Registered OME-TIFF file size abnormally larger than original image

[pimooook]

        registrar = registration.Valis(img_list=[he, exp],src_dir='', dst_dir=subdir)
        rigid_registrar, non_rigid_registrar, error_df = registrar.register(brightfield_processing_cls=CustomProcessor)
        registrar.warp_and_save_slides(subdir, non_rigid=False)

I performed registration using the code above, but the registered image is much larger than the original. The original .tiff is 1–2 GB, while the registered .ome.tiff ends up being as large as 10 GB. Could you explain why this happens?

[cdgatenbee]

Hi @pimooook,

I suspect that this is due to the compression method being used. By default, "deflate" compression is used, as it works with most datatypes. However, if your images are uint8 RGB, you could use jpeg compression, which should help reduce the file size. This can be specified when saving the warped slides, i.e. registrar.warp_and_save_slides(subdir, non_rigid=False, compression="jpeg"). Please try that out and let me know if it helps.

Best,
-Chandler

[pimooook]

This fixes some issues. The generated OME-TIFF file has become smaller, but it is still quite large.
My original TIFF is 2.5 GB. The OME-TIFF was 30 GB before using JPEG compression, and it is 10 GB after enabling JPEG.