+// ImageFile::comparativeStatistics Calculate comparative stats
+//
+// OUTPUT
+// d Normalized root mean squared distance measure
+// r Normalized mean absolute distance measure
+// e Worst case distance measure
+//
+// REFERENCES
+// G.T. Herman, Image Reconstruction From Projections, 1980
+
+bool
+ImageFile::comparativeStatistics (const ImageFile& imComp, double& d, double& r, double& e) const
+{
+ if (imComp.nx() != m_nx && imComp.ny() != m_ny) {
+ sys_error (ERR_WARNING, "Image sizes differ [ImageFile::comparativeStatistics]");
+ return false;
+ }
+ ImageFileArrayConst v = getArray();
+ if (v == NULL || m_nx == 0 || m_ny == 0)
+ return false;
+
+ ImageFileArrayConst vComp = imComp.getArray();
+
+ double myMean = 0.;
+ for (unsigned int ix = 0; ix < m_nx; ix++) {
+ for (unsigned int iy = 0; iy < m_ny; iy++) {
+ myMean += v[ix][iy];
+ }
+ }
+ myMean /= (m_nx * m_ny);
+
+ double sqErrorSum = 0.;
+ double absErrorSum = 0.;
+ double sqDiffFromMeanSum = 0.;
+ double absValueSum = 0.;
+ for (unsigned int ix = 0; ix < m_nx; ix++) {
+ for (unsigned int iy = 0; iy < m_ny; iy++) {
+ double diff = v[ix][iy] - vComp[ix][iy];
+ sqErrorSum += diff * diff;
+ absErrorSum += fabs(diff);
+ double diffFromMean = v[ix][iy] - myMean;
+ sqDiffFromMeanSum += diffFromMean * diffFromMean;
+ absValueSum += fabs(v[ix][iy]);
+ }
+ }
+
+ d = sqrt (sqErrorSum / sqDiffFromMeanSum);
+ r = absErrorSum / absValueSum;
+
+ int hx = m_nx / 2;
+ int hy = m_ny / 2;
+ double eMax = -1;
+ for (int ix = 0; ix < hx; ix++) {
+ for (int iy = 0; iy < hy; iy++) {
+ double avgPixel = 0.25 * (v[2*ix][2*iy] + v[2*ix+1][2*iy] + v[2*ix][2*iy+1] + v[2*ix+1][2*iy+1]);
+ double avgPixelComp = 0.25 * (vComp[2*ix][2*iy] + vComp[2*ix+1][2*iy] + vComp[2*ix][2*iy+1] + vComp[2*ix+1][2*iy+1]);
+ double error = fabs (avgPixel - avgPixelComp);
+ if (error > eMax)
+ eMax = error;
+ }
+ }
+
+ e = eMax;
+
+ return true;
+}
+
+
+bool
+ImageFile::printComparativeStatistics (const ImageFile& imComp, ostream& os) const
+{
+ double d, r, e;
+
+ if (comparativeStatistics (imComp, d, r, e)) {
+ os << " Normalized root mean squared distance (d): " << d << endl;
+ os << " Normalized mean absolute distance (r): " << r << endl;
+ os << "Worst case distance (2x2 pixel average) (e): " << e << endl;
+ return true;
+ }
+ return false;
+}
+
+
+void
+ImageFile::printStatistics (ostream& os) const
+{
+ double min, max, mean, mode, median, stddev;
+
+ statistics (min, max, mean, mode, median, stddev);
+
+ os << " min: " << min << endl;
+ os << " max: " << max << endl;
+ os << " mean: " << mean << endl;
+ os << " mode: " << mode << endl;
+ os << "median: " << median << endl;
+ os << "stddev: " << stddev << endl;
+}
+
+
+void
+ImageFile::statistics (double& min, double& max, double& mean, double& mode, double& median, double& stddev) const
+{
+ int nx = m_nx;
+ int ny = m_ny;
+ ImageFileArrayConst v = getArray();
+
+ if (v == NULL || nx == 0 || ny == 0)
+ return;
+
+ mean = 0;
+ min = v[0][0];
+ max = v[0][0];
