ngmix: config-selectable UberSeg neighbour masking (BLEND_HANDLING)

example/cfis/config_tile_Ng_template.ini

@@ -83,5 +83,25 @@ PIXEL_SCALE = 0.186
 # noisy for stars and flagged as incorrect — see #767).
 CENTROID_SOURCE = wcs
 
+# BLEND_HANDLING (optional): neighbour treatment. "noisefill" (default,
+# historical) replaces a neighbour's pixels with a noise realisation;
+# "uberseg" hard-masks (weight -> 0) every pixel closer to a neighbour's
+# segmentation footprint than to the central object. "uberseg" REQUIRES
+# SEG_VIGNET_PATH below.
+# BLEND_HANDLING = uberseg
+
+# SEG_VIGNET_PATH (optional): coadd-frame SExtractor segmentation vignets
+# (the CLASSIC-mode VIGNETMAKER_RUNNER_RUN_3 seg output), row-aligned to the
+# tile catalogue and on the same 51x51 grid as the coadd VIGNET. Required for
+# BLEND_HANDLING = uberseg; when set, the file must exist for every tile
+# (missing file -> error). Omit for the noise-fill path.
+# SEG_VIGNET_PATH = $SP_RUN/output/run_sp_tile_PiViVi/vignetmaker_runner_run_3/output/seg_vignet{file_number_string}.fits
+
+# DILATE_NEIGHBOUR (optional): binary-dilation iterations enlarging the uberseg
+# neighbour mask, to absorb the few-pixel coadd-vs-epoch seg-overlay offset.
+# Ignored unless BLEND_HANDLING = uberseg. Default 1 (~one pixel); 0 recovers
+# the pure Sheldon UberSeg mask.
+# DILATE_NEIGHBOUR = 1
+
 ID_OBJ_MIN = X
 ID_OBJ_MAX = X

example/cfis/config_tile_PiViVi_canfar_sx.ini

@@ -21,7 +21,7 @@ RUN_NAME = run_sp_tile_PiViVi
 # Module name, single string or comma-separated list of valid module runner names
 #MODULE = psfex_interp_runner,
 
-MODULE = psfex_interp_runner, vignetmaker_runner, vignetmaker_runner
+MODULE = psfex_interp_runner, vignetmaker_runner, vignetmaker_runner, vignetmaker_runner
 
 # Parallel processing mode, SMP or MPI
 MODE = SMP
@@ -166,3 +166,39 @@ PREFIX =
 ME_IMAGE_EXP_DIR = $SP_EXP
 ME_IMAGE_EXP_RUNNERS = split_exp_runner, split_exp_runner, split_exp_runner, sextractor_runner, sextractor_runner
 ME_IMAGE_PATTERN = flag, image, weight, background, background_rms
+
+
+[VIGNETMAKER_RUNNER_RUN_3]
+
+# Cut per-object coadd-frame segmentation stamps from the tile SExtractor
+# SEGMENTATION check image (config_tile_Sx.ini: CHECKIMAGE = BACKGROUND,
+# SEGMENTATION). Integer labels, no interpolation, zero-padded — CLASSIC mode
+# guarantees this. Row-aligned to the tile catalogue on the same XWIN/YWIN
+# centres and 51x51 grid as the coadd VIGNET, so ngmix can overlay the seg
+# stamp directly for uberseg neighbour masking (shapepipe#776).
+
+INPUT_DIR = run_sp_tile_Sx:sextractor_runner
+
+FILE_PATTERN = sexcat, segmentation
+
+FILE_EXT = .fits, .fits
+
+# NUMBERING_SCHEME (optional) string with numbering pattern for input files
+NUMBERING_SCHEME = -000-000
+
+MASKING = False
+MASK_VALUE = 0
+
+# CLASSIC: cut stamps at object positions in the coadd (tile) frame.
+MODE = CLASSIC
+
+# Coordinate frame type, one in PIX (pixel frame), SPHE (spherical coordinates)
+COORD = PIX
+POSITION_PARAMS = XWIN_IMAGE,YWIN_IMAGE
+
+# Vignet size in pixels — MUST equal the coadd VIGNET size (51) so the seg
+# stamp overlays the galaxy stamp on an identical grid.
+STAMP_SIZE = 51
+
+# Output file name prefix, file name is <PREFIX>_vignet.fits
+PREFIX = seg

