- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Digital Image Interpolation in MATLAB? || Covariance-Based Interpolation
摘要： The previous chapter has shown the importance of maintaining the image edges in image interpolation to obtain a natural-looking interpolated image. We have discussed the basic structure and model of image edges. The multi-resolution analysis presented in the chapter on wavelet (Chapter 6) has shown that an ideal step edge obeys the geometric regularity property [43], which refers to the correlation structure of an ideal step edge being independent of the scale of the image. In other words, the correlation structure of the local region that has enclosed an edge feature in the low-resolution image should have a similar correlation structure in the corresponding region in the high-resolution image. The edge-directed interpolated algorithms presented in the last chapter aim to preserve the correlation structures across scales by estimating the unknown pixels with the consideration of the locations and orientations of the image edges. The locations and the orientations of the image edges are specified by explicit edge map obtained through some kind of edge detection techniques. There are several problems associated with such approach. Firstly, the edge detection technique quantized the edge orientation in finite number of cases. As a result, the interpolation results can only preserve limited classes of correlation structures during the interpolation process. In other words, the geometric regularity cannot be fully preserved between the low-resolution image and the interpolated high-resolution image. Secondly, the edge detection algorithm has detection accuracy problems in both the spatial location of the edge pixel and the orientation of the associated edge. As a result, the edge-directed interpolation algorithm might falsely preserve a nonexisting edge structure and results in image artifacts with unnatural appearance and low in peak signal-to-noise ratio (PSNR). To achieve good image interpolation result, the geometric regularity property should be fully exploited. Various algorithms have been proposed in literature that aim to preserve the geometric regularity between the low-resolution image and the interpolated high-resolution image, which include directly considering the geometric regularity in spatial domain [12, 38], reformulating the problem into a set of partial differential equations [6, 47], and constructing a convex set of geometric regularity [54], and proposed a projection-onto-convex-set algorithm to achieve an interpolated image with the best matched correlation structure between the low-resolution image and the interpolated high-resolution image.
关键词： geometric regularity,MATLAB,edge-directed interpolation,NEDI,covariance-based interpolation,image interpolation
更新于2025-09-23 15:22:29
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Weighted Sum-Based Color Filter Array Interpolation Using Taylor Series Cubic Approximation
摘要： In this paper, we introduce a weighted sum-based color filter array interpolation method using Taylor series cubic approximation. We use a high-order approximation to predict accurate pixel values during the reconstruction of quincunx grid-sampled green channels, and perform a weighted average-based interpolation in a large local window. We also perform prediction utilizing a color difference model in a small local window to generate additional green values. By applying the weighted sum method to the predicted green values in two local windows, green channel can be enhanced. The remaining color components, namely, the rectangular grid-sampled red and blue channels, are interpolated utilizing the weighted average method of the color difference model. Additionally, we propose a post-processing method that removes the zipper artifacts generated during the interpolation process. Experimental results demonstrate that the proposed color filter array interpolation system outperforms existing algorithms in terms of both objective and subjective performance.
关键词： image interpolation,Color filter array interpolation,Bayer pattern,Taylor series approximation,demosaicking
更新于2025-09-09 09:28:46
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[IEEE 2018 Tenth International Conference on Quality of Multimedia Experience (QoMEX) - Cagliari (2018.5.29-2018.6.1)] 2018 Tenth International Conference on Quality of Multimedia Experience (QoMEX) - A Hybrid Quality Metric for Non-Integer Image Interpolation
摘要： A great need of High-Resolution (HR) images has boosted the development of interpolation techniques. However, it is still a challenging task to objectively evaluate the perceptual quality of interpolated images, especially when the interpolation factor is a non-integer. To address this issue, we propose a hybrid quality metric for non-integer image interpolation that combines both reduced-reference and no-reference philosophies. To validate the proposed metric, we construct a non-integer interpolated image database and conduct a subjective user study to collect subjective opinions for each image. Experiments on the new database show that the proposed metric outperforms previous methods by a large margin.
关键词： high-resolution images,perceptual image processing,Image quality assessment,image interpolation
更新于2025-09-04 15:30:14