A stroboscopic online three-dimensional measurement for fast rotating object with binary dithered patterns

2017 ◽  
Vol 40 (8) ◽  
pp. 2660-2668 ◽  
Author(s):  
Yuting Chen ◽  
Yiping Cao ◽  
Han Yuan ◽  
Yingying Wan
Keyword(s):  
Three Dimensional ◽  
Control Unit ◽  
Ccd Camera ◽  
Fixed Position ◽  
Charge Coupled Device ◽  
Object A ◽  
Phase Measuring Profilometry ◽  
Three Dimensional Measurement ◽  
Binary Grating ◽  
Fast Rotating

In the three-dimensional (3D) measurement, phase measuring profilometry (PMP) requires no less than three deformed sinusoidal patterns, limiting its applications to static scenarios only. In this paper, a stroboscopic online PMP for fast rotating object with binary dithered patterns is proposed. N frames of novel circular binary grating patterns are designed to measure a rotating object. A defocused digital light projector projects the designed patterns onto the object with stroboscopic method, the corresponding deformed patterns can be “frozen” by charge-coupled device (CCD) camera. Owing to the repeatability and periodicity of rotating movement, a synchronization control unit is used to keep the object at the fixed position in each “frozen” deformed pattern. Every projected pattern is shifted from the previous pattern by a factor of 2π/N. This method makes the images of the object appear stationary in the deformed patterns. The experimental results show the accurate 3D shape of fast rotating object can be reconstructed with the proposed method.

scholarly journals Single-Shot Phase Measuring Profilometry Based on Quaternary Grating Projection

2021 ◽  
Vol 11 (6) ◽  
pp. 2536
Author(s):  
Chaozhi Yang ◽  
Yiping Cao ◽  
Xiuzhang Huang
Keyword(s):  
Fringe Pattern ◽  
Three Dimensional ◽  
Measuring Method ◽  
Relative Displacement ◽  
Single Shot ◽  
Refresh Rate ◽  
Charge Coupled Device ◽  
Phase Measuring Profilometry ◽  
Color Fringe ◽  
Binary Grating

In this paper, we propose a new single-shot three-dimensional (3D) measuring method based on quaternary grating projection. In traditional binary grating phase measuring profilometry (PMP), a multi-step or color fringe pattern are usually used to extract the sinusoidal fringes. In our proposed method, by using the DLP4500’s 2-bit gray coding mode, the grayscale is quaternary. The three non-zero grayscales cyclically arranged in equal width, and the fourth grey value is 0 which is not encoded in the fringe pattern but represents the shadow information in the deformed pattern, where a quaternary grating is encoded. When the DLP4500 projects the quaternary grating onto the measured object, the charge coupled device (CCD) captures the corresponding deformed pattern synchronously. Three frames of binary deformed patterns with 1/3 duty cycle and a relative displacement of 1/3 period can be decomposed by the segmentation algorithm proposed in this paper. Three sinusoidal deformed patterns with a 2π/3 shift-phase can be obtained by extracting the fundamental frequency of the three binary deformed patterns correspondingly, and the 3D shape of the object can be reconstructed by PMP. Experimental results show the effectiveness and feasibility of the proposed method. Because the DLP4500 only needs 2-bit coded grating for projection, the refresh rate of the projected grating is as high as 1428 Hz, which will have a broad application prospect in real time and fast online measurement.

Method for Binary Grating Generation Using Defocused Projection for Three-Dimensional Measurement

2016 ◽  
Vol 36 (8) ◽  
pp. 0812005
Author(s):  
赵立伟 Zhao Liwei ◽  
达飞鹏 Da Feipeng ◽  
郑东亮 Zheng Dongliang
Keyword(s):  
Three Dimensional ◽  
Dimensional Measurement ◽  
Three Dimensional Measurement ◽  
Binary Grating

Automated Three Dimensional Measurement Using Multiple CCD Camera Views

1995 ◽  
Vol 15 (85) ◽  
pp. 27-42 ◽  
Author(s):  
T. A. Clarke ◽  
M. A. R. Cooper ◽  
J. Chen ◽  
S. Robson
Keyword(s):  
Three Dimensional ◽  
Ccd Camera ◽  
Dimensional Measurement ◽  
Three Dimensional Measurement

scholarly journals Measurement of Three-Dimensional Structural Displacement Using a Hybrid Inertial Vision-Based System