example/cfis/config_tile_Sx.ini

@@ -97,7 +97,7 @@ BKG_FROM_HEADER = False
 # BACKGROUND, BACKGROUND_RMS, INIBACKGROUND,
 # MINIBACK_RMS, -BACKGROUND, #FILTERED,
 # OBJECTS, -OBJECTS, SEGMENTATION, APERTURES
-CHECKIMAGE = BACKGROUND 
+CHECKIMAGE = BACKGROUND, SEGMENTATION
 
 # File name suffix for the output sextractor files (optional)
 SUFFIX = sexcat

example/cfis/final_cat.param

@@ -26,6 +26,9 @@ NGMIX_G2_PSF_ORIG_NOSHEAR
 N_EPOCH
 NGMIX_N_EPOCH
 
+# Blend flag: coadd seg stamp held a non-central footprint (shapepipe#776)
+NGMIX_NEIGHBOUR_FLAG
+
 ## Shape measurement outputs
 ## Ngmix: model fitting
 

src/shapepipe/modules/make_cat_package/make_cat.py

@@ -327,9 +327,11 @@ def _save_ngmix_data(self, ngmix_cat_path, moments=False):
         Save the NGMIX catalogue into the final one.
 
         Column grammar: ``NGMIX[m]_<COMPONENT>[_ERR][_<OBJECT>]_<SHEAR>``,
-        plus three OBJECT/SHEAR-less per-object metadata columns
+        plus four OBJECT/SHEAR-less per-object metadata columns
         (``NGMIX[m]_MCAL_FLAGS``, ``NGMIX_N_EPOCH``,
-        ``NGMIX_MCAL_TYPES_FAIL``). The galaxy is the implicit default object
+        ``NGMIX_MCAL_TYPES_FAIL``, ``NGMIX_NEIGHBOUR_FLAG`` — the last a blend
+        flag set when the coadd seg stamp held a non-central footprint,
+        shapepipe#776). The galaxy is the implicit default object
         and carries NO ``OBJECT`` token (``NGMIX_G1_NOSHEAR``, dropping the
         ``GAL`` segment carried by the pre-#761 names). The explicit PSF
         objects are ``PSF_ORIG``
@@ -369,6 +371,9 @@ def _save_ngmix_data(self, ngmix_cat_path, moments=False):
             #return err_msg
 
         ngmix_mcal_types_fail = ngmix_cat_file.get_data()["mcal_types_fail"]
+        # Per-object blend flag (shapepipe#776): the seg stamp held a
+        # non-central footprint. Galaxy-only (non-moments), like N_EPOCH.
+        ngmix_neighbour_flag = ngmix_cat_file.get_data()["neighbour_flag"]
         # Needed in both moments and non-moments modes (used unconditionally
         # below), so read them outside the branch.
         ngmix_mcal_flags = ngmix_cat_file.get_data()["mcal_flags"]
@@ -384,6 +389,7 @@ def _save_ngmix_data(self, ngmix_cat_path, moments=False):
 
             self._add2dict("NGMIX_N_EPOCH", np.zeros(n_obj))
             self._add2dict("NGMIX_MCAL_TYPES_FAIL", np.zeros(n_obj))
+            self._add2dict("NGMIX_NEIGHBOUR_FLAG", np.zeros(n_obj))
 
         prefix = f"NGMIX{m}"
 
@@ -535,6 +541,11 @@ def _save_ngmix_data(self, ngmix_cat_path, moments=False):
                         ngmix_mcal_types_fail[ind[0]],
                         idx,
                     )
+                    self._add2dict(
+                        "NGMIX_NEIGHBOUR_FLAG",
+                        ngmix_neighbour_flag[ind[0]],
+                        idx,
+                    )
 
         ngmix_cat_file.close()