Introduce ColorMode enum

imageprocessing/src/main/java/org/fairscan/imageprocessing/ColorDetection.kt

@@ -26,7 +26,7 @@ import org.opencv.imgproc.Imgproc
 import org.opencv.imgproc.Imgproc.fillConvexPoly
 import kotlin.math.roundToInt
 
-fun isColoredDocument(
+fun autoColorMode(
     img: Mat,
     mask: Mask,
     quad: Quad,
@@ -34,7 +34,7 @@ fun isColoredDocument(
     proportionThreshold: Double = 0.0003,
     luminanceMin: Double = 40.0,
     luminanceMax: Double = 180.0
-): Boolean {
+): ColorMode {
 
     // Work on a reasonable size (for correct performance)
     val resizedImg = resizeForMaxPixels(img, 1024.0 * 768.0)
@@ -90,10 +90,13 @@ fun isColoredDocument(
     restrictedMask.release()
     docMask.release()
 
-    if (totalPixels == 0) return false
+    if (totalPixels == 0) return ColorMode.GRAYSCALE
 
     val proportion = coloredPixels.toDouble() / totalPixels.toDouble()
-    return proportion > proportionThreshold
+    return if (proportion > proportionThreshold)
+        ColorMode.COLOR
+    else
+        ColorMode.GRAYSCALE
 }
 
 private fun chroma(a: Mat, b: Mat): Mat {

imageprocessing/src/main/java/org/fairscan/imageprocessing/DocumentDetection.kt

@@ -154,7 +154,7 @@ fun extractDocument(
     inputMat: Mat,
     quad: Quad,
     rotationDegrees: Int,
-    isColored: Boolean,
+    colorMode: ColorMode,
     maxPixels: Long,
 ): Mat {
     val widthTop = norm(quad.topLeft, quad.topRight)
@@ -184,7 +184,7 @@ fun extractDocument(
     Imgproc.warpPerspective(inputMat, warped, transform, outputSize)
 
     val resized = resizeForMaxPixels(warped, maxPixels.toDouble())
-    val enhanced = enhanceCapturedImage(resized, isColored)
+    val enhanced = enhanceCapturedImage(resized, colorMode)
     val rotated = rotate(enhanced, rotationDegrees)
 
     warped.release()

imageprocessing/src/main/java/org/fairscan/imageprocessing/PostProcessing.kt

@@ -25,11 +25,15 @@ import org.opencv.imgproc.Imgproc
 import kotlin.math.max
 import kotlin.math.min
 
-fun enhanceCapturedImage(img: Mat, isColored: Boolean): Mat {
-    return if (isColored) {
-        multiScaleRetinexOnL(img)
-    } else {
-        enhanceGrayscaleImage(img)
+enum class ColorMode {
+    COLOR,
+    GRAYSCALE,
+}
+
+fun enhanceCapturedImage(img: Mat, colorMode: ColorMode): Mat {
+    return when (colorMode) {
+        ColorMode.COLOR -> multiScaleRetinexOnL(img)
+        ColorMode.GRAYSCALE -> enhanceGrayscaleImage(img)
     }
 }