Started with scene sequence overlap

src/main/java/com/elphel/imagej/tileprocessor/Interscene.java

@@ -162,32 +162,77 @@ public class Interscene {
 		// Index is easier, no need to change
 //		QuadCLT[]              quadCLTs_half = new QuadCLT[(quadCLTs.length+1)/2];
 //		QuadCLT.SetChannels [] set_channels_half;
+		// consider if it is using initial DSI from previous in overlap mode
+    	boolean overlap_sequences =  clt_parameters.imp.overlap_sequences;
 		int [] start_ref_pointers1 = new int[2];
+		// try to read previously adjusted half-range
+		ErsCorrection ers_reference = quadCLTs[ref_index].getErsCorrection();
 		int cent_index =        earliest_scene + (ref_index - earliest_scene) / 2;
-		int min_num_scenes_half =        min_num_scenes / 2; 
-// TODO: add ref scene itself to the list?		
-		cent_index = setInitialOrientationsIms(
-				clt_parameters,      // final CLTParameters          clt_parameters,
-				min_num_scenes_half,     // int                          min_num_scenes,
-				colorProcParameters, // final ColorProcParameters    colorProcParameters,
-				quadCLTs,            // final QuadCLT[]              quadCLTs, //
-				ref_index,           // final int                    ref_index,
-				set_channels,        // final QuadCLT.SetChannels [] set_channels,
-				batch_mode,          // final boolean                batch_mode,
-				cent_index,     // int                          earliest_scene,
-				start_ref_pointers1, // int []                       start_ref_pointers, // [0] - earliest valid scene, [1] ref_index
-				threadsMax,          // final int                    threadsMax,  // int               threadsMax,
-				updateStatus,        // final boolean                updateStatus,
-				debugLevel);         // final int                    debugLevel)
-		if (cent_index < 0) {
-			System.out.println("setInitialOrientationsIms() first half failed. Consider more graceful bail out.");
-			start_ref_pointers[0] = start_ref_pointers1[0];
-			return cent_index;
+		int min_num_scenes_half =        min_num_scenes / 2;
+		boolean reused_overlap = false;
+		if (overlap_sequences) {
+			int adjusted_scene_index =  ref_index - 1;
+			for (; adjusted_scene_index >= 0 ; adjusted_scene_index--) {
+				// to include ref scene photometric calibration
+				quadCLTs[adjusted_scene_index] = quadCLTs[ref_index].spawnNoModelQuadCLT(
+						set_channels[adjusted_scene_index].set_name,
+						clt_parameters,
+						colorProcParameters, //
+						threadsMax,
+						debugLevel-2);
+				String ts = quadCLTs[adjusted_scene_index].getImageName();
+				if (ts == null) {
+					break;
+				}
+				if (adjusted_scene_index < (min_num_scenes_half-1)) {
+					if (debugLevel > -3) {
+						System.out.println("Overlap mode, too few scenes left for the second half, shortening first to "+
+								(ref_index - adjusted_scene_index - 1));
+					}
+					break;
+				}
+			} // split cycles to remove output clutter
+			adjusted_scene_index++;
+			if ((ref_index - adjusted_scene_index) >= min_num_scenes_half) {
+				if (debugLevel > -3) {
+					System.out.println("Overlap mode, reusing previous scenes adjustment scenes, number of scenes = "+
+							(ref_index - adjusted_scene_index));
+				}
+				cent_index = adjusted_scene_index;
+				reused_overlap = true;
+			} else {
+				if (debugLevel > -3) {
+					System.out.println("Overlap mode, too few scenes to reuse: "+
+							(ref_index - adjusted_scene_index)+" < "+ min_num_scenes_half);
+				}
+			}
+		}
+		if (!reused_overlap) {
+			// TODO: add ref scene itself to the list?		
+			cent_index = setInitialOrientationsIms(
+					clt_parameters,      // final CLTParameters          clt_parameters,
+					min_num_scenes_half,     // int                          min_num_scenes,
+					colorProcParameters, // final ColorProcParameters    colorProcParameters,
+					quadCLTs,            // final QuadCLT[]              quadCLTs, //
