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Hello everyone, I'm posting here my question because I have some issues with interpolation algorithm.

Indeed, I'm working with astronomical images and I need to make some transformations on the images. To do that I'm using the function warpPerspective and the Lanczos4 algorithm:

• Transformation can be rotation, shift, shear (very few), but generally not scale.

The problem is that I have artefact with the interpolation all around stars. This is normal, I know but I would like to know the best way to proceed to remove these artectacts. Is there a protect algorithm ? I tried the super sampling algorithm:

• I multiply the size of the image by 2 (cubic)
• I make the transformation
• I divide the size of the image by 2 (cubic)

but results is blured, while artefacts have disapeared. In fact, in this last case, the final images looks like the interpolation algorithm used for super sampling. If I use Lanczos4 for resizing the image, I will see the artefacts again.

You can see examples at this adress: http://hpics.li/1859d75

So am I doing something wrong ? What is the best practice ?

Best Regards

Hello everyone, I'm posting here my question because I have some issues with interpolation algorithm.

Indeed, I'm working with astronomical images and I need to make some transformations on the images. To do that I'm using the function warpPerspective and the Lanczos4 algorithm:

• Transformation can be rotation, shift, shear (very few), but generally not scale.

The problem is that I have artefact artifact with the interpolation all around stars. This is normal, I know but I would like to know the best way to proceed to remove these artectacts. artifacts. Is there a protect algorithm ? I tried the super sampling algorithm:

• I multiply the size of the image by 2 (cubic)
• I make the transformation
• I divide the size of the image by 2 (cubic)

but results is blured, while artefacts artifacts have disapeared. In fact, in this last case, the final images looks like the interpolation algorithm used for super sampling. If I use Lanczos4 for resizing the image, I will see the artefacts artifacts again.

You can see examples at this adress: http://hpics.li/1859d75

So am I doing something wrong ? What is the best practice ?

Best Regards

Hello everyone, I'm posting here my question because I have some issues with interpolation algorithm.

Indeed, I'm working with astronomical images and I need to make some transformations on the images. To do that I'm using the function warpPerspective and the Lanczos4 algorithm:

• Transformation can be rotation, shift, shear (very few), but generally not scale.

The problem is that I have artifact with the interpolation all around stars. This is normal, I know but I would like to know the best way to proceed to remove these artifacts. Is there a protect algorithm ? I tried the super sampling algorithm:

• I multiply the size of the image by 2 (cubic)
• I make the transformation
• I divide the size of the image by 2 (cubic)

but results is blured, while artifacts have disapeared. In fact, in this last case, the final images looks like the interpolation algorithm used for super sampling. If I use Lanczos4 for resizing the image, I will see the artifacts again.

You can see examples at this adress: http://hpics.li/1859d75

So am I doing something wrong ? What is the best practice ?

Best Regards

Hello everyone, I'm posting here my question because I have some issues with interpolation algorithm.

Indeed, I'm working with astronomical images and I need to make some transformations on the images. To do that I'm using the function warpPerspective and the Lanczos4 algorithm:

• Transformation can be rotation, shift, shear (very few), but generally not scale.

The problem is that I have artifact with the interpolation all around stars. This is normal, I know but I would like to know the best way to proceed to remove these artifacts. Is there a protect algorithm ? I tried the super sampling algorithm:

• I multiply the size of the image by 2 (cubic)
• I make the transformation
• I divide the size of the image by 2 (cubic)

but results is blured, while artifacts have disapeared. In fact, in this last case, the final images looks like the interpolation algorithm used for super sampling. If I use Lanczos4 for resizing the image, I will see the artifacts again.

You can see examples at this adress: http://hpics.li/1859d75

So am I doing something wrong ? What is the best practice ?

Best Regards