// Helper returns true if the null_char is the winner at t, and it beats the
// null_threshold, or the next choice is space, in which case we will use the
// null anyway.
static bool NullIsBest(const NetworkIO& output, float null_thr,
int null_char, int t) {
if (output.f(t)[null_char] >= null_thr) return true;
if (output.BestLabel(t, null_char, null_char, NULL) != UNICHAR_SPACE)
return false;
return output.f(t)[null_char] > output.f(t)[UNICHAR_SPACE];
}
// Helper computes min and mean best results in the output.
void LSTMRecognizer::OutputStats(const NetworkIO& outputs, float* min_output,
float* mean_output, float* sd) {
const int kOutputScale = MAX_INT8;
STATS stats(0, kOutputScale + 1);
for (int t = 0; t < outputs.Width(); ++t) {
int best_label = outputs.BestLabel(t, NULL);
if (best_label != null_char_ || t == 0) {
float best_output = outputs.f(t)[best_label];
stats.add(static_cast<int>(kOutputScale * best_output), 1);
}
}
*min_output = static_cast<float>(stats.min_bucket()) / kOutputScale;
*mean_output = stats.mean() / kOutputScale;
*sd = stats.sd() / kOutputScale;
}
// Converts the network output to a sequence of labels, with scores, using
// the simple character model (each position is a char, and the null_char_ is
// mainly intended for tail padding.)
void LSTMRecognizer::LabelsViaSimpleText(const NetworkIO& output,
GenericVector<int>* labels,
GenericVector<int>* xcoords) {
labels->truncate(0);
xcoords->truncate(0);
int width = output.Width();
for (int t = 0; t < width; ++t) {
float score = 0.0f;
int label = output.BestLabel(t, &score);
if (label != null_char_) {
labels->push_back(label);
xcoords->push_back(t);
}
}
xcoords->push_back(width);
}
