DE112015004196T5 - GATE CARRIER COORDINATE GAUGE WITH A 2D CAMERA AND METHOD FOR OBTAINING 3D DISPLAYS - Google Patents

Abstract

A portable articulated arm coordinate measuring machine includes a non-contact 3D measuring device that includes a projector configured to emit a first pattern of light on an object, a scanner camera arranged to reflect the first pattern of light that reflects from the surface of the object receives, receives, an edge-detecting camera arranged to receive light reflected from an edge feature of the object and a processor configured to obtain first 3D coordinates of an edge point of the edge feature based on electrical signals to determine which are received by the scanner camera and the edge detecting camera.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of US Patent Application Number 14 / 485,876, filed Sep. 15, 2014, the contents of which are incorporated herein by reference in their entirety.

BACKGROUND

The present disclosure relates to a coordinate measuring machine, and more particularly, to a portable articulated arm coordinate measuring machine having a connector on a probe end of the coordinate measuring machine, which enables the detachable connection of additional devices using a strip light for non-contact three-dimensional measurement with the coordinate measuring machine.

Portable articulated arm CMMs have found widespread use in the manufacture or production of parts where the dimensions of the part need to be inspected quickly and accurately during various stages of manufacture or production (eg, machining) of the part. Portable articulated arm CMMs are a vast improvement over known stationary or fixed, expensive, and relatively difficult to use measuring devices, particularly in terms of the time required to perform the size measurements of relatively complex parts. Normally, a user of a portable articulated arm CMM simply inserts a probe along the surface of the part or object to be measured. The measurement data is then recorded and made available to the user. In some cases, the data is provided to the operator in an optical form, for example in three-dimensional (3D) form on a computer screen. In other cases, the data is provided numerically to the user, for example, when measuring the diameter of a hole when the text "diameter = 1.0034" is displayed on a computer screen.

An example of a portable articulated arm CMM of the prior art is in the U.S. Patent No. 5,402,582 ('582) of the same assignee, which is incorporated herein by reference in its entirety. The '582 patent discloses a 3D measuring system that includes a manually operated articulated arm CMM with a support base at one end and a probe at the other end. The U.S. Patent No. 5,611,147 ('147) of the same assignee, which is incorporated herein by reference in its entirety, discloses a similar articulated arm CMM. In the '147 patent, the articulated arm CMM includes several features including an additional rotation axis at the probe end, providing one arm with a configuration of either two-two-two or two-two-three axes (the latter being a seven-axis arm ).

Three-dimensional surfaces can also be measured using non-contact techniques. One type of non-contact device, sometimes referred to as a laser line probe or laser line scanner, emits laser light either at a point or along a line. An imaging device, such as a Charge-Coupled Device (CCD), is positioned adjacent to the laser. The laser is arranged to emit a line of light that is reflected from the surface. The surface of the measured object causes diffuse reflection, which is detected by the imaging device. The image of the reflected line on the sensor changes as the distance between the sensor and the surface changes. By knowing the relationship between the imaging sensor and the laser and the position of the laser image on the sensor, triangulation techniques can be used to measure three-dimensional coordinates of points on the surface. A problem that arises with laser line probes is that the density of measured points may change depending on the speed with which the laser line probe is moved across the surface of the object. The faster the laser line probe is moved, the greater the distance between the dots and the dot density becomes smaller. In a streak light scanner, the dot pitch is typically uniform in each of the two dimensions, generally providing a uniform measurement of surface points on the workpiece. Another problem that arises in obtaining 3-D plots from scan data is that there is often a blurred area around edges or holes.

Although existing CMMs are suitable for their intended purposes, there is a need for a portable articulated arm CMM with certain features of embodiments of the present invention.

SUMMARY OF THE INVENTION

According to one embodiment of the invention, there is provided a portable articulated arm coordinate measuring machine (articulated arm CMM) for measuring three-dimensional (3D) coordinates of an object in space, comprising a base; a manually positionable arm portion having a first and an opposite second end, the arm portion rotatably coupled to the base, the arm portion including a plurality of connected arm segments, each arm segment including at least one position sensing system for generating a position signal; a processor; an electronic circuit receiving the position signal from the at least one displacement encoder in each arm segment, the electronic circuit configured to send a first electrical signal to the processor in response to the position signal; a probe end coupled to the first end; a non-contact 3D measuring device coupled to the probe end, the non-contact 3D measuring device comprising a projector and a scanner camera, the projector being adapted to emit a first light pattern on the object, the scanner camera being arranged to read the one of the Receives object reflected first light patterns and in response sends a second electrical signal to the processor; an edge-detecting camera coupled to the probe end, wherein the edge-detecting camera is one of the scanner camera and a second camera different from the scanner camera, the edge-detecting camera being positioned so as to be one of a Edge feature of the object receives second reflected light and in response sends a third electrical signal to the processor; and wherein the processor is configured to determine first 3D coordinates of first points on a surface of the object based at least in part on the first light pattern from the projector, the first electrical signal, and the second electrical signal, wherein the processor is further configured therefor to determine a first beam from the edge-detecting camera to the object, the first beam based at least in part on the first electrical signal and the third electrical signal, the processor being further configured to determine second 3D coordinates of an edge point of the edge feature wherein the second 3D coordinates are based at least in part on an intersection of the first beam with the first 3D coordinates of the first surface.

According to another embodiment of the invention, a method of measuring an edge point with a portable articulated arm CMM comprises providing the articulated arm CMM, the articulated arm CMM comprising: a base; a manually positionable arm portion having first and one opposite second end, wherein the arm portion is rotatably coupled to the base, wherein the arm portion comprises a plurality of connected arm segments, each arm segment comprises at least one position encoder for generating a position signal, a processor, an electronic circuit, a probe end coupled to the first end a non-contact 3D measuring device coupled to the probe end, the non-contact 3D measuring device having a projector and a scanner camera, the articulated arm CMM further comprising an edge-detecting camera coupled to the probe end, the edge-detecting camera having one of the scanner camera and a second camera that differs from the scanner camera; receiving, by the electronic circuit, the position signal from the at least one displacement measuring system in each arm segment; sending, from the electronic circuit, a first electrical signal to the processor in response to the position signal; radiating, from the projector, a first pattern of light onto the object; receiving, with the scanner camera, the first light pattern reflected from the object, and sending a second electrical signal to the processor in response thereto; receiving, with the edge detecting camera, a second light reflected from an edge feature of the object and sending a third electrical signal to the processor in response thereto, the edge feature having an edge point, the edge point being a point on the edge feature; determining, with the processor, first 3D coordinates of first points on a surface of the object, wherein the first 3D coordinates are based at least in part on the first pattern of light from the projector, the first electrical signal, and the second electrical signal; further determining, with the processor, a first beam from the edge-detecting camera to the object, the first beam based at least in part on the first electrical signal and the third electrical signal; further determining, at the processor, second 3D coordinates of the edge point based, at least in part, on an intersection of the first beam with the first 3D coordinates of the first surface; and storing the second 3D coordinates of the edge point.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings, exemplary embodiments are shown which are not to be construed as limiting the entire scope of the disclosure, and wherein the elements in several figures are numbered alike:

1 including 1A and 1B FIGS. 5, 5 and 5 are perspective views of a portable articulated arm coordinate measuring machine (articulated arm CMM) incorporating embodiments of various aspects of the present invention;

2 including 2A - 2D Taken together, is a block diagram of the electronics used as part of the articulated arm CMM of 1 is used according to one embodiment;

3 including 3A and 3B taken together, is a block diagram showing detailed features of the electronic data processing system of 2 according to one embodiment;

4 is an isometric view of the probe end of the articulated arm CMM 1 ;

5 is a side view of the probe end 4 with the handle coupled thereto;

6 is a side view of the probe end 4 with the handle attached;

7 is an enlarged partial side view of the interface portion of the probe end 6 ;

8th Figure 4 is a further enlarged partial side view of the interface portion of the probe end 5 ;

9 is an isometric view of the handle 4 , partly in section;

10 is an isometric view of the probe end of the articulated arm CMM 1 with a strip light device to which a single camera is attached;

11 is an isometric view of the device 10 , partly in section;

12 is an isometric view of the probe end of the articulated arm CMM 1 with another strip light device with two attached cameras;

13A and 13B are schematic views illustrating the operation of the device 10 illustrate when this at the probe end of the articulated arm CMMs 1 is appropriate;

14 - 17 are sequential projections with an uncoded binary pattern coming from the strip light device 10 or 12 can be broadcast, according to an embodiment of the present invention;

18 - 19 are spatially varying color-coded patterns emanating from the strip light device 10 or 12 can be emitted according to an embodiment of the invention;

20 - 23 are spatially varying band index coded patterns emanating from the strip light device 10 or 12 can be emitted according to an embodiment of the invention;

24 - 31 are two-dimensional lattice patterns that emanate from the strip light device 10 or 12 can be emitted according to an embodiment of the invention;

32 Fig. 10 is a schematic illustration of a photometric technique for detecting patterns of fringe light under a variety of lighting conditions;

33 Fig. 10 is an illustration of a stripe light scanner device operable independently of an articulated arm CMM according to another embodiment of the invention;

34 Figure 11 is an isometric drawing of a probe end with a triangulation scanner and a camera used together to produce sharp 3D representations;

35 Figure 12 is a schematic illustration of rays projected through a camera perspective center to provide sharp edges for 3D representations; and

36 Figure 4 is an illustration having a hole with edges with a surrounding area having a "blur".

DETAILED DESCRIPTION

Portable articulated arm CMMs are used in a variety of applications to obtain measurements of objects. Embodiments of the present invention provide advantages in that an operator can easily and quickly couple accessory devices that use fringe light to enable non-contact measurement of a three-dimensional object to a probe end of the articulated arm CMM. Embodiments of the present invention provide further advantages in providing communication data representing a point cloud measured by the strip light device within the articulated arm CMM. Embodiments of the present invention offer advantages of greater uniformity in the distribution of measurement points, which can provide improved accuracy. Embodiments of the present invention provide further advantages in that that they provide power and data communication to a detachable accessory without external connections or wiring. Embodiments of the present invention provide further advantages in that edges of features in 3D representations become sharper.

