Bad tag conversion with dicom

[George]

Hello,

I have a dicom that when I display using a dicom viewer I see that it is an RGB picture rather than a monochrome which should be.
so I do I exactly convert such dicom file to have correct display in dicom viewer?

Best Regards
George Zaher

[Marco Eichelberg]

If I understand the question correctly, you want to convert a color image into a monochrome image. That requires calculation of the gray values using the RGB to gray conversion formula, the computation of a new PixelData array, and the adaptation of a few attributes such as Samples per Pixel, Photometric Interpretation, Image Type, and SOP Instance UID, since you are generating a different, derived image.