White line error after using Slice assembly

Microwave Toolbox
#1

Dear all,
I used two methods over my AOI for pre-processing of GRD Sentinel-1 data and results are presented in image 1 and 2:

white line.PNG
white line.PNG1271×765 181 KB

Preprocessing steps for image 1:

  1. Apply orbit file
  2. Thermal noise removal
  3. Calibration to beta naught
    4. Radiometric terrain flattering
  4. S1 Slice Assembly

Preprocessing steps for image 2:

  1. Apply orbit file
  2. Thermal noise removal
  3. Calibration to sigma naught
  4. S1 Slice Assembly (as I am interested to bigger area, so I used Slice Assembly to expand my AOI by using two Sentinel-1 images)

I used same data sets:

S1A_IW_GRDH_1SDV_20210626T153344_20210626T153409_038513_048B7E_9894.zip
S1A_IW_GRDH_1SDV_20210626T153409_20210626T153434_038513_048B7E_DB6C.zip

However, I do not know why I see a white line in image 1 and NOT in image 2? I only applied one more step (4.Radiometric terrain flattering) in ‘Preprocessing steps for image 1’, can this caused this white line problem for me?

#2

Looks like the line goes along the border of both scenes, right?
If so, maybe you first apply slice assembly and terrain Flattening afterwards.

#3

Yes @ABraun the line goes along the border of both scenes.

Thanks it works but something is strange for me. I did these processing also for another two image with same relative orbit but a bit different location (you can see differences in below image):

PREVIOUS Images:

S1B_IW_GRDH_1SDV_20210620T153251_20210620T153316_027442_0346FC_DDFA.zip

S1B_IW_GRDH_1SDV_20210620T153316_20210620T153341_027442_0346FC_64FD.zip

and I applied:

  1. Apply orbit file
  2. Thermal noise removal
  3. Calibration to beta naught
  4. Radiometric terrain flattering
  5. S1 Slice Assembly
    WHITE LINE_PROBLEM.PNG
    WHITE LINE_PROBLEM.PNG1351×755 111 KB

And it did not make this white line and everything was OK but I do not know why for new pair, I had this problem. This is a bit strange for me.