+ for (int ix = 0; ix < nx; ix++) {
+ for (int iy = 0; iy < ny; iy++) {
+ if (v[ix][iy] > max)
+ max = v[ix][iy];
+ if (v[ix][iy] < min)
+ min = v[ix][iy];
+ mean += v[ix][iy];
+ }
+ }
+ mean /= (nx * ny);
+
+ static const int nbin = 256;
+ int hist[ nbin ] = {0};
+ double spread = max - min;
+ mode = 0;
+ stddev = 0;
+ for (int ix = 0; ix < nx; ix++) {
+ for (int iy = 0; iy < ny; iy++) {
+ int b = static_cast<int>((((v[ix][iy] - min) / spread) * (nbin - 1)) + 0.5);
+ hist[b]++;
+ double diff = (v[ix][iy] - mean);
+ stddev += diff * diff;
+ }
+ }
+ stddev = sqrt(stddev / (nx * ny));
+
+ int max_binindex = 0;
+ int max_bin = -1;
+ for (int ibin = 0; ibin < nbin; ibin++) {
+ if (hist[ibin] > max_bin) {
+ max_bin = hist[ibin];
+ max_binindex = ibin;
+ }
+ }
+
+ mode = (max_binindex * spread / (nbin - 1)) + min;
+
+ median = 0.;
+}
+
+
+void
+ImageFile::getMinMax (double& min, double& max) const
+{
+ int nx = m_nx;
+ int ny = m_ny;
+ ImageFileArrayConst v = getArray();
+
+ if (v == NULL || nx == 0 || ny == 0)
+ return;
+
+ min = v[0][0];
+ max = v[0][0];
+ for (int ix = 0; ix < nx; ix++) {
+ for (int iy = 0; iy < ny; iy++) {
+ if (v[ix][iy] > max)
+ max = v[ix][iy];
+ if (v[ix][iy] < min)
+ min = v[ix][iy];
+ }
+ }
+}
+
+void
+ImageFile::writeImagePGM (const char *outfile, int nxcell, int nycell, double densmin, double densmax)
+{
+ FILE *fp;
+ int nx = m_nx;
+ int ny = m_ny;
+ ImageFileArray v = getArray();
+
+ unsigned char rowp [nx * nxcell];
+
+ if ((fp = fopen (outfile, "wb")) == NULL)
+ return;
+
+ fprintf(fp, "P5\n");
+ fprintf(fp, "%d %d\n", nx, ny);
+ fprintf(fp, "255\n");
+
+ for (int irow = ny - 1; irow >= 0; irow--) {
+ for (int icol = 0; icol < nx; icol++) {
+ int pos = icol * nxcell;
+ double dens = (v[icol][irow] - densmin) / (densmax - densmin);
+ dens = clamp (dens, 0., 1.);
+ for (int p = pos; p < pos + nxcell; p++) {
+ rowp[p] = static_cast<unsigned int> (dens * 255.);
+ }
+ }
+ for (int ir = 0; ir < nycell; ir++) {
+ for (int ic = 0; ic < nx * nxcell; ic++)
+ fprintf(fp, "%c ", rowp[ic]);
+ }
+ }
+
+ fclose(fp);
+}
+
+void
+ImageFile::writeImagePGMASCII (const char *outfile, int nxcell, int nycell, double densmin, double densmax)
+{
+ FILE *fp;
+ int nx = m_nx;
+ int ny = m_ny;
+ ImageFileArray v = getArray();
+
+ unsigned char rowp [nx * nxcell];
+ if (rowp == NULL)
+ return;
+
+ if ((fp = fopen (outfile, "wb")) == NULL)
+ return;
+
+ fprintf(fp, "P2\n");
+ fprintf(fp, "%d %d\n", nx, ny);
+ fprintf(fp, "255\n");
+
+ for (int irow = ny - 1; irow >= 0; irow--) {
+ for (int icol = 0; icol < nx; icol++) {
+ int pos = icol * nxcell;
+ double dens = (v[icol][irow] - densmin) / (densmax - densmin);
+ dens = clamp (dens, 0., 1.);
+ for (int p = pos; p < pos + nxcell; p++) {
+ rowp[p] = static_cast<unsigned int> (dens * 255.);
+ }
+ }
+ for (int ir = 0; ir < nycell; ir++) {
+ for (int ic = 0; ic < nx * nxcell; ic++)
+ fprintf(fp, "%d ", rowp[ic]);
+ fprintf(fp, "\n");
+ }
+ }
+
+ fclose(fp);
+}
+
+
+#ifdef HAVE_PNG