As used herein, the term "fringe light" means a two-dimensional light pattern that is projected onto a continuous and enclosed area of an object that conveys information that can be used to determine coordinates of points on the object. A striped light pattern includes at least three non-collinear pattern elements located within the contiguous and enclosed area. Each of the three non-collinear pattern elements conveys information that can be used to determine the point coordinates.

In general, there are two types of strip light, a coded light pattern, and an uncoded light pattern. As used herein, a coded light pattern is one in which the three-dimensional coordinates of an illuminated surface of the object can be determined by the detection of a single image. In some cases, the projection device may move relative to the object. In other words, in a coded light pattern, there is no significant temporal relationship between the projected pattern and the captured image. Typically, a coded light pattern includes a set of elements (eg, geometric shapes) arranged such that at least three of the elements are non-collinear. In some cases, the set of elements may be arranged into collections of lines. If at least three of the elements are non-collinear, this ensures that the pattern is not a simple line pattern, such as would be projected by a laser line scanner. As a result, the pattern elements are recognizable due to the arrangement of the elements.

In contrast, an uncoded striped light pattern, as used herein, is a pattern that does not permit measurement by a single pattern as the projector moves relative to the object. An example of an uncoded light pattern is one that requires a series of sequential patterns, and thus the acquisition of a series of sequential images. Due to the temporal nature of the projection pattern and the capture of the image, there should be no relative movement between the projector and the object.

It is understood that fringe light is different from light projected by a laser line probe or a laser line scanner type device which generates a line of light. To the extent that laser line probes used with articulated arms today have irregularities or other aspects that can be considered as features within the generated lines, these features are arranged in a collinear array. Consequently, such features within a single generated line are not considered to change the projected light to a fringe light.

The 1A and 1B illustrate in perspective an articulated arm CMM 100 according to various embodiments of the present invention, wherein an articulated arm is a kind of coordinate measuring machine. As in the 1A and 1B shown, the exemplary articulated arm CMM 100 a joint measuring device with six or seven axes with one probe end 401 having at one end to an arm portion 104 the articulated arm CMM 100 coupled probe housing 102 includes. The arm section 104 includes a first arm segment 106 that through a first grouping of bearing inserts 110 (eg two bearing inserts) to a second arm segment 108 is coupled.

A second grouping of bearing inserts 112 (eg two bearing inserts) couples the second arm segment 108 to the probe housing 102 , A third group of bearing inserts 114 (eg three bearing inserts) couples the first arm segment 106 to a lower part 116 at the other end of the arm section 104 the articulated arm CMM 100 is arranged. Each grouping of bearing inserts 110 . 112 . 114 provides multiple axes of articulation. In addition, the probe end 401 a probe housing 102 comprising the shaft of the seventh axis portion of the articulated arm CMM 100 (For example, an insert containing an encoder system that detects movement of the gauge, such as a probe 118 , in the seventh axis of the articulated arm CMM 100 certainly). In this embodiment, the probe end may 401 rotate around an axis extending through the center of the probe housing 102 extends. The lower part 116 is in the use of the articulated arm CMM 100 usually attached to a work surface.

Each bearing insert in each bearing insert grouping 110 . 112 . 114 typically includes an encoder system (eg, an optical encoder system). The encoder system (ie, a transmitter) provides an indication of the position of the respective arm segments 106 . 108 and the corresponding warehouse operations groupings 110 . 112 . 114 ready, all together giving an indication of the position of the probe 118 in relation to the lower part 116 (and thus the position of the through the articulated arm CMM 100 measured object in a given reference system - for example, a local or global Reference system). The arm segments 106 . 108 may be made of a suitably rigid material, such as, but not limited to, a carbon fiber composite material. A portable articulated arm CMM 100 having six or seven axes of articulation (ie degrees of freedom) provides benefits in allowing the operator to probe 118 at a desired location within a 360 ° area around the base 116 to position, with an arm section 104 which can be easily handled by the operator. It is understood, however, that the representation of an arm section 104 with two arm segments 106 . 108 as an example and that the claimed invention should not be limited thereby. An articulated arm CMM 100 may comprise any number of arm segments which are coupled together by bearing inserts (and thus have more or less than six or seven axes of articulation or degrees of freedom).

The probe 118 is on the probe housing 102 releasably attached, which with the bearing insert grouping 112 connected is. A handle 126 is in relation to the probe housing 102 for example, by means of a quick connector terminal removable. As will be discussed later, the handle can 126 be replaced by another device adapted to emit a strip light to provide non-contact measurement of three-dimensional objects, thereby providing benefits to the operator with the same articulated arm CMM 100 Make contact measurements and non-contact measurements. The probe housing 102 accommodates a detachable probe in exemplary embodiments 118 which is a contact meter and different tips 118 which physically contact the object to be measured and include, but are not limited to: ball-type probes, touch-sensitive, curved and extendable probes. In other embodiments, the measurement, for example, by a non-contact device, such. A coded stripe light scanner device. The handle 126 In one embodiment, it is replaced by the coded stripe light scanner device using the quick connector connector. Other types of measuring devices may have the removable handle 126 replace to provide additional functionality. Examples of such measuring devices include, but are not limited to, for example, one or more illumination lamps, a temperature sensor, a thermal scanner, a bar code scanner, a projector, a paint spray gun, a camera, or the like.

As in the 1A and 1B shown includes the articulated arm CMM 100 the removable handle 126 which provides the advantages that accessories or functionalities can be changed without the probe housing 102 from the warehouse operations grouping 112 must be removed. As with reference to 2D will be discussed in more detail below, the removable handle 126 Also include an electrical connector that allows electrical energy and data to be handled 126 and the one in the probe end 401 arranged to be replaced corresponding electronics.

In various embodiments, each grouping of bearing inserts allows 110 . 112 . 114 in that the arm section 104 the articulated arm CMM 100 moved around several axes of rotation. As already mentioned, each storage unit grouping comprises 110 . 112 . 114 corresponding encoder systems such as optical encoders, each coaxial with the corresponding axis of rotation z. B. the arm segments 106 . 108 are arranged. The optical encoder system detects a rotational movement (pivotal movement) or transverse movement (joint movement) of, for example, each of the arm segments 106 . 108 about the corresponding axis and transmits a signal to an electronic data processing system in the articulated arm CMM 100 as will be described in more detail below. Each individual unprocessed encoder count is sent separately as a signal to the electronic data processing system where it is further processed into measurement data. It is not one of the articulated arm CMM 100 even separate position calculator (eg a serial box) as required in the U.S. Patent No. 5,402,582 ('582) of the same assignee.

The lower part 116 may be a fastening or mounting device 120 include. The mounting device 120 allows removable mounting of the articulated arm CMM 100 at a desired location, such as an inspection table, a machining center, a wall or the floor. The lower part 116 in one embodiment comprises a handle portion 122 which provides a convenient location at which the operator the lower part 116 can hold while the articulated arm CMM 100 is moved. In one embodiment, the base comprises 116 Further, a movable cover portion 124 which is foldable to release a user interface, such as a screen.

According to one embodiment, the lower part contains or harbors 116 Portable Articulated Arm CMM 100 an electronic circuit comprising an electronic data processing system comprising two primary components: a base processing system which stores the data of the various encoder systems in the articulated arm CMM 100 and processing data representing other arm parameters to support three-dimensional (3D) position calculations; and a user interface processing system that includes an integrated operating system, a touch-sensitive display, and resident application software that facilitates the implementation of relatively complete metrology functions within the articulated arm CMM 100 without having to connect to an external computer.

The electronic data processing system in the lower part 116 Can with the encoder systems, sensors and other peripheral hardware, the remote from the base 116 is arranged (for example, a strip light device, the removable handle 126 on the articulated arm CMM 100 can be mounted), communicate. The electronics that support these peripheral hardware devices or features can be found in any of the portable articulated arm CMMs 100 arranged camp use groupings 110 . 112 . 114 are located.

2 FIG. 12 is a block diagram of the electronics that are used in an articulated arm CMM according to one embodiment 100 is used. In the 2A illustrated embodiment includes an electronic data processing system 210 that is a base processor card 204 for implementing the base processing system, a user interface card 202 , a basic energy card 206 to provide energy, a Bluetooth module 232 and a base pitch card 208 includes. The user interface card 202 includes a computer processor for executing the application software to execute the user interface, the screen, and other functions described herein.

As in the 2A and 2 B can be seen is the electronic data processing system 210 over one or more Armbusse 218 with the aforementioned multiple encoder systems in combination. Each encoder system generates at the in 2 B and 2C 1 and 2 illustrates encoder data and includes: an encoder arm interface 214 , a digital coder signal processor (DSP) 216 , an encoder readhead interface 234 and a temperature sensor 212 , Other devices, such as strain sensors, can attach to the arm 218 be connected.

In 2D is also the probe-end electronics 230 shown with the arm 218 communicates. The probe-end electronics 230 includes a probe-end DSP 228 , a temperature sensor 212 , a handle / device interface bus 240 in one embodiment, via the quick connect connector to the handle 126 or the coded strip light scanner device 242 connected, and a probe interface 226 , The quick connector allows access to the handle 126 to the data bus, control lines, from the encoded stripe light scanner device 242 used power bus and other accessories. The probe-end electronics 230 in one embodiment is in the probe housing 102 on the articulated arm CMM 100 arranged. The handle 126 can be removed from the quick connect connector in one embodiment, and the measurement can be made with the strip light device 242 via the interface bus 240 with the probe-end electronics 230 the articulated arm CMM 100 communicates. In one embodiment, the electronic data processing system 210 in the lower part 116 the articulated arm CMM 100 , the probe-end electronics 230 in the probe housing 102 the articulated arm CMM 100 and the encoder systems in the bearing cartridge assemblies 110 . 112 . 114 arranged. The probe interface 226 may, by any suitable communication protocol, include the commercially available products of Maxim Integrated Products, Inc. as a 1- ^Wire® communication protocol 236 are formed with the probe-end DSP 228 get connected.