+					ref_index,           // final int                    ref_index,
+					set_channels,        // final QuadCLT.SetChannels [] set_channels,
+					batch_mode,          // final boolean                batch_mode,
+					cent_index,     // int                          earliest_scene,
+					start_ref_pointers1, // int []                       start_ref_pointers, // [0] - earliest valid scene, [1] ref_index
+					threadsMax,          // final int                    threadsMax,  // int               threadsMax,
+					updateStatus,        // final boolean                updateStatus,
+					debugLevel);         // final int                    debugLevel)
+			if (cent_index < 0) {
+				System.out.println("setInitialOrientationsIms() first half failed. Consider more graceful bail out.");
+				start_ref_pointers[0] = start_ref_pointers1[0];
+				return cent_index;
+			}
 		}
 		// create new dsi for quadCLTs[earliest_scene1]
 		OpticalFlow.buildRefDSI( // returned is a different instance than input -FIXED
 				clt_parameters,                   // CLTParameters                                 clt_parameters,
 				false,                            // boolean  fast,
+				true,                             // boolean                                       skip_photo,
 				debayerParameters,                // EyesisCorrectionParameters.DebayerParameters  debayerParameters,
 				colorProcParameters,              // ColorProcParameters                           colorProcParameters,
 			    rgbParameters, // EyesisCorrectionParameters.RGBParameters      rgbParameters,
@@ -237,11 +282,12 @@ public class Interscene {
 		}
 		// invert first half, reference to the cent_index, add to cent_index map, generate ref_index ponter and cent_index,
 		// write config for both ref_index and cent_index scenes
-		ErsCorrection ers_reference = quadCLTs[ref_index].getErsCorrection();
+//		ErsCorrection ers_reference = quadCLTs[ref_index].getErsCorrection();
 		ErsCorrection ers_center =    quadCLTs[cent_index].getErsCorrection();
 		String cent_ts = quadCLTs[cent_index].getImageName();
 		double [][] center_xyzatr = new double [][] {ers_reference.getSceneXYZ(cent_ts), ers_reference.getSceneATR(cent_ts)};
 		double [][] inv_cent_xyzatr = ErsCorrection.invertXYZATR(center_xyzatr);
+		// Invert half-sequence to reference cent_index
 		for (int scene_index = cent_index; scene_index <= ref_index; scene_index++) { // include cent_index itself to the map
 			double [][] scene_xyzatr,dxyzatr_dt;
 			if (scene_index == ref_index) {
@@ -259,13 +305,17 @@ public class Interscene {
 					);
 		}
 		// set pointers
-		quadCLTs[ref_index].setRefPointer(cent_ts);
-		quadCLTs[cent_index].setFirstLastPointers(quadCLTs[earliest_scene2],quadCLTs[ref_index]);		
-		quadCLTs[ref_index].set_orient(1); // first orientation // applicable to the center?
-		quadCLTs[ref_index].set_accum(0);  // reset accumulations ("build_interscene") number
+		quadCLTs[ref_index].setRefPointer(cent_ts); // write pointer to center scene to reference scene
+		quadCLTs[cent_index].setFirstLastPointers(quadCLTs[earliest_scene2],quadCLTs[ref_index]);// set first/last to center scene
+		// set quadCLTs[ref_index].set_orient(0); // ? as it has only half?
+		
+//		quadCLTs[ref_index].set_orient(1); // first orientation // applicable to the center?
+//		quadCLTs[ref_index].set_accum(0);  // reset accumulations ("build_interscene") number
 		quadCLTs[ref_index].saveInterProperties( // save properties for interscene processing (extrinsics, ers, ...)  // null pointer
 				null, // String path,             // full name with extension or w/o path to use x3d directory
 				debugLevel+1);
+		
+		
 		quadCLTs[cent_index].set_orient(1); // first orientation
 		quadCLTs[cent_index].set_accum(0);  // reset accumulations ("build_interscene") number
 		quadCLTs[cent_index].saveInterProperties( // save properties for interscene processing (extrinsics, ers, ...)  // null pointer

