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Posts Tagged ‘Banding’

More about banding on the Shroud of Turin

August 29, 2014 13 comments

imageHugh Farey has prepared a helpful, four page, image rich PDF document on Banding on the Shroud of Turin. He points out, for instance, in referring to this image on the right:

This is the top of the alleged band which Barrie
Schwortz felt needed adjusting in density to
restore the image to a more realistic
appearance. It is two ‘pitches’ (1) wide, and
defined on the right by a bunch of thin warp
threads (2) forming the prominent stripe
visible on the Enrie image, and on the left, less
clearly, by the adjacent pitch (3), which is
darkened by ‘hair.’

Hugh concludes:

Conclusion. The weave of the cloth does produce the illusion of bands according to its illumination, which serve to enhance a viewer’s perception of the intensity of the image at various places, and give the illusion of over-defined dark and light bands in various places which are not as clearly vertical sided as they appear.. So the light vertical areas defining the sides of the cheeks are really present, but they are not as precise or as well defined as they appear, and are not merely artifacts of the cloth, but real areas where the image making process just didn’t happen.

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A new paradigm for banding?

August 29, 2014 6 comments

photo (1)WmW writes in a comment:

HF has made what seems to be a brilliant observation (see Aug 28, 3:42 am). Would love to see some pictures of just what he is looking at. Is that possible? This may be a whole new paradigm for banding

I made the screen shot shown here. You should be able to click on it to enlarge it.

This is what Hugh Farey wrote:

In Shroud 2.0, longitudinal banding is very clear, and is definitely related to the pitch of the zigzag, specifically the darkness of the shadows cast by the overlying warp threads onto the underlying weft threads. Thus the entire Shroud is covered in alternating lighter and darker bands. This pattern is not seen on the Durante photo. Here the various longitudinal stripes seem to me to be much thinner, where you can see them, and appear to be related to the ‘spines’ of the herringbone ribs, which may have formed into slight ridges or troughs as part of the rolling up process. I cannot find a good positive Enrie image, but the large scale negatives, which can be found at the link above among others, show a variety of bands, some very thin and some as thick as a width of a pitch. However they are much less consistent and the thick ones do not appear to be lighting artifacts as they sometimes extend over two or three bands of alternating pitch. It is not clear in any case that the pale vertical areas defning the sides of the cheeks, or the dark vertical areas defing the fall of the hair, are due to imperfections in the weave or the lighting of a photo rather than the shape of the image model itself. As such, attempts to ‘correct’ the image by removing them are probably misguided.

Colin Berry certainly agrees. Here, and in his blog, he writes, “Brilliant. Hugh. Possibly, nay probably the best contribution to ‘banding’ in all time.”

Two “brilliants.” I think I see what Hugh is talking about. I may need to agree with Colin. But, “the shape of the image model itself.”? Model? I would like to see pictures with pointed narrative. Hugh, can you send along a couple of screen shots from your perspective?

image
To make screen shots in Shroud 2.0, hold down the round “Home” button on the front of the iPad or iPhone and press the “Sleep/Wake” button. The screen shot is in your Pictures folder.

Banding? Is it Real?

August 27, 2014 53 comments

Can anyone explain how the image* on Colin Berry’s blog can begin to convince us that banding is not really all that real. Maybe you can understand what Colin is saying. Something about “bilateral symmetry.” If anything, it helps to convince me that there really is banding there. You really need to see it in its full size in Colin’s blog space so CLICK HERE.

Barrie Schwortz did some of the earliest technical work to show one optical illusion effect of the banding. (Use Google translation after obtaining the linked-to page in order to see it in English). It is well worth reading.

The left image shows vertical banding on the outside portion of each cheek that extends upward and downward well above and below the face, particularly so on the right side. The middle image shows the area Barrie chose to add +20 points (Photoshop calibration) of RGB luminance. The effect is immediately obvious in the right picture.

image


The banding is particularly obvious when shown with transmitted light. 

image


One day I received an email from Robert Doumax, an imaging expert in Bordeaux, France. He had created a Fourier transform filter to isolate both vertical and horizontal banding in the fabric of the shroud. His filter produced the bottom image of three below.


Subtracting one image from the other image produces a tentative, partial banding map:


* About the colorful ImageJ image.  It has not been copied, stored or reproduced in anyway. The thumbnail preview is like a window into Colin’s site. It is an inline link to Colin’s blog space. By clicking on the image you can see it in its full size on Colin’s site. Even so, the use of a thumb nail image is considered fair use. Wikipedia is a good place to being reading about this.

[A] pointer causes a user’s browser to jump to the proprietor’s server and fetch the image file to the user’s computer. US courts have considered this a decisive fact in copyright analysis. Thus, in Perfect 10, Inc. v. Amazon.com, Inc.,[6] the United States Court of Appeals for the Ninth Circuit explained why inline linking did not violate US copyright law . . .

The thumb nail is too small to be a copyright concern. It is merely a graphical link.

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