diff --git a/plugins/ImageReader/ImageReader.py b/plugins/ImageReader/ImageReader.py
index ce3cab0b8f..50825f2464 100644
--- a/plugins/ImageReader/ImageReader.py
+++ b/plugins/ImageReader/ImageReader.py
@@ -101,8 +101,10 @@ class ImageReader(MeshReader):
         for x in range(0, width):
             for y in range(0, height):
                 qrgb = img.pixel(x, y)
-                luminance = (0.2126 * qRed(qrgb) + 0.7152 * qGreen(qrgb) + 0.0722 * qBlue(qrgb)) / 255 # fast computation ignoring gamma
-                height_data[y, x] = luminance
+                if use_logarithmic_function:
+                    height_data[y, x] = (0.299 * math.pow(qRed(qrgb) / 255.0, 2.2) + 0.587 * math.pow(qGreen(qrgb) / 255.0, 2.2) + 0.114 * math.pow(qBlue(qrgb) / 255.0, 2.2))
+                else:
+                    height_data[y, x] = (0.212655 * qRed(qrgb) + 0.715158 * qGreen(qrgb) + 0.072187 * qBlue(qrgb)) / 255 # fast computation ignoring gamma and degamma
 
         Job.yieldThread()