src/main/java/com/elphel/imagej/tileprocessor/IntersceneMatchParameters.java

@@ -78,6 +78,7 @@ public class IntersceneMatchParameters {
 				ims_mount_atr[2] * Math.PI/180};
 	}
 	public  boolean center_reference =   false;
+	public  boolean overlap_sequences =  false; // overlap sequences: scan down from the previous center  
 	public  boolean reset_photometric =  true;  // reset photometric calibration - once for each new series
 	public  boolean force_ref_dsi =      false; // true;
 	public  boolean force_orientations = false;
@@ -527,6 +528,8 @@ public class IntersceneMatchParameters {
 		
 		gd.addCheckbox ("Use center scene as a reference",           this.center_reference,
 				"True for mapping with post-processing. If false, use the last scene as a reference (driving).");
+		gd.addCheckbox ("Overlap sequences",                         this.overlap_sequences,
+				"Overlap sequences by half - start (down) from the previous center.");
 		gd.addCheckbox ("Reset photometric calibration",             this.reset_photometric,
 				"Reset photometric calibration, will use basic one before re-calibrating.");
 		gd.addCheckbox ("Force reference scene DSI calculation",     this.force_ref_dsi,
@@ -1228,6 +1231,7 @@ public class IntersceneMatchParameters {
 		this.sfm_extrapolate =                gd.getNextBoolean();
         
 		this.center_reference =               gd.getNextBoolean();
+		this.overlap_sequences =              gd.getNextBoolean();
 		this.reset_photometric =              gd.getNextBoolean();
 		this.force_ref_dsi =                  gd.getNextBoolean();
 		this.force_orientations =             gd.getNextBoolean();
@@ -1612,6 +1616,7 @@ public class IntersceneMatchParameters {
 		properties.setProperty(prefix+"sfm_extrapolate",               this.sfm_extrapolate + "");             // boolean
 
 		properties.setProperty(prefix+"center_reference",              this.center_reference + "");            // boolean
+		properties.setProperty(prefix+"overlap_sequences",             this.overlap_sequences + "");           // boolean
 		properties.setProperty(prefix+"reset_photometric",             this.reset_photometric + "");           // boolean
 		properties.setProperty(prefix+"force_ref_dsi",                 this.force_ref_dsi + "");               // boolean
 		properties.setProperty(prefix+"force_orientations",            this.force_orientations + "");          // boolean
@@ -1956,6 +1961,7 @@ public class IntersceneMatchParameters {
 		if (properties.getProperty(prefix+"sfm_extrapolate")!=null)    this.sfm_extrapolate=Boolean.parseBoolean(properties.getProperty(prefix+"sfm_extrapolate"));		
 		
 		if (properties.getProperty(prefix+"center_reference")!=null)              this.center_reference=Boolean.parseBoolean(properties.getProperty(prefix+"center_reference"));		
+		if (properties.getProperty(prefix+"overlap_sequences")!=null)             this.overlap_sequences=Boolean.parseBoolean(properties.getProperty(prefix+"overlap_sequences"));		
 		if (properties.getProperty(prefix+"reset_photometric")!=null)             this.reset_photometric=Boolean.parseBoolean(properties.getProperty(prefix+"reset_photometric"));		
 		if (properties.getProperty(prefix+"force_ref_dsi")!=null)                 this.force_ref_dsi=Boolean.parseBoolean(properties.getProperty(prefix+"force_ref_dsi"));		
 		if (properties.getProperty(prefix+"force_orientations")!=null)            this.force_orientations=Boolean.parseBoolean(properties.getProperty(prefix+"force_orientations"));		
@@ -2327,6 +2333,7 @@ public class IntersceneMatchParameters {
 		imp.sfm_extrapolate               = this.sfm_extrapolate;
 
 		imp.center_reference              = this.center_reference;
+		imp.overlap_sequences             = this.overlap_sequences;
 		imp.reset_photometric             = this.reset_photometric;
 		imp.force_ref_dsi                 = this.force_ref_dsi;
 		imp.force_orientations            = this.force_orientations;

