Fast 3D position measurement with two unsynchronized cameras

Fujiyoshi, Hironobu; Shimizu, Shoichi; Nishi, Takayuki; Nagasaka, Yasunori; Takahashi, Tomoichi

doi:10.1109/cira.2003.1222174

Cited by 11 publications

(5 citation statements)

References 5 publications

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“…It is usually used in online inspecting and measuring. In 2003, Hironobu Fujiyoshi had constucted a vision system which used two normal, unsynchronized cameras for calculating the 3D position of objects [4]. 3D positions are measured as a crossing point of lines in 3D through the detected position on the latest kame and estimated 3D position calculated by past frames.…”

Section: D Position Measurement Based On Machine Visionmentioning

confidence: 99%

Indirectly online 3D position measurement based on machine vision using auxiliary gauge

2008

SPIE Proceedings

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Accurate and rapid 3D position measurement is required in many industrial applications. Traditional 3D position measurements is usually applied in laboratories using coordinate measuring machine(CMM). CMM can achieve a high accuracy, but efficiency is low. Machine vision is a new technology in position measuring. Measurement based on machine vision has non-touch, high speed, high accuracy and other prominent advantages. Because depth information is lost during the process of image formation, synthesizing operation become more complicated, direct 3D position measurement based on machine vision has hardly been used in online industry application. In this paper, an indirectly online 3D position measurement system is discussed. This system is consisted with an assistant gauge, one set of machine vision system and a computer. Through the assistant gauge, 3D position measurement is transffered to 2D measurement. Thus, making full use of existing 2D image processing theory and method, accuracy and speed of measurement of 3D position measurement may be promoted effectively.Keywrds: 3D position measurement, machine vision, auxiliary gauge INTRODUCTIONTRADITIONAL

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Section: D Position Measurement Based On Machine Visionmentioning

confidence: 99%

Indirectly online 3D position measurement based on machine vision using auxiliary gauge

2008

SPIE Proceedings

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“…With the conditions above, the approximation of the difference of the absolute differences for the consecutive frames can be achieved. Without loss of generality, th is is illustrated mathemat ically by using (6) where the second steps in the equations are based on the two aforementioned assumptions. The DAD operation done in Fig.…”

Section: Mathematical Approximation For Computation Efficiencymentioning

confidence: 99%

Difference of the Absolute Differences – A New Method for Motion Detection

Youssef¹,

Woo²

2012

IJISA

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This article presents a new method, wh ich reduces costs and processing time fo r spatial object motion detection by focusing on the bare-hand motion that mimics co mputer mouse functions to allow the user to move the mouse pointer in real-t ime by the motion of h is/her hand without any gloves worn, any object carried, or any key h it. In this article, the study of this topic is fro m the viewpoint of co mputer vision and image processing. The principals of the difference of the absolute differences (DAD) are investigated. A new method based on the DAD principles, wh ich is conceptually different fro m all the existing approaches to spatial object motion detection, is developed and applied successfully to the bare-hand motion. The realtime imp lementation of the bare-hand motion detection demonstrates the accuracy and efficiency of the DAD method.

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“…Because camera synchronization is crucial to some applications, there are some in which the interpolation and prediction of the frames of unsynchronized cameras are used to synchronize the camera [45]. Alleviation of synchronization between the projector and camera can be achieved by using wired external triggers; however, in some applications, there is a need for synchronization without an external trigger, such as in a VLC system.…”

Section: Introductionmentioning

confidence: 99%

Visual-Feedback-Based Frame-by-Frame Synchronization for 3000 fps Projector–Camera Visual Light Communication

et al. 2021

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This paper proposes a novel method for synchronizing a high frame-rate (HFR) camera with an HFR projector, using a visual feedback-based synchronization algorithm for streaming video sequences in real time on a visible-light communication (VLC)-based system. The frame rates of the camera and projector are equal, and their phases are synchronized. A visual feedback-based synchronization algorithm is used to mitigate the complexities and stabilization issues of wire-based triggering for long-distance systems. The HFR projector projects a binary pattern modulated at 3000 fps. The HFR camera system operates at 3000 fps, which can capture and generate a delay signal to be given to the next camera clock cycle so that it matches the phase of the HFR projector. To test the synchronization performance, we used an HFR projector–camera-based VLC system in which the proposed synchronization algorithm provides maximum bandwidth utilization for the high-throughput transmission ability of the system and reduces data redundancy efficiently. The transmitter of the VLC system encodes the input video sequence into gray code, which is projected via high-definition multimedia interface streaming in the form of binary images 590 × 1060. At the receiver, a monochrome HFR camera can simultaneously capture and decode 12-bit 512 × 512 images in real time and reconstruct a color video sequence at 60 fps. The efficiency of the visual feedback-based synchronization algorithm is evaluated by streaming offline and live video sequences, using a VLC system with single and dual projectors, providing a multiple-projector-based system. The results show that the 3000 fps camera was successfully synchronized with a 3000 fps single-projector and a 1500 fps dual-projector system. It was confirmed that the synchronization algorithm can also be applied to VLC systems, autonomous vehicles, and surveillance applications.

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Fast 3D position measurement with two unsynchronized cameras

Cited by 11 publications

References 5 publications

Indirectly online 3D position measurement based on machine vision using auxiliary gauge

Indirectly online 3D position measurement based on machine vision using auxiliary gauge

Difference of the Absolute Differences – A New Method for Motion Detection

Visual-Feedback-Based Frame-by-Frame Synchronization for 3000 fps Projector–Camera Visual Light Communication

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