diff --git a/pom.xml b/pom.xml
index 994ccfcd24..c8b65480a5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>org.scijava</groupId>
 		<artifactId>pom-scijava</artifactId>
-		<version>20.0.0</version>
+		<version>22.4.0</version>
 		<relativePath />
 	</parent>
 
@@ -293,5 +293,10 @@
 			<artifactId>imglib2-ij</artifactId>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.scijava</groupId>
+			<artifactId>scijava-io-http</artifactId>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 </project>
diff --git a/src/main/java/net/imagej/ops/filter/FilterNamespace.java b/src/main/java/net/imagej/ops/filter/FilterNamespace.java
index 136eb763a1..527cec382b 100644
--- a/src/main/java/net/imagej/ops/filter/FilterNamespace.java
+++ b/src/main/java/net/imagej/ops/filter/FilterNamespace.java
@@ -6,13 +6,13 @@
  * %%
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
- * 
+ *
  * 1. Redistributions of source code must retain the above copyright notice,
  *    this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright notice,
  *    this list of conditions and the following disclaimer in the documentation
  *    and/or other materials provided with the distribution.
- * 
+ *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
@@ -136,7 +136,7 @@ public <I extends RealType<I>, O extends RealType<O>> O addPoissonNoise(
 
 	/**
 	 * Executes a bilateral filter on the given arguments.
-	 * 
+	 *
 	 * @param in
 	 * @param out
 	 * @param sigmaR
@@ -757,7 +757,7 @@ RandomAccessibleInterval<V> dog(final RandomAccessibleInterval<T> in,
 
 	/**
 	 * Executes the "Frangi Vesselness" filter operation on the given arguments.
-	 * 
+	 *
 	 * @param in - input image
 	 * @param out - output image
 	 * @param spacing - n-dimensional array indicating the physical distance
@@ -1271,6 +1271,20 @@ public <T extends RealType<T>> IterableInterval<T> sigma(
 		return result;
 	}
 
+	// -- Shadows
+
+	/** Executes the "shadows" filter operation on the given arguments. */
+	@OpMethod(op = net.imagej.ops.filter.shadow.DefaultShadows.class)
+	public <T extends RealType<T>> RandomAccessibleInterval<T> shadows(
+		final RandomAccessibleInterval<T> in, final double angle)
+	{
+		@SuppressWarnings("unchecked")
+		final RandomAccessibleInterval<T> result =
+			(RandomAccessibleInterval<T>) ops().run(Ops.Filter.Shadows.class, in,
+				angle);
+		return result;
+	}
+
 	// -- Sobel
 