src/main/java/com/elphel/imagej/tileprocessor/OpticalFlow.java

@@ -3966,6 +3966,7 @@ public class OpticalFlow {
 	public static void buildRefDSI(
 			CLTParameters                                 clt_parameters,
 			boolean                                       fast,
+			boolean                                       skip_photo,
 			EyesisCorrectionParameters.DebayerParameters  debayerParameters,
 			ColorProcParameters                           colorProcParameters,
 			EyesisCorrectionParameters.RGBParameters      rgbParameters,
@@ -4109,7 +4110,7 @@ public class OpticalFlow {
 		boolean ran_photo_each = false;
 		quadCLT_ref.tp.resetCLTPasses();
 		// perform photometric here, after first DSI
-		if (photo_each && (!quadCLT_ref.isPhotometricThis() || !batch_mode)) {
+		if (!skip_photo && (photo_each && (!quadCLT_ref.isPhotometricThis() || !batch_mode))) {
 //			if (debugLevel > -3) {
 //				System.out.println("**** Running photometric equalization for "+quadCLT_ref.getImageName()+
 //						", current was from scene "+quadCLT_ref.getPhotometricScene()+" ****");
@@ -4240,13 +4241,12 @@ public class OpticalFlow {
 		quadCLT_ref.saveDSIAll (
 				"-DSI_MAIN", // String suffix, // "-DSI_MAIN"
 				dsi);
+		quadCLT_ref.set_orient(0); // reset orientations
+		quadCLT_ref.set_accum(0);  // reset accumulations ("build_interscene") number
 		quadCLT_ref.saveInterProperties( // save properties for interscene processing (extrinsics, ers, ...)
 				null, // String path,             // full name with extension or w/o path to use x3d directory
 				//							 	null, // Properties properties,   // if null - will only save extrinsics)
 				debugLevel);
-		
-		quadCLT_ref.set_orient(0); // reset orientations
-		quadCLT_ref.set_accum(0);  // reset accumulations ("build_interscene") number
 	}
 	
