diff --git a/hgdriver/hgdev/hg_scanner.cpp b/hgdriver/hgdev/hg_scanner.cpp
index 71dd9d4..b3ca39b 100644
--- a/hgdriver/hgdev/hg_scanner.cpp
+++ b/hgdriver/hgdev/hg_scanner.cpp
@@ -205,12 +205,11 @@ hg_scanner::hg_scanner(ScannerSerial serial, const char* dev_name, usb_io* io, i
 
 	custom_gamma_val_ = new SANE_Gamma;
 	memset(custom_gamma_val_, 0, sizeof(SANE_Gamma));
+	for (int i = 0; i < ARRAY_SIZE(custom_gamma_val_->table); ++i)
+		custom_gamma_val_->table[i] = i & 0x0ff;
 
 	paper_size_mm_.cx = 210;
 	paper_size_mm_.cy = 297;
-	custom_gamma_val_->pt_count_r = custom_gamma_val_->pt_count_g = custom_gamma_val_->pt_count_b = 0;
-	for (int i = 0; i < ARRAY_SIZE(custom_gamma_val_->table); ++i)
-		custom_gamma_val_->table[i] = i & 0x0ff;
 
 	VLOG_MINI_2(LOG_LEVEL_DEBUG_INFO, "%s(%s) constructed\n", name_.c_str(), hg_log::format_ptr(this).c_str());
 	image_prc_param_.value = 0;
@@ -2847,17 +2846,22 @@ void hg_scanner::adjust_color(hg_imgproc::HIMGPRC handle)
 		if (img_conf_.pixtype == COLOR_MODE_BLACK_WHITE || img_conf_.pixtype == COLOR_MODE_256_GRAY)
 		{
 			tableLength = 256;
-			memcpy(buffer1, custom_gamma_val_->table, tableLength);
+			memcpy(buffer1, custom_gamma_val_->table + 256 * GAMMA_INDEX_GRAY, tableLength);
 		}
 		else
 		{
 			// convert R[256] + G[256] + B[256] to BGR[256] ...
+			//
+			// To be modified: here should be color[256] + R[256] + G[256] + B[256] to BGR[256], final pixel = color[R[x]] - commented on 2023-08-07
 			tableLength = 256 * 3;
 			for (int i = 0; i < 256; ++i)
 			{
-				buffer1[i * 3 + 0] = custom_gamma_val_->table[256 * 2 + i];
-				buffer1[i * 3 + 1] = custom_gamma_val_->table[256 * 1 + i];
-				buffer1[i * 3 + 2] = custom_gamma_val_->table[256 * 0 + i];
+				//buffer1[i * 3 + 0] = custom_gamma_val_->table[256 * GAMMA_INDEX_BLUE + i];
+				//buffer1[i * 3 + 1] = custom_gamma_val_->table[256 * GAMMA_INDEX_GREEN + i];
+				//buffer1[i * 3 + 2] = custom_gamma_val_->table[256 * GAMMA_INDEX_RED + i];
+				buffer1[i * 3 + 0] = custom_gamma_val_->table[256 * GAMMA_INDEX_COLOR + custom_gamma_val_->table[256 * GAMMA_INDEX_BLUE + i]];
+				buffer1[i * 3 + 1] = custom_gamma_val_->table[256 * GAMMA_INDEX_COLOR + custom_gamma_val_->table[256 * GAMMA_INDEX_GREEN + i]];
+				buffer1[i * 3 + 2] = custom_gamma_val_->table[256 * GAMMA_INDEX_COLOR + custom_gamma_val_->table[256 * GAMMA_INDEX_RED + i]];
 			}
 		}
 	}