Surface structured light three-dimensional measurement system

Abstract

The utility model discloses a surface structured light three-dimensional measurement system, which is characterized in that a computer is connected with a projector through an HDMI (High Definition Multimedia Interface) of the computer and an HDMI of the projector, so that the computer controls the projector to project a to-be-projected structured light image to a to-be-measured workpiece in a mode same as a mode of controlling a screen of the computer; the left camera and the right camera are respectively connected with the computer, and the computer triggers the left camera and the right camera to collect images of the workpiece to be detected. According to the three-dimensional measurement system, traditional structured light three-dimensional measurement can be achieved, the application requirement that a projector and a camera need to have a real-time interaction function can be met, for example, the application scene that structured light three-dimensional measurement such as error projection is combined with other functions can be met, and the function expansibility is high.

Description

Technical Field

[0001] The utility model belongs to the field of three-dimensional measurement, and more specifically relates to a surface structured light three-dimensional measurement system. Background Art

[0002] The three-dimensional measurement system includes a computer, a projector, a left camera and a right camera. The commonly used connection method is: the computer is connected to the projector through a USB interface, and the projector is directly connected to the left and right cameras through a USB interface or a network port respectively; the structured light image to be projected is pre-stored in the projector, and the projection command issued by the computer is transmitted to the projector via USB. After receiving the projection command, the projector projects the structured light image stored therein onto the workpiece to be measured, and sends a projection completion signal to the left and right cameras to trigger the left and right cameras to collect the image of the workpiece to be measured.

[0003] The connection method of the above hardware structure means that the traditional 3D measurement system can only realize the traditional structured light 3D measurement, and cannot meet the application requirements that require the projector and camera to have real-time interactive functions, such as error projection, which is an application scenario where structured light 3D measurement is combined with other functions. Utility Model Content

[0004] In view of the above defects or improvement needs of the prior art, the utility model provides a surface structured light three-dimensional measurement system, which can not only realize traditional structured light three-dimensional measurement, but also meet the application requirements that require the projector and camera to have real-time interactive functions.

[0005] To achieve the above-mentioned object, according to one aspect of the utility model, a surface structured light three-dimensional measurement system is provided, comprising: a projector, a computer, and left and right cameras, wherein the projector is arranged between the left and right cameras, and the optical axes of the left and right cameras are symmetrical with respect to the optical axis of the projector;

[0006] The computer and the projector are connected via an HDMI interface of the computer and an HDMI interface of the projector, and the computer is used to control the projector to project a structured light image onto the workpiece to be measured;

[0007] The left and right cameras are connected to the computer respectively, and the computer is also used to transmit control signals to the left and right cameras after a preset delay after the projector projects the structured light image to the workpiece to be measured; wherein the preset delay is greater than the response time of the projector to the projection instruction;

[0008] The left and right cameras are used to collect images of the workpiece to be measured when receiving a control signal.

[0009] Preferably, the structured light image is stored in the computer;

[0010] Alternatively, the structured light image is obtained by computer processing.

[0011] Preferably, the exposure time of the left and right cameras are both integer multiples of the projector refresh period.

[0012] Preferably, the projector model is DLP4500SL02, the digital micromirror device is TI 0.45" WXGA DMD, the resolution is 1280×800, the refresh rate of 1-bit binary graphics is 4225Hz / s, the refresh rate of 8-bit grayscale graphics is 120Hz / s, the HDMI interface is Mini HDMI, the operating current is DC 12V / 3A, and the total power is <30W.

[0013] Preferably, the camera model is BFLY-U3-23S6M-C, the size is 29mm×29mm×30mm, the resolution is 1920×1200, the pixel accuracy level is 2.3 million pixels, the sensor model is Sony IMX249 CMOS sensor, the data interface is USB, the spectrum is monochrome, the exposure range is 0.019ms to 3.9s, the maximum standard frame rate is 41, the gain range is 0dB to 29.9dB, it is powered by USB, the power supply voltage is 5V, the power consumption is <3W, and a Jasmine 16mm lens is installed.

[0014] Preferably, the camera is equipped with a blue light band bandpass filter adapted to the projector.

[0015] Preferably, the angles between the optical axes of the left and right cameras and the optical axis of the projector are both 15 degrees.