 	public static void reuseRefDSI(
@@ -4760,6 +4760,7 @@ public class OpticalFlow {
 		scenes_xyzatr[last_index] = new double[2][3]; // all zeros
 		// See if build_ref_dsi is needed
 		if (!build_ref_dsi) {
+			// try reading full
 			quadCLTs[last_index] = (QuadCLT) quadCLT_main.spawnNoModelQuadCLT( // will conditionImageSet
 					set_channels[last_index].set_name,
 					clt_parameters,
@@ -4771,10 +4772,24 @@ public class OpticalFlow {
 						null, // String path,             // full name with extension or null to use x3d directory
 						false, // boolean all_properties,//				null, // Properties properties,   // if null - will only save extrinsics)
 						debugLevel);
-				int center_index =quadCLTs[last_index].getReferenceIndex(null);
-				if (center_index == -1) {
-					build_ref_dsi = true;
-				} else {
+				int center_index =quadCLTs[last_index].getReferenceIndex(new QuadCLT[] {quadCLTs[last_index]}); // null); self, may return 0
+				int [] first_last_index = quadCLTs[last_index].getFirstLastIndex(new QuadCLT[] {quadCLTs[last_index]});				
+				if ((center_index == -1) || (center_index == 0)) { // 0 - was self-referencing, TODO: debug, should not be
+					// -2 - reference somewhere, not to itself
+					// -1 - no reference to a center
+					// 0 - reference
+					// with overlap it may already have *-DSI_MAIN or even *-INTER-INTRA-LMA.tiff
+//					int [] first_last_index = quadCLTs[last_index].getFirstLastIndex(quadCLTs);
+					if (first_last_index == null) {
+						build_ref_dsi = true;
+					} else { // should have DSI 
+						if (debugLevel >-2) {
+							System.out.println("no link to center, but this seems to be other's center "+quadCLTs[last_index].getReferenceTimestamp()+
+									", forcing initial orientation.");
+						}
+						force_initial_orientations = true;
+					}
+				} else { // -2 - reference somewhere, not to itself
 					QuadCLT try_ref_scene = (QuadCLT) quadCLT_main.spawnQuadCLT( // will conditionImageSet
 							quadCLTs[last_index].getReferenceTimestamp(), // set_channels[last_index].set_name,
 							clt_parameters,
@@ -4785,6 +4800,7 @@ public class OpticalFlow {
 						if (debugLevel >-2) {
 							System.out.println("DSI data for scene "+quadCLTs[last_index].getReferenceTimestamp()+
 									" does not exist, forcing initial orientation.");
+							// consider copyJP4src for the lower half (now it is not needed) 
 						}
 						force_initial_orientations = true;
 					}
@@ -4848,6 +4864,7 @@ public class OpticalFlow {
 				buildRefDSI( // returned is a different instance than input -FIXED
 						clt_parameters,                   // CLTParameters                                 clt_parameters,
 						fast,                             // boolean  fast,
+						false,                            // boolean                                       skip_photo,
 						debayerParameters,                // EyesisCorrectionParameters.DebayerParameters  debayerParameters,
 						colorProcParameters,              // ColorProcParameters                           colorProcParameters,
 					    rgbParameters, // EyesisCorrectionParameters.RGBParameters      rgbParameters,
@@ -4884,7 +4901,7 @@ public class OpticalFlow {
 						updateStatus,		 // final boolean       updateStatus,
 						debugLevel);         // int            debugLevel)
 				if (center_reference) {
-//					center_ts = getReferenceTimestamp();
+//					center_ts = getReferenceTimestamp(); //??
 				}
 			}
 		} // while (blue_sky == null) 
@@ -5054,7 +5071,11 @@ public class OpticalFlow {
 			int [] first_last_index = quadCLTs[ref_index].getFirstLastIndex(quadCLTs);
 			if (first_last_index == null) {
 				System.out.println("BUG: saved reference scene "+quadCLTs[ref_index].getImageName()+
-						" does not have first/last scenes defined");
+						" is not really a reference");
+				System.out.println();
+			} else 	if ((first_last_index [0] < 0) || (first_last_index [1] < 0)) {
+				System.out.println("BUG: saved reference scene "+quadCLTs[ref_index].getImageName()+
+						" does not have both first/last scenes defined: ["+first_last_index [0]+", "+first_last_index [1]+"]");
 				System.out.println();
 			} else {
 				earliest_scene = first_last_index[0];
@@ -5100,17 +5121,18 @@ public class OpticalFlow {
 //						num_avg_pairs = last_index - ref_index;
 //					}
 					QuadCLT[][][] scenes_seq_pairs = new QuadCLT[3][num_avg_pairs][2];
+					int ref_index_mod1 = Math.max(ref_index, earliest_scene + num_avg_pairs - 1);
+					int ref_index_mod2 = Math.min(ref_index, last_index);
 					
 					// TODO: calculate horizontal offset and compare with sfm_min_base
 					for (int i = 0; i < num_avg_pairs; i++) {
-//						scenes_seq_pairs[0][i][0] = quadCLTs[ref_index + num_avg_pairs - 1 - i];
 						scenes_seq_pairs[0][i][0] = quadCLTs[last_index - i];
 						scenes_seq_pairs[0][i][1] = quadCLTs[earliest_scene + num_avg_pairs - 1 - i];
 						
 						scenes_seq_pairs[1][i][0] = quadCLTs[last_index - i];
-						scenes_seq_pairs[1][i][1] = quadCLTs[ref_index - i];
+						scenes_seq_pairs[1][i][1] = quadCLTs[ref_index_mod1 - i];
 						
