Painting X-Ray	Original X-Ray Swatch

Signal processing aids the area of art forensics by developing algorithms for assessing paintings in various ways. As part of the Thread Counting Project centered at Cornell, Professor Johnson developed the best performing algorithm for determining canvas weave densities in x-ray images made of van Gogh paintings (provided to the Project by the Van Gogh Museum, Amsterdam). An example x-ray from a portion of a van Gogh painting and the 2D spectrum shows how the weave of the canvas corresponds distinctive spectral points. By estimating the frequency at which the vertical-axis peak occurs for swatches taken throughout the painting’s x-ray, a map of how the horizontal-thread count varies across the canvas can be obtained. A paper describes the theoretical underpinnings of the algorithm. Papers describing the approach without equations can be found here and here. A short presentation describes our basic approach. Some complications in interpreting thread-density pattern matches are described in a recent paper and in a summary webpage. The process for submitting images of paintings for thread counting is not complicated.

Spectrum

Weave Map