Forum Technical Discussions      Re: Aggressive Radiographic Auditors Need to Take a Closer Look! Posted by: Ed Ginzel    (PID_67), E-mail: Address, on January 05, 2009 at 18:00 : In Reply to: Re: Aggressive Radiographic Auditors Need to Take a Closer Look! posted by : Nigel Armstrong , E-mail: Address, on January 05, 2009 at 14:36 : Nigel: I think that a radiographer should be able to address this independently (which is why I was hoping to get the technique of using a mask incorporated into Standards to eliminate the false calls and to ensure a simple arbitration method with auditors). Dent's question about this phenomenon occurring on digital radiographs is probably one he could answer better than I. The effect is NOT actually equipment dependent as it is the brain's reaction to a chemical stimulous in the eyes. If we can see this effect on our computer monitors from the examples of optical illustions then I suspect that there is a potential that the human viewer will also see the effect on a digital version of a radiograph. ----------- Start Original Message ----------- : Happy and healthy New Year to all NDT.netters. : Thanks for the links to sites showing these phenomena Ed - I've not yet explored them but I shall. : Intuitively, I had grasped the contrast problem, never really taught at NDT school though. Viewers with in-built adjustable masks are very useful for this. I assume that these effects may lead predominantly to assuming a linear indication exists, in which case the RI tech often calls in a trusted UT tech to see if a reflector exists in the area of concern. Is this a reasonable action or a display of lack-of-confidence on the part of the RI tech? : : : Ed, : : After reading the .pdf I now see how this is an issue. The mach bands are of particular interest. I am surprised this was never touched on in training. It will be from now on! : : Thanks, : : TJ ------------ End Original Message ------------ Follow Ups: Re: Aggressive Radiographic Auditors Need to Take a Closer Look! Dent McIntyre 15:27 Jan-06-2009 (0) Post a Followup: Name: E-Mail: Subject: Comments: ----------- Start Original Message ----------- : Nigel: : I think that a radiographer should be able to address this independently (which is why I was hoping to get the technique of using a mask incorporated into Standards to eliminate the false calls and to ensure a simple arbitration method with auditors). : Dent's question about this phenomenon occurring on digital radiographs is probably one he could answer better than I. The effect is NOT actually equipment dependent as it is the brain's reaction to a chemical stimulous in the eyes. If we can see this effect on our computer monitors from the examples of optical illustions then I suspect that there is a potential that the human viewer will also see the effect on a digital version of a radiograph. : : Happy and healthy New Year to all NDT.netters. : : Thanks for the links to sites showing these phenomena Ed - I've not yet explored them but I shall. : : Intuitively, I had grasped the contrast problem, never really taught at NDT school though. Viewers with in-built adjustable masks are very useful for this. I assume that these effects may lead predominantly to assuming a linear indication exists, in which case the RI tech often calls in a trusted UT tech to see if a reflector exists in the area of concern. Is this a reasonable action or a display of lack-of-confidence on the part of the RI tech? : : : : : Ed, : : : After reading the .pdf I now see how this is an issue. The mach bands are of particular interest. I am surprised this was never touched on in training. It will be from now on! : : : Thanks, : : : TJ ------------ End Original Message ------------ Optional Link URL: Example: "http://www....html". Alternative write "http://www.ndt.net/wshop/attach/filename.htm" if you transfered a filename.htm via FTP Page Title: is important! Optional Image URL: http://www....gif Attention! Please click the button only once. This may take a moment to process Forum Technical Discussions Help