Character Inspection/OCR

角色检查/OCR

角色检查是检查，检查，识别或确定印刷在零件或产品上的字符。该技术也称为打印检查，用于各种任务，例如：

读取QR码（2D代码）在金属零件上盖章
零件号或型号的字符检查
Checking expiration dates on food containers

零件和产品标有到期日期或产品编号。但是，当无法准确读取，识别，判断，存储和管理此信息时，这无用。近年来，基于从捕获的图像数据中提取的字符认可或判断，角色检查已变得广泛。本页介绍了有关OCR（光学字符识别）和OCV（光学字符验证）以及字符检查的基本原理的基本信息。

Basic principle of character inspection/OCR for reading characters such as expiration dates from images

Advantages of introducing image processing

Character strings are indispensable for showing information such as expiration dates for food/medicine and part numbers of assembly parts in manufacturing. They are also essential for sales order management. These strings are vitally important for management; however, management of characters can be a lot of trouble.

For example, assume that you manage orders and inventory on paper in handwriting. Management through handwriting may cause mistakes or omissions. If the book is lost, there might be no way to retrieve the orders and inventory.

除了防止人体错误外，图像处理越来越多地用于使管理更可靠并降低劳动力和成本。用图像处理系统替换人手执行的角色的识别，检查和管理带来以下优势：

Preventing mistakes and omissions in books

In character inspection, the captured characters are compared with those in the registered dictionary (character font groups) and each is recognized as the character with the closest shape. The recognized characters are compared with the judgment string and the pass/fail output of the final inspection is produced. It is also possible to store the output judgment result on a server or other storage device. This type of reliable procedure prevents mistakes or omissions that may occur with management through handwriting.

可靠的信息管理

使用图像处理技术的角色检查允许操作员将识别的字符信息上传到服务器或其他设备，因此对诸如编写错误字符之类的错误不必担心。产品编号或其他由许多字符组成的项目通常不正确地编写。处理它们作为数字信息可以防止问题。

Thorough management of product numbers and other information also allows tracking of parts or products and collecting them quickly in case of the outflow of defective products or a product recall. It is also possible to track problems upstream to identify a problematic process to improve operations. Reliable information management is also effective for ensuring traceability.

同时阅读条形码或2D代码

In recent years, barcodes or 2D codes have been introduced for product management. To read barcodes or 2D codes only, you can use a barcode reader or a handheld mobile computer. In many cases, however, an expiration date is also marked on the label along with the barcode or 2D code. Character inspection can recognize both codes and characters simultaneously. This improves efficiency dramatically because you can read all data at once and manage them together instead of reading each type of data separately.

100％检查，最低劳动力

为防止outfl最有效的方法ow of defective workpieces is 100% inspection. However, checking characters visually not only takes time and labor but also involves a risk of oversight. Using image processing enables reliable inline character inspection to achieve both quality assurance and reduced labor costs. It also improves the yield rate in the inspection process and is highly effective for increasing production efficiency.

Download

角色检查的基础知识

角色检查有多种类型：标记的存在，标记质量，光学特征验证（OCV）和光学特征识别（OCR）。

Presence of marking

An inspection to detect the presence or absence of marking.
Marking quality

An inspection to detect illegible characters.
OCV

An inspection to compare marked characters and a judgment string and make pass/fail judgment.
OCR

An inspection to read marked characters and output them for verification or control.

Although the purposes are different, the basic operation of character inspection is to extract characters one by one from a captured image, compare them with characters in the registered dictionary, and identify characters.

1.角色提取

Extract characters one by one from the captured data.

2.与词典的比较

将每个提取的字符与注册字符进行比较。

Download

Techniques for improving recognition accuracy

过去，有人抱怨性格识别的准确性较低。通过各种技术创新，角色识别的准确性得到了显着提高。

Sub-pattern registration

Registering several patterns for one character improves recognition stability. By registering various fonts as sub-patterns, you can prevent failed recognition due to different font types.

Automatic fitting

Automatic fitting is an automatic fine adjustment of characters to allow extraction in optimum conditions. Since slight variations in the status among characters are corrected individually before verification, the correlation level is increased.

Image enhance filters

When the background of the marking has patterns or is made of metal or other reflective material, the accuracy of character inspection may decrease. Even when reading is difficult due to these or other reasons, applying image enhance filters enables stable character inspection.

Inspection of expiration dates on food containers

由于背景的影响，正常的灰色处理图像特征提取是不稳定的。

使用CV-5000颜色到灰色处理，字符和背景之间的对比足以使检查稳定。

Download

Practical applications

本节介绍了实际使用的例子g image processing for character inspection not only to prevent the outflow of defective workpieces but also for quality improvement by building a thorough management system and ensuring traceability.