消除背景算法更新

hgdriver/ImageProcess/ImageApplyFadeBackGroundColor.cpp

@@ -48,91 +48,97 @@ void CImageApplyFadeBackGroudColor::apply(cv::Mat& pDib, int side)
 
     cv::add(pDib, cv::Scalar::all(255 + m_offset) - mean_bgr, pDib, mask);
 #else
-    fadeBackground(pDib.data, pDib.step, pDib.rows, m_threshold, m_offset, m_range);
+    fadeBackground(pDib.data, pDib.cols, pDib.rows, pDib.step, m_threshold, m_offset, m_range);
 #endif
 }
 
-void CImageApplyFadeBackGroudColor::fadeBackground(unsigned char* data, int bytesPerLine, int height, int threshold, int offset, int range)
+/// <summary>
+/// 除文稿底色算法，仅支持24位图像
+/// </summary>
+/// <param name="data">图像数据头指针</param>
+/// <param name="bytesPerLine">每行数据大小</param>
+/// <param name="height">图像高度</param>
+/// <param name="threshold">阈值，参考值为100</param>
+/// <param name="offset">文稿底色增亮偏移量，默认为0。值越大，背景越白，反之越暗</param>
+void CImageApplyFadeBackGroudColor::fadeBackground(unsigned char* data, int width, int height, int bytesPerLine, int threshold, int offset, int range)
 {
+    memset(m_table1, 255, 768);
+    memset(m_table1, 0, threshold * 3);
+    memset(m_table2, 255, 256 * 3);
+
+    for (uint i = 0; i < 256; i++)
+        m_table2[i] = i;
+
     int hist_bgr[3][256] = { 0 };
 
-    int width = bytesPerLine / 3;
     unsigned char* mask = new unsigned char[width * height];
     unsigned char* ptr_data = data;
     unsigned char* ptr_mask = mask;
+    unsigned char b = 0;
 
-    //创建掩模mask，并且统计三通道的直方图
+    for (uint i = 0; i < height; i++, ptr_data += bytesPerLine, ptr_mask += width)
-    for (size_t i = 0; i < height; i++)
+        for (uint j = 0, x = 0; j < width; j++, x += 3)
-    {
-        int x = 0;
-        unsigned char b = 0;
-        for (size_t j = 0; j < width; j++)
         {
             b = m_table1[ptr_data[x] + ptr_data[x + 1] + ptr_data[x + 2]];
             ptr_mask[j] = b;
-            for (size_t k = 0; k < 3; k++)
+            for (uint k = 0; k < 3; k++)
                 hist_bgr[k][ptr_data[x + k] & b]++;
-            x += 3;
         }
-        ptr_data += bytesPerLine;
-        ptr_mask += width;
-    }
 
-    //统计背景色
     int max_vals[3] = { 0 };
     int max_indexes[3] = { 0 };
 
-    for (size_t i = 1; i < 256; i++)
+    for (uint i = 1; i < 256; i++)
-        for (size_t j = 0; j < 3; j++)
+        for (uint j = 0; j < 3; j++)
             if (hist_bgr[j][i] > max_vals[j])
             {
                 max_vals[j] = hist_bgr[j][i];
                 max_indexes[j] = i;
             }
 
-    //创建背景色误查值表，在误差±range范围内的颜色被同样视为背景色
+    uchar table_rgb[3][256] = { 0 };
-    for (size_t i = 0; i < 3; i++)
+    for (uint i = 0; i < 3; i++)
     {
-        memset(m_table_rgb[i], 0, 256);
         int start = cv::max(max_indexes[i] - range, 0);
         int end = cv::min(max_indexes[i] + range, 255);
-        memset(m_table_rgb[i] + start, 255, end - start + 1);
+        memset(table_rgb[i] + start, 255, cv::min(end - start + 1, 256 - start));
     }
 
