Switch to GTM_AUTO and add settings dump for debugging

GTM_AUTO lets the SDK auto-detect grayscale polarity instead of
manually specifying GTM_INVERTED + GTM_ORIGINAL. Also dumps the
effective template settings to console after initSettings() to
verify the configuration is actually being applied.

Author: Tom-Dynamsoft

lab/vin-scanner/index.html

@@ -355,6 +355,14 @@ <h1>VIN Scanner</h1>
       loadingText.textContent = "Loading VIN template...";
       await cvRouter.initSettings("./template.json");
 
+      // DEBUG: dump effective settings to verify GTM_INVERTED is applied
+      try {
+        const effectiveSettings = await cvRouter.outputSettings("ReadVIN");
+        console.log("=== Effective ReadVIN settings ===", JSON.parse(effectiveSettings));
+      } catch (e) {
+        console.warn("Could not dump settings:", e);
+      }
+
       // Cross-frame filtering
       const filter = new Dynamsoft.Utility.MultiFrameResultCrossFilter();
       filter.enableResultCrossVerification("barcode", true);

lab/vin-scanner/template.json

@@ -232,7 +232,7 @@
       "BaseImageParameterName": "",
       "ApplicableStages": [
         { "Stage": "SST_CONVERT_TO_GRAYSCALE", "ColourConversionModes": [{ "BlueChannelWeight": -1, "GreenChannelWeight": -1, "Mode": "CICM_GENERAL", "RedChannelWeight": -1, "ReferChannel": "H_CHANNEL" }] },
-        { "Stage": "SST_TRANSFORM_GRAYSCALE", "GrayscaleTransformationModes": [{ "Mode": "GTM_INVERTED" }, { "Mode": "GTM_ORIGINAL" }] },
+        { "Stage": "SST_TRANSFORM_GRAYSCALE", "GrayscaleTransformationModes": [{ "Mode": "GTM_AUTO" }] },
         { "Stage": "SST_ENHANCE_GRAYSCALE", "GrayscaleEnhancementModes": [{ "Mode": "GEM_GENERAL" }] },
         { "Stage": "SST_BINARIZE_IMAGE", "BinarizationModes": [{ "Mode": "BM_LOCAL_BLOCK", "MorphOperation": "Erode", "ThresholdCompensation": 10 }] },
         { "Stage": "SST_DETECT_TEXTURE", "TextureDetectionModes": [{ "Mode": "TDM_GENERAL_WIDTH_CONCENTRATION", "Sensitivity": 5 }] },
@@ -245,7 +245,7 @@
       "BaseImageParameterName": "",
       "ApplicableStages": [
         { "Stage": "SST_CONVERT_TO_GRAYSCALE", "ColourConversionModes": [{ "BlueChannelWeight": -1, "GreenChannelWeight": -1, "Mode": "CICM_GENERAL", "RedChannelWeight": -1, "ReferChannel": "H_CHANNEL" }] },
-        { "Stage": "SST_TRANSFORM_GRAYSCALE", "GrayscaleTransformationModes": [{ "Mode": "GTM_INVERTED" }, { "Mode": "GTM_ORIGINAL" }] },
+        { "Stage": "SST_TRANSFORM_GRAYSCALE", "GrayscaleTransformationModes": [{ "Mode": "GTM_AUTO" }] },
         { "Stage": "SST_ENHANCE_GRAYSCALE", "GrayscaleEnhancementModes": [{ "Mode": "GEM_GENERAL" }] },
         { "Stage": "SST_BINARIZE_IMAGE", "BinarizationModes": [{ "Mode": "BM_LOCAL_BLOCK", "MorphOperation": "Close", "ThresholdCompensation": 10 }] },
         { "Stage": "SST_DETECT_TEXTURE", "TextureDetectionModes": [{ "Mode": "TDM_GENERAL_WIDTH_CONCENTRATION", "Sensitivity": 5 }] },
@@ -258,7 +258,7 @@
       "BaseImageParameterName": "",
       "ApplicableStages": [
         { "Stage": "SST_CONVERT_TO_GRAYSCALE", "ColourConversionModes": [{ "BlueChannelWeight": -1, "GreenChannelWeight": -1, "Mode": "CICM_GENERAL", "RedChannelWeight": -1, "ReferChannel": "H_CHANNEL" }] },
-        { "Stage": "SST_TRANSFORM_GRAYSCALE", "GrayscaleTransformationModes": [{ "Mode": "GTM_INVERTED" }, { "Mode": "GTM_ORIGINAL" }] },
+        { "Stage": "SST_TRANSFORM_GRAYSCALE", "GrayscaleTransformationModes": [{ "Mode": "GTM_AUTO" }] },
         { "Stage": "SST_ENHANCE_GRAYSCALE", "GrayscaleEnhancementModes": [{ "Mode": "GEM_GENERAL" }, { "Mode": "GEM_GRAY_EQUALIZE", "Sensitivity": 9 }] },
         { "Stage": "SST_BINARIZE_IMAGE", "BinarizationModes": [{ "Mode": "BM_LOCAL_BLOCK", "MorphOperation": "Close", "ThresholdCompensation": 10 }] },
         { "Stage": "SST_DETECT_TEXTURE", "TextureDetectionModes": [{ "Mode": "TDM_GENERAL_WIDTH_CONCENTRATION", "Sensitivity": 5 }] },