ANSCORE/modules/ANSOCR/ANSONNXOCR/ONNXOCRRecognizer.cpp

#include "ONNXOCRRecognizer.h"

#include <opencv2/imgproc.hpp>
#include <iostream>
#include <algorithm>
#include <numeric>
#include <cmath>
#include <cfloat>
#include <cstring>
#include <chrono>

namespace ANSCENTER {
namespace onnxocr {

ONNXOCRRecognizer::ONNXOCRRecognizer(const std::string& onnx_path, unsigned int num_threads)
    : BasicOrtHandler(onnx_path, num_threads) {
}

ONNXOCRRecognizer::ONNXOCRRecognizer(const std::string& onnx_path,
                                     const OrtHandlerOptions& options,
                                     unsigned int num_threads)
    : BasicOrtHandler(onnx_path, options, num_threads) {
}

bool ONNXOCRRecognizer::LoadDictionary(const std::string& dictPath) {
    keys_ = LoadDict(dictPath);
    if (keys_.size() < 2) {
        std::cerr << "[ONNXOCRRecognizer] Failed to load dictionary: " << dictPath << std::endl;
        return false;
    }
    std::cout << "[ONNXOCRRecognizer] Loaded dictionary with " << keys_.size()
              << " characters from: " << dictPath << std::endl;
    return true;
}

Ort::Value ONNXOCRRecognizer::transform(const cv::Mat& mat) {
    // Not used directly - recognition uses custom preprocess with dynamic width
    cv::Mat resized = ResizeRecImage(mat, imgH_, imgMaxW_);
    resized.convertTo(resized, CV_32FC3);
    auto data = NormalizeAndPermuteCls(resized);

    input_values_handler.assign(data.begin(), data.end());
    return Ort::Value::CreateTensor<float>(
        *memory_info_handler, input_values_handler.data(), input_values_handler.size(),
        input_node_dims.data(), input_node_dims.size());
}

Ort::Value ONNXOCRRecognizer::transformBatch(const std::vector<cv::Mat>& images) {
    // Not used - recognizer processes single images with dynamic widths
    if (!images.empty()) {
        return transform(images[0]);
    }
    return Ort::Value(nullptr);
}

// ----------------------------------------------------------------------------
// Width buckets — every recognizer input is padded up to one of these widths
// before reaching ORT. This bounds the number of distinct shapes cuDNN ever
// sees to four, so its HEURISTIC algorithm cache hits on every subsequent
// call instead of re-tuning per plate. Buckets cover the realistic range:
//   320 px  → short Latin/Japanese plates (most common)
//   480 px  → wider Latin plates with two rows of text
//   640 px  → long single-row plates / multi-line stacked text
//   960 px  → safety upper bound (== kRecImgMaxW)
// ----------------------------------------------------------------------------
static constexpr int kRecBucketWidths[] = { 320, 480, 640, 960 };
static constexpr int kRecNumBuckets = sizeof(kRecBucketWidths) / sizeof(kRecBucketWidths[0]);

int ONNXOCRRecognizer::RoundUpToBucket(int resizedW) const {
    const int capped = std::min(resizedW, imgMaxW_);
    for (int b = 0; b < kRecNumBuckets; ++b) {
        if (kRecBucketWidths[b] >= capped) return kRecBucketWidths[b];
    }
    return imgMaxW_;
}

// Resize + normalize a single crop into a CHW float vector at width
// `bucketW`, padding with zeros on the right when needed. The returned
// vector has exactly 3*imgH_*bucketW elements.
static std::vector<float> PreprocessCropToBucket(const cv::Mat& crop,
                                                 int imgH, int bucketW) {
    cv::Mat resized = ResizeRecImage(crop, imgH, bucketW);
    int resizedW = resized.cols;
    resized.convertTo(resized, CV_32FC3);
    auto normalizedData = NormalizeAndPermuteCls(resized);

    if (resizedW == bucketW) {
        return normalizedData;
    }

    // Zero-pad on the right (CHW layout)
    std::vector<float> padded(3 * imgH * bucketW, 0.0f);
    for (int c = 0; c < 3; c++) {
        for (int y = 0; y < imgH; y++) {
            std::memcpy(
                &padded[c * imgH * bucketW + y * bucketW],
                &normalizedData[c * imgH * resizedW + y * resizedW],
                resizedW * sizeof(float));
        }
    }
    return padded;
}

