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app/src/main/java/com/ectrip/checkincar/plate/BaiduPlateRecognizer.java 3.71 KB
0fd093a2   李进   初始提交:手持车牌核销应用
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  package com.ectrip.checkincar.plate;
  
  import android.content.Context;
  import android.graphics.Bitmap;
  import android.text.TextUtils;
  
  import com.baidu.vis.ocrgve.plate.OcrgveEnginePlate;
  import com.baidu.vis.ocrgve.plate.OcrgvesdkResponsePlate;
  import com.ectrip.checkincar.core.prefs.AppPrefs;
  import com.ectrip.checkincar.license.LicenseManager;
  import com.ectrip.checkincar.model.PlateInfo;
  
  import java.util.ArrayList;
  
  /** 百度车牌离线 SDK 封装。构造在后台线程完成(含授权+模型初始化)。 */
  public class BaiduPlateRecognizer implements PlateRecognizer {
  
      private boolean ready;
      private String error = "未初始化";
  
      public BaiduPlateRecognizer(Context context) {
          ready = LicenseManager.get().ensureReady(context);
          if (!ready) {
              error = LicenseManager.get().getLastError();
          }
      }
  
      public String getError() {
          return error;
      }
  
      @Override
      public boolean isReady() {
          return ready;
      }
  
      @Override
      public PlateInfo recognize(Bitmap bitmap) {
          OcrgveEnginePlate engine = LicenseManager.get().getEngine();
          if (!ready || engine == null || bitmap == null) {
              return null;
          }
          try {
              int w = bitmap.getWidth();
              int h = bitmap.getHeight();
              int[] pixels = new int[w * h];
              bitmap.getPixels(pixels, 0, w, 0, 0, w, h);
              byte[] rgba = new byte[w * h * 4];
              for (int i = 0; i < pixels.length; i++) {
                  int c = pixels[i];
                  rgba[i * 4] = (byte) ((c >> 16) & 0xFF); // R
                  rgba[i * 4 + 1] = (byte) ((c >> 8) & 0xFF); // G
                  rgba[i * 4 + 2] = (byte) (c & 0xFF); // B
                  rgba[i * 4 + 3] = (byte) ((c >> 24) & 0xFF); // A
              }
  
              ArrayList<OcrgvesdkResponsePlate> results =
                      engine.processOcrgvesdk(rgba, OcrgveEnginePlate.PIX_RGBA, w, h, 0);
              if (results == null || results.isEmpty()) {
                  return null;
              }
              float threshold = AppPrefs.getThreshold();
              OcrgvesdkResponsePlate best = null;
              float bestProb = 0f;
              for (OcrgvesdkResponsePlate r : results) {
                  if (r == null || !"plate_number".equals(r.name) || TextUtils.isEmpty(r.mystring)) {
                      continue;
                  }
                  float p = minCharProb(r.recgProb);
                  if (p >= threshold && p > bestProb) {
                      bestProb = p;
                      best = r;
                  }
              }
              if (best == null) {
                  return null;
              }
              return new PlateInfo(best.mystring.trim(), normalizeColor(best.color),
                      bestProb > 0 ? bestProb : best.detScore, false);
          } catch (Throwable t) {
              return null;
          }
      }
  
      @Override
      public void release() {
          // 引擎单例由 LicenseManager 统一持有,随进程存活,不在此释放
      }
  
      /** 字符置信度取最小值;recgProb 为空时退回检测分 */
      private static float minCharProb(float[] probs) {
          if (probs == null || probs.length == 0) {
              return 0f;
          }
          float min = 1f;
          for (float p : probs) {
              if (p < min) {
                  min = p;
              }
          }
          return min;
      }
  
      private static String normalizeColor(String color) {
          if (color == null) {
              return "unknown";
          }
          switch (color) {
              case "blue":
              case "yellow":
              case "green":
              case "white":
              case "black":
                  return color;
              default:
                  return "unknown";
          }
      }
  }