3 is a block diagram showing the detailed features of the electronic data processing system 210 the articulated arm CMM 100 according to one embodiment. The electronic data processing system 210 is in one embodiment in the lower part 116 the articulated arm CMM 100 arranged and includes the base processor card 204 , the user interface card 202 , a basic energy card 206 , a Bluetooth module 232 and a base tilt module 208 ,

At an in 3A The embodiment shown includes the base processor card 204 the various functional blocks presented there. A basic processor function 302 For example, it is used to acquire the measurement data of the articulated arm CMM 100 to support and receive over the arm 218 and a bus control module function 308 unprocessed arm data (eg, encoder system data). The memory function 304 stores programs and static arm configuration data. The base processor card 204 further includes a port function provided for an external hardware option 310 to interface with any external hardware devices or accessories, such as a coded strip light scanner device 242 , to communicate. A real-time clock (RTC) and a protocol 306 , a battery pack interface (IF; interface) 316 and a diagnostic port 318 are in one embodiment of in 3A pictured base processor card 204 also included in the functionality.

The base processor card 204 also manages all the wired and wireless data communication with external (host computer) and internal (screen processor 202 ) Devices. The base processor card 204 is able to have an ethernet function 320 with an Ethernet network (eg, using a clock synchronization standard, such as IEEE (Institute of Electrical and Electronics Engineers) 1588) via a LAN function 322 with a Wireless Local Area Network (WLAN) and a Parallel-to-Serial Communication (PSK) feature 314 with a Bluetooth module 232 to communicate. The base processor card 204 further includes a connection to a universal serial bus device (USB) 312 ,

The base processor card 204 transmits and collects unprocessed measurement data (eg encoder system counts, temperature measurements) for processing into measurement data without the need for any preprocessing, such as in the serial box of the former Patents' 582 is disclosed. The base processor 204 sends the processed data via an RS485 interface (IF) 326 to the screen processor 328 on the user interface card 202 , In one embodiment, the base processor sends 204 also the unprocessed measurement data to an external computer.

Referring now to the user interface card 202 in 3B are the angle and position data received from the base processor on the screen processor 328 used applications to provide an autonomous metrological system in the articulated arm CMM 100 provide. The applications can be on the screen processor 328 Among other things, it can be used to support, among other things, the following functions: measurement of features, instructional and training graphics, remote diagnostics, temperature corrections, control of various operating characteristics, connection to different networks and display of measured objects. The user interface card 202 includes along with the screen processor 328 and a user interface for a liquid crystal display (LCD screen) 338 (such as a touch-sensitive LCD screen) have multiple interface options, including a Secure Digital Card (SD Card) Interface 330 , a store 332 , a USB host interface 334 , a diagnostic port 336 , a camera port 340 , an audio / video interface 342 , a dial-up / wireless modem 344 and a port 346 belong to the Global Positioning System (GPS).

This in 3A pictured electronic data processing system 210 further includes a base energy card 206 with an environment recorder 362 for recording environmental data. The basic energy card 206 also provides energy for the electronic data processing system 210 ready, being an AC to DC converter 358 and a battery charger controller 360 be used. The basic energy card 206 is via a serial single-ended bus 354 having an Inter-Integrated Circuit (I2C) and a Serial DMA Peripheral Interface (DSPI) 357 with the base processor card 204 in connection. The basic energy card 206 is via an input / output extension function (I / O expansion function) 364 that are in the base energy card 206 is implemented, with a tilt sensor and a radio frequency identification module (RFID module) 208 connected.

Although depicted as separate components, all or a subset of the components in other embodiments may be physically located at various locations and / or may perform functions other than those described in U.S. Patent Nos. 4,674,866 3A and 3B be shown combined. For example, the base processor card 204 and the user interface card 202 combined in one embodiment in a physical map.

Well with respect to the 4 - 9 is an exemplary embodiment of a probe end 401 with a probe housing 102 is shown with a mechanical and electrical quick connector connection, the coupling of a removable and replaceable device 400 to the articulated arm CMM 100 allowed. In the exemplary embodiment, the device comprises 400 a housing 402 which has a handle section 404 which is sized and shaped to be held in the hand of an operator, such as a piston handle. The housing 402 is a thin-walled structure with a cavity 406 ( 9 ). The cavity 406 is sized and executed to be a controller 408 can record. The controller 408 may be a digital circuit, for example with a microprocessor, or an analog circuit. In one embodiment, the controller communicates 408 asynchronous and bidirectional with the electronic data processing system 210 ( 2 and 3 ). The communication connection between the controller 408 and the electronic data processing system 210 can be wired (eg via the controller 420 ), or it may be a direct or indirect wireless connection (eg Bluetooth or IEEE 802.11), or a combination of a wired and a wireless connection. In the exemplary embodiment, the housing is 402 in two halves 410 . 412 formed, for example, from an injection-molded plastic material. The halves 410 . 412 can by fasteners, such as Example screws 414 , be attached to each other. In other embodiments, the housing halves 410 . 412 For example, by adhesives or ultrasonic welding to be attached to each other.

The grip section 404 also includes buttons or actuators 416 . 418 which can be manually activated by the operator. The actuators 416 . 418 are to the controller 408 coupled to a controller 420 inside the probe housing 102 transmits a signal. In the exemplary embodiments, the actuators result 416 . 418 the functions of the actuators 422 . 424 , out, on the probe housing 102 opposite the device 400 are arranged. It can be seen that the device 400 may include additional switches, buttons or other actuators, which may also be used to the device 400 , the articulated arm CMM 100 , or vice versa. The device 400 For example, it may also include display devices such as light emitting diodes (LEDs), sounders, gauges, displays, or gauges. In one embodiment, the device 400 a digital voice recorder that allows the synchronization of verbal comments with a measured point. In yet another embodiment, the device comprises 400 a microphone that allows the operator to voice commands to the electronic data processing system 210 transferred to.

In one embodiment, the handle portion 404 be configured so that it can be used with each operator's hand or with a particular hand (eg, left hand or right hand). The grip section 404 may also be configured to be operated by operators with disabilities (eg, operators lacking fingers or operators with an arm prosthesis). Furthermore, the handle portion 404 removed and the probe housing 102 be used alone, if the space conditions are cramped. As discussed above, the probe end 401 also the shaft of the seventh axis of the articulated arm CMM 100 exhibit. In this embodiment, the device 400 be arranged so that it rotates about the seventh axis of the articulated arm CMMs.

The probe end 401 includes a mechanical and electrical interface 426 with a first connector 429 ( 8th ) on the device 400 that with a second connector 428 on the probe housing 102 interacts. The connectors 428 . 429 may include electrical and mechanical features that facilitate coupling of the device 400 to the probe housing 102 allow. In one embodiment, the interface comprises 426 a first surface 430 with a mechanical coupler 432 and an electrical connector disposed thereon 434 , The housing 402 also includes a second surface 436 that are adjacent to the first surface 430 and offset to this position. In the exemplary embodiment, the second surface is 436 a planar surface spaced about 1.27 cm (0.5 inches) from the first surface 430 is offset. This offset creates space for the operator's fingers when using a fastener, such as a collar 438 , attracts or releases. the interface 426 creates a relatively fast and secure electronic connection between the device 400 and the probe housing 102 without the need to align connector pins and without the need for separate cables or connectors.

The electrical connector 434 extends from the first surface 430 and includes one or more connector pins 440 asynchronously bidirectional with the electronic data processing system 210 are electrically coupled ( 2 and 3 ), such as one or more armlets 218 , The bi-directional communication link may be (eg via the arm 218 ) be wired, wireless (eg Bluetooth or IEEE 802.11) or a combination of a wired and a wireless connection. In one embodiment, the electrical connector 434 electrically to the controller 420 coupled. The controller 420 can be asynchronously bidirectional with the electronic data processing system 210 communicate, such as through one or more armles 218 , The electrical connector 434 is positioned so that there is a relatively fast and secure electronic connection to the electrical connector 442 on the probe housing 102 offers. The electrical connectors 434 . 442 are connected together when the device 400 on the probe housing 102 is appropriate. The electrical connectors 434 . 442 For example, each may have a metal sheathed connector housing that provides shielding against electromagnetic interference and protects the connector pins, as well as when mounting the device 400 on the probe housing 102 supports the alignment of the pens.

The mechanical coupler 432 creates a relatively rigid mechanical coupling between the device 400 and the probe housing 102 to support relatively precise applications where the position of the device 400 at the end of the arm section 104 the articulated arm CMM 100 preferably not moving or moving. Any such movement may typically result in undesirable degradation of the accuracy of the measurement result. These desired results are obtained using various structural features of the mechanical attachment configuration portion of the mechanical and electronic quick connector terminal of an embodiment of the present invention achieved.

In an embodiment, the mechanical coupler comprises 432 a first advantage 444 that at one end 448 (the leading edge or the "face" of the device 400 ) is positioned. The first advantage 444 may include a rounded, notched, or slanted interface that has an edge 446 forms, extending from the first projection 444 extends. The edge 446 is sized to fit in a slot 450 can be absorbed by a projection 452 is defined, extending from the probe housing 102 extends ( 8th ). It can be seen that the first projection 444 and the slot 450 together with the collar 438 form a coupler arrangement, so that when the edge 446 inside the slot 450 is positioned, the slot 450 can be used to both the longitudinal and the lateral movement of the device 400 restrict if this on the probe housing 102 is appropriate. As will be discussed in more detail later, the rotation of the collar can 438 used to the edge 446 inside the slot 450 to secure.

Opposite the first lead 444 can the mechanical coupler 432 a second projection 454 include. The second projection 454 can have a rounded, notched or inclined interface surface 456 exhibit ( 5 ). The second projection 454 is positioned so that it fits into the probe housing 102 associated fastening device, such as the collar 438 , engages. As will be discussed in more detail later, the mechanical coupler includes 432 a raised surface from the surface 430 protrudes, which connects to the electrical connector 434 adjoins or is arranged around this, which is a pivot point for the interface 426 offers ( 7 and 8th ). This serves as the third of three points of mechanical contact between the device 400 and the probe housing 102 when the device 400 attached to it.

The probe housing 102 includes a collar 438 coaxially disposed at one end. The collar 438 includes a threaded portion that is movable between a first position (FIG. 5 ) and a second position ( 7 ) is movable. By turning the collar 438 can the collar 438 used to the device 400 to fix or release, without external tools are necessary. Turning the collar 438 moves the collar 438 along a relatively coarse cylinder 474 with square thread. The use of such large contoured surfaces with square thread allows a significant clamping force with a minimum torque. The rough pitch of the threads of the cylinder 474 further allows the collar 438 can be tightened or loosened by minimal rotation.

