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#include <string>
#include <algorithm> // for reverse
#include <stdio.h>
#include <stddef.h>
#include "gr.hh"
#include "extern.hh"
#include "image_ex.hh"
static bool filter_butterworth(double *x, double *xout, int nx, double *a, double *b, int nab);
static bool filter_image(int horl);
void highpass_image();
void lowpass_image();
#define ODD(n) (2 * ((n) / 2) != (n))
// filter grid rows|columns recursively a[0] a[1] ... b[0] b[1] ...
// 0 1 2 3 4
bool
filter_gridCmd()
{
if (_nword <= 3) {
NUMBER_WORDS_ERROR;
return false;
}
if (!word_is(3, "recursively")) {
err("Fourth word must be `recursively'");
return false;
}
bool do_rows = true;
if (word_is(2, "rows")) {
do_rows = true;
} else if (word_is(2, "columns")) {
do_rows = false;
} else {
err("Third word must be `rows' or `columns'");
return false;
}
// Get the coefficients
int nab = _nword - 4; // number (a,b) coefficients
if (nab < 1) {
err("No filter coefficients given.");
return false;
}
if (ODD(nab)) {
err("Must give even number of filter coefficients.");
return false;
}
nab = nab / 2;
vector<double> a((size_t)nab, 0.0);
vector<double> b((size_t)nab, 0.0);
unsigned int i, row, col;
for (i = 0; i < (unsigned int) nab; i++) {
a[i] = atof(_word[4 + i]);
b[i] = atof(_word[4 + i + nab]);
}
// Do the filtering
if (do_rows) {
vector<double> orig((size_t)_num_ymatrix_data, 0.0);
vector<double> copy((size_t)_num_ymatrix_data, 0.0);
for (col = 0; col < _num_xmatrix_data; col++) {
for (row = 0; row < _num_ymatrix_data; row++)
orig[row] = _f_xy(col, row);
filter_butterworth(orig.begin(), copy.begin(), _num_ymatrix_data,
a.begin(), b.begin(), nab);
for (row = 0; row < _num_ymatrix_data; row++)
_f_xy(col, row) = copy[row];
}
} else {
vector<double> orig((size_t)_num_xmatrix_data, 0.0);
vector<double> copy((size_t)_num_xmatrix_data, 0.0);
for (row = 0; row < _num_ymatrix_data; row++) {
for (col = 0; col < _num_xmatrix_data; col++)
orig[col] = _f_xy(col, row);
filter_butterworth(orig.begin(), copy.begin(), _num_xmatrix_data,
a.begin(), b.begin(), nab);
for (col = 0; col < _num_xmatrix_data; col++)
_f_xy(col, row) = copy[col];
}
}
return true;
}
// filter column x|y|z|u|v|r|theta recursively a[0] a[1] ... b[0] b[1] ...
bool
filter_columnCmd()
{
int i;
int nab; // number of a, b coefficients
int num = 0; // length of column
Require(_nword > 3,
NUMBER_WORDS_ERROR);
Require(word_is(3, "recursively"),
err("Fourth word must be `recursively'"));
double *orig; // point to data
if (word_is(2, "x")) {
num = _colX.size();
orig = _colX.begin();
} else if (word_is(2, "y")) {
num = _colY.size();
orig = _colY.begin();
} else if (word_is(2, "z")) {
num = _colZ.size();
orig = _colZ.begin();
} else if (word_is(2, "u")) {
num = _colU.size();
orig = _colU.begin();
} else if (word_is(2, "v")) {
num = _colV.size();
orig = _colV.begin();
} else if (word_is(2, "r")) {
num = _colR.size();
orig = _colR.begin();
} else if (word_is(2, "theta")) {
num = _colTHETA.size();
orig = _colTHETA.begin();
} else {
orig = 0; // prevent compiler warning
err("Unknown item.");
}
Require (num > 0,
err("No data in column named '", _word[2], "'", "\\"));
nab = _nword - 4;
Require(nab > 0,
err("No filter coefficients given."));
Require(!ODD(nab),
err("Must give even number of filter coefficients."));
nab = nab / 2;
vector<double> a((size_t)nab, 0.0);
vector<double> b((size_t)nab, 0.0);
for (i = 0; i < nab; i++) {
a[i] = atof(_word[4 + i]);
b[i] = atof(_word[4 + i + nab]);
}
vector<double> copy((size_t)num, 0.0);
filter_butterworth(orig, copy.begin(), num, a.begin(), b.begin(), nab);
for (i = 0; i < num; i++)
orig[i] = copy[i];
return true;
}
// filter_butterworth() -- do butterworth filtering, forward+back
// Input is x[] (unaltered), output is xout[]; recursive-style coefficients are
// a[]; moving average-style coefficients are b[].