TextLine ONNXOCRRecognizer::Recognize(const cv::Mat& croppedImage) {
    std::lock_guard<std::mutex> lock(_mutex);

    if (!ort_session || croppedImage.empty() || keys_.empty()) {
        return {};
    }

    try {
        // Step 1: aspect-preserving resize to height=imgH_, width capped
        // at imgMaxW_. Then round resized width up to the next bucket.
        cv::Mat resized = ResizeRecImage(croppedImage, imgH_, imgMaxW_);
        const int bucketW = RoundUpToBucket(resized.cols);

        std::vector<float> inputData = PreprocessCropToBucket(croppedImage, imgH_, bucketW);

        std::array<int64_t, 4> inputShape = { 1, 3, imgH_, bucketW };
        Ort::Value inputTensor = Ort::Value::CreateTensor<float>(
            *memory_info_handler, inputData.data(), inputData.size(),
            inputShape.data(), inputShape.size());

        auto outputTensors = ort_session->Run(
            Ort::RunOptions{ nullptr },
            input_node_names.data(), &inputTensor, 1,
            output_node_names.data(), num_outputs);

        float* outputData = outputTensors[0].GetTensorMutableData<float>();
        auto outputShape = outputTensors[0].GetTensorTypeAndShapeInfo().GetShape();

        int seqLen     = static_cast<int>(outputShape[1]);
        int numClasses = static_cast<int>(outputShape[2]);

        return CTCDecode(outputData, seqLen, numClasses);
    }
    catch (const Ort::Exception& e) {
        std::cerr << "[ONNXOCRRecognizer] Inference failed: " << e.what() << std::endl;
        return {};
    }
}

void ONNXOCRRecognizer::RunBatchAtWidth(const std::vector<cv::Mat>& crops,
                                        const std::vector<size_t>& origIndices,
                                        int bucketW,
                                        std::vector<TextLine>& out) {
    if (crops.empty()) return;

    try {
        const size_t batchN = crops.size();
        const size_t perImage = static_cast<size_t>(3) * imgH_ * bucketW;

        // Stack N preprocessed crops into one [N,3,H,W] buffer
        std::vector<float> batchInput(batchN * perImage, 0.0f);
        for (size_t i = 0; i < batchN; ++i) {
            auto img = PreprocessCropToBucket(crops[i], imgH_, bucketW);
            std::memcpy(&batchInput[i * perImage], img.data(),
                        perImage * sizeof(float));
        }

        std::array<int64_t, 4> inputShape = {
            static_cast<int64_t>(batchN), 3,
            static_cast<int64_t>(imgH_),
            static_cast<int64_t>(bucketW)
        };
        Ort::Value inputTensor = Ort::Value::CreateTensor<float>(
            *memory_info_handler, batchInput.data(), batchInput.size(),
            inputShape.data(), inputShape.size());

        auto outputTensors = ort_session->Run(
            Ort::RunOptions{ nullptr },
            input_node_names.data(), &inputTensor, 1,
            output_node_names.data(), num_outputs);

        float* outputData = outputTensors[0].GetTensorMutableData<float>();
        auto outputShape  = outputTensors[0].GetTensorTypeAndShapeInfo().GetShape();

        // Expected output: [N, seqLen, numClasses]
        if (outputShape.size() < 3) {
            std::cerr << "[ONNXOCRRecognizer] Unexpected batch output rank: "
                      << outputShape.size() << std::endl;
            return;
        }
        const int outBatch   = static_cast<int>(outputShape[0]);
        const int seqLen     = static_cast<int>(outputShape[1]);
        const int numClasses = static_cast<int>(outputShape[2]);
        const size_t perRow  = static_cast<size_t>(seqLen) * numClasses;

        for (int i = 0; i < outBatch && i < static_cast<int>(batchN); ++i) {
            TextLine tl = CTCDecode(outputData + i * perRow, seqLen, numClasses);
            out[origIndices[i]] = std::move(tl);
        }
    }
    catch (const Ort::Exception& e) {
        // ORT will throw if the model doesn't support a batch dimension > 1.
        // Fall back to per-image inference for this group.
        std::cerr << "[ONNXOCRRecognizer] Batch inference failed at bucketW="
                  << bucketW << " (" << e.what()
                  << ") — falling back to single-image path." << std::endl;
        for (size_t i = 0; i < crops.size(); ++i) {
            // Direct call (we already hold _mutex via the public RecognizeBatch
            // wrapper). Replicate the single-image preprocessing here to avoid
            // re-entering Recognize() and double-locking the mutex.
            try {
                cv::Mat resized = ResizeRecImage(crops[i], imgH_, imgMaxW_);
                int singleBucket = RoundUpToBucket(resized.cols);
                auto inputData = PreprocessCropToBucket(crops[i], imgH_, singleBucket);
                std::array<int64_t, 4> inputShape = { 1, 3, imgH_, singleBucket };
                Ort::Value inputTensor = Ort::Value::CreateTensor<float>(
                    *memory_info_handler, inputData.data(), inputData.size(),
                    inputShape.data(), inputShape.size());
                auto outputTensors = ort_session->Run(
                    Ort::RunOptions{ nullptr },
                    input_node_names.data(), &inputTensor, 1,
                    output_node_names.data(), num_outputs);
                float* outData = outputTensors[0].GetTensorMutableData<float>();
                auto outShape = outputTensors[0].GetTensorTypeAndShapeInfo().GetShape();
                int seqLen = static_cast<int>(outShape[1]);
                int numClasses = static_cast<int>(outShape[2]);
                out[origIndices[i]] = CTCDecode(outData, seqLen, numClasses);
            } catch (const Ort::Exception& e2) {
                std::cerr << "[ONNXOCRRecognizer] Single-image fallback also failed: "
                          << e2.what() << std::endl;
                out[origIndices[i]] = {};
            }
        }
    }
}

std::vector<TextLine> ONNXOCRRecognizer::RecognizeBatch(const std::vector<cv::Mat>& croppedImages) {
    std::lock_guard<std::mutex> lock(_mutex);

    std::vector<TextLine> results(croppedImages.size());
    if (!ort_session || croppedImages.empty() || keys_.empty()) {
        return results;
    }

