Correction: Intrinsic Image Decomposition via Structure-Preserving Image Smoothing and Material Recognition.

[This corrects the article DOI: 10.1371/journal.pone.0166772.]

Intrinsic Image Decomposition via Structure-Preserving Image Smoothing and Material Recognition

<div><p>Decoupling shading and reflectance from complex scene-images is a long-standing problem in computer vision. We introduce a framework for decomposing an image into the product of an illumination component and a reflectance component. Due to the ill-posed nature of the problem, prior information on shading and reflectance is mandatory. The proposed method adopts the premise that pixels in a region with similar chromaticity values should have the same reflectance. This assumption was used to minimize the <i>l</i>_<i>2</i> norm of the local per-pixel reflectance gradients to extract the shading and reflectance components. To obtain smooth chromatic regions, texture was treated in a new style. Texture was removed in the first step of the algorithm and the smooth image was processed for intrinsic decomposition. In the final step, texture details were added to the intrinsic components based on the material of each pixel. In addition, user-assistance was used to further refine the results. The qualitative and quantitative evaluation on the MIT intrinsic dataset indicated that the quality of intrinsic image decomposition was improved in comparison with previous methods.</p></div

Intrinsic image decomposition results from our method and methods of [19] and [38].

<p>(A, F) The original image and added user brushes, (B, C) reflectance components without and with user brushes, (D) reflectance component obtained in Bi et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.ref019" target="_blank">19</a>], (E) reflectance component obtained in Bell et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.ref038" target="_blank">38</a>]. (G, H) shading component from our method without and with user brushes, (I) shading component obtained from Bi et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.ref019" target="_blank">19</a>] and (J) shading component obtained from the method of Bell et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.ref038" target="_blank">38</a>] (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.s007" target="_blank">S7 File</a>).</p

Structure-preserving image smoothing.

<p>(A) Original image, (B) smooth image (image selected from the MINC database [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.ref018" target="_blank">18</a>] (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.s002" target="_blank">S2 File</a>)).</p

Illustration of the intrinsic image decomposition pipe-line.

<p>(A) Original image, (B) smooth image with added user brushes, (C) material segmentation, (D) reflectance material, (E) shading material, (F) reflectance component obtained from <i>J</i>, (G) reflectance component with added texture detail, (H) reflectance component obtained by applying user brushes, (I) shading component of the smooth image, (J) shading component with added texture details, and (K) shading component with added user brushes (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.s005" target="_blank">S5 File</a>).</p

Comparison of LMSE values of our results and the results by previous works [7, 22, and 39] on the MIT dataset.

<p>Comparison of LMSE values of our results and the results by previous works [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.ref007" target="_blank">7</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.ref022" target="_blank">22</a>, and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.ref039" target="_blank">39</a>] on the MIT dataset.</p

Effect of image smoothing in the intrinsic image decomposition.

<p>(A) Original image, (B) smooth image, (C) texture image, Images (D,E,F,G) show the reflectance and shading components when using our method and Shen et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.ref007" target="_blank">7</a>] respectively (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.s009" target="_blank">S9 File</a>).</p

Example of reflectance and shading components extracted from the MIT intrinsic image dataset.

<p>For each example the following are shown in order: Original image, ground truth reflectance, reflectance component from our method, reflectance component from Shen et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.ref007" target="_blank">7</a>], ground truth shading component, shading component obtained from our method, shading component obtained from Shen el al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.ref007" target="_blank">7</a>].</p

Reflectance component for the smooth input image with and without user brushes.

<p>(A) Original image, (B) image with added user brushes, (C, D) reflectance components without and with user brushes (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0166772#pone.0166772.s003" target="_blank">S3 File</a>).</p