How to modified the proposed SR to train with y_only input ?

[vincentweisen1357]

Hi all,

In BasicSR, we can add the 'color: y' option to the .YAML file to train with y_only grayscale image.
For instance:

datasets:
train:
name: DIV2K
type: PairedImageDataset
color: y

However, RealESRGANDataset do not provide this option, so that I tried to modify myself in RealESRGANDataset like this before function return:

    **img_gt = bgr2ycbcr(img_gt, y_only=True)[..., None]**
    img_gt = img2tensor([img_gt], bgr2rgb=True, float32=True)[0]
    kernel = torch.FloatTensor(kernel)
    kernel2 = torch.FloatTensor(kernel2)

But still report an error in realesrnet_model.py

line102 : "Input image tensor permitted channel values are [3], but found 1"
out = random_add_poisson_noise_pt(
out,
scale_range=self.opt['poisson_scale_range'],
gray_prob=gray_noise_prob,
clip=True,
rounds=False)

Anyone can help please?