/**
* osp_device_take_spectrum_internal:
**/
static CdSpectrum *
osp_device_take_spectrum_internal (GUsbDevice *device,
guint64 sample_duration,
GError **error)
{
CdSpectrum *sp;
gdouble val;
gsize data_len;
guint i;
g_autofree guint8 *data = NULL;
g_autoptr(GTimer) t = NULL;
/* set integral time in us */
if (!osp_device_send_command (device, OSP_CMD_SET_INTEGRATION_TIME,
(guint8 *) &sample_duration, 4, error))
return NULL;
/* get spectrum */
t = g_timer_new ();
if (!osp_device_query (device, OSP_CMD_GET_AND_SEND_RAW_SPECTRUM,
NULL, 0, &data, &data_len, error))
return NULL;
g_debug ("For integration of %.0fms, sensor took %.0fms",
sample_duration / 1000.f, g_timer_elapsed (t, NULL) * 1000.f);
/* check values */
if (data_len != 2048) {
g_set_error (error,
OSP_DEVICE_ERROR,
OSP_DEVICE_ERROR_INTERNAL,
"Expected %i bytes, got %" G_GSIZE_FORMAT,
2048, data_len);
return NULL;
}
/* export */
sp = cd_spectrum_sized_new (1024);
for (i = 0; i < 1024; i++) {
val = data[i*2+1] * 256 + data[i*2+0];
cd_spectrum_add_value (sp, val / (gdouble) 0xffff);
}
/* the maximum value the hardware can return is 0x3fff */
val = cd_spectrum_get_value_max (sp);
if (val > 0.25) {
g_set_error (error,
OSP_DEVICE_ERROR,
OSP_DEVICE_ERROR_INTERNAL,
"spectral max should be <= 0.25f, was %f",
val);
cd_spectrum_free (sp);
return NULL;
}
return sp;
}
/**
* cd_spectrum_to_string:
* @spectrum: a #CdSpectrum instance
* @max_width: the terminal width
* @max_height: the terminal height
*
* Returns a graphical representation of the spectrum.
*
* Return value: a printable ASCII string
*
* Since: 1.3.1
**/
gchar *
cd_spectrum_to_string (CdSpectrum *spectrum, guint max_width, guint max_height)
{
GString *str = g_string_new ("");
guint i, j;
gdouble val_max;
gdouble nm_scale;
/* make space for the axes */
max_width -= 9;
max_height -= 2;
/* find value maximum */
val_max = cd_spectrum_get_value_max (spectrum);
if (val_max < 0.001)
val_max = 0.001;
nm_scale = (cd_spectrum_get_end (spectrum) -
cd_spectrum_get_start (spectrum)) / (gdouble) (max_width - 1);
/* draw grid */
for (i = 0; i < max_height; i++) {
gdouble val;
val = val_max / (gdouble) max_height * (max_height - i);
g_string_append_printf (str, "%7.3f |", val);
for (j = 0; j < max_width; j++) {
gdouble nm;
nm = ((gdouble) j * nm_scale) + cd_spectrum_get_start (spectrum);
if (cd_spectrum_get_value_for_nm (spectrum, nm) >= val)
g_string_append (str, "#");
else
g_string_append (str, "_");
}
g_string_append (str, "\n");
}
/* draw x axis */
g_string_append_printf (str, "%7.3f ", 0.f);
for (j = 0; j < max_width; j++)
g_string_append (str, "-");
g_string_append (str, "\n");
/* draw X labels */
g_string_append_printf (str, " %.0fnm",
cd_spectrum_get_start (spectrum));
for (j = 0; j < max_width - 10; j++)
g_string_append (str, " ");
g_string_append_printf (str, "%.0fnm",
cd_spectrum_get_end (spectrum));
g_string_append (str, "\n");
/* success */
return g_string_free (str, FALSE);
}
/**
* osp_device_take_spectrum:
* @device: a #GUsbDevice instance.
* @error: A #GError or %NULL
*
* Returns a spectrum. The optimal sample duration is calculated automatically.
*
* Return value: A #CdSpectrum, or %NULL for error
*
* Since: 1.2.11
**/
CdSpectrum *
osp_device_take_spectrum (GUsbDevice *device, GError **error)
{
const guint sample_duration_max_secs = 3;
gboolean relax_requirements = FALSE;
gdouble max;
gdouble scale = 0.f;
guint64 sample_duration = 10000; /* us */
CdSpectrum *sp = NULL;
guint i;
g_return_val_if_fail (G_USB_IS_DEVICE (device), NULL);
g_return_val_if_fail (error == NULL || *error == NULL, NULL);
/* loop until we're in 1/4 to 3/4 FSD */
for (i = 0; i < 5; i++) {
g_autoptr(CdSpectrum) sp_probe = NULL;
/* for the last try, relax what we deem acceptable so we can
* measure very black things with a long integration time */
if (i == 4)
relax_requirements = TRUE;
/* take a measurement */
sp_probe = osp_device_take_spectrum_full (device,
sample_duration,
error);
if (sp_probe == NULL)
return NULL;
/* sensor picked up nothing, take action */
max = cd_spectrum_get_value_max (sp_probe);
if (max < 0.001f) {
sample_duration *= 100.f;
g_debug ("sensor read no data, setting duration "
"to %" G_GUINT64_FORMAT ,
sample_duration);
continue;
}
/* sensor is saturated, take action */
if (max > 0.99f) {
sample_duration /= 100.f;
g_debug ("sensor saturated, setting duration "
"to %" G_GUINT64_FORMAT,
sample_duration);
continue;
}
/* break out if we got valid readings */
if (max > 0.25f && max < 0.75f) {
sp = cd_spectrum_dup (sp_probe);
break;
}
/* be more accepting */
if (relax_requirements && max > 0.01f) {
sp = cd_spectrum_dup (sp_probe);
break;
}
/* aim for FSD / 2 */
scale = (gdouble) 0.5 / max;
sample_duration *= scale;
g_debug ("for max of %f, using scale=%f for duration %" G_GUINT64_FORMAT,
max, scale, sample_duration);
/* limit this to something sane */
if (sample_duration / G_USEC_PER_SEC > sample_duration_max_secs) {
g_debug ("limiting duration from %us to %us",
(guint) (sample_duration / G_USEC_PER_SEC),
(guint) (sample_duration_max_secs));
sample_duration = sample_duration_max_secs * G_USEC_PER_SEC;
relax_requirements = TRUE;
}
}
/* no suitable readings */
if (sp == NULL) {
g_set_error_literal (error,
OSP_DEVICE_ERROR,
OSP_DEVICE_ERROR_NO_DATA,
"Got no valid data");
return NULL;
}
/* scale with the new integral time */
cd_spectrum_set_norm (sp, cd_spectrum_get_norm (sp) / scale);
g_debug ("normalised spectral max is %f", cd_spectrum_get_value_max (sp));
return sp;
}
