Despeckle gives UnsupportedPixelFormat error

[pankaj5k]

I have to provide a Despeckle filter for Tiff files and it seems to work for very small tiff files but on some files i get GdPicture status 62 i.e "UnsupportedPixelFormat".

Why do i get this error and are there any specific files requirements for this.

The file is a 1221*1500 pixels in size with bit depth 24 and LZW compression at 96*96 dpi.

It has 22 pages in all.

Also, wanted to confirm that the filter will only apply to the current selected page or all pages when the files is being shown in Gdviewer with DisplayFromGdPictureImage

Thanks

[Loïc]

Hello,

I think you are talking about the FxBitonalDespeckle() filter, right ?

From the reference guide:

Only 1 bit per pixel images with black and white palette are supported

If you need a version for other pixel format just use the BitonalDespeckle() method.

Kind regards,

Loïc

[pankaj5k]

Hi Loic,

I am now using FxMedian for non bitonal files and it works well. The only problem is that it eats away some written text in the scanned documents.

I tired to reduce the KernelSize but even setting it to 1 means 9 pixels which is equivalent to the FxDespeckle Method.

Is there a way to only reduce the noise and not make the text unlegible?

[SamiKharma]

Hi,

9 Pixels is the least you can have in any 2D kernel convolution operation. If you want a less effect on the text, BitonalDespeckle might help. If the problem is with the bit depth, then convert the document to 1bpp, call the BitonalDespeckle, and convert the bit depth back.

If the problem still persists, then I advise the use of a higher dpi while scanning so that the text size is not too small and nearing the size of the noise.

Best,
Sami

[pankaj5k]

Hi Sami,

I tried using the convert to 1bpp method and then use BitonalDespeckle but that doesnt help also.

I will try increasing the dpi and then test it.

Thanks for your quick response as always.