From ced8727c070b2077366ab4329e2e639a6923098a Mon Sep 17 00:00:00 2001 From: Scott Date: Wed, 22 Jan 2020 12:06:14 +1030 Subject: [PATCH] filter: create a simple difference motion filter using gocv --- filter/difference.go | 114 +++++++++++++++++++++++++++++++++++++++++ revid/config/config.go | 12 +++-- revid/revid.go | 11 +++- 3 files changed, 132 insertions(+), 5 deletions(-) create mode 100644 filter/difference.go diff --git a/filter/difference.go b/filter/difference.go new file mode 100644 index 00000000..97df94b9 --- /dev/null +++ b/filter/difference.go @@ -0,0 +1,114 @@ +// +build !circleci + +/* +DESCRIPTION + A filter that detects motion and discards frames without motion. The + algorithm calculates the absolute difference for each pixel between + two frames, then finds the mean. If the mean is above a given threshold, + then it is considered motion. + +AUTHORS + Scott Barnard + +LICENSE + difference.go is Copyright (C) 2020 the Australian Ocean Lab (AusOcean) + + It is free software: you can redistribute it and/or modify them + under the terms of the GNU General Public License as published by the + Free Software Foundation, either version 3 of the License, or (at your + option) any later version. + + It is distributed in the hope that it will be useful, but WITHOUT + ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + for more details. + + You should have received a copy of the GNU General Public License + in gpl.txt. If not, see http://www.gnu.org/licenses. +*/ + +package filter + +import ( + "fmt" + "image" + "image/color" + "io" + + "gocv.io/x/gocv" +) + +// DiffFilter is a filter that provides basic motion detection. DiffFilter calculates +// the absolute difference for each pixel between two frames, then finds the mean. If +// the mean is above a given threshold, then it is considered motion. +type DiffFilter struct { + dst io.WriteCloser + thresh float64 + prev gocv.Mat + debug bool + windows []*gocv.Window +} + +// NewDiffFilter returns a pointer to a new DiffFilter. +func NewDiffFilter(dst io.WriteCloser, debug bool, threshold float64) *DiffFilter { + var windows []*gocv.Window + if debug { + windows = []*gocv.Window{gocv.NewWindow("Diff: Bounding boxes"), gocv.NewWindow("Diff: Motion")} + } + return &DiffFilter{dst, threshold, gocv.NewMat(), debug, windows} +} + +// Implements io.Closer. +// Close frees resources used by gocv, because it has to be done manually, due to +// it using c-go. +func (d *DiffFilter) Close() error { + d.prev.Close() + for _, window := range d.windows { + window.Close() + } + return nil +} + +// Implements io.Writer. +// Write applies the motion filter to the video stream. Only frames with motion +// are written to the destination encoder, frames without are discarded. +func (d *DiffFilter) Write(f []byte) (int, error) { + if d.prev.Empty() { + d.prev, _ = gocv.IMDecode(f, gocv.IMReadColor) + return 0, nil + } + + img, _ := gocv.IMDecode(f, gocv.IMReadColor) + defer img.Close() + + imgDelta := gocv.NewMat() + defer imgDelta.Close() + + // Seperate foreground and background. + gocv.AbsDiff(img, d.prev, &imgDelta) + gocv.CvtColor(imgDelta, &imgDelta, gocv.ColorBGRToGray) + + mean := imgDelta.Mean().Val1 + + // Update History + d.prev = img.Clone() + + // Draw debug information. + if d.debug { + if mean >= d.thresh { + gocv.PutText(&img, fmt.Sprintf("motion - mean:%f", mean), image.Pt(32, 32), gocv.FontHersheyPlain, 2.0, color.RGBA{255, 0, 0, 