import com.google.zxing.common.BlackPointEstimator;
/**
- * This object implements MonochromeBitmapSource around an Android Bitmap. Rather than capturing an
- * RGB image and calculating the grey value at each pixel, we ask the camera driver for YUV data and
- * strip out the luminance channel directly. This should be faster but provides fewer bits, i.e.
- * fewer grey levels.
+ * This object implements MonochromeBitmapSource around an Android Bitmap.
*
* @author dswitkin@google.com (Daniel Switkin)
* @author srowen@google.com (Sean Owen)
row.clear();
}
int[] pixelRow = new int[getWidth];
- image.getPixels(pixelRow, 0, getWidth, startX, y, getWidth, 1);
- for (int i = 0; i < getWidth; i++) {
- if (computeRGBLuminance(pixelRow[i]) < blackPoint) {
- row.set(i);
+ image.getPixels(pixelRow, 0, getWidth, startX, y, getWidth, 1);
+
+ // If the current decoder calculated the blackPoint based on one row, assume we're trying to
+ // decode a 1D barcode, and apply some sharpening.
+ // TODO: We may want to add a fifth parameter to request the amount of shapening to be done.
+ if (lastMethod == BlackPointEstimationMethod.ROW_SAMPLING) {
+ int left = computeRGBLuminance(pixelRow[0]);
+ int center = computeRGBLuminance(pixelRow[1]);
+ for (int i = 1; i < getWidth - 1; i++) {
+ int right = computeRGBLuminance(pixelRow[i + 1]);
+ // Simple -1 4 -1 box filter with a weight of 2
+ int luminance = ((center << 2) - left - right) >> 1;
+ if (luminance < blackPoint) {
+ row.set(i);
+ }
+ left = center;
+ center = right;
+ }
+ } else {
+ for (int i = 0; i < getWidth; i++) {
+ if (computeRGBLuminance(pixelRow[i]) < blackPoint) {
+ row.set(i);
+ }
}
}
return row;
/**
* An optimized approximation of a more proper conversion from RGB to luminance which
* only uses shifts. See BufferedImageMonochromeBitmapSource for an original version.
+ *
+ * @param pixel An ARGB input pixel
+ * @return An eight bit luminance value
*/
private static int computeRGBLuminance(int pixel) {
// Instead of multiplying by 306, 601, 117, we multiply by 256, 512, 256, so that