 	@OpMethod(op = net.imagej.ops.filter.sobel.SobelRAI.class)
diff --git a/src/main/java/net/imagej/ops/filter/shadow/DefaultShadows.java b/src/main/java/net/imagej/ops/filter/shadow/DefaultShadows.java
new file mode 100644
index 0000000000..5decb25cce
--- /dev/null
+++ b/src/main/java/net/imagej/ops/filter/shadow/DefaultShadows.java
@@ -0,0 +1,153 @@
+
+package net.imagej.ops.filter.shadow;
+
+import net.imagej.Extents;
+import net.imagej.Position;
+import net.imagej.ops.Ops;
+import net.imagej.ops.special.function.AbstractUnaryFunctionOp;
+import net.imglib2.Cursor;
+import net.imglib2.FinalInterval;
+import net.imglib2.RandomAccess;
+import net.imglib2.RandomAccessible;
+import net.imglib2.RandomAccessibleInterval;
+import net.imglib2.algorithm.neighborhood.Neighborhood;
+import net.imglib2.algorithm.neighborhood.RectangleNeighborhood;
+import net.imglib2.algorithm.neighborhood.RectangleNeighborhoodFactory;
+import net.imglib2.algorithm.neighborhood.RectangleShape.NeighborhoodsAccessible;
+import net.imglib2.type.numeric.RealType;
+import net.imglib2.util.Util;
+import net.imglib2.view.Views;
+
+import org.scijava.plugin.Parameter;
+import org.scijava.plugin.Plugin;
+
+@Plugin(type = Ops.Filter.Shadows.class)
+public class DefaultShadows<T extends RealType<T>> extends
+	AbstractUnaryFunctionOp<RandomAccessibleInterval<T>, RandomAccessibleInterval<T>>
+	implements Ops.Filter.Shadows
+{
+
+	// cos(theta) and sin(theta) LUTs used for 3x3 neighborhood calculations where
+	// index 4 is the center of the neighborhood and theta increases around the
+	// edges of the neighborhood (note that theta does not increase as the index
+	// increase but instead increases as if this array was mapped to a 3x3
+	// square, then theta increases counterclockwise).
+	static final double[] cos = { -0.7071067811865475, 0, 0.7071067811865476,
+		-1.0, 0, 1.0, -0.7071067811865477, 0, 0.7071067811865474 };
+	static final double[] sin = { 0.7071067811865476, 1.0, 0.7071067811865475, 0,
+		0.0, 0.0, -0.7071067811865475, -1.0, -0.7071067811865477 };
+	static final double[] kernel = new double[9];
+	double scale;
+
+	@Parameter(min = "0", max = "2 * Math.PI")
+	private double theta;
+
+	@Override
+	public RandomAccessibleInterval<T> calculate(
+		final RandomAccessibleInterval<T> input)
+	{
+		final RandomAccessibleInterval<T> output = ops().copy().rai(input);
+
+		final long[] planeDims = new long[input.numDimensions() - 2];
+		for (int i = 0; i < planeDims.length; i++)
+			planeDims[i] = input.dimension(i + 2);
+		final Extents extents = new Extents(planeDims);
+		final Position planePos = extents.createPosition();
+		if (planeDims.length == 0) {
+			computePlanar(planePos, input, output);
+		}
+		else {
+			while (planePos.hasNext()) {
+				planePos.fwd();
+				computePlanar(planePos, input, output);
+			}
+
+		}
+
+		return output;
+
+	}
+
+	private void computePlanar(final Position planePos,
+		final RandomAccessibleInterval<T> input,
+		final RandomAccessibleInterval<T> output)
+	{
+
+		// angle vector
+		final double cosTheta = Math.cos(theta);
+		final double sinTheta = Math.sin(theta);
+
+		// kernel equal to unit vector of (x dot angle)
+		for (int i = 0; i < kernel.length; i++) {
+			kernel[i] = 2 * (cos[i] * cosTheta + sin[i] * sinTheta);
+		}
+		// N.B. the rules of the surrounding pixels do not apply to the center pixel
+		kernel[4] = 1;
+
+		scale = 0;
+		for (final double d : kernel)
+			scale += d;
+		if (scale == 0) scale = 1; // TODO is this necessary?
+
+		final T type = Util.getTypeFromInterval(input);
+
+		final long[] imageDims = new long[input.numDimensions()];
+		input.dimensions(imageDims);
+
+		// create all objects needed for NeighborhoodsAccessible
+		RandomAccessibleInterval<T> slicedInput = ops().copy().rai(input);
+		for (int i = planePos.numDimensions() - 1; i >= 0; i--) {
+			slicedInput = Views.hyperSlice(slicedInput, input.numDimensions() - 1 - i,
+				planePos.getLongPosition(i));
+		}
+
+		final RandomAccessible<T> refactoredInput = Views.extendMirrorSingle(
+			slicedInput);
+		final RectangleNeighborhoodFactory<T> factory = RectangleNeighborhood
+			.factory();
+		final FinalInterval neighborhoodSpan = new FinalInterval(new long[] { -1,
+			-1 }, new long[] { 1, 1 });
+
+		final NeighborhoodsAccessible<T> neighborhoods =
+			new NeighborhoodsAccessible<>(refactoredInput, neighborhoodSpan, factory);
+
+		// create cursors and random accesses for loop.
+		final Cursor<T> cursor = Views.iterable(input).localizingCursor();
+		final RandomAccess<T> outputRA = output.randomAccess();
+		for (int i = 0; i < planePos.numDimensions(); i++) {
+			outputRA.setPosition(planePos.getLongPosition(i), i + 2);
+		}
+		final RandomAccess<Neighborhood<T>> neighborhoodsRA = neighborhoods
+			.randomAccess();
+
+		int algorithmIndex = 0;
+		double sum;
+		final double[] n = new double[9];
+		while (cursor.hasNext()) {
+			cursor.fwd();
+			neighborhoodsRA.setPosition(cursor);
+			final Neighborhood<T> current = neighborhoodsRA.get();
+			final Cursor<T> neighborhoodCursor = current.cursor();
+
+			algorithmIndex = 0;
+			sum = 0;
+			while (algorithmIndex < n.length) {