-						scenes_seq_pairs[2][i][0] = quadCLTs[last_index - i];
+						scenes_seq_pairs[2][i][0] = quadCLTs[ref_index_mod2 + num_avg_pairs - 1 - i];
 						scenes_seq_pairs[2][i][1] = quadCLTs[earliest_scene + num_avg_pairs - 1 - i];
 					}
 					double [][] sfm_dsn = StructureFromMotion.sfmPairsSet(

src/main/java/com/elphel/imagej/tileprocessor/QuadCLTCPU.java

@@ -273,7 +273,7 @@ public class QuadCLTCPU {
     public int getReferenceIndex(QuadCLTCPU [] scenes) {
     	if (timestamp_reference != null) {
     		if (scenes != null) {
-    			for (int i = 0; i < scenes.length; i++) {
+    			for (int i = 0; i < scenes.length; i++) if (scenes[i] != null){
     				if (timestamp_reference.equals(scenes[i].getImageName())) {
     					return i;
     				}
@@ -286,33 +286,36 @@ public class QuadCLTCPU {
     
     /**
      * If this scene is a reference scene, then return array of {first_index, last_index}.
-     * If this scene is not a reference or the array does not contain both the first and
-     * the last scene - return null.
+     * If this scene is not a reference - return null.
      * @param scenes array of scenes (QuadCLTCPU instances)
      * @return a pair of {first_index, last_index}
      */
     public int [] getFirstLastIndex(QuadCLTCPU [] scenes) { // should be ordered accending ts
-		int [] fl = new int [] {-1,-1};
-    	if ((timestamp_first != null) && (timestamp_last != null)) {
-    		int i = 0;
-    		for (; i < scenes.length; i++) {
-    			if (timestamp_first.equals(scenes[i].getImageName())) {
-    				fl[0] = i;
-    				break;
-    			}
-    		}
-    		for (; i < scenes.length; i++) {
-    			if (timestamp_last.equals(scenes[i].getImageName())) {
-    				fl[1] = i;
-    				break;
-    			}
-    		}
-    	}
-    	if ((fl[0] >= 0) && (fl[1] >= 0)) {
-    		return fl;
-    	} else {
-    		return null;
-    	}
+		int [] fl = null;
+		if ((timestamp_first != null) && (timestamp_last != null)) {
+			fl = new int [] {-1,-1};
+			if (scenes != null) {
+				int i = 0;
+				for (; i < scenes.length; i++) if (scenes[i] != null) {
+					if (timestamp_first.equals(scenes[i].getImageName())) {
+						fl[0] = i;
+						break;
+					}
+				}
+				for (; i < scenes.length; i++) if (scenes[i] != null) {
+					if (timestamp_last.equals(scenes[i].getImageName())) {
+						fl[1] = i;
+						break;
+					}
+				}
+			}
+		}
+    	return fl;
+//    	if ((fl[0] >= 0) && (fl[1] >= 0)) {
+//    		return fl;
+//    	} else {
+//    		return null;
+//    	}
     }
 
     /**

src/main/java/com/elphel/imagej/tileprocessor/TwoQuadCLT.java

@@ -8531,6 +8531,7 @@ if (debugLevel > -100) return true; // temporarily !
 			final boolean    updateStatus,
 			final int        debugLevel)  throws Exception
     {
+    	boolean overlap_sequences =  clt_parameters.imp.overlap_sequences;
 		int     stereo_gap =         clt_parameters.imp.stereo_gap;
 		double  stereo_intereye =    clt_parameters.imp.stereo_intereye;
 		double  stereo_phone_width = clt_parameters.imp.stereo_phone_width; // 0 - no padding
@@ -8669,17 +8670,13 @@ if (debugLevel > -100) return true; // temporarily !
 					}
 					Files.createSymbolicLink(link.toPath(), pathRelative);
 				}
-				if (start_ref_pointers[0] < (min_num_scenes-1)) {
+				if (start_ref_pointers[0] < (min_num_scenes-1)) { 
 					break;
 				}
-				ref_index = start_ref_pointers[0]; // continue from the same attached to the previous reference
+				ref_index = start_ref_pointers[overlap_sequences? 1 : 0]; // continue from the same attached to the previous reference
 			}
 		}
 		