To the device 400 to the probe housing 102 to couple, the edge becomes 446 in the slot 450 introduced and the device pivoted to the second projection 454 to the surface 458 turn around as indicated by the arrow 464 is displayed ( 5 ). The collar 438 is turned, causing the collar 438 in the direction of the arrow 462 displayed direction moves or moves and with the surface 456 engages. The movement of the collar 438 against the angled surface 456 drives the mechanical coupler 432 against the raised surface 460 , This can overcome any potential problems regarding the distortion of the interface or foreign objects on the surface of the interface, which is the rigid seat of the device 400 on the probe housing 102 be assisted. The force applied through the collar 438 on the second lead 454 causes the mechanical coupler 432 moved forward, taking the edge 446 into a seat on the probe housing 102 pressed. While the collar 438 is further tightened, the second projection 454 upwards towards the probe housing 102 pressed, whereby pressure is exerted on a fulcrum. As a result, a kind of rocker arrangement is created, the pressure on the second projection 454 , the edge 446 and applies the center pivot point to move or wobble the device 400 to reduce or prevent. The pivot presses directly against the ground on the probe housing 102 while the edge 446 a downward force on the end of the probe housing 102 exercises. 5 includes arrows 462 . 464 to the direction of movement of the device 400 and the collar 438 to show. 7 includes arrows 466 . 468 . 470 To determine the direction of the applied pressure within the interface 426 to show when the collar 438 is attracted. It can be seen that the distance of the offset of the surface 436 the device 400 a gap 472 between the collar 438 and the surface 436 creates ( 6 ). The gap 472 allows the operator to have a firmer grip on the collar 438 while preserving the danger of pinching fingers while turning the collar 438 is reduced. In one embodiment, the probe housing 102 sufficient rigidity to reduce the distortion or prevent when the collar 438 is attracted.

Embodiments of the interface 426 allow the correct alignment of the mechanical coupler 432 and the electrical connector 434 and also protect the electronics interface from applied strains that otherwise due to the clamping action of the collar 438 , the edge 446 and the surface 456 could occur. This creates the advantage of damaging the on a circuit board 476 mounted electrical connectors 434 . 442 , which may have soldered terminals, can be reduced or prevented by loading. The embodiments also offer the advantage over known approaches that a user does not need any tools to handle the device 400 with the probe housing 102 to connect or disconnect from this. This allows the operator to use the device 400 manually with the probe housing 102 relatively easy to connect or disconnect.

Due to the relatively high number of shielded electrical connections with the interface 426 are possible, can the articulated arm CMM 100 and the device 400 share a relatively large number of features. For example, switches, buttons, or other actuators that attach to the articulated arm CMM 100 are used to the device 400 to control, or vice versa. Furthermore, commands and data from the electronic data processing system 210 to the device 400 be transmitted. In one embodiment, the device is 400 a video camera, the data of a recorded image for storage in a memory in the base processor 204 or to display on the screen 328 transfers. In another embodiment, the device 400 an image projector that retrieves data from the electronic data processing system 210 receives. Also, either in the articulated arm CMM 100 or in the device 400 arranged temperature sensors are shared with the other one. It will be appreciated that embodiments of the present invention provide the advantage of providing a flexible interface that enables a wide variety of accessory devices 400 Fast, easy and reliable on the articulated arm CMM 100 to pair. Furthermore, the possibility of sharing functions through the articulated arm CMM 100 and the device 400 to reduce the size, power consumption and complexity of the articulated arm CMM 100 lead by having to exist only once.

In one embodiment, the controller 408 the operation or functionality of the probe end 401 the articulated arm CMM 100 to change. For example, the controller 408 Indicator lights on the probe housing 102 change so that either a light of a different color or a different light intensity is emitted, or that the light is turned on and off at other times when the device 400 attached, in contrast to the situation in which the probe housing 102 used alone. In one embodiment, the device comprises 400 a rangefinder sensor (not shown) that measures the distance to an object. In this embodiment, the controller 408 Indicator lights on the probe housing 102 to give the operator an indication of how far the object is from the probe tip 118 is removed. In another embodiment, the controller 408 change the color of the indicator lights based on the quality of the image captured by the encoded stripe light scanner device. This creates advantages in that the requirements of the controller 420 be simplified and allows for improved or higher functionality by adding accessory devices.

With reference to the 10 - 13 Embodiments of the present invention provide advantages in terms of projector interface, camera, signal processing, control, and display for a non-contact, three-dimensional measurement device 500 , The device 500 includes a pair of optical devices, such as a light projector 508 and a camera 510 which project a striped light pattern and receive a two-dimensional pattern from an object 501 has been reflected. The device 500 uses triangulation-based methods based on the known emitted pattern and the captured image to determine a point cloud, the X, Y, Z coordinate data for the object 501 for each pixel of the received image. In one embodiment, the stripe light pattern is coded so that a single image is sufficient to determine the three-dimensional coordinates of object points. It can also be said that such a coded stripe light pattern measures three-dimensional coordinates in a single shot.

In the exemplary embodiment, the projector uses 508 a visible light source that illuminates a pattern generator. The visible light source may be a laser, a super-radiating diode, an incandescent light, a light-emitting diode (LED) or another light-emitting device. In the exemplary embodiment, the pattern generator is a chrome-on-glass photo with a stripe light pattern etched thereon. The photograph may have a single pattern or patterns moving in and out of position as needed. The photograph can be manually or automatically installed in the operating position. In other embodiments, the source pattern may be light generated by a digital micro-mirror device (DMD) such as a digital light projector (DLP) manufactured by Texas Instruments Corporation, a liquid crystal device (LCD), a liquid crystal Silicon (LCOS) device or similar device is used, reflected or transmitted in the transmission mode rather than the reflection mode. The projector 508 can also be a lens system 515 which changes the outgoing light to have the desired focal characteristics.

The device 500 further comprises a shell 502 with a handle section 504 , In one embodiment, the device 500 also an interface 426 at one end, which comprise the device 500 mechanically and electrically to the probe housing 102 coupled as described hereinabove. In other embodiments, the device may 500 into the probe housing 102 to get integrated. the interface 426 offers advantages in that the device 500 Quick and easy on the articulated arm CMM without the need for additional tools 100 coupled and can be removed from this.

The camera 510 includes a photosensitive sensor that generates a digital image / representation of the area within the field of view of the sensor. The sensor 508 For example, a charge coupled device type sensor or a complementary metal oxide semiconductor (CMOS) type sensor may be used. The camera 510 may also include other components, such as, but not limited to, a lens 503 and other optical devices. In the exemplary embodiment, the projector 508 and the camera 510 arranged at such an angle that the sensor from the surface of the object 501 can receive reflected light. In one embodiment, the projector 508 and the camera 510 positioned so that the device 500 with the attached probe tip 118 can be operated. Furthermore, it can be seen that the device 500 essentially relative to the probe tip 118 is fixed and forces on the grip section 504 the orientation of the device 500 relative to the probe tip 118 do not influence. In one embodiment, the device 500 an additional actuator (not shown) that allows the operator to intercept data from the device 500 and the probe tip 118 switch back and forth.

The projector 508 and the camera 510 are electrically connected to a controller 512 coupled inside the case 502 is arranged. The controller 512 may include one or more microprocessors, digital signal processors, memory and signal conditioning circuits. Because of the digital signal processing and the device 500 generated large data volume, the controller 512 within the grip section 504 to be ordered. The controller 512 is via an electrical connector 434 electrically with the bracelets 218 coupled. The device 500 can also actuators 514 . 516 which can be manually operated by the operator to control the operation and data acquisition by the device 500 initiate. In one embodiment, the image processing for determining the X, Y, Z coordinate data becomes the object 501 performing point cloud through the controller 512 performed, and the coordinate data is transmitted over the bus 240 to the electronic data processing system 210 transfer. In another embodiment, images are sent to the electronic data processing system 210 The coordinates are calculated by the electronic data processing system 210 ,

In one embodiment, the controller is 512 designed with the electronic data processing system 210 to communicate strip light pattern images from the electronic data processing system 210 to obtain. In yet another embodiment, the pattern emitted on the object may be processed by the electronic data processing system 210 be changed either automatically or in response to an input from the operator. This can offer advantages in terms of obtaining more accurate measurements with less processing time by allowing the use of patterns that are easier to decode, if conditions permit, and the use of the more complex patterns, if desired, the degree of accuracy desired To achieve degree of dissolution.

In other embodiments of the present invention, the device comprises 520 ( 12 ) a pair of cameras 510 , The cameras 510 are at an angle relative to the projector 508 arranged to reflect reflected light from the object 501 to recieve. The use of multiple cameras 510 may provide benefits in some applications to provide redundant images to increase the accuracy of the measurement. In still other embodiments, the redundant images may allow sequential patterns to be retrieved from the device 500 be detected quickly by the capture speed of images by alternately operating the camera 510 is increased.

Well with respect to the 13A and 13B becomes the operation of the strip light device 500 described. The device 500 beams first with the projector 508 on the surface 524 of the object 501 a stripe light pattern 522 out. The stripe light pattern 522 may include the patterns disclosed in the journal article "DLP-Based Structured Light 3D Imaging Technologies and Applications" by Jason Geng, published in "Proceedings of SPIE", vol. 7932, herein incorporated by reference is included. The stripe light pattern 522 may also include one of the following in the 14 - 32 include patterns shown. The light 509 from the projector 508 gets off the surface 524 reflected and the reflected light 511 is from the camera 510 receive. It is understood that changes to the surface 524 such as the lead 526 To create distortions in the stripe pattern when the image of the pattern from the camera 510 is detected. Since the pattern is formed by strip light, it is possible in some cases for the controller 512 or the electronic data processing system 210 a one-to-one correspondence between the pixels in the emitted pattern, such as the pixel 513 , and the pixels in the imaged pattern, such as pixels 515 , determine. This allows the use of triangulation principles to determine the coordinates of each pixel in the imaged pattern. The acquisition of three-dimensional coordinates of the surface 524 is sometimes referred to as a point cloud. By moving the device 500 over the surface 524 can be a point cloud of the entire object 501 be generated. It is understood that in some embodiments, coupling the device 500 offers advantages to the probe end in that the position and orientation of the device 500 the electronic data processing system 210 are known, so that the position of the object 501 relative to the articulated arm CMM 100 can also be determined.