+				neighborhoodCursor.fwd();
+				n[algorithmIndex++] = neighborhoodCursor.get().getRealDouble();
+			}
+
+			for (int i = 0; i < kernel.length; i++) {
+				sum += kernel[i] * n[i];
+			}
+
+			double value = sum / scale;
+
+			outputRA.setPosition(cursor.getLongPosition(0), 0);
+			outputRA.setPosition(cursor.getLongPosition(1), 1);
+			if (value > type.getMaxValue()) value = type.getMaxValue();
+			if (value < type.getMinValue()) value = type.getMinValue();
+			outputRA.get().setReal(value);
+		}
+	}
+
+}
diff --git a/src/main/templates/net/imagej/ops/Ops.list b/src/main/templates/net/imagej/ops/Ops.list
index e38e8c72f6..28e471a13e 100644
--- a/src/main/templates/net/imagej/ops/Ops.list
+++ b/src/main/templates/net/imagej/ops/Ops.list
@@ -122,6 +122,7 @@ namespaces = ```
 		[name: "paddingIntervalCentered",        iface: "PaddingIntervalCentered"],
 		[name: "paddingIntervalOrigin",          iface: "PaddingIntervalOrigin"],
 		[name: "tubeness",                       iface: "Tubeness"],
+		[name: "shadows",                        iface: "Shadows"],
 		[name: "sigma",                          iface: "Sigma",               aliases: ["sigmaFilter", "filterSigma"]],
 		[name: "sobel",                          iface: "Sobel"],
 		[name: "variance",                       iface: "Variance",            aliases: ["varianceFilter", "filterVariance", "var", "varFilter", "filterVar"]],
diff --git a/src/test/java/net/imagej/ops/filter/shadows/DefaultShadowsTest.java b/src/test/java/net/imagej/ops/filter/shadows/DefaultShadowsTest.java
new file mode 100644
index 0000000000..9dff62b3d7
--- /dev/null
+++ b/src/test/java/net/imagej/ops/filter/shadows/DefaultShadowsTest.java
@@ -0,0 +1,121 @@
+/*
+ * #%L
+ * ImageJ software for multidimensional image processing and analysis.
+ * %%
+ * Copyright (C) 2014 - 2018 ImageJ developers.
+ * %%
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ * #L%
+ */
+
+package net.imagej.ops.filter.shadows;
+
+import io.scif.SCIFIOService;
+import io.scif.services.DatasetIOService;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.util.concurrent.ExecutionException;
+
+import net.imagej.Dataset;
+import net.imagej.ops.AbstractOpTest;
+import net.imagej.ops.OpService;
+import net.imagej.ops.filter.shadow.DefaultShadows;
+import net.imglib2.img.Img;
+import net.imglib2.type.numeric.real.FloatType;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.scijava.Context;
+import org.scijava.app.StatusService;
+import org.scijava.download.DiskLocationCache;
+import org.scijava.download.Download;
+import org.scijava.download.DownloadService;
+import org.scijava.io.IOService;
+import org.scijava.io.http.HTTPLocation;
+import org.scijava.io.location.FileLocation;
+
+/**
+ * Tests for {@link DefaultShadows}
+ *
+ * @author Gabe Selzer
+ */
+public class DefaultShadowsTest extends AbstractOpTest {
+
+	private Dataset input;
+
+	@Override
+	protected Context createContext() {
+		return new Context(OpService.class, IOService.class, DownloadService.class,
+			SCIFIOService.class, StatusService.class);
+	}
+
+	@Before
+	public void init() throws IOException, InterruptedException,
+		ExecutionException, URISyntaxException
+	{
+		// URL of test image
+		final URL imageSrc = new URL("http://imagej.net/images/abe.tif");
+
+		// FileLocation that we want to store this image in.
+		final File destFile = File.createTempFile(getClass().getName(), ".tif");
+		final FileLocation inputDest = new FileLocation(destFile);
+
+		downloadOnce(imageSrc.toURI(), inputDest);
+
+		final String srcPath = inputDest.getFile().getAbsolutePath();
+		final DatasetIOService dio = context.service(DatasetIOService.class);
+		input = dio.open(srcPath);
+	}
+
+	// move to DownloadService
+	public void downloadOnce(final URI srcURI, final FileLocation inputDest)
+		throws URISyntaxException, InterruptedException, ExecutionException
+	{
+		final DownloadService ds = context.service(DownloadService.class);
+		final DiskLocationCache cache = new DiskLocationCache();
+		cache.getBaseDirectory().mkdirs();
+
+		final HTTPLocation inputSrc = new HTTPLocation(srcURI);
+
+		// download the data from the URI to inputDest. Once we are done the method
+		// calling downloadOnce can access the File from the FileLocation passed
+		// through.
+		final Download download = ds.download(inputSrc, inputDest, cache);
+		download.task().waitFor();
+	}
+
+	@Test
+	public void testRegression() throws IOException {
+		final IOService io = context.getService(IOService.class);
+		final double north = Math.PI / 2;
+		final Img<FloatType> actualOutput = (Img<FloatType>) ops.run(
+			"filter.shadows", input, north);
+		final Img<FloatType> expectedOutput = (Img<FloatType>) io.open(
+			"src/test/resources/net/imagej/ops/filter/shadows/ExpectedShadowsNorth.tif");
+		assertIterationsEqual(actualOutput, expectedOutput);
+	}
+
+}
diff --git a/src/test/resources/net/imagej/ops/filter/shadows/ExpectedShadowsNorth.tif b/src/test/resources/net/imagej/ops/filter/shadows/ExpectedShadowsNorth.tif
new file mode 100644
index 0000000000..6b8aa226f5
Binary files /dev/null and b/src/test/resources/net/imagej/ops/filter/shadows/ExpectedShadowsNorth.tif differ