Spatial/Temporal Filter

yokonav · August 13, 2024, 4:04am

How can we set/enable the spatial/temporal filter in the OpenMV Cam RT1062 with a Flir Lepton 3.5?

kwagyeman · August 13, 2024, 4:57am

I don’t know what that is. Can you elaborate?

yokonav · August 13, 2024, 5:10am

It is part of the Video pipeline.

7.3 Spatial / Temporal Filtering
The image pipeline includes a number of sophisticated image filters designed to enhance signal-to-noise ratio
(SNR) by eliminating temporal noise and residual non-uniformity. The filtering suite includes a scene-based
non-uniformity correction (SBNUC) algorithm which relies on motion within the scene to isolate fixed pattern
noise (FPN) from image content.

There is a function already in the OpenMV repo. I wanted to know how can we enable it or it is already enabled by default?

github.com

openmv/openmv/blob/eaf0cbd014048c3dc31ad108bfbb6e8cd986e0e5/src/drivers/lepton/src/LEPTON_OEM.c#L967


      
             {
                return( LEP_BAD_ARG_POINTER_ERROR );
             }
             result = LEP_GetAttribute( portDescPtr,
                                        ( LEP_COMMAND_ID )LEP_CID_OEM_BAD_PIXEL_REPLACE_CONTROL,
                                        ( LEP_ATTRIBUTE_T_PTR )BadPixelReplaceControlPtr,
                                        attributeWordLength );
             return( result );
          }
          
          LEP_RESULT LEP_SetOemTemporalFilterControl( LEP_CAMERA_PORT_DESC_T_PTR portDescPtr,
                                                      LEP_OEM_TEMPORAL_FILTER_CONTROL_T TemporalFilterControl )
          {
             LEP_RESULT result = LEP_OK;
             LEP_UINT16 attributeWordLength = 2; /* one enum = two words */
          
             /* Perform Command
             ** Writing the Camera's current video freeze enable state
             */
             result = LEP_SetAttribute( portDescPtr,
                                        ( LEP_COMMAND_ID )LEP_CID_OEM_TEMPORAL_FILTER_CONTROL,

kwagyeman · August 13, 2024, 5:27pm

I’ve never thought it was needed. However, you can do this yourself via the ioctls in the sensor module.

sensor.ioctl(*args , **kwargs )→ Any¶

sensor.IOCTL_LEPTON_SET_ATTRIBUTE - Pass this enum to set a FLIR Lepton SDK attribute.
- The first argument is the 16-bit attribute ID to set (set the FLIR Lepton SDK).
- The second argument is a MicroPython byte array of bytes to write (should be a multiple of 16-bits). Create the byte array using struct following the FLIR Lepton SDK.
sensor.IOCTL_LEPTON_GET_ATTRIBUTE - Pass this enum to get a FLIR Lepton SDK attribute.
- The first argument is the 16-bit attribute ID to set (set the FLIR Lepton SDK).
- Returns a MicroPython byte array of the attribute. Use struct to deserialize the byte array following the FLIR Lepton SDK.

See this document: 1 (sparkfun.com)

Note, I recommend just looking at the C code to determine the 16-bit value and struct format: openmv/src/drivers/lepton/include/LEPTON_OEM.h at eaf0cbd014048c3dc31ad108bfbb6e8cd986e0e5 · openmv/openmv (github.com)

yokonav · August 14, 2024, 3:28am

Thanks, @kwagyeman for the detailed information.

BTW, it seems enabled by default.

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Spatial/Temporal Filter

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