Advanced Imaging


Advanced Imaging Magazine

Updated: January 12th, 2011 10:01 AM CDT

The Wonderful World of Color

When is it worthwhile to purchase a color MV camera?
Ripeness Check of Products
Color machine vision allows inspectors to check for ripeness and product quality
Single-chip area scan
Toshiba Imaging Systems
Fig. 2: Single-chip area scan cameras use a single sensor that is covered by a color filter with a fixed, repetitive pattern. To reconstruct a complete color image the red, green and blue information is interpolated across several adjacent cells to determine the total color content of each individual cell.
3CCD Cameras
Toshiba Imaging Systems
Fig. 3: 3CCD cameras contain three image sensors and a prism that divides the incoming light rays into their red, green, and blue components. Each chip then receives a single color at full resolution.
JAI’s CV-M9 GE camera
JAI’s CV-M9 GE camera is based on 3CCD prism technology, but has a GigE Vision interface.

By Barry Hochfelder

In the automotive industry, one might think of paint inspection, but car manufacturers have used automated paint systems for years without the need of automated visual inspection, Howison points out. “Today, the bulk of the effort goes into inspecting the fine visual details that make up the user interface. For example, making sure the consistency and evenness of the instrument-cluster light panel is important because the look and overall quality of that panel and the dashboard go a long way toward contributing to a driver’s impression of the car’s quality.”

Another area where color is making inroads is sports television and the reality TV programming craze, says Toshiba’s Pitre. “The broadcast market is seeking out 3CCD remote cameras for head-cam shots. They produce much better color fidelity over single-chip color cameras and the reproductions quality is essential for them. It’s critical for the color imagery to look as close to the quality of the high-end broadcast cameras as possible when they switch.”

Other applications include print inspection (quality and registration), CD and DVD labels, pharmaceutical inspection (label verification), printed circuit board (PCB) inspection, and part presence and/or detection. In addition, there are numerous quality and grading applications that involve color and texture classification for things like wood, textiles and ceramic tile.

Some applications make the choice easy, but if there is any doubt, Howison says, ask yourself these questions:

  • Is the object’s color quality and consistency a key factor in the overall quality of your product?
  • Can the object’s color help you ascertain the relative quality of your product?
  • Will color facilitate detection of the object?

If the answer to any of the three is yes, consider color machine vision.

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