the optical axis FF are discussed herein in relation to the plane shown in fig. 2 (i.e., the plane passing through the optical center of the condenser lens 13 and perpendicular to the intersection of the pattern generation plane AB and the projection plane CE). On this plane, the first stripe 122 and the second stripe 123 are a plurality of alternately bright and dark line segments. A line segment below the optical axis FF is formed by the first strip 122, and a line segment above the optical axis FF is formed by the second strip 123.
Preferably, the first strip 122 is wider the farther away from the optical axis FF. In this way, the projection stripes 141 formed on the projection plane CE by the plurality of first stripes 122 can have a relatively uniform width, as shown in fig. 4.
Preferably, the second band 123, which is farther from the optical axis FF, is narrower. In this way, the plurality of second stripes 123 may form a projection stripe 142 with a relatively uniform width on the projection plane CE, as shown in fig. 4.
Note that, when the optical axis FF is aligned with the boundary between the two bands, as shown in fig. 3, one of the first bands 122 closest to the optical axis FF may have the same width as one of the second bands 123 closest to the optical axis FF. Alternatively, the width of one of the first stripes 122 closest to the optical axis FF may be slightly larger than the width of one of the second stripes 123 closest to the optical axis FF. That is, the following rules may be followed: the farther away from the intersection of the pattern generation plane AB and the projection plane CE the wider the band. In this way, the projection stripes 141 and 142 formed by all the stripes on the projection plane CE can be made to have a relatively uniform width, as shown in fig. 4.
Of course, the optical axis FF may also be aligned with a band, below which is the first band and above which is the second band. The plurality of first stripes may satisfy the following relationship: the first stripe 122 is wider the farther from the optical axis FF. The plurality of second stripes may satisfy the following relationship: the second band 123, which is farther from the optical axis FF, is narrower. Of course, the plurality of first stripes and the plurality of second stripes may also satisfy the above-described relationship at the same time, and may each have a stripe in which the optical axis FF is aligned as a reference. In this case, all the strips may also satisfy: the farther away from the intersection of the pattern generation plane AB and the projection plane CE the wider the band.
When the stripe pattern is projected at a large angle (i.e. the included angle between the projection plane CE and the lens plane MN is large), the projection density is not uniform due to the non-uniform line width caused by the perspective principle. By designing the widths of the stripes on the pattern generating unit 12 to satisfy the above conditions, it is possible to form stripes of uniform width on the projection plane CE even in large-angle projection, and thus it is possible to improve the accuracy of three-dimensional reconstruction.
A boundary is formed between any two adjacent strips. Two adjacent stripsOne is a bright band and the other is a dark band, so the border lines are used to define the boundaries of adjacent bright and dark bands. In fig. 3, a boundary line passing through the optical axis FF of the condenser lens 13 is defined as a 0 th boundary line, a 1 st boundary line, a 2 nd boundary line, and a 3 rd boundary line … are formed in this order among the plurality of first stripes 122 in a direction away from the optical axis FF, and a-1 st boundary line, a-2 nd boundary line, and a-3 rd boundary line … are formed in this order among the plurality of second stripes 123 in a direction away from the optical axis FF. Referring back to fig. 2, the intersection points of the optical axis FF with the pattern generation plane AB and the projection plane CE are points U, respectively 0 And V 0 . Boundary line 0 corresponds to point U 0 The No. 1 boundary line corresponds to the point U 1 The nth boundary line corresponds to point U n . And, the projection point of the No. 0 boundary line on the projection plane CE corresponds to the point V 0 The projection point of No. 1 boundary on the projection plane CE corresponds to the point V 1 The projection point of the n-th boundary on the projection plane CE corresponds to the point V n . Where n is an integer, that is, for boundary line No. 1, n is 1; for boundary line No. 2, n is 2 …; for boundary line-1, n ═ 1; for boundary-2, n-2 ….
