Algorithms for Old Master painting canvas thread counting from x-rays

2009 IEEE 13th Digital Signal Processing Workshop and 5th IEEE Signal Processing Education Workshop

Klein

et al. 2009

Self Cite

Thread counting algorithms seek to determine the vertical and horizontal weave densities of the canvas underlying a painting. X-ray images of a painting serve as the raw data. Canvas texture can be modeled as a sum of two sinusoids having nearly orthogonal spatial frequencies. The actual painting serves as an additive signal that only distracts from the thread-counting process. The algorithm employs a variant of short-time Fourier analysis to the image domain. In simple cases, two-dimensional Fourier transforms of small areas reveal isolated peaks at the proper vertical and horizontal frequencies. In more challenging cases, even within the same painting, additional peaks appear in the expected frequency range, requiring heuristics to extract from the spectral measurements representative thread-count estimates for a painting. The resulting algorithm, while still under development, can analyze weave density for entire paintings with an accuracy comparable to human measurements.

Section: The Canvas Thread Counting Problemmentioning

confidence: 99%

A thread counting algorithm for art forensics

2009 IEEE 13th Digital Signal Processing Workshop and 5th IEEE Signal Processing Education Workshop

Klein

et al. 2009

Self Cite

“…The standard method to perform an automatic counting lies on the hypothesis that the threads follow an approximately periodic pattern. This pattern may be supposed to follow a sinusoidal model [8], [9] or other shapes like rectangles [13]. In any case, it is assumed that both horizontal and vertical strands have a fundamental frequency of repetition.…”

Section: Standard Dft Methods For Thread Countingmentioning

confidence: 99%

“…Most of previous studies have used two-dimensional discrete Fourier transforms (2-D DFTs) to develop computerassisted tools for analyzing canvas weaves [8]- [17]. To summarize, the locations of spectral peaks on the horizontal and vertical axes of the 2-D DFT correspond to the thread densities.…”

Section: Introductionmentioning

confidence: 99%

On the power spectral density applied to the analysis of old canvases

Simois

Murillo-Fuentes

2018

Signal Processing

A routine task for art historians is painting diagnostics, such as dating or attribution. Signal processing of the X-ray image of a canvas provides useful information about its fabric. However, previous methods may fail when very old and deteriorated artworks or simply canvases of small size are studied. We present a new framework to analyze and further characterize the paintings from their radiographs. First, we start from a general analysis of lattices and provide new unifying results about the theoretical spectra of weaves. Then, we use these results to infer the main structure of the fabric, like the type of weave and the thread densities. We propose a practical estimation of these theoretical results from paintings with the averaged power spectral density (PSD), which provides a more robust tool. Furthermore, we found that the PSD provides a fingerprint that characterizes the whole canvas. We search and discuss some distinctive features we may find in that fingerprint. We apply these results to several masterpieces of the 17th and 18th centuries from the Museo Nacional del Prado to show that this approach yields accurate results in thread counting and is very useful for paintings comparison, even in situations where previous methods fail.

“…The Thread Count Automation Project seeks to develop signal processing algorithms that can detail the variations in the canvas thread density across a painting [6] and to search for other paintings having a canvas weave pattern that matches it. In his Dutch and late French periods, van Gogh ordered canvas in rolls and, for small to moderate sized paintings, he would cut a rectangular section and mount it on a stretching frame with tacks.…”

Section: Introductionmentioning

confidence: 99%

Matching canvas weave patterns from processing x-ray images of master paintings

Sun

2010 IEEE International Conference on Acoustics, Speech and Signal Processing

et al. 2010

Thread counting algorithms seek to determine from x-ray images the vertical and horizontal thread counts (frequencies) of the canvas weave comprising a painting's support. Our spectral-based algorithm employs a variant of short-time Fourier analysis to the image domain that reveals isolated peaks at the proper vertical and horizontal frequencies. Paintings made on canvas sections cut from the same canvas roll have been hypothesized to have similar, distinctive weave characteristics, allowing art historians to more accurately date paintings. Spatial variation of weave frequency measurements across a painting were cross-correlated using a new measure to determine possible common weave patterns between pairs of x-rays. By analyzing a database of x-rays made from 180 paintings by van Gogh, our algorithms confirmed situations where paintings were known to have been made on canvases cut from the same roll and found new ones.