19.01.2023, 22:14
Hello Selur,
thanks for your release. I performed some tests and I think that could be useful share the results obtained.
The problem that required the implementation of additional filters after the resizing, is mainly due to the fact that realesr-general, which is a very good resizer, sometime introduces artifacts on the resized image that are very bad. Of course, if the video to be resized is very good these problems are absent, but probably in this case would be not necessary to use realesr-general. An example of artifacts introduced by realesr-general is shown in the following link:
https://imgsli.com/MTQ4NTE3
the video contained some noise so I applied KMNL with strength 2.0 to remove it (KMNL is a good and fast denoise). As it is possible to see, with realesr the face was deformed and were removed many terrain details. To overcome this problem, it is not possible to simply apply a DeHalo filter (usually used to remove the dark halos from too strong "Edge Enhancement") to improve the images, because in this case the image is already deformed. To solve this problem is necessary to substitute part of the image with an image not deformed.
A simple solution is to merge the video resized with realeser with a video resized with a simpler resize (spline36 or lanczos) at the following link there is the comparison of the merge with weight 0.3 and 0.5:
https://imgsli.com/MTQ4NTI0
In this way the terrain details were restored and with weight 0.3 was removed also the artifact on the face (with weight 0.5 is still a little visible).
It is possible to improve the quality ?: theoretically by performing a weighted merge, could be possible to improve the quality. To do that is available the function MaskedMerge. The problem with this function is that the weights are contained in the mask, there is not the possibility to apply an additional weight to the function call. To solve this problem was decided to use the filter BlindDeHalo3 (BDH3) to add more control on the weights. In the following link there is an example of mask generated using BDH3 with strength 25 and 300:
https://imgsli.com/MTQ4NTI2
As it is possible to see the mask built using BDH3 with strength 300 has the white edges softer (less weight) and thicker respect to the one built with strength 25. What is the effect of this mask on the image? at the following link there is the answer:
https://imgsli.com/MTQ4NTM1
unfortunately the effect is not very good, this because the artifact is located on dark part of the mask that is replaced with the frame resized with realeser. So it is necessary to invert the mask. The inverted masks are shown at the following link:
https://imgsli.com/MTQ4NTM2
This could be a good solution, since realesr is very good in enhance the details and the edges of the objects. Using the inverted mask, only the dark lines (the edges) will be replaced with realesr. It is interesting to note that BDH3(300) allows to reduce the weights on the edges, especially on the face of the woman. Let’s see the impact of these masks on the final image:
https://imgsli.com/MTQ4NTM4
In both the images the artifact on the face was almost removed, with BDH3(25) providing a sharper image.
Finally in the following link there is the comparison between the image obtained with a simple weight of 0.3 the one obtained using the inverted mask built with BDH3(25):
https://imgsli.com/MTQ4NTQw
The 2 images are similar but the one obtained with BDH3(25) is a little sharper, because with the mask was possible to apply more weight on the edges obtained with realesr.
To see better the effect of the filters applied, in this link there is the comparison between the original image and the final one obtained with the inverted mask built with BDH3(25):
https://imgsli.com/MTQ4NTQz
I’d like thanks again Selur without whose help it would not have been possible to produce the test images.
Dan
thanks for your release. I performed some tests and I think that could be useful share the results obtained.
The problem that required the implementation of additional filters after the resizing, is mainly due to the fact that realesr-general, which is a very good resizer, sometime introduces artifacts on the resized image that are very bad. Of course, if the video to be resized is very good these problems are absent, but probably in this case would be not necessary to use realesr-general. An example of artifacts introduced by realesr-general is shown in the following link:
https://imgsli.com/MTQ4NTE3
the video contained some noise so I applied KMNL with strength 2.0 to remove it (KMNL is a good and fast denoise). As it is possible to see, with realesr the face was deformed and were removed many terrain details. To overcome this problem, it is not possible to simply apply a DeHalo filter (usually used to remove the dark halos from too strong "Edge Enhancement") to improve the images, because in this case the image is already deformed. To solve this problem is necessary to substitute part of the image with an image not deformed.
A simple solution is to merge the video resized with realeser with a video resized with a simpler resize (spline36 or lanczos) at the following link there is the comparison of the merge with weight 0.3 and 0.5:
https://imgsli.com/MTQ4NTI0
In this way the terrain details were restored and with weight 0.3 was removed also the artifact on the face (with weight 0.5 is still a little visible).
It is possible to improve the quality ?: theoretically by performing a weighted merge, could be possible to improve the quality. To do that is available the function MaskedMerge. The problem with this function is that the weights are contained in the mask, there is not the possibility to apply an additional weight to the function call. To solve this problem was decided to use the filter BlindDeHalo3 (BDH3) to add more control on the weights. In the following link there is an example of mask generated using BDH3 with strength 25 and 300:
https://imgsli.com/MTQ4NTI2
As it is possible to see the mask built using BDH3 with strength 300 has the white edges softer (less weight) and thicker respect to the one built with strength 25. What is the effect of this mask on the image? at the following link there is the answer:
https://imgsli.com/MTQ4NTM1
unfortunately the effect is not very good, this because the artifact is located on dark part of the mask that is replaced with the frame resized with realeser. So it is necessary to invert the mask. The inverted masks are shown at the following link:
https://imgsli.com/MTQ4NTM2
This could be a good solution, since realesr is very good in enhance the details and the edges of the objects. Using the inverted mask, only the dark lines (the edges) will be replaced with realesr. It is interesting to note that BDH3(300) allows to reduce the weights on the edges, especially on the face of the woman. Let’s see the impact of these masks on the final image:
https://imgsli.com/MTQ4NTM4
In both the images the artifact on the face was almost removed, with BDH3(25) providing a sharper image.
Finally in the following link there is the comparison between the image obtained with a simple weight of 0.3 the one obtained using the inverted mask built with BDH3(25):
https://imgsli.com/MTQ4NTQw
The 2 images are similar but the one obtained with BDH3(25) is a little sharper, because with the mask was possible to apply more weight on the edges obtained with realesr.
To see better the effect of the filters applied, in this link there is the comparison between the original image and the final one obtained with the inverted mask built with BDH3(25):
https://imgsli.com/MTQ4NTQz
I’d like thanks again Selur without whose help it would not have been possible to produce the test images.
Dan