[0016] In general, the above technical solutions conceived by the utility model can achieve the following beneficial effects compared with the prior art:

[0017] The surface structured light three-dimensional measurement system provided by the utility model is that the computer and the projector are connected through the HDMI interface of the computer and the HDMI interface of the projector, so that the computer controls the projector to project the structured light image to be projected onto the workpiece to be measured in the same way as controlling its own screen. Compared with the traditional structured light three-dimensional measurement, which requires manual storage of the structured light image in the projector through cumbersome burning operations in advance, the utility model greatly simplifies the process; the left and right cameras are respectively connected to the computer, and the left and right cameras are triggered by the computer to collect the image of the workpiece to be measured. The three-dimensional measurement system can not only realize the traditional structured light three-dimensional measurement, but also meet the application requirements that require the projector and the camera to have real-time interactive functions, such as the application scenario of error projection, which combines structured light three-dimensional measurement with other functions, and has strong functional expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1It is a schematic diagram of the position relationship between a projector and left and right cameras in a three-dimensional measurement system provided by the utility model. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model. In addition, the technical features involved in each embodiment of the utility model described below can be combined with each other as long as they do not conflict with each other.

[0020] The utility model provides a surface structured light three-dimensional measurement system, comprising: a projector, a computer, and left and right cameras, wherein the projector is arranged between the left and right cameras, and the optical axes of the left and right cameras are symmetrical with respect to the optical axis of the projector;

[0021] The computer and the projector are connected via an HDMI interface of the computer and an HDMI interface of the projector, so that the computer controls the projector to project the structured light image to be projected onto the workpiece to be measured in the same manner as controlling its own screen;

[0022] The left and right cameras are connected to the computer respectively, and the computer is also used to transmit control signals to the left and right cameras after a preset delay after the projector projects the structured light image to be projected onto the workpiece to be measured; wherein the preset delay is greater than the response time of the projector to the projection instruction;

[0023] The left and right cameras are used to collect images of the workpiece to be measured when receiving a control signal.

[0024] Specifically, the HDMI interface of the computer and the HDMI interface of the projector are connected through a data cable to realize HDMI protocol communication between the computer and the projector. Based on this connection method, the projector is controlled as an extended screen of the computer, and the computer controls the projector in the same way as controlling its own screen to project the structured light image to be projected onto the workpiece to be measured.

[0025] The left and right cameras are connected to the computer via a USB interface or a network port, respectively. Based on this connection mode, after the computer sends a projection command to the projector, it can send a control signal to the left and right cameras at the same time to trigger the left and right cameras to synchronously capture the image of the workpiece to be measured. In addition, considering that the projector has a certain response time to the projection command, and it also takes a certain amount of time to complete the projection of the projector, in order to avoid the phenomenon that the left and right cameras capture images before the projector completes the projection, causing the pixel grayscale values ​​in the camera-captured images to be unstable and inconsistent between multiple frames, thereby affecting the structured light three-dimensional reconstruction, the computer sends a projection command to the projector, and then sends a control signal to the left and right cameras after a preset delay; accordingly, the preset delay is greater than the response time of the projector to the projection command.

[0026] The three-dimensional point cloud of the workpiece to be measured can be reconstructed according to the images of the workpiece to be measured collected by the left and right cameras. The above calculation process is a prior art and will not be repeated here. It can be understood that the above calculation can be performed by the computer in the system or by a separate computer.

[0027] Preferably, the structured light image to be projected is stored in the computer;

[0028] Alternatively, the structured light image to be projected is obtained by computer processing.

[0029] Specifically, compared with the traditional structured light three-dimensional measurement, the present invention can store the structured light image to be projected in the computer, so there is no storage function requirement for the projector.

[0030] For measurement requirements that require the projector and camera to have real-time interactive functions, such as error projection, the structured light image to be projected can be obtained by computer processing.

[0031] Those skilled in the art know that the method of error projection is: first reconstruct the three-dimensional shape of the workpiece to be measured, then compare the reconstructed three-dimensional shape with the standard data model of the workpiece to be measured, calculate the error and project it onto the workpiece, and display the error distribution of the workpiece in an intuitive way. In this application scenario, the traditional structured light three-dimensional measurement system can only realize the above-mentioned error projection function in an offline manner, that is, after calculating the error separately, it is stored in the projector, which has low work efficiency and poor automation. The structured light three-dimensional measurement system provided by the present application can realize the above-mentioned function online, that is, the error is calculated online by a computer and projected onto the workpiece in real time.