static bool
filter_butterworth(double *x, double *xout, int nx, double *a, double *b, int nab)
{
if (nab >= nx)
return false;
vector<double> z((size_t)nx, 0.0);
register int ix, iab;
// pass 1 -- forward
for (ix = 0; ix < nab; ix++) {
// beginning part -- just copy
z[ix] = x[ix];
}
for (ix = nab; ix < nx; ix++) {
z[ix] = b[0] * x[ix];
for (iab = 1; iab < nab; iab++)
z[ix] += b[iab] * x[ix - iab] - a[iab] * z[ix - iab];
}
// pass 2 -- backward
reverse(z.begin(), z.begin() + nx);
for (ix = 0; ix < nab; ix++)
xout[ix] = z[ix];
for (ix = nab; ix < nx; ix++) {
xout[ix] = b[0] * z[ix];
for (iab = 1; iab < nab; iab++)
xout[ix] += b[iab] * z[ix - iab] - a[iab] * xout[ix - iab];
}
reverse(xout, xout + nx);
return true;
}
bool
filter_imageCmd()
{
if (_nword != 3) {
demonstrate_command_usage();
NUMBER_WORDS_ERROR;
} else if (!strcmp(_word[2], "highpass"))
filter_image(1);
else if (!strcmp(_word[2], "lowpass"))
filter_image(0);
else {
demonstrate_command_usage();
err("Can only do `highpass' or `lowpass' filter");
return false;
}
return true;
}
static bool
filter_image(int horl)
{
unsigned char *imPtr;
register int i, j;
int nx, ny, nx1, ny1, newval, change;
Require(image_exists(), err("no image exists"));
nx = _image.ras_width;
nx1 = nx - 1;
ny = _image.ras_height;
ny1 = ny - 1;
vector<unsigned char> imagenew((size_t)(nx * ny), (unsigned char)0);
for (j = ny - 1; j > -1; j--) {
imagenew[j] = _image.image[j];
imagenew[nx1 * ny + j] = _image.image[nx1 * ny + j];
}
for (i = 0; i < nx; i++) {
imagenew[i * ny] = _image.image[i * ny];
imagenew[i * ny + ny1] = _image.image[i * ny + ny1];
}
for (j = 1; j < ny1; j++) {
for (i = 1; i < nx1; i++) {
imPtr = _image.image + i * ny + j;
change = *(imPtr + 1); // i,j+1
change += *(imPtr - 1); // i,j-1
change += *(imPtr - ny); // i-1,j
change += *(imPtr + ny); // i-1,j
change -= *imPtr * 4;
change = (int) (0.125 * (double) change);
switch (horl) {
case 0: // low pass
newval = *imPtr + change;
break;
case 1: // high pass
default:
newval = *imPtr - change;
break;
}
if (newval < 0)
imagenew[i * ny + j] = (unsigned char) 0;
else if (newval > 255)
imagenew[i * ny + j] = (unsigned char) 255;
else
imagenew[i * ny + j] = (unsigned char) newval;
}
}
nx *= ny;
for (i = 0; i < nx; i++)
_image.image[i] = imagenew[i];
return true;
}
void
highpass_image()
{
filter_image(1);
}
void
lowpass_image()
{
filter_image(0);
}
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