To determine the coordinates of the pixel, it is known that the angle of each projected light beam 509 who is the object 522 in one point 527 corresponds to a projection angle phi (Ф), so that Ф information is encoded into the emitted pattern. In one embodiment, the system is configured to enable detection of the Ф value corresponding to each pixel in the mapped pattern. Also known is an angle omega (Ω) for each pixel in the camera, as well as the baseline "D" distance between the projector 508 and the camera. Therefore, the distance "Z" from the camera 510 to the place that mapped the pixel, according to the equation: Z / D = sin (Φ) / sin (Ω + Φ) (1) Thus, three-dimensional coordinates can be calculated for each pixel in the captured image.

In general, there are two categories of strip light, namely coded and uncoded strip light. A common form of uncoded strip light, as in the 14 - 17 and 28 - 30 is based on a striped pattern which varies periodically along one dimension. These types of patterns are normally applied in a sequence to provide an approximate distance to the object. Some embodiments of uncoded patterns, such as the sinusoidal patterns, may provide relatively high accuracy measurements. However, for these types of patterns to be effective, it is usually necessary for the scanner device and the object to be held stationary relative to each other. If the scanner device or object is in motion (relative to each other), then a coded pattern as shown in the FIGS 18 - 27 is shown to be preferred. An encoded pattern allows the analysis of the image using a single captured image. Some encoded patterns may be placed in a particular orientation on the projector pattern (eg, perpendicular to projector plane epipolar lines), thereby simplifying the analysis of the three-dimensional surface coordinates based on a single image.

Epipolar lines are mathematical lines created by cutting epipolar planes and the source plane 517 or the picture plane 521 (the level of the camera sensor) in 13B be formed. An epipolar plane can be any plane passing through the viewer's perspective center 519 and the camera perspective center goes through. The epipolar lines at the source level 517 and the picture plane 521 may be parallel in some cases, but are generally not parallel. One aspect of epipolar lines is that of a given epipolar line at the projector level 517 a corresponding epipolar line on the image plane 521 Has. Therefore, any particular pattern that is on an epipolar line at the projector level 517 is known, immediately in the picture plane 521 be observed and evaluated. For example, if there is a coded pattern along an epipolar line in the projector plane 517 is placed, the space between the coded elements in the image plane 521 using the pixels from the camera sensor 510 be read out. This information can be used to get the three-dimensional coordinates of a point 527 on the object 501 to determine. It is also possible to tilt coded patterns at a known angle with respect to an epipolar line and to effectively extract object surface coordinates. Examples of coded patterns are in the 20 - 29 shown.

In embodiments having a periodic pattern, such as a sinusoidal repeating pattern, the sinusoidal period represents a plurality of pattern elements. Since there are a variety of periodic patterns in two dimensions, the pattern elements are non-collinear. In some In cases, a striped pattern with strips of varying width may represent a coded pattern.

Well with respect to the 14 - 17 Embodiments of uncoded striped light patterns are shown. Some of the patterns use a simple pattern of on-off (or 1.0) type and are referred to as binary patterns. In some cases, the binary pattern is one that is known to have a particular sequence, referred to as a Gray code sequence. The term gray code, as used in the field of three-dimensional metrology based on strip light, is other than the term used in the field of electrical engineering, where the term gray code usually means the sequential change of a single one Bits means. The present application follows the use of the term Gray code, as is common in the field of three-dimensional metrology, where the Gray code typically represents a sequence of binary black and white values. 14A shows an example of a binary pattern, which has multiple sequential images 530 . 532 . 534 each with a different striped pattern on them. Usually the stripes alternate between bright (lighted) and dark (not lighted) striped regions. Sometimes the terms white and black are used to refer to illuminated or not illuminated. So if the pictures 530 . 532 . 534 sequentially on the surface 524 be projected as it is in 14B shown is a composite picture 536 shows. It should be noted that the lower two patterns 535 . 537 out 14B in 14A for the sake of clarity are not illustrated. For every point on the object 501 (represented by a camera pixel in the image) has the composite pattern 536 a unique binary value created by the sequential projection of patterns 530 . 532 . 534 . 535 . 537 which corresponds to a relatively small range of possible projection angles Ф. By using these projection angles together with the known pixel angle Ω for a given pixel and the known baseline distance D, Eq. (1) are used to find the distance Z from the camera to the object point. A two-dimensional angle is known for each camera pixel. The two-dimensional angle generally corresponds to the one-dimensional angle omega used in calculating the distance Z according to Eq. (1) is used. However, a line drawn by each camera pixel through the camera perspective center intersecting the object at a point defines a two-dimensional angle in space. When combined with the calculated value Z, the two pixel angles provide three-dimensional coordinates corresponding to a point on the object surface.

Similarly, instead of a binary pattern, a sequential series of gray patterns with stripes of varying gray level values may be used. When used in this context, the term gray level usually refers to an amount of irradiance at a point on the object from white (maximum light) to different gray levels (less light), to black (minimum light). This same nomenclature is also used when the projected light has a color like red, and the grayscale values correspond to levels of red illumination. In one embodiment, the pattern has ( 15 ) several pictures 538 . 540 . 542 with stripes of varying light output levels, such as black, gray and white, that are used to create a radiated pattern on the object 501 to create. The gray level values can be used to determine the possible projection angles Ф within a relatively small range of possible values. As discussed hereinabove, Eq. (1) can be used to determine the distance Z.

In another embodiment, the distance Z to an object point may be found by measuring a phase shift observed in multiple images. For example, in a vary in 16 shown embodiment, the gray scale intensities 546 . 548 . 550 a projector pattern 552 in a sinusoidal manner but with a phase shift between projected patterns. For example, in the first projector pattern, the sinusoid grayscale intensity 546 (which represents the light output per unit area) at a particular point have a phase of zero degrees. In the second projector pattern has the sinusoidal intensity 548 a phase of 120 degrees at the same point. In the third projector pattern, the sinusoidal intensity 550 have a phase of 240 degrees at the same point. This is like saying that the sinusoidal pattern is shifted to the left (or right) by one-third of a period at each step. A phase shift method is used to determine a phase of the projected light at each camera pixel, which eliminates the need to consider information from adjacent pixels, as in the case of the single shot of the coded pattern. Many methods can be used to determine the phase of a camera pixel. One method involves performing a multiply and summate procedure and then taking an arctangent of a quotient. This method is well known to one of ordinary skill in the art and will not be discussed further. In addition, in the phase shift method, the background light is canceled out in the calculation of the phase. For these reasons, the value Z, which is for a given pixel is calculated, usually more accurately than the value Z, which is calculated using a method of taking a single coded pattern. In a single acquisition of sinusoidal patterns, such as those in 16 are shown, all calculated phases vary from 0 to 360 degrees. In a particular strip light triangulation system, these calculated phases may be sufficient if the "thickness" of the object under test does not vary too much, since the angle for each projected strip is known in advance. However, if the object is too thick, an ambiguity may occur between the phase calculated for a particular pixel, since that pixel may be affected by the first projected light beam striking the object at a first position or a second projected light beam incident on one second position on the object was obtained. In other words, if there is a possibility that the phase may vary by more than 2π radians for each pixel in the camera array, then the phases may not be properly decoded and the desired one-to-one correspondence is not achieved.

17A shows a sequence 1-4 of projected Gray code intensities 554 according to a method by which the ambiguity at the distance Z can be eliminated based on a calculated phase. A collection of Gray code patterns is projected sequentially onto the object. In the example shown there are four sequential patterns on the left side of 554 in 17A are indicated by 1, 2, 3, 4. The sequential pattern 1 is dark (black) in the left half of the pattern (elements 0-15) and light (white) in the right half of the pattern (elements 16-31). The sequential pattern 2 has a dark band toward the center (elements 8-23) and bright bands toward the edges (elements 2-7, 24-31). The sequential pattern 3 has two separate bright bands near the center (elements 4-11, 20-27) and three bright bands (elements 0-3, 12-19, 28-31). The sequential pattern 4 has four separate dark bands (elements 2-5, 10-13, 18-21, 26-29) and five separate bright bands (elements 0-1, 6-9, 14-17, 22-25, 30-31). For any given pixel in the camera, this sequence of patterns allows for an improvement of the "object thickness range" of the object by a factor of 16 as compared to an initial object thickness range corresponding to all elements 0 to 31.

In another process 556 , this in 17C is illustrated, a phase shift method similar to the method 16 executed. In the in 17C embodiment shown becomes a pattern 556A during four sinusoidal periods projected onto an object. For reasons discussed hereinabove, there may be ambiguity in a distance Z to an object using the pattern 17C give. One way to reduce or eliminate the ambiguity is to have one or more additional sinusoidal patterns 556B . 556C to project, each pattern having a different stripe period (distance). For example, in 17B a second sinusoidal pattern 555 projected onto an object with three fringe periods instead of four fringe periods. In one embodiment, the difference in phases may be for the two patterns 555 . 556 can be used to help eliminate ambiguity in the distance Z to the target.

Another method of eliminating ambiguity is to use another type of method, such as the Gray code method 17A to eliminate the ambiguity in the distances Z calculated using the sinusoidal phase shift method.

For applications where the object and the device 500 Moving relative to each other, it may be desirable to use a single pattern, that of the camera 510 allows to capture an image that provides sufficient information about the three-dimensional characteristics of the object 501 to measure without having to project sequential images. Well with respect to the 18 and 19 have the patterns 558 . 566 a distribution of colors, which in some cases allows the measurement of the object based on a single (coded) image. In the embodiment of 18 uses the pattern 558 Lines with a continuously spatially varying wavelength of light to create a pattern in which the color changes continuously, for example, from blue to green to yellow to red to fuchsia. Thus, for each particular spectral wavelength, a one-to-one correspondence may be made between the emitted image and the imaged pattern. With the established correspondence, the three-dimensional coordinates of the object 501 determined by a single imaged pattern. In one embodiment, the stripes are the pattern 558 aligned perpendicular to the epipolar lines at the projector level. Since the epipolar lines on the projector plane are imaged in epipolar lines on the camera stabilizing plane, it is possible to obtain an association between projector points and camera points by moving along the direction of epipolar lines in the camera stabilizing plane and in any case to note the color of the line. It is understood that each pixel in the camera plane corresponds to a two-dimensional angle. The color allows determination of the one-to-one correspondence between particular projection angles and particular camera angles. This correspondence information, combined with the distance between the camera and the projector (the baseline distance D) and the angles of the camera and the projector relative to the baseline, are sufficient to allow the determination of the distance Z from the camera to the object.

