本課題針封影像數位化的原理與步驟進行探討,更進一步將數位影像在工程上的應用做一完整的描述與程式化。本文中對於一晶粒影像進行數位化處理,並強化影像物件之幾何特徵並加以篩選,同時建立符合既定條件之特性值,以程式化與自動化處理影像物件之目標。
課題內介紹與結合基礎影像處理步驟,並與LabView軟體結合。使用LabView內建的虛擬裝置(Virtual Instrument),得以與介面影像連結與控制,且使用IMAQ的影像處理虛擬裝置,針對灰階影像或彩色影像進行物件萃收、篩選、量測、統計、報告輸出等程式化之結構,以令自動化影像處理在工程上之應用予以實現。
本文內介紹空間域(Spatial)內使用的高通、低通濾波器之原理,包括Laplacian、Gradient、Gaussian等,在數位影像上的計算與應用,尤其對於雜訊消除與物件週綠、線段之增強效果,使影像物件篩選得以進行,此外物件影像之量測與分析使用IMAQ之虛擬裝置程式化之做法亦有詳細之敘述。
The study focuses on the digital image processing and analysis to the application of engineering metrology. The fundamental concepts of digital image processing-the manipulation of images by computer-are introduced. Several algorithms of image enhancement run on a personal computer are the main subjects in the article.
This paper presents the theory and the steps of image digitization, transformation, and signal filtering. The algorithm of digital image processing relies on the convolution theory. The basic digital convolution sets up the foundation of all image processing procedures. For instance, the digital algorithm of high-pass filter for edge enhancement utilizes Gradient and Laplacian filters, and the low-pass filter for smoothing the contrast of object comprises smoothing and Gaussian filters.
In this study, material grain images taken from a CCD camera were converted to digital images and further enhanced by feature extraction techniques. The goal was to calculate area of each grain and to count the number of the grains in the image automatically. The task of the digital image processing was implemented on the LabView software from National Instrument. TX.
Subjects of LabView programming and the virtual instruments are detailed. Use of the virtual instrument with the IMAQ modules connects and controls the interface image. The functions of IMAQ's virtual instruments facilitate the particle collection, filtering, measurement, statistics, and report production on both gray level and color images. The experimental results on the scenes of material grains demonstrate the robustness and suitability of the LabView system. With the integration of the LabView system, engineering metrology using digital image processing techniques is realized.