filter.dog breaks with an UnsignedByteType input and a FloatType output

[gselzer]

I feel like the following should work, as a user, but it doesn't. May be an Ops issue, just filing it here because this is where I'm seeing it.

1. Run `filter.dog(img "out"?, img "in", number "sigma1", number "sigma2", outOfBoundsFactory "fac"?) -> (img "out"?)
2. in -> the bricks sample image
3. 2 as sigma1
4. 5 as sigma2
5. Create a new image of type float32 as the output image
6. Click Run
7. See the following error:

java.lang.ClassCastException: net.imglib2.type.numeric.integer.UnsignedByteType cannot be cast to net.imglib2.type.numeric.real.FloatType
	at net.imglib2.type.numeric.real.FloatType.sub(FloatType.java:56)
	at net.imagej.ops.math.IIToIIOutputII$Subtract.compute(IIToIIOutputII.java:181)
	at net.imagej.ops.math.IIToIIOutputII$Subtract.compute(IIToIIOutputII.java:137)
	at net.imagej.ops.special.hybrid.BinaryHybridCI1.mutate(BinaryHybridCI1.java:61)
	at net.imagej.ops.special.hybrid.BinaryHybridCFI1.mutate(BinaryHybridCFI1.java:75)
	at net.imagej.ops.special.hybrid.BinaryHybridCI1.run(BinaryHybridCI1.java:70)
	at net.imagej.ops.special.hybrid.BinaryHybridCFI1.run(BinaryHybridCFI1.java:65)
	at net.imagej.ops.special.hybrid.BinaryHybridCFI.run(BinaryHybridCFI.java:68)
	at net.imagej.ops.special.hybrid.BinaryHybridCFI.run(BinaryHybridCFI.java:75)
	at org.scijava.command.CommandModule.run(CommandModule.java:196)
	at net.imagej.ops.OpEnvironment.run(OpEnvironment.java:960)
	at net.imagej.ops.OpEnvironment.run(OpEnvironment.java:157)
	at net.imagej.ops.filter.dog.DefaultDoG.compute(DefaultDoG.java:94)
	at net.imagej.ops.filter.dog.DefaultDoG.compute(DefaultDoG.java:54)
	at net.imagej.ops.special.chain.UHCFViaUHCF.compute(UHCFViaUHCF.java:63)
	at net.imagej.ops.filter.dog.DoGSingleSigmas.compute(DoGSingleSigmas.java:98)
	at net.imagej.ops.filter.dog.DoGSingleSigmas.compute(DoGSingleSigmas.java:54)
	at net.imagej.ops.special.hybrid.UnaryHybridCF.run(UnaryHybridCF.java:75)
	at net.imagej.ops.special.hybrid.UnaryHybridCF.run(UnaryHybridCF.java:97)
	at org.scijava.command.CommandModule.run(CommandModule.java:196)
	at net.imagej.ops.OpEnvironment.run(OpEnvironment.java:960)
	at net.imagej.ops.OpEnvironment.run(OpEnvironment.java:136)
	at net.imagej.ops.OpListingModule.run(OpListingModule.java:68)
	at org.scijava.module.ModuleRunner.run(ModuleRunner.java:165)
	at org.scijava.module.ModuleRunner.call(ModuleRunner.java:125)
	at org.scijava.module.ModuleRunner.call(ModuleRunner.java:64)
	at org.scijava.thread.DefaultThreadService.lambda$wrap$2(DefaultThreadService.java:247)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:750)