fixed valid min/max before scaling

plugins/Bpm.py

@@ -659,7 +659,6 @@ def construct_bvdata(bpm):
     if not bpm.autoscale:
         min_val = bpm.min_max[0]
         max_val = bpm.min_max[1]
-        if max_val == 0: max_val = 1
         scale_image = image.buffer.clip(min_val, max_val)
 
     # auto scaling: use natural image intensity
@@ -668,6 +667,7 @@ def construct_bvdata(bpm):
         max_val = image.buffer.max()
         if max_val == 0: max_val = 1
         scale_image = image.buffer
+
 
     # logarithmic scaling
     if bpm.lut_method=="LOG":
@@ -677,9 +677,10 @@ def construct_bvdata(bpm):
             scale_image = numpy.log10(scale_image.clip(1, None))
             min_val += 1
         min_val = numpy.log10(min_val)
-        max_val = numpy.log10(max_val if max_val > 0 else 1)
+        max_val = numpy.log10(max_val)
 
     # scale the image to the whole range 16bit before palette transformation for 0 to 65535
+    if max_val == min_val: max_val+=1
     scaling = (2**16 - 1.) / (max_val - min_val)
     scale_image = ((scale_image - min_val) * scaling).astype(numpy.uint16)