How to Choose an Imaging Colorimeter for Machine Vision Inspection

imaging colorimeter for machine vision inspectionDemand for flat panel displays (FPDs) and consumer lighting products has skyrocketed in recent years, driving a need for high-speed machine vision inspection of color and luminance.

Imaging colorimeters have several components and there are many possible configurations. It can be difficult to choose the right one for your application. It helps to first understand what an imaging colorimeter does, and what your main options are.

What is an Imaging Colorimeter in Machine Vision Applications?

An imaging colorimeter typically consists of an imaging lens, a set of color filters, a CCD sensor and image processing hardware and software.

An imaging colorimeter is used to detect color and luminance in light sources quickly and efficiently. Imaging colorimeters have consistently high spatial resolutions, allowing them to inspect every single pixel simultaneously in a given display.

How Do You Know Which Imaging Colorimeter is Right For Your Machine Vision Application?

Once you understand your options for imaging colorimeters, you can then align the needs of your application with the pros and cons of various systems.

Although there are hundreds of possible imaging colorimeter configurations, there are mainly three options available for commercial use.

First is an imaging colorimeter with an interline transfer CCD with on-chip filters. This configuration provides high speed at a low cost, but the dynamic range and color accuracy are limited. They aren’t suited for examining small-scale features, but they’re a good choice for many on-line or at-line production inspection applications.

The second configuration also includes an interline transfer CCD sensor, but with external CIE matched filters. This solution is a good compromise on cost and performance, and is suited for machine vision inspection of most FPDs.

The third configuration includes a full-frame CCD sensor with CIE matched color filters. This option provides the best performance, with a dynamic range up to 16-bits and excellent color accuracy. The downside, of course, is the cost. However, this configuration is great for high-demand applications.

Choosing an imaging colorimeter can be difficult, especially if you’re unsure of the components you need and the most common options available. Knowing what’s most readily available and widely used can help you decide.

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