issue about pre-trained model

[zhujiawen1994]

Hi, thanks for your working. Why is the psnr value on Set14/bridge I get with _Test/model/MSRNx2.pt not so good? this is psnr， it different from you provided: x2 3 bridge.png: PSNR= 26.207258 SSIM= 0.839023

how do you compute the PSNR and SSIM on this bridge image? It is gray image, but the output of net is RGB image.

[CV-JunchengLi]

Following previous works（e.g., EDSR、RCAN）, our model was trained on RGB images, and the reconstructed images are RGB images. For benchmark datasets, all our SR results are evaluated on the Y channel of transformed YCbCr space. You can use MSRN-PyTorch/MSRN/Test/Prepare_TestData_HR_LR.m to generate test images, and use MSRN-PyTorch/MSRN/Test/Evaluate_PSNR_SSIM.m to test PSNR and SSIM. Noticed that our model was trained on bicubic degenerate images.

[zhujiawen1994]

Thanks for your reply. In OriginalTestData/Set14, I got the correct PSNR and SSIM values(same as you provided) except for the image bridge(the third image). I found that the image bridge is a single-channel image and the output of the network is a RGB image. So, I convert the output RGB image into a YCbCr image, take the Y channel, and then measure the psnr value with the bridge image in OriginalTestData/Set14. But I got this psnr and ssim: x2 3 bridge.png: PSNR= 26.207258 SSIM= 0.839023 this is what you provide: x2 3 bridge_MSRN_x2.png: PSNR= 29.516140 SSIM= 0.869215 I mean how to measure the PSNR and SSIM just on this bridge image in OriginalTestData/Set14? Thanks again.

[CV-JunchengLi]

我用中文回复你可能更清楚一点~ Set14中的 bridge 图像确实是单通道的灰度图，但因为EDSR、RCAN以及我们的MSRN都是基于RGB3通道进行训练的。所以我们都做了一个处理，那就是对于单通道的图像，我们都先扩展到了3通道，然后再送入到网络中进行重建。最后网络的输出也都是3通道的图像，然后在测试PSNR和SSIM的时候，遵循前人都只对比Y通道的原则，我们将着5个数据集重建后的图像全部转到了YCbCr空间，然后取Y通道进行测试。

Prepare_TestData_HR_LR.m 这个脚本中 if size(im_ori, 3) == 1 im_ori = cat(3, im_ori, im_ori, im_ori); end 该语句会对图像进行扩展。如果你不用该脚本准备测试集也没事，你输入到网络中的时候，重建代码也有一样的通道扩展代码。所以我们的代码都会先把单通道图像扩展为3通道的图像，再进行重建。

在测试bridge这张图的时候，其HR图像也是经过扩展成3通道的，最后在转换为YCbCr空间，取Y通道，与SR的Y通道进行比较。而不是拿bridge重建后的图像的Y通道和bridge的原图进行比较，因为原图实质上是gray image，并不是YCbCr空间上的Y通道图像

[zhujiawen1994]

噢噢 明白了 爱你么么哒

[zhujiawen1994]

你好。不好意思又一次打扰你。 我想问一下，option.py 里的参数resume和load是什么关系。resume是加载模型所用，那load是什么用呢？ 谢谢你啦^_^

[CV-JunchengLi]

如果你想加载预训练好的模型，或者想加载训练一半的模型，直接使用 --pre_train 参数就行，其他参数用不到