Changeset 24382 for trunk/magic/remove/src/streaksextern.c

Timestamp:

Jun 11, 2009, 6:09:52 PM (17 years ago)

Author:

eugene

Message:

modifications to support a two-pass check on the line range, limiting the initial ra,dec range to the region of the chip of interest using just the projection portion

File:

• trunk/magic/remove/src/streaksextern.c (modified) (2 diffs)

trunk/magic/remove/src/streaksextern.c

@@ -36 +36 @@
     StreakPixels *pixels = psArrayAllocEmpty (1024);
     int streaksOnComponent = 0;
+
+    int minX, minY, maxX, maxY;
+
+    // find the chip dimensions in the tangent-plane coordinates (length of hypotenuse)
+    componentBounds (&minX, &minY, &maxX, &maxY, astrom, numCols, numRows);
+
     for (i = 0; i != streaks->size; ++i)
     {
@@ -41 +47 @@
 
         line.width = streaks->list[i].width;
-        if (skyToCell (&line.begin, astrom,
-                       streaks->list[i].ra1, streaks->list[i].dec1) &&
-            skyToCell (&line.end, astrom,
-                       streaks->list[i].ra2, streaks->list[i].dec2) &&
+
+        /* Use tangent plane coordinates to narrow down the ra,dec range of the line closer to
+         * the chip boundaries.  Use these new ra,dec positions to generate the line on the
+         * chip using the full non-linear astrometry */
+           
+        // project the ends of the line using a linear projection centered on the chip center:
+        Line full;
+        SkyToLocal (&full.begin, astrom, streaks->list[i].ra1, streaks->list[i].dec1);
+        SkyToLocal (&full.end,   astrom, streaks->list[i].ra2, streaks->list[i].dec2);
+
+        // clip the line to a square box with diameter = hypotenuse of the chip image centerd
+        // on the chip center in tangent-plane coordinates.  skip the rest of this streak if
+        // the line does not intersect this region
+        if (!LineClipFull (&full, minX, minY, maxX, maxY)) {
+            continue;
+        }
+
+        // convert the end points back into ra, dec pairs:
+        strkPt sky1, sky2;
+        LocalToSky (&sky1, astrom, &full.begin);
+        LocalToSky (&sky2, astrom, &full.end);
+
+        if (skyToCell (&line.begin, astrom, sky1.x, sky1.y) &&
+            skyToCell (&line.end,   astrom, sky2.x, sky2.y) &&
             LineClip (&line, numCols, numRows))
         {