School of Electronic Information Engineering, Tianjin University, Tianjin, China.
Opt Lett. 2013 May 15;38(10):1706-8. doi: 10.1364/OL.38.001706.
We present an effective method for defocus map estimation from a single natural image. It is inspired by the observation that defocusing can significantly affect the spectrum amplitude at the object edge locations in an image. By establishing the relationship between the amount of spatially varying defocus blur and spectrum contrast at edge locations, we first estimate the blur amount at these edge locations, then a full defocus map can be obtained by propagating the blur amount at edge locations over the entire image with a nonhomogeneous optimization procedure. The proposed method takes into consideration not only the affect of light refraction but also the blur texture of an image. Experimental results demonstrate that our proposed method is more reliable in defocus map estimation compared to various state-of-the-art methods.
我们提出了一种从单张自然图像中估计离焦图的有效方法。它的灵感来源于这样一个观察结果，即离焦会显著影响图像中物体边缘位置的光谱幅度。通过建立空间变化离焦模糊量与边缘位置光谱对比度之间的关系，我们首先估计这些边缘位置的模糊量，然后通过非均匀优化过程将边缘位置的模糊量传播到整个图像上，从而获得完整的离焦图。所提出的方法不仅考虑了光折射的影响，还考虑了图像的模糊纹理。实验结果表明，与各种最先进的方法相比，我们提出的方法在离焦图估计方面更可靠。
