Improve performance of VideoStreamFrame.on_frame (#131)

* Simplify, improve the performance of `on_frame` by ~40%

* Temporarily add the `performance_tracker.py` to test performance on another PC

* Remove temporarily `performance_tracker.py` and references

* The default dynamic range that does not require scaling on simulated camera is 255, not 256.

Author: Baharis

src/instamatic/config/camera/simulate.yaml

@@ -12,7 +12,7 @@ camera_rotation_vs_stage_xy: -2.24
 default_binsize: 1
 default_exposure: 0.1
 dimensions: [516, 516]
-dynamic_range: 11800
+dynamic_range: 255
 interface: simulate
 physical_pixelsize: 0.055
 possible_binsizes: [1]

src/instamatic/gui/videostream_frame.py

@@ -239,23 +239,15 @@ def on_frame(self, event=None):
         self.stream.lock.release()
 
         if frame is not None:
-            # the display range in ImageTk is from 0 to 256
-            if self.auto_contrast:
-                frame = frame * (
-                    256.0 / (1 + np.percentile(frame[::4, ::4], 99.5))
-                )  # use 128x128 array for faster calculation
-
-                image = Image.fromarray(frame)
-            elif self.display_range != self.display_range_default:
-                image = np.clip(frame, 0, self.display_range)
-                image = (256.0 / self.display_range) * image
-                image = Image.fromarray(image)
-            else:
-                image = Image.fromarray(frame)
-
-            if self.brightness != 1:
-                image = ImageEnhance.Brightness(image.convert('L')).enhance(self.brightness)
-                # Can also use ImageEnhance.Sharpness or ImageEnhance.Contrast if needed
+            # the display range in ImageTk is from 0 to 255
+            if self.display_range != 255.0 or self.brightness != 1.0:
+                if self.auto_contrast:
+                    display_range = 1 + np.percentile(frame[::4, ::4], 99.5)
+                else:
+                    display_range = self.display_range
+                frame = (self.brightness * 255 / display_range) * frame
+            frame = np.clip(frame.astype(np.int16), 0, 255).astype(np.uint8)
+            image = Image.fromarray(frame)
 
             if self.resize_image:
                 image = image.resize((950, 950))