From: Kevin M. Rosenberg Date: Thu, 22 Mar 2018 19:08:16 +0000 (-0600) Subject: Interim developed on DDA for projecting through imagefiles X-Git-Url: http://git.kpe.io/?p=ctsim.git;a=commitdiff_plain;h=dca8d386ab6a4e33050b456cff4547d6adfdf249 Interim developed on DDA for projecting through imagefiles --- diff --git a/libctsim/scanner.cpp b/libctsim/scanner.cpp index 34864fb..204c9cb 100644 --- a/libctsim/scanner.cpp +++ b/libctsim/scanner.cpp @@ -308,11 +308,17 @@ Scanner::collectProjections (Projections& proj, const Phantom& phm, const int iS { m_trace = trace; double start_angle = (iStartView + iOffsetView) * proj.rotInc(); + int parallel_enabled = 1; + UNUSED(parallel_enabled); -#ifdef HAVE_OPENMP - #pragma omp parallel for +#if HAVE_SGP + if (pSGP && (m_trace >= Trace::TRACE_PHANTOM)) + parallel_enabled = 0; #endif +#if HAVE_OPENMP + #pragma omp parallel for if (parallel_enabled) +#endif for (int iView = 0; iView < iNumViews; iView++) { double viewAngle = start_angle + (iView * proj.rotInc()); @@ -591,6 +597,133 @@ Scanner::traceShowParamRasterOp (int iRasterOp, const char *szLabel, const char } } +void swap_xy_points (double& x1, double& y1, double& x2, double& y2) +{ + double temp = x1; x1 = x2; x2 = temp; + temp = y1; y1 = y2; y2 = temp; +} + +class WeightedPoint { +public: + int x, y; + double weight; + WeightedPoint (int _x, int _y, double _weight) + : x(_x), y(_y), weight(_weight) + {} +}; + + +/* FUNCTION + * Name: projection_pixel_weights + * Purpose: Returns a vector of WeightedPoint with the length of + * line that intersects with each pixel + */ + +void +projection_pixel_weights (std::vector& wp, const int nx, const int ny, + double x1, double y1, double x2, double y2) +{ + double ylen = fabs(y2-y1); + double xlen = fabs(x2-x1); + bool swap_xy = false, invert_slope = false; + double slope; + + if (ylen > xlen) { + swap_xy = true; + slope = xlen / ylen; + if (y2 < y1) // swap start/end so always moving from bottom to top + swap_xy_points (x1, y1, x2, y2); + if (x2 < x1) { + invert_slope = true; + } + } else { +#if DEBUG + if (ylen == xlen) + sys_error(ERR_WARNING, "Slope == 1"); +#endif + slope = ylen / xlen; + if (x2 < x1) // swap start/end so always moving from left to right in image + swap_xy_points (x1, y1, x2, y2); + if (y2 < y1) { + invert_slope = true; + } + } + double angle = atan(fabs(slope)); + double minor_dist = sin(angle); // distance along minor axis + double pixel_len = 1 / cos(angle); + + int minor_dir = 1; + if (invert_slope) { + minor_dir = -1; + slope = -slope; + } + + double x = x1, y = y1; + int ix = floor(x); + int iy = floor(y); + double ydelta = y - iy; + double xdelta = x - ix; + + double min_delta; + int *imaj, *imin; + int max_maj, max_min; + if (swap_xy) { + min_delta = xdelta; + imaj = &iy; + imin = &ix; + max_maj = ny; + max_min = nx; + } else { + min_delta = ydelta; + imaj = &ix; + imin = &iy; + max_maj = nx; + max_min = ny; + } + +#if DEBUG + sys_error(ERR_TRACE, "m=%6.3f swap_xy=%d invert=%d len=%8.6f min_delta=%.4g minor_dist=%6.3f (%.3f,%.3f)-(%.3f,%.3f)", + slope, swap_xy, invert_slope, pixel_len, min_delta, minor_dist, x1, y1, x2, y2); +#endif + + // if position of minor axis is at edge of image, but will be moving into pixel within image + if (*imin == max_min && invert_slope) { + (*imin)--; // select the pixel within image +#if DEBUG + sys_error(ERR_TRACE, "Moving pixel inside image, adding %f to min_delta", (1+slope)); +#endif + min_delta += (1+slope); + } + + while (*imaj < max_maj && *imin < max_min && *imin >= 0) { + double next_min_delta = min_delta + slope; + + if (((!invert_slope) && (next_min_delta < 1)) || + (invert_slope && (next_min_delta > 0))) { + // stay within same pixel + double w = pixel_len; + WeightedPoint p (ix, iy, w); + wp.push_back(p); +#if DEBUG + sys_error(ERR_TRACE, " Full pixel: (%3d,%3d)=%.4g, min_delta=%.4g", ix, iy, w, min_delta); +#endif + min_delta = next_min_delta; + } else { + // Scale partial pixel_len into pixel + double norm_delta = invert_slope ? min_delta : (1 - min_delta); + double p1_line = norm_delta * pixel_len; + WeightedPoint p1 (ix, iy, p1_line); + wp.push_back (p1); +#if DEBUG + sys_error(ERR_TRACE, " Part pixel: (%3d,%3d)=%.4g, min_delta=%.4g", ix, iy, p1_line, min_delta); +#endif + (*imin) += minor_dir; + min_delta = next_min_delta - minor_dir; + } + (*imaj)++; + } + +} /* NAME @@ -613,30 +746,36 @@ Scanner::projectSingleLine (const Phantom& phm, double x1, double y1, double x2, const ImageFile* im = phm.getImagefile(); const ImageFileArray v = im->getArray(); - int nx = im->nx(), ny = im->ny(); - // Convert endpoints into image pixel coordinates + // Get image axis extents + int nx = im->nx(), ny = im->ny(); double xmin=0, xmax=nx, ymin=0, ymax=ny; // default coordinate if (! im->getAxisExtent (xmin, xmax, ymin, ymax)) { sys_error(ERR_WARNING, "Axis extent not available [Scanner::projectSingleLine]"); } + + // Clip line in image object coordinates double rect[4]; rect[0] = xmin; rect[1] = ymin; - rect[2] = xmax; rect[3] = ymax; + rect[2] = xmax; rect[3] = ymax; bool accept = clip_rect (x1, y1, x2, y2, rect); if (! accept) return (0.0); - double xlen = xmax - xmin, ylen = ymax - ymin; + // Convert to pixel coordinates + double xlen = xmax - xmin; + double ylen = ymax - ymin; double px1 = nx * (x1 - xmin) / xlen; double px2 = nx * (x2 - xmin) / xlen; double py1 = ny * (y1 - ymin) / ylen; double py2 = ny * (y2 - ymin) / ylen; - // Use Bresenham integer line stepping to step to each pixel, and walked through image - - sys_error(ERR_WARNING, "Not yet able to project through imagefile. Line (%.3f,%.3f) - (%.3f,%.3f)", px1, py1, px2, py2); - + std::vector wp; + projection_pixel_weights (wp, nx, ny, px1, py1, px2, py2); + for (unsigned int i = 0; i < wp.size(); i++) { + WeightedPoint& p = wp[i]; + rsum += v[p.x][p.y] * p.weight; + } } else { // Project through each pelem in Phantom