Problems with implementing PostProcessing filters

[jb455]

Hi!

First, thanks for sharing this wrapper, it's very useful though could do with being signposted from eg https://www.orbbec.com/developers/orbbec-sdk/, I spent a while messing around with C++ before finding this.

In my fork (https://github.com/jb455/OrbbecSDK_CSharp/tree/postprocessing) I'm trying to implement PostProcessing filters so I can use them in my project but I'm having a couple of errors when running it:

• Calling ob_get_filter_name returns the error "Invalid stream!
• Calling ob_filter_is_enable throws System.AccessViolationException

I'm guessing both are these are from how I'm initialising the Filter from the FilterList here but I'm not sure how to do it otherwise, it seems to follow the pattern used in similar cases like streamprofiles etc. Does anyone have any ideas please? Also, is the source for the C++ API available anywhere so I can see how it implements the C and emulate that for the C# wrapper?

I added a PostProcessing sample too which you can run to see the errors, though I'm not very well versed on cmake stuff so it's in as a csproj for now.

Thanks
James

[zhonghong322]

@obwh Please take a look at this issue.

[obwh]

We will release C# SDK cover all C++ OpenOrbbecSDK API next month, thank you!

[jb455]

Hi, thanks for updating this repo, it's good to see it's in active development.
I've updated my project to use the latest version (v2.0.2) and I have a couple of questions about post processing filters still.
I can use CreateRecommendedFilters to get a filter list for my device (Gemini 335) but I only get back DecimationFilter, HDRMerge, SequenceIdFilter and ThresholdFilter. I'm interested in using some of the other filters though (Spatial, Temporal and Noise Removal), does the fact that they're not on this list mean they aren't compatible or shouldn't be used with this camera? Though I can enable them all in the OrbbecViewer app.
I've started to implement the filters in the wrapper again myself but it appears a lot of the native API calls are no longer available (ie, ob_create_[x]_filter and ob_[x]_filter_set_[y]_value) though are still listed in obNative.cs. Have they moved to \extensions\filters\FilterProcessor.dll maybe? If they aren't available any more in V2, replacing create_x_filter() with create_filter(x) is ok using the filter name strings from here, but it's not obvious how to replace the get/set parameter functions. It's not clear how to use UpdateConfig in Filter.cs. Judging by how it's used in the c++ sdk eg here, it appears to need the length of the parameter array and a pointer to the first element, something like this perhaps:

SpatialAdvancedFilter spatialAdvancedFilter = new SpatialAdvancedFilter();
var spatialparams = new[] { "5", "0.7", "16000", "5" };
unsafe
{
    fixed (string* paramsPtr = &spatialparams[0])
    {
        spatialAdvancedFilter.UpdateConfig((ushort)spatialparams.Length, paramsPtr);
    }
}

but that doesn't compile as it's expecting a string, not string*.
I also tried implementing ob_filter_[get/set]_config_value but could only find a few parameter names in the c++ code here, though I get the message "Filter@NoiseRemovalFilter: config item NoiseRemovalFilter#0 doesn't exist" if I try to use it. Do you have a list of valid parameter names for all the filters I can refer to please?

If you could please point me in the right direction to solve these issues I'm happy to finish implementing all the filters and submit a PR to contribute.

Thanks
James

[zhonghong322]

I understand what you mean,How can we use the post-processing filters that are not enabled by default in the recommended list? I will inform our C# development colleagues to take a look.