Assume the distance between boundary line 0 and boundary line 1
The distance between the 0 th boundary and the n th boundary
Projection width of the first strip between the No. 0 boundary and the No. 1 boundary on the projection plane CE
The projection width of the first strip between the No. 0 boundary and the No. n boundary on the projection plane CE
It is desirable that the projection width of each stripe on the pattern generation unit 12 on the projection plane CE is uniform, so that the following relationship exists: d n ＝nD 1 . Pattern(s)Generating intersection of plane AB and projection plane CE to point U 0 The distance between
Intersection of pattern-generating plane AB and projection plane CE to point V 0 The distance between
According to the projective geometrical relationship:
left side:
right side:
therefore, the temperature of the molten metal is controlled,
in addition, based on
u cotα＝v cotβ
u'sinα＝u
v'sinβ＝v
It can be derived that:
wherein the content of the first and second substances,
illustratively, to meet a particular spatial coding requirement, a plurality of points 124 having a brightness difference with the stripe are disposed within each stripe 122. That is, the light transmittance of the dots on the light band is poor, and the light transmittance of the dots on the dark band is good. The point 124 may be used to further spatially encode on the basis of using the slices to spatially encode. For example, spatial encoding is performed with stripes, thereby performing three-dimensional reconstruction; and carrying out further space coding by using the points, thereby splicing a plurality of three-dimensional models obtained by three-dimensional reconstruction or two-dimensional expansion images corresponding to the three-dimensional models.
Illustratively, each point 124 may be circular or polygonal. Polygons include triangles, quadrilaterals, pentagons, and the like. When the dots are quadrilateral, the width of the dots may coincide with the width of the strips on which they are located, and thus, when viewed as a whole, the pattern formed by the pattern generating device 12 may be in the form of a grid. Illustratively, the size of the point on the first strip 122 that is farther from the optical axis FF is larger. In this way, the projected spots formed by the points on the first stripe 122 on the projection plane CE can be made to have a relatively uniform size.
Illustratively, the size of the dots on the second stripe 123 that are farther from the optical axis FF is smaller. In this way, the projected spots formed by the points on the second stripe 123 on the projection plane CE can be made to have a relatively uniform size.
Of course, these dots 124 may be set to be larger in size as a whole for dots on the band farther from the intersection line of the pattern generating plane AB and the projection plane CE. In this way, the projected spots formed on the projection plane CE by the points on all the strips can be made to have a relatively uniform size.
Illustratively, the ratio between the size of each dot 124 and the width of the strip is in the range of 1/3 to 2/3. Illustratively, the distance between the center of each of the plurality of points 124 to the two lines of demarcation that form the strip at which the point is located is equal. Illustratively, the plurality of points within each strip are arranged in a line along the direction of extension of the strip.
According to another aspect of the present invention, there is provided a non-contact three-dimensional image capturing system, as shown in fig. 5. The non-contact three-dimensional image acquisition system may include any of the structured light projectors 10 and image acquisition devices 30 described above. Taking the measured object as a fingerprint, the fingerprint of the finger 40 may be located on the projection plane. The image capture device 30 is aligned with the projection plane for capturing an image of a three-dimensional object placed on the projection plane. The optical axis of the image capturing device 30 may be perpendicular to the projection plane, thereby preventing the captured fingerprint image from being distorted, and thus improving the accuracy of three-dimensional reconstruction.
In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the orientation words such as "front", "rear", "upper", "lower", "left", "right", "horizontal", "vertical", "horizontal" and "top", "bottom", etc. are usually based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplification of description, and in the case of not making a contrary explanation, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore, should not be interpreted as limiting the scope of the present invention; the terms "inner" and "outer" refer to the interior and exterior relative to the contours of the components themselves.
For ease of description, relative terms of regions such as "above … …", "above … …", "on … …", "above", etc. may be used herein to describe the regional positional relationship of one or more components or features to other components or features shown in the figures. It is to be understood that the relative terms of the regions are intended to encompass not only the orientation of the element as depicted in the figures, but also different orientations in use or operation. For example, if an element in the drawings is turned over in its entirety, the articles "over" or "on" other elements or features will include the articles "under" or "beneath" the other elements or features. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". Further, these components or features may also be positioned at various other angles (e.g., rotated 90 degrees or other angles), all of which are intended to be encompassed herein.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, elements, components, and/or combinations thereof, unless the context clearly indicates otherwise.
