fix: bad inference result conversion

pkg/steering/steering.go

@@ -7,6 +7,7 @@ import (
 	"github.com/cyrilix/robocar-base/service"
 	"github.com/cyrilix/robocar-protobuf/go/events"
 	"github.com/cyrilix/robocar-steering-tflite-edgetpu/pkg/metrics"
+	"github.com/cyrilix/robocar-steering-tflite-edgetpu/pkg/tools"
 	"github.com/disintegration/imaging"
 	mqtt "github.com/eclipse/paho.mqtt.golang"
 	"github.com/golang/protobuf/proto"
@@ -15,7 +16,6 @@ import (
 	"go.uber.org/zap"
 	"image"
 	_ "image/jpeg"
-	"sort"
 	"time"
 )
 
@@ -212,43 +212,21 @@ func (p *Part) Value(img image.Image) (float32, float32, error) {
 	}
 
 	output := p.interpreter.GetOutputTensor(0)
+
 	outputSize := output.Dim(output.NumDims() - 1)
+
 	b := make([]byte, outputSize)
-	type result struct {
-		score float64
-		index int
-	}
 	status = output.CopyToBuffer(&b[0])
 	if status != tflite.OK {
 		return 0., 0., fmt.Errorf("output failed: %v", status)
 	}
 
-	var results []result
-	minScore := 0.2
-	for i := 0; i < outputSize; i++ {
-		score := float64(b[i]) / 255.0
-		if score < minScore {
-			continue
-		}
-		results = append(results, result{score: score, index: i})
-	}
-
-	if len(results) == 0 {
-		zap.L().Warn(fmt.Sprintf("none steering with score > %0.2f found", minScore))
-		return 0., 0., nil
-	}
-	zap.S().Debugf("raw result: %v", results)
-
-	sort.Slice(results, func(i, j int) bool {
-		return results[i].score > results[j].score
-	})
-
-	steering := float64(results[0].index)*(2./float64(outputSize)) - 1
+	steering, score := tools.LinearBin(b, 15, -1, 2.0)
 	zap.L().Debug("found steering",
 		zap.Float64("steering", steering),
-		zap.Float64("score", results[0].score),
+		zap.Float64("score", score),
 	)
-	return float32(steering), float32(results[0].score), nil
+	return float32(steering), float32(score), nil
 }
 
 var registerCallbacks = func(p *Part) error {