Another embodiment using color patterns is in 19 shown. In this embodiment, multiple color patterns with varying intensities 560 . 562 . 564 combined to a color pattern 566 to accomplish. In one embodiment, the plurality of color pattern intensities 560 . 562 . 564 Primary colors, leaving the pattern 560 the intensity of the color red varies, the pattern 562 the intensity of the color green varies and the pattern 564 the intensity of the color blue varies. Since the color ratios are known, the resulting emitted image has a known relationship that can be decoded in the imaged pattern. As in the embodiment of 18 As soon as the correspondence has been established, the three-dimensional coordinates of the object can be determined 501 be determined. Different from the pattern 18 in which a single cycle of unique colors is projected, the pattern projects 19 three complete cycles of almost identical colors. In the pattern of 18 There is a small possibility of ambiguity in the measured distance Z (at least in the case where the projected lines are perpendicular to epipolar lines), since each camera pixel recognizes a particular color, which alone corresponds to a particular projection direction. Since the camera angle and the projection angles are known, the triangulation can be used to determine the three-dimensional object coordinates at each pixel position using only a single camera image. This can make the process 18 be considered as a coded method with a picture. In contrast, there are in 19 a possibility of ambiguity in the distance Z to an object point. For example, if the camera sees a purple color, the projector may have projected from three different angles. Based on the triangulation geometry, three different distances Z are possible. If it is known in advance that the thickness of the object is within a relatively small value range, then it may be possible to eliminate two of the values, thereby obtaining three-dimensional coordinates in a single shot. In the general case, however, it would be necessary to use additional projected patterns to eliminate the ambiguity. For example, the spatial period of the color pattern may be changed and then used to illuminate the object a second time. In this case, this method of projected fringe light is regarded as a sequential method and not a coded method with a picture.

Well with respect to the 20 - 23 For example, coded stripe light patterns are shown for a single image capture based on a stripe indexing technique. In the embodiments 20 and 21 become patterns with color stripes 568 . 570 from the projector 508 broadcast. This technique utilizes a characteristic of image sensors where the sensor has three independent color channels, such as red, green, blue or cyan, yellow, magenta. The combinations of values generated by these sensor channels can yield a large number of color patterns. As in the embodiment of 19 If the ratio of the color distribution is known, therefore, the relationship between the emitted patterns and the imaged pattern can be determined, and the three-dimensional coordinates can be calculated. Still other types of color patterns may be used, such as a pattern based on the De Bruijn sequence. The stripe indexing techniques and De Bruijn sequence are well known to one of ordinary skill in the art and therefore will not be discussed further.

In the embodiments of the 22 and 23 a strip indexing technique without color is used. In the embodiment of 22 represents the pattern 572 Groups of strips with multiple intensity levels (grayscale levels) and different widths ready. As a result, a particular group of stripes within the overall picture has a unique grayscale pattern. Due to the uniqueness of the groups, a one-to-one correspondence between the emitted pattern and the imaged pattern can be determined about the coordinates of the object 501 to calculate. In the embodiment of 23 represents the pattern 574 a set of strips with a segmented pattern ready. Since each line has a unique segment design, the correspondence between the emitted pattern and the imaged pattern can be determined to be the coordinates of the object 501 to calculate. In the 20 - 23 Additional benefits can be achieved by aligning the projected lines 572 . 574 perpendicular to epipolar lines, such that in the camera plane, since this facilitates the determination of a second dimension in finding the one-to-one correspondence between the camera and projector patterns.

Well, with respect to the 24 - 27 shown encoded strip light patterns using a two-dimensional space grid patterning technique. These pattern types are arranged such that a subwindow, such as the window 576 on the pattern 578 , is unique relative to other subwindows within the pattern. In the embodiment of 24 becomes a binary structured pseudo-random pattern 578 used. The pattern 578 uses a grid with elements, such as revolve 579 that form the coded pattern. It is understood that elements with other geometric shapes can also be used, such as, for example, squares, rectangles, and triangles. In the embodiment of 25 is a pattern 580 of a multi-valued pseudo-random structure, each of the numerical values being an assigned form 582 Has. These forms 582 form a unique subwindow 584 which allows a correspondence between the emitted pattern and the imaged pattern to the coordinates of the object 501 to calculate. In the embodiment of 26 is the grid 586 color-coded with stripes perpendicular to the projector plane. The pattern off 26 does not necessarily provide a pattern that can be decoded in a single shot, but the color information can help simplify the analysis. In the embodiment of 27 becomes a structure 588 of colored shapes, such as squares or circles, used to form the pattern.

Well with respect to the 28A - 28B is an exemplary sinusoidal pattern 720 shown. In one embodiment, the lines are 734 perpendicular to epipolar lines at the projector level. The sinusoidal pattern 720 consists of thirty lines 722 , which are repeated once, to a total number of lines 722 to get from sixty. Every line 722 has a sinusoidal characteristic 723 which is about 180 degrees out of phase with the overlying line and the underlying line. This serves to make the lines 722 as close as possible to each other, and it also allows a greater depth of field, as the lines on the projected surface or the captured image can be blurred and still be recognized. Every single line 722 can be uniquely decoded using only the phase of this line, where the line length must be at least one wavelength of the sinusoid.

Because the pattern 720 it would generally cause ambiguity in line identification. However, this problem is solved in this system by the geometry of the field of view and the depth of field of the camera. For a single view of the camera, ie a series of pixels within the depth of field in which the lines can be visually resolved, two lines with the same phase can not be imaged. For example, the first row of pixels on the camera can only receive reflected light from lines 1-30 of the pattern. On the other hand, further down the camera sensor, another row receives only reflected light from lines 2-31 of the pattern, etc. In 28B is an enlarged section of the pattern 720 shown by three lines, with the phase between successive lines 722 is about 180 °. It is also shown how the phase of each individual line is sufficient to unambiguously decode the lines.

Well with respect to the 29A - 29B is another pattern 730 shown with rectangular pattern elements. In one embodiment, the lines are 732 perpendicular to epipolar lines at the projector level. The rectangular pattern 730 contains 27 lines 732 before the pattern 730 is repeated, and has a total number of lines of 59. The code elements 734 of the pattern 730 be through the phase of the square wave from left to right in 29B distinguished.The pattern 730 is so encrypted that a group of sequential lines 732 is distinguished by the relative phases of its elements. Within the image, sequential lines are found by scanning the lines vertically. In one embodiment, vertical scanning means scanning along epipolar lines in the camera plane. Sequential lines within a vertical camera pixel column are paired and their relative phases determined. Four sequential paired lines are required to decode the group of lines and those within the pattern 730 to locate. There is also an ambiguity in this pattern 730 due to the repetition, but this is also done in a similar way as above with respect to the sinusoidal pattern 720 discussed solved. 29B shows an enlarged view of four lines 732 of the rectangular pattern. This embodiment shows that the phase of a single line 732 alone is not able to uniquely decode a line, since the first and third lines have the same absolute phase.

This approach to encoding the relative phases over the absolute phases offers advantages in that there is a higher tolerance for the positions of the phases. Minor errors in the design of the projector, which can cause the phases of the lines to be shifted through the entire depth of field of the camera, as well as errors due to the projector and camera lenses make it extremely difficult to determine an absolute phase. This can be overcome in the absolute phase method by increasing the period so that it is sufficiently large to overcome the error in determining the phase.

It is understood that for the case of a two-dimensional pattern projecting a coded light pattern, the three non-collinear pattern elements are recognizable by their codes, and since they are projected in two dimensions, the at least three pattern elements are non-collinear. In the case of the periodic pattern, such as the sinusoidal repeating pattern, each sinusoidal period represents several pattern elements. Since there are a plurality of periodic patterns in two Dimensions, the pattern elements are non-collinear. In contrast, in the case of the laser line scanner emitting a light line, all the pattern elements are in a straight line. Although the line has a width and the trailing portion of the cross section of the line may have a lower light output than the peak of the signal, these aspects of the line are not evaluated separately in determining surface coordinates of an object and therefore do not constitute separate pattern elements Line may contain several pattern elements, these pattern elements are collinear.

Furthermore, the various patterning techniques as in the 30 - 31 be combined to be either a binary ( 30 ) uncoded checkerboard pattern 590 or a colored ( 31 ) uncoded checkerboard pattern 592 to build. In yet another embodiment, which is in 32 can be used, a photometric stereo technique can be used with multiple images 594 on the object 501 be absorbed, the light source 596 is moved to several places.

Now referring to 33 is another embodiment of a system 700 for capturing three-dimensional coordinates of an object 702 shown. In this embodiment, the device 704 independently operable when removed from the articulated arm CMM 100 is removed. The device 704 includes a controller 706 and possibly an ad 708 , The ad 708 can in the case of the device 704 integrated or a separate component attached to the device 704 is coupled when independent of the articulated arm CMM 100 is used. In embodiments where the display 708 from the device 704 is removable, the ad can 708 include a controller (not shown) that provides additional functionality to enable independent operation of the device 704 to facilitate. In one embodiment, the controller is 706 arranged inside the detachable display.

The controller 706 includes a communication circuit configured to receive data, such as images or coordinate data, over a communication link 712 wirelessly to the articulated arm CMM 100 , to a separate arithmetic unit 710 or to transmit a combination of both. The computing device 710 This can be, for example, a computer, a laptop, a tablet computer, a personal digital assistant (PDA) or a mobile phone. The ad 708 may allow the operator to capture the captured images or the point cloud of captured coordinates of the object 702 to see. In one embodiment, the controller decodes 706 the patterns in the captured image to determine the three-dimensional coordinates of the object. In another embodiment, the images are from the device 704 and either to the articulated arm CMM 100 , the computing device 710 or a combination of both.

The device 704 may further include a jig assembly 714 include. The attitude device assembly may include one or more inertial navigation sensors, such as a Global Positioning System (GPS) sensor, a gyroscopic or gyro sensor, or an accelerometer sensor. Such sensors can be electrically connected to the controller 706 be connected. Gyro and accelerometer sensors can be single axis or multi-axis devices. The layout setup 714 is designed to be the controller 706 to allow the orientation of the device 704 to measure or maintain when moving from the articulated arm CMM 100 is removed. A gyroscope within the jig assembly 714 may be a gyroscopic MEMS device, a solid state ring laser device, a fiber optic gyroscope device, or other type.

