[[alternative]]Studies on the laser marking system by image processing

碩士機電工程學系[[abstract]]雷射加工系統廣泛運用在切割、焊接、鑽孔及標印等工業上。不同製程所使用之加工系統也不同。一般分成雷射直接加工、同步掃描與電流計式掃描等加工方式。本文研發電流計式掃描加工系統並利用特殊的影像處理，進行不同材料之文字與圖像標印。 首先，利用影像處理技術中的半色調演算法於雷射圖像標印上，以有限階數色調來模擬連續調影像，利用網點排列的不同來呈現不同灰階，人眼視覺系統因具有低頻濾波器特性，視覺上會產生錯覺，將密佈的網點當成連續調影像，因此在標印圖像上可利用此一特性，解決標印設備的問題。最後以PSNR評估半色調影像品質，藉以判斷不同演算法之優劣。 關鍵字:雷射加工系統、雷射標印、半色調處理[[abstract]]Laser processing system is applied to several manufacturing processes such as cutting, welding and marking. In various fabrication producers, the laser processing includes manufacturing, synchronized image scanning and galvanometric scanning marking. The galvanometric scanning and marking system with image processing are discussed in this thesis. This research utilizes the laser processing system with specific image processing to mark characters and patterns on different kinds of materials. First, we used the half-toning processing algorithm to simulate continuous tone pictures in the image processing. Variations of the network points can represent different tone of grey. Due to the characteristic of the low pass filter for human eyes, it will create a visual effect that could be considered a tight distribution of network points as continuous tone images. Therefore, it can overcome problems produced by the marking equipment for pattern marking in this method. Finally, we use PSNR (peak signal noise ratio) method to assess the halftone image quality and determine the performance of the different algorithms. Keyword: laser machining system, laser marking, half-toning processin