Optimal Design of Multichannel Equalizers for the Structural Similarity Index

Chai, Lu; Sheng, Yuxia

doi:10.1109/tip.2014.2367320

Cited by 9 publications

(1 citation statement)

References 34 publications

(55 reference statements)

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“…Subjective evaluation is to observe, analyze, and judge the result of speckle suppression from human vision, which is mainly reflected in the preservation of image texture and detail information. Objective evaluation uses undistorted images as evaluation, and the commonly used indexes are peak signal to noise ratio (PSNR) [61], structural similarity index (SSIM) [62], equivalent numbers of looks (ENL) [63], mean value [64], and standard deviation [65]. In this paper, PSNR and SSIM are used to evaluate the simulated SAR experiment, and ENL is used to evaluate the real SAR image experiment.…”

Section: Evaluation Index Of Sar Image Speckle Suppressionmentioning

confidence: 99%

Convolutional Neural Network with a Learnable Spatial Activation Function for SAR Image Despeckling and Forest Image Analysis

et al. 2021

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Synthetic aperture radar (SAR) images are often disturbed by speckle noise, making SAR image interpretation tasks more difficult. Therefore, speckle suppression becomes a pre-processing step. In recent years, approaches based on convolutional neural network (CNN) achieved good results in synthetic aperture radar (SAR) images despeckling. However, these CNN-based SAR images despeckling approaches usually require large computational resources, especially in the case of huge training data. In this paper, we proposed a SAR image despeckling method using a CNN platform with a new learnable spatial activation function, which required significantly fewer network parameters without incurring any degradation in performance over the state-of-the-art despeckling methods. Specifically, we redefined the rectified linear units (ReLU) function by adding a convolutional kernel to obtain the weight map of each pixel, making the activation function learnable. Meanwhile, we designed several experiments to demonstrate the advantages of our method. In total, 400 images from Google Earth comprising various scenes were selected as a training set in addition to 10 Google Earth images including athletic field, buildings, beach, and bridges as a test set, which achieved good despeckling effects in both visual and index results (peak signal to noise ratio (PSNR): 26.37 ± 2.68 and structural similarity index (SSIM): 0.83 ± 0.07 for different speckle noise levels). Extensive experiments were performed on synthetic and real SAR images to demonstrate the effectiveness of the proposed method, which proved to have a superior despeckling effect and higher ENL magnitudes than the existing methods. Our method was applied to coniferous forest, broad-leaved forest, and conifer broad-leaved mixed forest and proved to have a good despeckling effect (PSNR: 23.84 ± 1.09 and SSIM: 0.79 ± 0.02). Our method presents a robust framework inspired by the deep learning technology that realizes the speckle noise suppression for various remote sensing images.

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