When the device 704 from the articulated arm CMM 100 A method is used to combine images obtained from multiple scans. In one embodiment, the images are each obtained by using coded patterns, so that only a single image is required to obtain three-dimensional coordinates corresponding to a particular position and orientation of the device 704 assigned. One way, several from the device 704 Combining captured images is to provide at least some overlap between adjacent images so that point cloud features can be customized. This adaptation function can be assisted by the inertial navigation devices described above.

Another method that can be used to accurately register images taken by the device 704 to support, is the use of reference markers. In one embodiment, the fiducial markers are small markers with an adhesive or adhesive support, for example, circular markers placed on an object to be measured or on objects. Even a relatively small number of such markers may be useful in registering multiple images, particularly if the measured object has a relatively small number of features to use for registration. In one embodiment, the fiducial markers may be projected as spots of light onto the object or objects to be examined. For example, a small portable projector that can emit several small dots may be in front of the one to be measured Object or objects are placed. An advantage of projected dots over sticky dots is that the dots do not have to be attached and later removed.

In one embodiment, the device projects the strip light over a continuous and enclosed area 716 and can take a picture about the area 716 within a range of 100 mm to 300 mm with an accuracy of 35 microns. In one embodiment, the vertical projection area is 716 in about 150-200 mm ² . At the camera or the cameras 510 It can be a digital camera with a 1.2-5.0 megapixel CMOS or CCD sensor.

Referring to 28 and 29 the method of decoding a coded pattern will be described. The first step in decoding an image of the pattern is to set the centers of gravity (cog) 724 ( 28C ) of the features of the projected pattern 720 to extract in the Y direction. This is done by calculating a moving average of the pixel grayscale values and moving down in the Y direction by processing each one column. When a pixel value in an image is above the moving average, a starting point for a feature is found. After a starting point is found, the width of the feature continues to increase until a pixel value falls below the moving average. Then, using the pixel values and their Y-positions between the starting point and the end point, a weighted average is calculated to calculate the cog 724 of the pattern feature 723 to surrender in the picture. The distances between the starting and ending points are also recorded for later use.

The resulting cogs 724 will be used next to the pattern lines 722 to find. This is done by moving from left to right (as seen from the direction shown in the figures) starting with the first column of the image. At every cog 724 in this column, the adjacent column immediately to the right after a cog 724 searched within a certain distance. If two matching cogs 724 were found, a potential line was determined. As the process progresses across the image, more new lines are determined and other previously determined lines are lengthened when additional cogs 724 be found within the tolerance. Once the entire image has been processed, a filter is applied to the extracted lines to ensure that only lines of a desired length corresponding to the wavelength of the pattern are used in the remaining steps. 28C also shows the recognized lines, all being longer than a single wavelength of the pattern. In one embodiment, there is no or a small delta between the cogs of adjacent columns.

The next step in the decoding process is to extract the projected pattern features along the X-direction lines in the form of block centers. Each pattern contains both wide blocks and narrow blocks. In the sinusoidal pattern 720 this concerns the peaks and valleys of the wave, and in the rectangular pattern 730 this concerns the wide rectangles and the narrow rectangles. This process continues similarly to the extraction of the features in the Y direction, however, the moving average is also calculated using the widths found in the first stage, and the moving direction is along the line. As described above, the features are extracted in the area where widths are above the moving average, but in this process, features are also extracted in the areas where the widths are below the moving average. The widths and the X positions are used to calculate a weighted average around the center of the block 726 to find out in the X direction. The Y positions of the cogs 724 between intersections of moving averages are also used to form a center for the block 726 in the Y direction. This is done by taking the average of the Y coordinates of the cogs. The starting and ending points of each line are also modified based on the features extracted in this step to ensure that both points are where the intersection of the moving averages occurs. In one embodiment, only complete blocks are used in the later processing steps.

The lines and blocks are then further processed to ensure that the distance between the block centers 726 on each line lies within a predetermined tolerance. This is done by taking the delta between the X center positions between two adjacent blocks on a line and checking that the delta is below the tolerance. If the delta is above the tolerance, the line is broken into smaller lines. If the break between the last two blocks on a line is required, the last block is removed and no additional line is created. If the break between the first and second or second and third blocks on a line is required, the blocks to the left of the break are also discarded and no additional line is created. In situations where the break occurs elsewhere along the line, the line becomes broken into two lines and a new line is created and the appropriate blocks are transferred to them. After this processing stage, the two patterns require different steps to complete the decoding.

The sinusoidal pattern 720 can now be decoded with an additional step of processing using the block centers on the lines. The modulus of each block X center and the wavelength of the pattern 720 on a line 722 are calculated and the average of these values gives the phase of the line 722 , The phase of the line 722 can then be used to draw the line in the pattern 720 decoding, which in turn determines an X, Y, Z coordinate position for all cogs 724 on this line 722 allowed.

Before the square pattern 730 decodes are first lines 732 connected vertically before any decoding can take place. This allows the identification of a group of lines, not just a single line, such as the sinusoidal pattern. It will be using the blocks 734 and the cogs contained in the block calculated in the first processing stage, connections 736 between lines 732 found. The first cog in every block on a line 732 is checked to find out if there is another cog immediately below it in the same column. If there is no cog below, there is no connection to another line at that point, so processing continues. If there is a cog below, the y-distance between the two cogs is determined and compared to a desired maximum distance between lines. If the distance is less than this value, the two lines are considered connected at that point, and the connection 736 is stored and processing continues to the next block. In one embodiment, a line connection is 736 unique, so no two lines more than one connection 736 between them.

The next step of processing the rectangular pattern 730 consists in the phase calculation between connected lines. Every pair of lines 732 is first processed to determine the length of the overlap between them. In one embodiment, there is at least one overlapping wavelength between the pair of lines to allow the calculation of the relative phase. If the lines have the desired overlap, the cog is determined at the center of the overlap area. The blocks 738 , which contain the center cog and the cog directly below, are determined, and the relative phase between the block X centers is calculated for this line connection. This process is repeated for all connections between lines. In one embodiment, the process is repeated only in the down direction on the Y axis. The reason for this is that the code is based on bindings below lines, and not vice versa or both. 29C shows the blocks 738 which could be used to calculate the relative phase for this set of lines. The relative phases in the embodiment 29C are 3, 1 and 2, and these phases would be used in the last stage to decode the top line.

The next step in decoding the rectangular pattern 730 is to perform a lookup using the relative phases calculated in the previous step. Every line 732 is done by tracking the line connections 736 processed until a connection depth of four is reached. This depth is used because this is the number of phases to decode the line. At each level the connection is made using the relative phase between the lines 732 definitely a hash. When the required connection depth is reached, the hash is used to look up the line code. When the hash issues a valid code, it is recorded and stored in a voting system. Every line 732 is processed in this way and all connections that have the desired depth are used to generate a voice if they are a valid phase combination. The final step is to find out which code has the most votes on each line 732 has received and the code of the line 732 assigned to this value. If there is no unique code that has received the most votes, no code is assigned to the line. The lines 732 are identified once a code has been assigned, and the X, Y, Z coordinate position for all cogs on that line 732 can now be found out.

It should be noted that although the above descriptions between line scanners and area scanners (strip light scanners) differ based on whether three or more pattern elements are collinear, it should be understood that the intent of this criterion is to distinguish between patterns that are designated as areas and projected as lines. Thus, patterns that are projected in a linear fashion and have information only along a single path are still line patterns, even though the one-dimensional pattern may be curved.

One difficulty sometimes encountered when making measurements with a triangulation scanner attached to the end of an articulated arm CMM is that edges are not very sharp. In other words, the edge may have a radius or bevel exhibit. Such edges may be edges of parts, holes in parts, or sharp aspects of other features. Blurred or inaccurately located edges can appear on line scanners or area scanners. Although the edges seen in the two-dimensional (2D) image of a triangulation scanner may be sharp, the exact distance to the edge may be less secure. Near an edge, a single pixel may have a spacing that is not clearly defined. At a portion of light reflected into the pixel, the light may come from a flat surface. At another portion of the pixel, the distance may be that of adjacent pixels on the side or bottom of a hole, or it may be a far distance in the case of an edge of a part. In most cases, due to lens focus, lens aberrations, and a limited modulation transfer function (MTF), multiple pixels (rather than a single pixel) may correspond to a feature, such as the edge of a hole. In this case, if the point in question is near an edge, the apparent distance to the pixel can not be determined to be a single distance to a point on the object. Sometimes the term "blended pixel" is used to denote the case in which the distance circumscribed to a single pixel on the last image is determined by multiple distances on the object. In such a case, the distance as determined by the triangulation scanner for the pixel in question may be a simple average of the distances over the extent of the pixel. In other cases, the distance as determined by the triangulation scanner may be a completely different value, such as when an "ambiguity range" is exceeded during a triangulation phase shift method. In this case, the distance may be erroneous by an amount that is difficult to predict.

According to one embodiment, one solution to this problem uses the sharp edges that appear in one or more 2D images of the measured feature. In many cases, such edge features can be clearly identified in 2D images, for example based on structural shading. These sharp edges can be determined in coordination with those surface coordinates that are accurately determined using triangulation techniques. By cutting the projected rays passing through the perspective center of the lens in the triangulation scanner with the 3D coordinates of the portion of the surface determined by triangulation methods to a relatively high accuracy, the 3D coordinates of the edge features can be accurately determined.

It will further be understood that edges seen in an image are never absolutely sharp, and so an imperfect edge discontinuity (for example, a fillet) must be relatively wide to be clearly seen by a camera. A position of an imperfect edge can still be computed using methods discussed herein (eg, taking a centroid) to obtain an edge value to a sub-pixel resolution. In other words, even though a camera responds to the width of an edge at a sub-pixel level, the methods given here are still valid because there is generally less uncertainty of position of an edge from a 2D image than from a 3D image which means a relatively higher amount of data noise compared to 2D images. In some cases, the surfaces meet to form a substantially 90 ° angle. In other instances, the surfaces may meet with an interface having an angle of less than 90 ° (eg, 45 °), such as a chamfer or bevel. In other cases, there may be a curved interface, such as a fillet. In other cases, the edge may be "broken", as when the intersection of the surfaces is machined with a file or rasp. The methods disclosed herein apply to edges having these properties. In some embodiments, empirical data may be collected to understand how the edge contrast in the captured image changes under prescribed lighting conditions.