+void
+ImageFile::writeImagePNG (const char *outfile, int bitdepth, int nxcell, int nycell, double densmin, double densmax)
+{
+ FILE *fp;
+ png_structp png_ptr;
+ png_infop info_ptr;
+ double max_out_level = (1 << bitdepth) - 1;
+ int nx = m_nx;
+ int ny = m_ny;
+ ImageFileArray v = getArray();
+
+ unsigned char rowp [nx * nxcell * (bitdepth / 8)];
+
+ if ((fp = fopen (outfile, "wb")) == NULL)
+ return;
+
+ png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+ if (! png_ptr)
+ return;
+
+ info_ptr = png_create_info_struct(png_ptr);
+ if (! info_ptr) {
+ png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
+ fclose(fp);
+ return;
+ }
+
+ if (setjmp(png_ptr->jmpbuf)) {
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+ fclose(fp);
+ return;
+ }
+
+ png_init_io(png_ptr, fp);
+
+ png_set_IHDR(png_ptr, info_ptr, nx * nxcell, ny * nycell, bitdepth, PNG_COLOR_TYPE_GRAY, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_DEFAULT);
+
+ png_write_info(png_ptr, info_ptr);
+ for (int irow = ny - 1; irow >= 0; irow--) {
+ png_bytep row_pointer = rowp;
+
+ for (int icol = 0; icol < nx; icol++) {
+ int pos = icol * nxcell;
+ double dens = (v[icol][irow] - densmin) / (densmax - densmin);
+ dens = clamp (dens, 0., 1.);
+ unsigned int outval = static_cast<unsigned int> (dens * max_out_level);
+
+ for (int p = pos; p < pos + nxcell; p++) {
+ if (bitdepth == 8)
+ rowp[p] = outval;
+ else {
+ int rowpos = p * 2;
+ rowp[rowpos] = (outval >> 8) & 0xFF;
+ rowp[rowpos+1] = (outval & 0xFF);
+ }
+ }
+ }
+ for (int ir = 0; ir < nycell; ir++)
+ png_write_rows (png_ptr, &row_pointer, 1);
+ }
+
+ png_write_end(png_ptr, info_ptr);
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+
+ fclose(fp);
+}
+#endif
+
+#ifdef HAVE_GD
+#include "gd.h"
+static const int N_GRAYSCALE=256;
+
+void
+ImageFile::writeImageGIF (const char *outfile, int nxcell, int nycell, double densmin, double densmax)
+{
+ gdImagePtr gif;
+ FILE *out;
+ int gs_indices[N_GRAYSCALE];
+ int nx = m_nx;
+ int ny = m_ny;
+ ImageFileArray v = getArray();
+
+ unsigned char rowp [nx * nxcell];
+ if (rowp == NULL)
+ return;
+
+ gif = gdImageCreate(nx * nxcell, ny * nycell);
+ for (int i = 0; i < N_GRAYSCALE; i++)
+ gs_indices[i] = gdImageColorAllocate(gif, i, i, i);
+
+ int lastrow = ny * nycell - 1;
+ for (int irow = 0; irow < ny; irow++) {
+ int rpos = irow * nycell;
+ for (int ir = rpos; ir < rpos + nycell; ir++) {
+ for (int icol = 0; icol < nx; icol++) {
+ int cpos = icol * nxcell;
+ double dens = (v[icol][irow] - densmin) / (densmax - densmin);
+ dens = clamp(dens, 0., 1.);
+ for (int ic = cpos; ic < cpos + nxcell; ic++) {
+ rowp[ic] = (unsigned int) (dens * (double) (N_GRAYSCALE - 1));
+ gdImageSetPixel(gif, ic, lastrow - ir, gs_indices[rowp[ic]]);
+ }
+ }
+ }
+ }
+
+ if ((out = fopen(outfile,"w")) == NULL) {
+ sys_error(ERR_FATAL, "Error opening output file %s for writing", outfile);
+ return (1);
+ }
+ gdImageGif(gif,out);
+ fclose(out);
+ gdImageDestroy(gif);
+}
+#endif