Understanding Sentinel-1 annotation Files

I‘m removing noise based on Sentinel-1 auxiliary files.

I opened the calibration xml file and noise xml file in Sentinel-1 annotation folder. And the Sentinel-1 TIFF image is 8992* 10376, the maximum line number in calibration files 9158(Fig. 1) while in noise file is 8991(Fig. 2).

Due to calibration and noise points based on sample points from TIFF image, why there exists 9158 in calibration xml file over 8992 rows of TIFF image?


                                      Fig. 2

I think the following website( Sentinel-1 Product Specification) merely introduces Sentinel-1 tiff file without the difference between calibration file and noise file.

The following website introduces thermal denoising of Products Generated by the S-1 IPF. Introducing how to remove noise using snappy.

I just adopted a method that maybe wrong way , I don’t using the last line of calibration xml because I found the last second line number is same as Sentinel-1 image rows. For my given xml information , Sentinel-1 image is 8992 rows.