-    //根据背景色误差查值表，更新掩模，排除背景色以外的内容
     ptr_data = data;
     ptr_mask = mask;
-    for (size_t i = 0; i < height; i++)
+    for (uint i = 0; i < height; i++, ptr_data += bytesPerLine, ptr_mask += width)
-    {
+        for (uint j = 0, x = 0; j < width; j++, x += 3)
-        int x = 0;
+            ptr_mask[j] &= table_rgb[0][ptr_data[x]] & table_rgb[1][ptr_data[x + 1]] & table_rgb[2][ptr_data[x + 2]];
-        for (size_t j = 0; j < width; j++)
-        {
-            ptr_mask[j] &= m_table_rgb[0][ptr_data[x]] & m_table_rgb[1][ptr_data[x + 1]] & m_table_rgb[2][ptr_data[x + 2]];
-            x += 3;
-        }
-        ptr_data += bytesPerLine;
-        ptr_mask += width;
-    }
 
-    //根据掩模，除背景色
     unsigned char offset_rgb[3];
-    for (size_t i = 0; i < 3; i++)
+    for (uint i = 0; i < 3; i++)
         offset_rgb[i] = 255 + offset - max_indexes[i];
 
+#if 1
     ptr_data = data;
     ptr_mask = mask;
-    for (size_t i = 0; i < height; i++)
+    for (uint i = 0; i < height; i++, ptr_data += bytesPerLine, ptr_mask += width)
-    {
+        for (uint j = 0, x = 0; j < width; j++, x += 3)
-        int x = 0;
+            for (uint k = 0; k < 3; k++)
-        for (size_t j = 0; j < width; j++)
-        {
-            for (size_t k = 0; k < 3; k++)
                 ptr_data[x + k] = m_table2[(int)ptr_data[x + k] + (offset_rgb[k] & ptr_mask[j])];
-            x += 3;
+#else
+    for (uint c = 0; c < 3; c++)
+    {
+        ptr_data = data + c;
+        ptr_mask = mask;
+        for (uint y = 0; y < height; y++)
+        {
+            int ptr_x = 0;
+            for (uint x = 0; x < width; x++)
+            {
+                ptr_data[ptr_x] = m_table2[(int)ptr_data[ptr_x] + (offset_rgb[c] & ptr_mask[x])];
+                ptr_x += 3;
+            }
+            ptr_data += bytesPerLine;
+            ptr_mask += width;
         }
-        ptr_data += bytesPerLine;
-        ptr_mask += width;
     }
+#endif
     delete[] mask;
 }
 

hgdriver/ImageProcess/ImageApplyFadeBackGroundColor.h

@@ -13,7 +13,8 @@
  *				 2021/10/28  v3.2 重构算法，改用纯C++代码实现功能，提高处理速度。
  *				 2021/10/29  v3.3 优化算法，增加range参数。针对复杂内容的图像，能够有效甄别背景和非背景内容。
  *				 2022/03/08  v3.4 修复变量未初始化的BUG。
- * 版本号：v3.4
+ *				 2022/10/22  v3.5 使opencv ROI的内存机制。
+ * 版本号：v3.5
 
  * ====================================================
  */
@@ -41,24 +42,24 @@ public:
 	virtual void apply(std::vector<cv::Mat>& mats, bool isTwoSide);
 
 private:
-
 	/// <summary>
 	/// 除文稿底色算法，仅支持24位图像
 	/// </summary>
 	/// <param name="data">图像数据头指针</param>
-	/// <param name="bytesPerLine">每行数据大小</param>
+	/// <param name="width">图像宽度</param>
 	/// <param name="height">图像高度</param>
-	/// <param name="threshold">阈值，参考值为100</param>
+	/// <param name="bytesPerLine">每行数据大小</param>
+	/// <param name="threshold">阈值。区分文稿和黑色背景。取值范围[0, 255],参考值为100</param>
 	/// <param name="offset">文稿底色增亮偏移量，默认为0。值越大，背景越白，反之越暗</param>
-	/// <param name="range">底色误差范围，色彩与识别到的底色误差在[-range, range]范围内，视为底色，否则不会被消除</param>
+	/// <param name="range">背景色彩的浮动范围。要求大于等于1。值越大范围越大，更多的色彩被判定为底色并除色。参考值40</param>
-	void fadeBackground(unsigned char* data, int bytesPerLine, int height, int threshold, int offset, int range);
+	void fadeBackground(unsigned char* data, int width, int height, int bytesPerLine, int threshold, int offset, int range);
 
 private:
 	int m_threshold;
 	int m_offset;
 	int m_range;
 	uchar m_table1[768];
-	uchar m_table2[512];
+	uchar m_table2[768];
 	uchar m_table_rgb[3][256];
 };