remote sensing - NDVI image value changes from -1 to 1 in ENVI to 0-255 in ArcGIS Desktop and ERDAS Imagine?

When i open NDVI image in ENVI, its value is still within the range (-1 to 1).

But when I open this NDVI image in ERDAS and ArcGIS Desktop, its value is 0-255.

What does it mean?

Is the NDVI image some problem?