It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein.
The present invention has been described in terms of the above embodiments, but it is to be understood that the above embodiments are for purposes of illustration and description only and are not intended to limit the invention to the described embodiments. Furthermore, it will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that many more modifications and variations are possible in light of the teaching of the present invention and are within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (13)
1. A structured light projector comprising a light source, a pattern generation unit disposed in front of the light source, the light source for projecting a pattern on the pattern generation unit onto a projection plane, and a condensing lens disposed on a light transmission path between the pattern generation unit and the projection plane,
wherein a projection point formed on the projection plane by a point on the pattern generating unit closer to the condensing lens is farther from the condensing lens.
2. The structured light projector of claim 1 wherein the pattern generation unit is positioned at a first non-zero angle α to a lens plane, the projection plane is positioned at a second non-zero angle β to the lens plane, and an intersection of the pattern generation plane and the projection plane is positioned on the lens plane, wherein the lens plane is a plane passing through an optical center of the converging lens and perpendicular to an optical axis thereof.
3. The structured light projector of claim 2 wherein the projected distance along the optical axis of the converging lens of the pattern generation plane to the lens plane is the distance of the pattern generation plane from the lens plane
Wherein f is a focal length of the converging lens, and v is a projection distance along an optical axis of the converging lens from the projection plane to the lens plane.
4. The structured light projector of claim 3 wherein the first included angle
5. The structured light projector of any one of claims 1 to 4 wherein the pattern generation unit comprises one or more of a grating and a diffractive optical element.
6. The structured light projector of any one of claims 1 to 4,
the pattern comprises a plurality of light and shade alternate stripes; or
The pattern comprises a plurality of light and shade alternate stripes, and a plurality of points with brightness difference with the stripes are arranged in each of the stripes.
7. The structured light projector of claim 6 wherein the plurality of stripes comprises a first plurality of stripes that are distal from an intersection of the pattern generation plane and the projection plane with respect to an optical axis of the converging lens and a second plurality of stripes that are proximal to the intersection with respect to the optical axis, wherein
The wider the first strip that is farther from the optical axis; and/or
The second band being narrower the further away from the optical axis.
8. The structured light projector of claim 7 wherein, where a plurality of points having a brightness difference from the strip are disposed within each of the plurality of strips,
the larger the size of a point on the first strip that is farther from the optical axis; and/or
The size of the point on the second strip further from the optical axis is smaller.
9. The structured light projector of claim 2 wherein the pattern comprises a plurality of alternating light and dark bands, the plurality of bands comprising a first plurality of bands spaced from the line of intersection relative to the optical axis and a second plurality of bands spaced from the line of intersection relative to the optical axis, a boundary being formed between any two adjacent bands, and a symbol distance between boundary 0 and boundary n
Wherein n is an integer, the optical axis of the convergent lens passes through the No. 0 boundary line, the No. 1 boundary line, the No. 2 boundary line and the No. 3 boundary line … are sequentially formed among the plurality of first stripes along the direction far away from the optical axis, and the No. 1 boundary line, the No. 2 boundary line and the No. 3 boundary line … are sequentially formed among the plurality of second stripes along the direction far away from the optical axis;
d 1 the symbolic distance from the No. 0 boundary to the No. 1 boundary, D 1 The projection width of a first strip between the No. 0 boundary and the No. 1 boundary on the projection plane;
u is the distance of the pattern generation plane to the lens plane along the optical axis of the converging lens; and is
v is the distance of the projection plane to the lens plane along the optical axis of the converging lens.
10. The structured light projector of claim 2 wherein the pattern comprises a plurality of alternating light and dark bands, wherein
The plurality of strips are parallel to the intersection line; and/or
The further away from the intersection the strip is wider.