0}, 2) + } + + d.windows[0].IMShow(img) + d.windows[1].IMShow(imgDelta) + d.windows[0].WaitKey(1) + } + + // Don't write to destination if there is no motion. + if mean < d.thresh { + return 0, nil + } + + // Write to destination. + return d.dst.Write(f) +} diff --git a/revid/config/config.go b/revid/config/config.go index b70a01b3..0192b1bd 100644 --- a/revid/config/config.go +++ b/revid/config/config.go @@ -127,6 +127,7 @@ const ( FilterMOG FilterVariableFPS FilterKNN + FilterDifference ) // OS names @@ -304,6 +305,8 @@ type Config struct { // Defines the rate at which frames from a file source are processed. FileFPS int + // Difference filter parameters. + DiffThreshold float64 // Intensity value from the Difference motion detection algorithm that is considered motion. } // TypeData contains information about all of the variables that @@ -317,9 +320,10 @@ var TypeData = map[string]string{ "CameraIP": "string", "CBR": "bool", "ClipDuration": "uint", + "DiffThreshold": "float", "Exposure": "enum:auto,night,nightpreview,backlight,spotlight,sports,snow,beach,verylong,fixedfps,antishake,fireworks", "FileFPS": "int", - "Filters": "enums:NoOp,MOG,VariableFPS,KNN", + "Filters": "enums:NoOp,MOG,VariableFPS,KNN,Difference", "FrameRate": "uint", "Height": "uint", "HorizontalFlip": "bool", @@ -340,13 +344,13 @@ var TypeData = map[string]string{ "MOGMinArea": "float", "MOGThreshold": "float", "MotionInterval": "int", - "RBCapacity": "uint", - "RBMaxElements": "uint", - "RBWriteTimeout": "uint", "Output": "enum:File,Http,Rtmp,Rtp", "OutputPath": "string", "Outputs": "enums:File,Http,Rtmp,Rtp", "Quantization": "uint", + "RBCapacity": "uint", + "RBMaxElements": "uint", + "RBWriteTimeout": "uint", "Rotation": "uint", "RTMPURL": "string", "RTPAddress": "string", diff --git a/revid/revid.go b/revid/revid.go index 94bd4a6f..fd7614f1 100644 --- a/revid/revid.go +++ b/revid/revid.go @@ -342,6 +342,8 @@ func (r *Revid) setupPipeline(mtsEnc func(dst io.WriteCloser, rate float64) (io. r.filters[i] = filter.NewVariableFPSFilter(dst, r.cfg.MinFPS, filter.NewMOGFilter(dst, r.cfg.MOGMinArea, r.cfg.MOGThreshold, int(r.cfg.MOGHistory), r.cfg.ShowWindows, r.cfg.MotionInterval)) case config.FilterKNN: r.filters[i] = filter.NewKNNFilter(dst, r.cfg.KNNMinArea, r.cfg.KNNThreshold, int(r.cfg.KNNHistory), int(r.cfg.KNNKernel), r.cfg.ShowWindows, r.cfg.MotionInterval) + case config.FilterDifference: + r.filters[i] = filter.NewDiffFilter(dst, r.cfg.ShowWindows, r.cfg.DiffThreshold) default: panic("Undefined Filter") } @@ -663,7 +665,7 @@ func (r *Revid) Update(vars map[string]string) error { } case "Filters": filters := strings.Split(value, ",") - m := map[string]int{"NoOp": config.FilterNoOp, "MOG": config.FilterMOG, "VariableFPS": config.FilterVariableFPS, "KNN": config.FilterKNN} + m := map[string]int{"NoOp": config.FilterNoOp, "MOG": config.FilterMOG, "VariableFPS": config.FilterVariableFPS, "KNN": config.FilterKNN, "Difference": config.FilterDifference} r.cfg.Filters = make([]int, len(filters)) for i, filter := range filters { v, ok := m[filter] @@ -811,6 +813,13 @@ func (r *Revid) Update(vars map[string]string) error { break } r.cfg.KNNThreshold = v + case "DiffThreshold": + v, err := strconv.ParseFloat(value, 64) + if err != nil { + r.cfg.Logger.Log(logger.Warning, pkg+"invalid DiffThreshold var", "value", value) + break + } + r.cfg.DiffThreshold = v case "KNNKernel": v, err := strconv.Atoi(value) if err != nil {