gl847 shading calibration refactor

backend/genesys.c

@@ -2958,6 +2958,165 @@ compute_coefficient (unsigned int coeff, unsigned int target, unsigned int value
   return result;
 }
 
+/** @brief compute shading coefficients for LiDE scanners
+ *
+The dark/white shading is actually performed _after_ reducing
+resolution via averaging. only dark/white shading data for what would be
+first pixel at full resolution is used.
+
+scanner raw input to output value calculation:
+  o=(i-off)*(gain/coeff)
+
+from datasheet:
+  off=dark_average
+  gain=coeff*bright_target/(bright_average-dark_average)
+works for dark_target==0
+
+what we want is these:
+  bright_target=(bright_average-off)*(gain/coeff)
+  dark_target=(dark_average-off)*(gain/coeff)
+leading to
+  off = (dark_average*bright_target - bright_average*dark_target)/(bright_target - dark_target)
+  gain = (bright_target - dark_target)/(bright_average - dark_average)*coeff
+ *
+ * @param dev scanner's device
+ * @param shading_data memory area where to store the computed shading coefficients
+ * @param pixels_per_line number of pixels per line
+ * @param words_per_color memory words per color channel
+ * @param channels number of color channels (actually 1 or 3)
+ * @param o shading coefficients left offset
+ * @param coeff 4000h or 2000h depending on fast scan mode or not (GAIN4 bit)
+ * @param target_bright value of the white target code
+ * @param target_dark value of the black target code
+*/
+#ifndef UNIT_TESTING
+static
+#endif
+void
+compute_averaged_planar (Genesys_Device * dev,
+			     uint8_t * shading_data,
+			     unsigned int pixels_per_line,
+			     unsigned int words_per_color,
+			     unsigned int channels,
+			     unsigned int o,
+			     unsigned int coeff,
+			     unsigned int target_bright,
+			     unsigned int target_dark)
+{
+  unsigned int x, i, j, br, dk, res, avgpixels, val;
+
+  /* initialize result */
+  /* memset (shading_data, 0xff, words_per_color * 3 * 2); */
+
+  /* duplicate half-ccd logic */
+  res = dev->settings.xres;
+  if ((dev->model->flags & GENESYS_FLAG_HALF_CCD_MODE)
+      && dev->settings.xres <= dev->sensor.optical_res / 2)
+    {
+      /* scanner is using half-ccd mode */
+      res *= 2;
+    }
+
+  /*this should be evenly dividable */
+  avgpixels = dev->sensor.optical_res / res;
+
+  /* gl841 and gl847 supports 1/1 1/2 1/3 1/4 1/5 1/6 1/8 1/10 1/12 1/15 averaging */
+  if (avgpixels < 1)
+    avgpixels = 1;
+  else if (avgpixels < 6)
+    avgpixels = avgpixels;
+  else if (avgpixels < 8)
+    avgpixels = 6;
+  else if (avgpixels < 10)
+    avgpixels = 8;
+  else if (avgpixels < 12)
+    avgpixels = 10;
+  else if (avgpixels < 15)
+    avgpixels = 12;
+  else
+    avgpixels = 15;
+
+  DBG (DBG_info, "compute_planar_averaged: averaging over %d pixels\n",
+       avgpixels);
+
+  for (x = 0; x <= pixels_per_line - avgpixels; x += avgpixels)
+    {
+
+      if ((x + o) * 2 * 2 + 3 > words_per_color * 2)
+	break;
+
+      for (j = 0; j < channels; j++)
+	{
+
+	  dk = 0;
+	  br = 0;
+	  for (i = 0; i < avgpixels; i++)
+	    {
+	      /* dark data */
+	      dk += (dev->dark_average_data[(x + i + pixels_per_line * j) * 2]
+                     | (dev-> dark_average_data[(x + i + pixels_per_line * j) * 2 + 1] << 8));
+
+	      /* white data */
