Figure 3 - uploaded by Marco Duarte
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The distance transform, based on Chamfer metric, applied to a subset of lines corresponding to a single "exposure" within the silverpoint study, i.e., the passage well aligned between the van Eyck portraits.
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The contemporary artist David Hockney has hypothesized that some early Renaissance painters secretly projected optical images onto their supports (canvas, paper, oak panel,...), directly traced these projections, and then filled in the tracings with paint [1]. Hockney has presented somewhat impressionistic image evidence for this claim, but he and...
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Context 1
... Chamfer distance computation can be illustrated by the distance transform. The distance transform of a curve (or set of points) C assigns to every pixel in an area the distance of that pixel to the nearest pixel in C. Figure 3 shows the distance transform applied to a subset of the full edge map of the silverpoint study. Each point is colored by its distance to the nearest point on the edge map: blue for short distances, red for large distances. ...
Context 2
... distance van Eyck oil (JvE) 5.6304 unaided (PvdW) 7.6476 mechanical (RvdW) 3.8507 mechanical (TS) 4.5356 Table 1: The average pixel distance between different copies and the van Eyck silverpoint computed on the region of the primary "exposure" (cf. Fig. 3). Our results show that talented artists using mechanical aids can indeed achieve fidelities that are comparable-in fact superior (smaller Chamfer distance)-to that found in van Eyck's oil copy. Our results strongly suggest further, but cannot prove, that van Eyck might have achieved his fidelity entirely "by ...
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Two modern Vietnamese portrait paintings were investigated. The paintings required conservation treatment in the form of consolidation due to extensive flaking, tenting, blind cleavage and friability of the paint layers. Both paintings were painted in Hanoi in 1963 by respected Vietnamese artist Nguyễn Trọng Kiệm. Due to the complex nature of the p...
Citations
... The full procedure required us to use thinning algorithms, to perform affine transformations (rotations, displacements, and uniform scaling), and other matters described in further detail elsewhere. 11 We found that a modern professional artist, using only mechanical copying/enlarging devices known from the time of van Eyck, could indeed achieve a fidelity (expressed as a Chamfer distance) roughly the same as van Eyck. Our experimental result, historical information, and physical evidence (pinprick holes), led us to reject as unpersuasive the claim that van Eyck used an optical projector when copying/enlarging this work. ...
This three-part series describes how a variety of methods adapted from computer vision, image analysis, and pattern recognition can be applied to visual arts and help answer questions in art history. In this final installment, David Stork discusses how shapes can be described. He outlines the challenges in quantifying shape and form analysis, and describes how techniques to compare shapes may be used to compare paintings to, for example, determine how a copy was made
... The full procedure required us to use thinning algorithms, to perform affine transformations (rotations, displacements, and uniform scaling), and other matters described in further detail elsewhere. 11 We found that a modern professional artist, using only mechanical copying/enlarging devices known from the time of van Eyck, could indeed achieve a fidelity (expressed as a Chamfer distance) roughly the same as van Eyck. Our experimental result, historical information, and physical evidence (pinprick holes), led us to reject as unpersuasive the claim that van Eyck used an optical projector when copying/enlarging this work. ...
Can computer systems help us understand paintings and the methods of great masters? In this three-part series, David C. Stork describes how he uses techniques adapted from computer vision and image analysis to shed light on art and problems in art history. In part 1, the subject is perspective, and among the questions posed: did the artists of the Renaissance use optical projections as has been recently hypothesized?
... The full procedure required us to use thinning algorithms, to perform affine transformations (rotations, displacements, and uniform scaling), and other matters described in further detail elsewhere. 11 We found that a modern professional artist, using only mechanical copying/enlarging devices known from the time of van Eyck, could indeed achieve a fidelity (expressed as a Chamfer distance) roughly the same as van Eyck. Our experimental result, historical information, and physical evidence (pinprick holes), led us to reject as unpersuasive the claim that van Eyck used an optical projector when copying/enlarging this work. ...
The authors comment on and refute several points made in Charles Falco's article regarding computer image analysis and art.