With reference to the 34 - 36 For example, an example of the method described above will be described in more detail for the embodiment having an object with a hole. The camera 508 of the triangulation scanner 3400 captures the image from the projector 510 on the surface of an object and light reflected from the object surface. The reflected rays of light pass through the perspective center 3414 the camera lens 3412 through and onto a photosensitive matrix 3416 inside the camera. The photosensitive matrix sends an electrical signal to an electrical circuit board 3420 comprising a processor for processing digital image data. Using the triangulation method described hereinabove, the processor determines the 3D coordinates for each point on the object surface. It is understood that the projected light may cover an area in a single projected image, or it may cover a more limited area, such as a stripe or a dot. The remarks made here apply to each of these cases.

The method of combining the 2D image captured by a camera, wherein the camera in some embodiments, the camera 508 but in other cases a separate camera 3410 can be, is the rays of light 3440 . 3442 according to the edges of the hole 3432A . 3432B taken from the photosensitive matrix 3416 from the corresponding points on the photosensitive matrix 3416 were recorded, so projecting that these rays are the edges of the surface 3430A . 3430B to cut. This intersection determines the 3D coordinates of the edge.

This method may be considered considering the example of an object 3600 with a flat area 3610 into the hole 3620 is drilled, to be understood more precisely. It extends an area from the edge of the hole 3620 to a perimeter boundary 3622 in which there is a relatively high degree of uncertainty due to the effects of the mixed pixels as discussed above. An assumption is made based on an already known knowledge of the part being inspected that the edge (in this case a hole) is sharp and the surface is generally flat. Therefore, by projecting the 2D image of the hole through the lens perspective center onto the flat area with coordinates determined by using triangulation, the 3D coordinates of the sharp edges of the hole can be determined with a relatively high accuracy. Similarly, the 3D coordinates of any kind of sharp edges can be determined.

In one embodiment, a characteristic of the uncertainty gap is 3424 provided by the triangulation system. In some cases, the uncertainty distance is based, at least in part, on the amount of noise that is observed in an area, or a measure of "smoothness" of edges, in areas of high noise or low smoothness, the uncertainty distance may increase. such as the light level, which is a level of ambient light, or a level of illumination from the device 401 can also be used in determining an appropriate uncertainty distance 3424 be taken into account.

It will now be a procedure 3700 for determining 3D coordinates of an edge point located on an edge feature using a combination of a projector, a scanner camera and an edge detecting camera with reference to FIG 37 described. In one step 3705 For example, an articulated arm CMM is provided that includes a projector, a scanner camera, an edge-detecting scanner, and a processor. The articulated arm CMM further includes mechanical elements, such as an arm portion rotatably coupled to a base. Each arm segment comprises at least one displacement measuring system, which in most cases is an angular encoder. The displacement encoder generates a position signal, which is usually an angular reading. One end of the arm portion is attached to the bottom and the other end to a probe end. The projector, the scanner camera and the edge-detecting scanners are coupled to a probe end. The edge-detecting camera may be the same camera as the scanner camera or a camera other than the scanner camera. The projector camera has a projector perspective center through which rays pass from a first light pattern on the way to an object. The first light pattern may be stripe light of the type described hereinabove, the first pattern possibly being a coded or sequential pattern. Alternatively, the first pattern may be projected as a light line or as a light spot. The light beams may result from a pattern of light reflected from a MEMS matrix or generated by an individual light source that transmits the light through suitable optical elements.

In one step 3710 An electronic circuit within the articulated arm CMM receives a position signal from the displacement measurement systems in the arm segments and sends a first electrical signal to the processor. In one step 3715 The projector emits a first light pattern on the object. In one step 3720 The scanner camera receives the first light pattern reflected from the object. In response to receiving the reflected light, the scanner camera sends a second electrical signal to the processor.

In one step 3725 The edge-detecting camera receives a second light reflected from the object and in response sends a third electrical signal to the processor. A portion of the second light is reflected by an edge feature of the object, the edge point being a point on the edge feature. The second light can come from several sources. It can be an ambient light originating from background light sources in the environment. The second light may be intentionally radiated from a light source element which is coupled to the probe end. The light source can provide uniform illumination over the surface. The second light can be sent to the object at a different time than the first light pattern

In one step 3730 the processor determines first 3D coordinates of first points on a surface of the object. These first 3D points are based, at least in part, on the first pattern of light from the projector and the second electrical signal resulting from the image captured by the scanner camera. Using triangulation techniques, the 3D coordinates of the first points on the surface in the local frame of reference of the projector and the scanner camera are determined. By further including the first electrical signals, the position of the object surface in an articulated arm CMM reference system can be determined.

In one step 3735 the processor further determines a first beam, the first beam passing from the object to the object. The first beam is the beam that passes from the edge point through the perspective center of the edge-detecting camera. The processor determines the first beam based at least in part on the third electrical signal that detects the edge in the image of a photosensitive array within the edge-detecting camera. In addition, the first beam is based on the first electrical signal necessary to determine the first beam within the articulated arm CMM reference frame. The first ray may be represented as a vector within the articulated arm CMM reference frame.

In one step 3740 The processor further determines 3D coordinates of the edge point based at least in part on an intersection of the first beam with the first 3D coordinates of the first surface. This can be done by determining a characteristic distance above which 3D data is considered less accurate than desired. The characteristic distance may be based on a rule associated with a given system, or it may be based on image quality - for example, jagged edges or noise in 3D points near the edge. The general approach is to mathematically project a smooth surface (characterized by 3D points) along a continuous path across the characteristic distance until the smooth surface intersects the first beam. In most cases, a large number of first rays will be along edge points on an edge feature and will be projected to intersect a smooth surface projection, allowing more accurate determination of 3D points on and near the edge feature. In one step 3745 The 3D coordinates of the edge point are saved.

While the invention has been described by way of exemplary embodiments, it will be apparent to those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, the use of the terms first (r / s), second (r / s), etc. does not say anything about the order or meaning, the terms first (r / s), second (r / s) etc. are used instead to distinguish one element from another element. Further, the use of the terms a, a, a, etc. does not mean any limitation on the amount, but rather means the presence of at least one of the named subject.

Claims (7)

A portable articulated arm CMM for measuring three-dimensional (3D) coordinates of an object in space, comprising: a base; a manually positionable arm portion having first and opposing second ends, the arm portion rotatably coupled to the base, the arm portion including a plurality of connected arm segments, each arm segment including at least one position sensing system for generating a position signal; a processor; an electronic circuit receiving the position signal from the at least one displacement encoder in each arm segment, the electronic circuit configured to send a first electrical signal to the processor in response to the position signal; a probe end coupled to the first end; a non-contact 3D measuring device coupled to the probe end, the non-contact 3D measuring device comprising a projector and a scanner camera, the projector being adapted to emit a first light pattern on the object, the scanner camera being arranged to read the one of the Receives object reflected first light patterns and in response sends a second electrical signal to the processor; an edge-detecting camera coupled to the probe end, wherein the edge-detecting camera is one of the scanner camera or a second camera different from the scanner camera, the edge-detecting camera being positioned so as to be one of one Edge feature of the object receives second reflected light and in response sends a third electrical signal to the processor; and wherein the processor is configured to determine first 3D coordinates of first points on a surface of the object based at least in part on the first pattern of light from the projector, the first electrical signal, and the second electrical signal, the processor further is adapted to determine a first beam from the edge detecting camera to the object, the first beam being based at least in part on the first electrical signal and the third electrical signal, the processor being further adapted to obtain second 3D coordinates of an edge point of the Edge feature to determine, wherein the second 3D coordinates based at least partially on an intersection of the first beam with the first 3D coordinates of the surface. Articulated arm CMM according to claim 1, wherein the first light pattern is a light line. Articulated arm CMM according to claim 1, wherein the first light pattern is a coded structured light pattern. The articulated arm CMM of claim 1, wherein the second light reflected from the object is a response to ambient light incident on the object. The articulated arm CMM of claim 1, wherein the second light reflected from the object is a response to light provided by a light source attached to the probe end, wherein the light provided by the light source is substantially uniform , The articulated arm CMM of claim 1, wherein the projector has a projector perspective center, and the scanner camera has a scanner camera perspective center, with light rays from the projector passing through the projector perspective center, beams from a second light pattern reflected from the object the scanner camera perspective center, wherein a baseline distance is a distance from the projector perspective center to the scanner camera perspective center, wherein the first 3D coordinates are further based on baseline spacing. A method of measuring an edge point with a portable articulated arm coordinate measuring machine (articulated arm CMM), the method comprising: Providing the articulated arm CMM, the articulated arm CMM comprising: a base, a manually positionable arm portion having first and opposite second ends, the arm portion rotatably coupled to the base, the arm portion including a plurality of connected arm segments; each arm segment comprises at least one position encoder for generating a position signal, a processor, an electronic circuit, a probe end coupled to the first end, a non-contact 3D measuring device coupled to the probe end, the non-contact 3D measuring device comprising a projector and a scanner camera the articulated arm CMM further comprises a camera detecting edges coupled to the probe end, wherein the edge detecting camera is one of the scanner camera or a second camera different from the scanner camera; Receiving, by the electronic circuit, the position signal from the at least one displacement measuring system in each arm segment; Sending, from the electronic circuit, a first electrical signal to the processor in response to the position signal; Radiating from the projector a first light pattern on the object; Receiving, with the scanner camera, the first light pattern reflected from the object and sending a second electrical signal to the processor in response thereto; Receiving, with the edge detecting camera, a second light reflected from an edge feature of the object and sending a third electrical signal to the processor in response thereto, the edge feature having an edge point, the edge point being a point on the edge feature; Determining, at the processor, first 3D coordinates of first points on a surface of the object, wherein the first 3D coordinates are based, at least in part, on the first pattern of light from the projector, the first electrical signal, and the second electrical signal; further determining, with the processor, a first beam from the edge-detecting camera to the object, the first beam based at least in part on the first electrical signal and the third electrical signal; further determining, with the processor, second 3D coordinates of the edge point based, at least in part, on an intersection of the first beam with the first 3D coordinates of the surface; and Save the second 3D coordinates of the edge point.

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