Editor's Note: Exploit the tools you have
Steve Scheiber, Technical Editor -- Test & Measurement World, 2/1/2004
One great frustration in our industry is that even widely available techniques are often used much less than they should be. Reluctance to include inspection in a "test" strategy provides one example.
This month's lead story reveals another such issue. Electronics makers (and contract manufacturers in particular) want to archive inspection images in case a quality issue arises later. Storing images consumes a lot of resources, forcing a tradeoff among the number of images, resolution, and required storage.
Compression allows storing more images of a given resolution in the same space. Searching archives (because disks and other media contain more images) becomes easier as well. Yet, manufacturers avoid compression because they expect that it loses information.
Although high compression can cause data loss, JPEG, for example, promises lossless compression ratios of 2:1. With JPEG 2000, the ratio jumps to as much as 4:1. Compute-intensive JPEG 2000 may prohibit software-only compression in real time, but hardware accelerators address that limitation. And even a software-only solution permits collecting images and compressing them later.
Image compression may seem like a minor issue. But many interesting test/inspection techniques have fallen by the wayside because "we've never done it that way." Some—like high-resolution infrared board inspection—have vanished altogether.
We should always explore available options before making strategy decisions. We might find our jobs both easier and more productive.
Contact Steve Scheiber at sscheiber@aol.com .