11. The structured light projector of claim 2 wherein the pattern comprises a plurality of alternating light and dark bands, each of the plurality of bands having a plurality of points disposed therein having a brightness difference from the band at which it is disposed, the greater the size of the points on the band that are further from the intersection.
12. The structured light projector of any one of claims 7 to 8 and 11,
the ratio between the size of each of the plurality of points and the width of the strip is in the range of 1/3 to 2/3; and/or
The distance between the center of each of the plurality of points and two boundary lines forming the strip where the point is located is equal; and/or
A plurality of points in each of the plurality of strips are arranged in a line along the extending direction of the strip; and/or
Each of the plurality of points is circular or polygonal.
13. A non-contact three-dimensional image acquisition system, comprising:
the structured light projector of any one of claims 1-12; and
and the image acquisition device is aligned to the projection plane and is used for acquiring the image of the three-dimensional target placed on the projection plane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220767379.9U CN217155312U (en) | 2022-03-31 | 2022-03-31 | Structured light projector and non-contact three-dimensional image acquisition system with same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220767379.9U CN217155312U (en) | 2022-03-31 | 2022-03-31 | Structured light projector and non-contact three-dimensional image acquisition system with same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN217155312U true CN217155312U (en) | 2022-08-09 |
Family
ID=82698704
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202220767379.9U Active CN217155312U (en) | 2022-03-31 | 2022-03-31 | Structured light projector and non-contact three-dimensional image acquisition system with same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN217155312U (en) |
-
2022
- 2022-03-31 CN CN202220767379.9U patent/CN217155312U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20210298605A1 (en) | Intraoral scanner | |
| JP4290733B2 (en) | Three-dimensional shape measuring method and apparatus | |
| US9142025B2 (en) | Method and apparatus for obtaining depth information using optical pattern | |
| EP2651118B1 (en) | Light receiving device, focus detection device and imaging device | |
| EP1595224B1 (en) | Acquisition of three-dimensional images by an active stereo technique using locally unique patterns | |
| CN101308012B (en) | Double monocular white light three-dimensional measuring systems calibration method | |
| US8538166B2 (en) | 3D geometric modeling and 3D video content creation | |
| KR101605224B1 (en) | Method and apparatus for obtaining depth information using optical pattern | |
| US20150015701A1 (en) | Triangulation scanner having motorized elements | |
| JP4379056B2 (en) | Three-dimensional imaging apparatus and method | |
| US20070211258A1 (en) | Three-dimensional shape measurement apparatus and method for eliminating2pi ambiguity of moire principle and omitting phase shifting means | |
| US20060164526A1 (en) | Image processing device and image capturing device | |
| CN105700280A (en) | Structured-Light Projector And Three-Dimensional Scanner Comprising Such A Projector | |
| KR101283635B1 (en) | Scanning system and method for oral cavity | |
| JP3975917B2 (en) | Position measurement system | |
| US20120293626A1 (en) | Three-dimensional distance measurement system for reconstructing three-dimensional image using code line | |
| CN113505626A (en) | Rapid three-dimensional fingerprint acquisition method and system | |
| US7830605B2 (en) | Longitudinal interference fringe pattern projection lens, optical system, and three-dimensional image acquisition apparatus | |
| CN217155312U (en) | Structured light projector and non-contact three-dimensional image acquisition system with same | |
| WO2018056810A1 (en) | Scanning system for creating 3d model | |
| CN114705131B (en) | Positionable multi-line scanning generation method and system for 3D measurement | |
| JP2012026998A (en) | Focal point three-dimensional coordinate measurement method and device using discrete divergent pencil-of-rays group | |
| EP4193905A1 (en) | Intraoral scanner, intraoral scanning system, method for performing intraoral scans and computer program product | |
| JP5853284B2 (en) | Shape measuring apparatus and shape measuring method | |
| TWM617812U (en) | Single-camera three-dimensional scanning projection device used in endoscope |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |