Xử lý ảnh introduction to machine vision Bách Khoa HN

TRƯỜNG ĐẠI HỌC BÁCH KHOA HÀ NỘI XỬ LÝ ẢNH TRONG CƠ ĐIỆN TỬ Machine Vision Giảng viên: TS Mạc Thị Thoa Đơn vị: Bộ môn Cơ điện tử, Viện Cơ khí Hà Nội, 2020 Chapter Introduction to machine vision Introduction (Giới thiệu) Basic elements of machine vision system (các thành phần thị giác máy) Classification (Phân loại) Technical specifications (thông số kỹ thuật) Designing a Machine Vision System (Thiết kế hệ thống thị giác máy ) Introduction Definition  Machine vision – thị giác máy (MV) is the technology and methods used to provide imaging-based automatic inspection and analysis for such applications as automatic inspection, process control, and robot guidance, usually in industry  Machine vision is a term encompassing a large number of technologies, software and hardware products, integrated systems, actions, methods and expertise  Machine vision as a systems engineering discipline can be considered distinct from computer vision, a form of computer science  It attempts to integrate existing technologies in new ways and apply them to solve real world problems Introduction Definition  Các q trình thị giác máy tính bao gồm lập kế hoạch chi tiết yêu cầu sau đưa giải pháp, bao gồm: lấy lưu trữ ảnh, trình xử lý ảnh, lấy thông tin cần thiết Introduction Definition https://en.wikipedia.org/wiki/Glossary_of_machine_vision Relation between Computer vision and various other fields Introduction Application: Locate  To find the object and report its position and orientation Introduction Application: Measure  To measure physical dimensions of the object Introduction Application: Inspect  To validate certain features Introduction Application: Inspect Introduction Application: Identify 10 Designing a Machine Vision System  5.5 Lens Design  Extension Tubes  The lens extension l can be increased using the focus adjustmentof the lens  If the distance cannot be increased, extension tubes can be used to focus close objects As a result, the depth of view is decreased  For higher magnifications, such as from 0.4 to 4, macro lenses offer better image quality Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 116 Designing a Machine Vision System  5.5 Lens Design  Lens Diameter and Sensor Size Areas illuminated by the lens and camera; the left side displays an appropriate choice Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 117 Designing a Machine Vision System  5.5 Lens Design  Sensor Resolution and Lens Quality  As for high resolution cameras, the requirements on the lens are higher than those for standard cameras  Using a low-budget lens might lead to poor image quality for high resolution sensors, whereas the quality is acceptable for lower resolutions Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 118 Designing a Machine Vision System  5.6 Choice of Illumination  Concept: Maximize Contrast  Direction of light: diffuse from all directions or directed from a range of angles  Light spectrum  Polarization: effect on surfaces, such as metal or glass Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 119 Designing a Machine Vision System  5.6 Choice of Illumination  Illumination Setups  Backlight and  Frontlight • Diffused light • Directed light • Confocal frontlight • Bright field • Dark field Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 120 Designing a Machine Vision System  5.6 Choice of Illumination  Light Sources  Fluorescent tubes  Halogen and xenon lamps  LED  Laser Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 121 Designing a Machine Vision System  5.6 Choice of Illumination  Approach to the Optimum Setup  A confirmation of the setup based on experiments with sample parts is mandatory  The alignment of light, the part and the camera needs to be documented  To balance between similar setups images have to be captured and compared for the maximum contrast Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 122 Designing a Machine Vision System  5.6 Choice of Illumination  Interfering Lighting  The influences of different lamps on the images have to be checked  To avoid interfering, a spatial separation can be achieved by using different camera stations  The part is imaged with different sets of cameras and illuminations Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 123 Designing a Machine Vision System  5.7 Mechanical Design  As the cameras, lenses, standoff distances, and illumination devices are determined, the mechanical conditions can be defined  As for mounting of cameras and lights the adjustment is important for installation, operation, and maintenance  The devices have to be protected against vibration or shock  The position of cameras and lights should be changed easily Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 124 Designing a Machine Vision System  5.8 Electrical Design  The power supply  The housing of cameras and illumination  The length of cables as well as their laying Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 125 Designing a Machine Vision System  5.9 Software  selection of a software library  design and implementation of the application-specific software Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 126 Designing a Machine Vision System  5.9 Software  Software Library  Software Structure  Image acquisition  Preprocessing  Feature localization  Feature extraction  Feature interpretation  Generation of results  Handling interfaces Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 127 Designing a Machine Vision System  5.9 Software  General Topics  Visualization of live images for all cameras  Possibility of image saving  Maintenance modus  Log files for the system state  Detailed visualization of the image processing  Crucial processing parameters Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 128 Designing a Machine Vision System  5.10 Costs  The development costs          project management base design hardware components software licenses software development installation test runs, feasibility tests, and acceptance test training documentation Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 129 Designing a Machine Vision System  5.10 Costs  The operating costs  maintenance, such as cleaning of the optical equipment  change of equipment, such as lamps  utility, for instance electrical power or compressed air if needed  costs for system modification due to product changes Alexander Hornberg, “Handbook of Machine Vision,” WILEY-VCH, Weinheim, 2006 130 ... ? ?Machine Vision Introduction, ” 2006 18 Basic elements of machine vision system  2.2 Illumination Illumination Principles SICK IVP, ? ?Machine Vision Introduction, ” 2006 19 Basic elements of machine. .. to as tools or functions 14 Basic elements of machine vision system  2.2 Illumination The goal of lighting in machine vision is to obtain a robust application by:  Enhancing the features to. . .Chapter Introduction to machine vision Introduction (Giới thiệu) Basic elements of machine vision system (các thành phần thị giác máy) Classification