-		
-		
-		
-		
 		// combine videos if generated
 		if ((video_sets_list.size() > 1) &&
 				(video_sets_list.get(0).getVideoPaths() != null) &&

src/main/java/com/elphel/imagej/tileprocessor/sfm/StructureFromMotion.java

@@ -948,28 +948,40 @@ public class StructureFromMotion {
     		}        
     	}
     	// check each pair has sufficient baseline and contains exactly 2 scenes
+    	int num_good_sets=0;
+    	boolean [] good_set = new boolean [num_sets];
     	for (int nset=0; nset < num_sets; nset++) {
     		int num_pairs = scene_pairs_sets[nset].length;
-    		for (int npair = 0; npair < num_pairs; npair++) {
-    			double [][][] scenes_xyzatr= scenes_xyzatr_sets[nset][npair];
-    			if (scenes_xyzatr.length != 2) {
-					System.out.println("sfmPairsSet(): BUG: Not a pair of scenes: scenes_xyzatr_sets["+nset+"]["+npair+
-							"].length = "+(scenes_xyzatr.length)+" != 2");
-					return null;
-    			}
-    			double dx = scenes_xyzatr[1][0][0] - scenes_xyzatr[0][0][0];
-    			double dy = scenes_xyzatr[1][0][1] - scenes_xyzatr[0][0][1];
-    			double base = Math.sqrt(dx*dx + dy*dy);
-    			if (base < sfm_min_base) {
-    				if (debugLevel > -3) {
-    					System.out.println("sfmPairsSet(): stereo base for nset="+nset+", npair="+npair+
-    							" = "+base+" < "+sfm_min_base+", bailing out from SfM ranging.");
+    		check_set: {
+    			for (int npair = 0; npair < num_pairs; npair++) {
+    				double [][][] scenes_xyzatr= scenes_xyzatr_sets[nset][npair];
+    				if (scenes_xyzatr.length != 2) {
+    					System.out.println("sfmPairsSet(): BUG: Not a pair of scenes: scenes_xyzatr_sets["+nset+"]["+npair+
+    							"].length = "+(scenes_xyzatr.length)+" != 2");
+    					return null;
+    				}
+    				double dx = scenes_xyzatr[1][0][0] - scenes_xyzatr[0][0][0];
+    				double dy = scenes_xyzatr[1][0][1] - scenes_xyzatr[0][0][1];
+    				double base = Math.sqrt(dx*dx + dy*dy);
+    				if (base < sfm_min_base) {
+    					if (debugLevel > -3) {
+    						System.out.println("sfmPairsSet(): stereo base for nset="+nset+", npair="+npair+
+    								" = "+base+" < "+sfm_min_base+".");
+    					}
+    					break check_set; // return null;
     				}
-    				return null;
     			}
+    			good_set[nset] = true;
+    			num_good_sets++;
     		}
+
     	}
     	
+    	if (num_good_sets == 0) {
+			if (debugLevel > -3) {
+				System.out.println("sfmPairsSet(): No good sets with sufficient base found, bailing out from SfM ranging.");
+			}
+    	}
     	for (int ntry = 0; ntry < num_readjust; ntry++) {
     		final SfmCorr [] sfmCorrCombo = new SfmCorr [tilesX*tilesY];
     		double [] sum_weights_ind= new double [tilesX*tilesY];
@@ -982,9 +994,7 @@ public class StructureFromMotion {
     		 */
     		final int [] corr_mode = new int [tilesX*tilesY]; 
     		
-    		for (int nset=0; nset < num_sets; nset++) {
-    			
-    			
+    		for (int nset=0; nset < num_sets; nset++) if (good_set[nset]){
     			SfmCorr [] sfmCorr = getSfmCorr(
     					clt_parameters,             // final CLTParameters  clt_parameters,
     					ref_scene,                  // final QuadCLT        ref_scene,
@@ -1009,7 +1019,7 @@ public class StructureFromMotion {
         			if (debugLevel > -3) {
         				System.out.println("sfmPairsSet(): not enough SfM tiles, bailing out");
         			}
-        			return null;
+        			continue; //return  null;
         		}
     			
     			if ((sfm_shrink > 0) || (fade_sigma > 0.0)) {