[0032] In order to eliminate the influence of the asynchronous projector refresh and camera exposure to ensure the consistency of camera pixel grayscale values ​​and meet the requirement of image grayscale consistency obtained by cameras in different projection frames in structured light three-dimensional measurement, preferably, the exposure time of the left and right cameras are both integer multiples of the projector refresh cycle.

[0033] Preferably, the projector model is DLP4500SL02, the digital micromirror device (DMD) is TI 0.45" WXGA DMD, the resolution is 1280×800, the refresh rate of 1-bit binary graphics is 4225Hz / s, the refresh rate of 8-bit grayscale graphics is 120Hz / s, the HDMI interface is Mini HDMI, the operating current is DC 12V / 3A, and the total power is <30W.

[0034] Preferably, the left and right camera models are BFLY-U3-23S6M-C, the dimensions [width × height × length] are 29mm × 29mm × 30mm, the resolution is 1920 × 1200, 2.3 million pixels, the sensor is a Sony IMX249 CMOS sensor, the data interface is the first generation USB3.1, the spectrum is monochrome, the exposure range is 0.019ms to 3.9s, the maximum standard frame rate is 41, the gain range is 0dB to 29.9dB, the power supply requirement is 5V via USB3.0, and the power consumption is <3W.

[0035] In order to improve the ability to resist interference from ambient light, preferably, the camera is equipped with a blue light band pass filter adapted to the projector.

[0036] Preferably, the angles between the optical axes of the left and right cameras and the optical axis of the projector are both 15 degrees.

[0037] like Figure 1 As shown, the optical axis of the projector installed in the middle is perpendicular to the fixed rod. When the models of the projector and the left and right cameras are as shown in the above embodiment, the optical axes of the left and right cameras installed on the left and right sides are symmetrical with respect to the optical axis of the projector and form an angle of 75 degrees with the fixed rod. This structural design takes into account the field of view and depth of field of the projector and the left and right cameras, ensures the stability of the relative position of the projector and the left and right cameras, and at the same time makes the effective common field of view of the three large.

[0038] It is easy for those skilled in the art to understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A surface structured light three-dimensional measurement system, comprising: A projector, a computer, and left and right cameras, wherein the projector is arranged between the left and right cameras, and the optical axes of the left and right cameras are symmetrical with respect to the optical axis of the projector; characterized in that: The computer and the projector are connected via an HDMI interface of the computer and an HDMI interface of the projector, and the computer is used to control the projector to project a structured light image onto the workpiece to be measured; The left and right cameras are connected to the computer respectively, and the computer is also used to transmit control signals to the left and right cameras after a preset delay after the projector projects the structured light image to the workpiece to be measured; wherein the preset delay is greater than the response time of the projector to the projection instruction; The left and right cameras are used to collect images of the workpiece to be measured when receiving a control signal.

2. The system according to claim 1, characterized in that The structured light image is stored in the computer; Alternatively, the structured light image is obtained by computer processing.

3. The system according to claim 1, characterized in that The exposure time of the left camera and the right camera are both integer multiples of the projector refresh cycle.

4. The system according to claim 1, characterized in that The projector model is DLP4500SL02, the digital micromirror device is TI 0.45" WXGA DMD, the resolution is 1280×800, the refresh rate of 1-bit binary graphics is 4225Hz / s, the refresh rate of 8-bit grayscale graphics is 120Hz / s, the HDMI interface is Mini HDMI, the operating current is DC 12V / 3A, and the total power is <30W.

5. The system according to claim 1 or 4, characterized in that: The model of the left and right cameras is BFLY-U3-23S6M-C, the size is 29mm×29mm×30mm, the resolution is 1920×1200, the pixel accuracy level is 2.3 million pixels, the sensor model is Sony IMX249 CMOS sensor, the data interface is USB, the spectrum is monochrome, the exposure range is 0.019ms to 3.9s, the maximum standard frame rate is 41, the gain range is 0dB to 29.9dB, it is powered by USB, the power supply voltage is 5V, the power consumption is <3W, and a Moritron 16mm lens is installed.

6. The system according to claim 5, characterized in that The left and right cameras are both equipped with blue light band bandpass filters adapted to the projector.

7. The system according to claim 5, characterized in that The angle between the optical axis of the left and right cameras and the optical axis of the projector is 15 degrees.

Images