Datei Diskussion:Polykontrast-Interferenzfotografie PIP Ray Girvan 2005.jpg

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JANUARY 17, 2005 Pseudocolour gives you the PIP false colour hand imageFalse colour (aka pseudocolour) is a standard image processing technique of applying a colour scale to 'mono' data (either monochrome photos, or data that's not in a visible range). As we don't distinguish grey-scales well, it can show up subtle contrast gradients and highlight useful data in, for instance, astronomical and satellite images. A useful variant is a composite, which effectively tints a true colour image with a false colour one, such as these images of forest cover and topography in Scott County, Virginia. The images at the left illustrate. 1: a digital photo of my hand on my desk. 2: that photo converted to monochrome. 3: the monochrome image with a nice psychedelic false colour palette applied. The concentric 'aura' effect is contours in the brightness of the diffuse reflection from the desktop from the table lamp I used to illuminate the scene. 4: a composite, created by digitally merging the true colour image 1 with the the false colour 3.

Compare and contrast, then, images such as this gallery of output from Polycontrast Interference Photography (PIP), a technique with a growing presence on the alternative health circuit. Devised by Harry Oldfield, inventor of various alternative diagnostic and therapeutic devices, PIP is described as an energy field imaging system that can show the body's aura, chakras, congestion and blockages in the meridians, and so on. But the technology can be explained far more tersely: it's a composite false colour image showing brightness levels in a photo of the subject taken against a strongly illuminated wall. The postulated mechanism is that the body's 'biofield' - a unproven form of energy - interacts with light. Mr Oldfield's own explanation is just about recognisable as a description of PC-based false colour processing. You'd not guess this from the descriptions of vendors, who have adopted this as a claimed scientific demonstration of several forms of alternative diagnosis and therapies to "balance the energy field" (whether Mr Oldfield's own electro-crystal therapy or longer-standing systems such as reiki). Typical shots show the difference between images before and after treatment (for instance, this EmoTrance page - which doesn't exactly go out of its way to explain that the striking colour bands are, as in the photo of my hand, just intensity contours in the reflections from lights shone on the subject). But even some believers in such techniques point out that PIP is extremely sensitive to position and ambient light. Detection of biofield - ambient light interactions has a candid technical description of the process, with images showing how even a few millimetres of movement between photos can give colour differences of the type that PIP practitioners would ascribe to changes in energy field. Such distances are well within the scope of breathing, minor differences in stance, how much you suck your belly in for the photo, etc. (This is a problem well-documented with the somewhat similar technique of contourography). None of the sites promoting PIP offer peer-reviewed studies, show any consideration of the possibility of such artifacts, or show evidence of consistency of multiple scans taken with the client (after stepping briefly away and back to the apparatus) in the same condition. Whatever is different in the 'after' scan is invariably interpreted as an improvement. The simplest hypothesis: PIP is wishful interpretation of the brightness levels in a picture due to ordinary optics. I think its appeal, like that of the Kirlian photography that preceded it, lies in its gloss of objective science and its ability to produce an attractive image that matches believers' expectations of what an aura or energy field might look like.

Update: August 22 2007 A topic at Bad Science, I've found a bonkers website, just mentioned a recent incarnation, a real-time version of PIP. Out of interest, I just dug out some images from 2004 when a correspondent asked me to demonstrate my claim above.

Top left: original image. Top right: PIP image. Bottom right: my faked PIP image, created by applying to the original image the colour table at bottom left (extracted, using Fractint's palette editor and a bit of guesswork, from the sample PIP output). PIP faking demo

Posted by Ray Girvan at Monday, January 17, 2005

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I'm a Web designer and technical writer living in Devon. Visit my work page at raygirvan.co.uk for that side of things. Otherwise, JSBlog is my main blog, covering book-inspired topics; Apothecary's Drawer is for general interest; and Poor Pothecary covers bad science debunking. The other sites are ones I manage, using Blogger as a CMS.