constrast enhancement for browser image

pkg/producer/jpg.go

@@ -8,6 +8,7 @@ import (
 	"github.com/airbusgeo/godal"
 	log "github.com/sirupsen/logrus"
 	"gocv.io/x/gocv"
+	"starwiz.cn/sjy01/image-proc/pkg/config"
 )
 
 func GTiffToJPG(ftiff, fjpg string, reversed bool) error {
@@ -58,12 +59,24 @@ func GTiffToJPG(ftiff, fjpg string, reversed bool) error {
 
 	channels := gocv.Split(img)
 	for i, ch := range channels {
-		// 2. 计算图像的最小值和最大值
-		minVal, maxVal, _, _ := gocv.MinMaxLoc(ch)
-		// 3. 将16位图像线性拉伸到8位图像
-		scale := 255.0 / (maxVal - minVal)
-		shift := -minVal * scale
-		ch.ConvertToWithParams(&channels[i], gocv.MatTypeCV8U, scale, shift)
+		switch config.GCONFIG.BrowserImg.Enhancement {
+		case NoEnhancement:
+		case StretchToMinimumMaximum:
+			minVal, maxVal, _, _ := gocv.MinMaxLoc(ch)
+			ce := NewContrastEnhancement(int(minVal), int(maxVal))
+			for y := 0; y < height; y++ {
+				for x := 0; x < width; x++ {
+					value := int(uint16(ch.GetShortAt(y, x)))
+					value = ce.enhance(value)
+					ch.SetShortAt(y, x, int16(value))
+				}
+			}
+		case StretchToCumulativeCutMinMax:
+			channels[i] = cumulativeCountCutEnhancement(ch,
+				config.GCONFIG.BrowserImg.CumulativeCutLower,
+				config.GCONFIG.BrowserImg.CumulativeCutUpper)
+			ch.Close()
+		}
 	}
 
 	img8bit := gocv.NewMat()
@@ -82,14 +95,16 @@ func GTiffToJPG(ftiff, fjpg string, reversed bool) error {
 		image.Point{X: img8bit.Cols() / 2, Y: img8bit.Rows() / 2},
 		0, 0, gocv.InterpolationCubic)
 
+	gocv.IMWrite(fjpg, img8bit)
+
 	// 7. 应用伽玛校正提升亮度
-	gammaCorrected := applyGammaCorrection(img8bit, 1.6) // 伽玛值
-	defer gammaCorrected.Close()
-	ok := gocv.IMWriteWithParams(fjpg, gammaCorrected, []int{gocv.IMWriteJpegOptimize, 1})
-	if !ok {
-		err = fmt.Errorf("error saving %s", fjpg)
-		return err
-	}
+	// gammaCorrected := applyGammaCorrection(img8bit, 1.6) // 伽玛值
+	// defer gammaCorrected.Close()
+	// ok := gocv.IMWriteWithParams(fjpg, gammaCorrected, []int{gocv.IMWriteJpegOptimize, 1})
+	// if !ok {
+	// 	err = fmt.Errorf("error saving %s", fjpg)
+	// 	return err
+	// }
 	return nil
 }