Get real exposure time and draw

include/mynteye/types.h

@@ -368,7 +368,7 @@ struct MYNTEYE_API ImgData {
   std::uint16_t frame_id;
   /** Image timestamp in 0.01ms */
   std::uint32_t timestamp;
-  /** Image exposure time in 0.01ms */
+  /** Image exposure time, virtual value in [1, 480] */
   std::uint16_t exposure_time;
 
   void Reset() {

include/mynteye/utils.h

@@ -30,6 +30,15 @@ MYNTEYE_API std::shared_ptr<Device> select();
 
 }  // namespace device
 
+namespace utils {
+
+/** Get real exposure time in ms from virtual value, according to its frame rate
+ */
+MYNTEYE_API float get_real_exposure_time(
+    std::int32_t frame_rate, std::uint16_t exposure_time);
+
+}  // namespace utils
+
 MYNTEYE_END_NAMESPACE
 
 #endif  // MYNTEYE_UTILS_H_ NOLINT