+	      br += (dev->white_average_data[(x + i + pixels_per_line * j) * 2]
+                     | (dev-> white_average_data[(x + i + pixels_per_line * j) * 2 + 1] << 8));
+	    }
+
+	  br /= avgpixels;
+	  dk /= avgpixels;
+
+	  if (br * target_dark > dk * target_bright)
+	    val = 0;
+	  else if (dk * target_bright - br * target_dark > 65535
+		   * (target_bright - target_dark))
+	    val = 65535;
+	  else
+	    val = (dk * target_bright - br * target_dark) / (target_bright
+							     - target_dark);
+
+	  /*fill all pixels, even if only the last one is relevant */
+	  for (i = 0; i < avgpixels; i++)
+	    {
+	      shading_data[(x + o + i) * 2 * 2 + words_per_color * 2 * j] = val & 0xff;
+	      shading_data[(x + o + i) * 2 * 2 + words_per_color * 2 * j + 1] = val >> 8;
+	    }
+
+	  val = br - dk;
+
+	  if (65535 * val > (target_bright - target_dark) * coeff)
+	    val = (coeff * (target_bright - target_dark)) / val;
+	  else
+	    val = 65535;
+
+	  /*fill all pixels, even if only the last one is relevant */
+	  for (i = 0; i < avgpixels; i++)
+	    {
+	      shading_data[(x + o + i) * 2 * 2 + words_per_color * 2 * j + 2] = val & 0xff;
+	      shading_data[(x + o + i) * 2 * 2 + words_per_color * 2 * j + 3] = val >> 8;
+	    }
+	}
+
+      /*fill remaining channels */
+      for (j = channels; j < 3; j++)
+	{
+	  for (i = 0; i < avgpixels; i++)
+	    {
+	      shading_data[(x + o + i) * 2 * 2 + words_per_color * 2 * j]
+		= shading_data[(x + o + i) * 2 * 2 + words_per_color * 0];
+	      shading_data[(x + o + i) * 2 * 2 + words_per_color * 2 * j + 1]
+		= shading_data[(x + o + i) * 2 * 2 + words_per_color
+			       * 2 * 0 + 1];
+	      shading_data[(x + o + i) * 2 * 2 + words_per_color * 2 * j + 2]
+		= shading_data[(x + o + i) * 2 * 2 + words_per_color
+			       * 2 * 0 + 2];
+	      shading_data[(x + o + i) * 2 * 2 + words_per_color * 2 * j + 3]
+		= shading_data[(x + o + i) * 2 * 2 + words_per_color
+			       * 2 * 0 + 3];
+	    }
+	}
+    }
+}
+
+
 /**
  * Computes shading coefficient using formula in data sheet. 16bit data values
  * manipulated here are little endian. For now we assume deletion scanning type
@@ -3305,9 +3464,19 @@ genesys_send_shading_coefficient (Genesys_Device * dev)
                             coeff, 
                             target_code);
       break;
-    case CCD_CANONLIDE35:
     case CIS_CANONLIDE100:
     case CIS_CANONLIDE200:
+    	compute_averaged_planar(dev,
+				shading_data,
+				pixels_per_line,
+				words_per_color,
+				channels,
+				4,
+				coeff,
+				0xfa00,
+				0x0a00);
+      break;
+    case CCD_CANONLIDE35:
       target_bright = 0xfa00;
       target_dark = 0xa00;
       o = 4;			/*first four pixels are ignored */
@@ -5531,7 +5700,7 @@ init_gamma_vector_option (Genesys_Scanner * scanner, int option)
  * @param size maximum size of the range
  * @return a poiter to a valid range or NULL
  */
-static create_range(SANE_Fixed size)
+static SANE_Range *create_range(SANE_Fixed size)
 {
 SANE_Range *range=NULL;
 

backend/genesys_devices.c

@@ -971,7 +971,7 @@ static Genesys_Model canon_lide_100_model = {
     | GENESYS_FLAG_DARK_CALIBRATION
     | GENESYS_FLAG_CUSTOM_GAMMA,
   GENESYS_HAS_SCAN_SW | GENESYS_HAS_COPY_SW | GENESYS_HAS_EMAIL_SW | GENESYS_HAS_FILE_SW,
-  50,
+  150,
   400
 };