diff --git a/src/UglyToad.PdfPig.Tests/PublicApiScannerTests.cs b/src/UglyToad.PdfPig.Tests/PublicApiScannerTests.cs
index 364bb53b..c9859252 100644
--- a/src/UglyToad.PdfPig.Tests/PublicApiScannerTests.cs
+++ b/src/UglyToad.PdfPig.Tests/PublicApiScannerTests.cs
@@ -98,6 +98,7 @@ public void OnlyExposedApiIsPublic()
                 "UglyToad.PdfPig.CrossReference.TrailerDictionary",
                 "UglyToad.PdfPig.Exceptions.PdfDocumentEncryptedException",
                 "UglyToad.PdfPig.Filters.BaseFilterProvider",
+                "UglyToad.PdfPig.Filters.DecodeParameterResolver",
                 "UglyToad.PdfPig.Filters.DefaultFilterProvider",
                 "UglyToad.PdfPig.Filters.IFilter",
                 "UglyToad.PdfPig.Filters.IFilterProvider",
diff --git a/src/UglyToad.PdfPig/Filters/DecodeParameterResolver.cs b/src/UglyToad.PdfPig/Filters/DecodeParameterResolver.cs
index 32d10a9c..9c66a6e3 100644
--- a/src/UglyToad.PdfPig/Filters/DecodeParameterResolver.cs
+++ b/src/UglyToad.PdfPig/Filters/DecodeParameterResolver.cs
@@ -5,8 +5,18 @@
     using Tokens;
     using UglyToad.PdfPig.Util;
 
-    internal static class DecodeParameterResolver
-    {
+    /// <summary>
+    /// Decode parameter resolver.
+    /// </summary>
+    public static class DecodeParameterResolver
+    {
+        /// <summary>
+        /// Get the filter parameters from a stream dictionary.
+        /// </summary>
+        /// <param name="streamDictionary">The stream dictionary.</param>
+        /// <param name="index">If the filter element is an <see cref="ArrayToken"/>, the index in the array to take the dictionary from.</param>
+        /// <exception cref="ArgumentNullException"></exception>
+        /// <exception cref="ArgumentOutOfRangeException"></exception>
         public static DictionaryToken GetFilterParameters(DictionaryToken streamDictionary, int index)
         {
             if (streamDictionary is null)