    // Group crops by their target bucket width
    std::vector<std::vector<cv::Mat>> groupCrops(kRecNumBuckets);
    std::vector<std::vector<size_t>>  groupIdx(kRecNumBuckets);

    for (size_t i = 0; i < croppedImages.size(); ++i) {
        if (croppedImages[i].empty()) continue;
        cv::Mat resized = ResizeRecImage(croppedImages[i], imgH_, imgMaxW_);
        const int bw = RoundUpToBucket(resized.cols);
        // Find bucket index
        int bucketIdx = kRecNumBuckets - 1;
        for (int b = 0; b < kRecNumBuckets; ++b) {
            if (kRecBucketWidths[b] == bw) { bucketIdx = b; break; }
        }
        groupCrops[bucketIdx].push_back(croppedImages[i]);
        groupIdx[bucketIdx].push_back(i);
    }

    // Run one batched inference per non-empty bucket
    for (int b = 0; b < kRecNumBuckets; ++b) {
        if (groupCrops[b].empty()) continue;
        RunBatchAtWidth(groupCrops[b], groupIdx[b], kRecBucketWidths[b], results);
    }

    return results;
}

void ONNXOCRRecognizer::Warmup() {
    std::lock_guard<std::mutex> lock(_mutex);
    if (_warmedUp || !ort_session) return;

    // Dummy 3-channel image, mid-grey, large enough to resize to imgH_
    cv::Mat dummy(imgH_ * 2, kRecBucketWidths[kRecNumBuckets - 1] * 2,
                  CV_8UC3, cv::Scalar(128, 128, 128));

    for (int b = 0; b < kRecNumBuckets; ++b) {
        const int bucketW = kRecBucketWidths[b];
        try {
            auto inputData = PreprocessCropToBucket(dummy, imgH_, bucketW);
            std::array<int64_t, 4> inputShape = { 1, 3, imgH_, bucketW };
            Ort::Value inputTensor = Ort::Value::CreateTensor<float>(
                *memory_info_handler, inputData.data(), inputData.size(),
                inputShape.data(), inputShape.size());

            auto t0 = std::chrono::high_resolution_clock::now();
            (void)ort_session->Run(
                Ort::RunOptions{ nullptr },
                input_node_names.data(), &inputTensor, 1,
                output_node_names.data(), num_outputs);
            auto t1 = std::chrono::high_resolution_clock::now();
            double ms = std::chrono::duration<double, std::milli>(t1 - t0).count();
            std::cout << "[ONNXOCRRecognizer] Warmup bucketW=" << bucketW
                      << "  " << ms << " ms" << std::endl;
        }
        catch (const Ort::Exception& e) {
            std::cerr << "[ONNXOCRRecognizer] Warmup failed at bucketW="
                      << bucketW << ": " << e.what() << std::endl;
        }
    }
    _warmedUp = true;
}

TextLine ONNXOCRRecognizer::CTCDecode(const float* outputData, int seqLen, int numClasses) {
    TextLine result;
    std::string text;
    std::vector<float> scores;

    int lastIndex = 0; // CTC blank is index 0

    for (int t = 0; t < seqLen; t++) {
        // Find argmax for this timestep
        int maxIndex = 0;
        float maxValue = -FLT_MAX;

        const float* timeStep = outputData + t * numClasses;
        for (int c = 0; c < numClasses; c++) {
            if (timeStep[c] > maxValue) {
                maxValue = timeStep[c];
                maxIndex = c;
            }
        }

        // CTC decode: skip blanks (index 0) and repeated characters
        if (maxIndex != 0 && maxIndex != lastIndex) {
            if (maxIndex > 0 && maxIndex < static_cast<int>(keys_.size())) {
                text += keys_[maxIndex]; // keys_[0]="#"(blank), keys_[1]=first_char, etc.
                // Use raw model output value as confidence (PaddleOCR v5 models include softmax)
                scores.push_back(maxValue);
            }
        }
        lastIndex = maxIndex;
    }

    result.text = text;
    if (!scores.empty()) {
        result.score = std::accumulate(scores.begin(), scores.end(), 0.0f) /
                       static_cast<float>(scores.size());
    }
    return result;
}

} // namespace onnxocr
} // namespace ANSCENTER