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4083
Author(s):  
Xinxiang Zhang ◽  
Yasha Zeinali ◽  
Brett A. Story ◽  
Dinesh Rajan
Keyword(s):  
Three Dimensional ◽  
Ccd Camera ◽  
Calibration Target ◽  
Charge Coupled Device ◽  
Out Of Plane ◽  
Monitoring Camera ◽  
Tilt Sensor ◽  
Movement Compensation ◽  
Operating Distance ◽  
The Cost

Accurate three-dimensional displacement measurements of bridges and other structures have received significant attention in recent years. The main challenges of such measurements include the cost and the need for a scalable array of instrumentation. This paper presents a novel Hybrid Inertial Vision-Based Displacement Measurement (HIVBDM) system that can measure three-dimensional structural displacements by using a monocular charge-coupled device (CCD) camera, a stationary calibration target, and an attached tilt sensor. The HIVBDM system does not require the camera to be stationary during the measurements, while the camera movements, i.e., rotations and translations, during the measurement process are compensated by using a stationary calibration target in the field of view (FOV) of the camera. An attached tilt sensor is further used to refine the camera movement compensation, and better infers the global three-dimensional structural displacements. This HIVBDM system is evaluated on both short-term and long-term synthetic static structural displacements, which are conducted in an indoor simulated experimental environment. In the experiments, at a 9.75 m operating distance between the monitoring camera and the structure that is being monitored, the proposed HIVBDM system achieves an average of 1.440 mm Root Mean Square Error (RMSE) on the in-plane structural translations and an average of 2.904 mm RMSE on the out-of-plane structural translations.

Reconstruction of Objects from their Projections Using Orthogonal Functions

1973 ◽  
Vol 31 ◽  
pp. 268-269
Author(s):  
Elrnar Zeitler
Keyword(s):  
Unit Area ◽  
Three Dimensional ◽  
One Dimension ◽  
Spatial Density ◽  
Dimensional Representation ◽  
Orthogonal Functions ◽  
Object A ◽  
Plane Normal ◽  
Dimensional Object ◽  
Spatial Density Distribution

Considering any finite three-dimensional object, a “projection” is here defined as a two-dimensional representation of the object's mass per unit area on a plane normal to a given projection axis, here taken as they-axis. Since the object can be seen as being built from parallel, thin slices, the relation between object structure and its projection can be reduced by one dimension. It is assumed that an electron microscope equipped with a tilting stage records the projectionWhere the object has a spatial density distribution p(r,ϕ) within a limiting radius taken to be unity, and the stage is tilted by an angle 9 with respect to the x-axis of the recording plane.

High-speed brightfield 3-D imaging and 3-D image analysis of thick and overlapped cell clusters in cytological preparations

1994 ◽  
Vol 52 ◽  
pp. 218-219
Author(s):  
Robert W. Mackin
Keyword(s):  
Image Analysis ◽  
High Speed ◽  
Three Dimensional ◽  
Image Data ◽  
Ccd Camera ◽  
Objective Lens ◽  
Array Processor ◽  
Vaginal Smears ◽  
Low Contrast ◽  
Computer Controlled

This paper presents two advances towards the automated three-dimensional (3-D) analysis of thick and heavily-overlapped regions in cytological preparations such as cervical/vaginal smears. First, a high speed 3-D brightfield microscope has been developed, allowing the acquisition of image data at speeds approaching 30 optical slices per second. Second, algorithms have been developed to detect and segment nuclei in spite of the extremely high image variability and low contrast typical of such regions. The analysis of such regions is inherently a 3-D problem that cannot be solved reliably with conventional 2-D imaging and image analysis methods.High-Speed 3-D imaging of the specimen is accomplished by moving the specimen axially relative to the objective lens of a standard microscope (Zeiss) at a speed of 30 steps per second, where the stepsize is adjustable from 0.2 - 5μm. The specimen is mounted on a computer-controlled, piezoelectric microstage (Burleigh PZS-100, 68/μm displacement). At each step, an optical slice is acquired using a CCD camera (SONY XC-11/71 IP, Dalsa CA-D1-0256, and CA-D2-0512 have been used) connected to a 4-node array processor system based on the Intel i860 chip.

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