mavpicviewer: hardcode fov and res for Siyi ZT6

Author: rmackay9

MAVProxy/tools/mavpicviewer/mavpicviewer_image.py

@@ -94,7 +94,7 @@ def __init__(self, folderpath, comm_pipe=None):
         self.update_image()
 
         # set camera parameters with default FOV
-        self.update_camera_settings(36.9)
+        self.update_camera_settings(25)
 
         # hard-code mount angles
         self.roll = 0
@@ -402,8 +402,8 @@ def update_camera_settings(self, FOV):
         if self.im is None:
             print(prefix_str + "failed to update camera settings because image is not set")
             return
-        # set camera parameters
-        self.cam1_params = camera_projection.CameraParams(xresolution=self.im.width, yresolution=self.im.height, FOV=FOV)
+        # set camera parameters (hard-coded for Siyi ZT6)
+        self.cam1_params = camera_projection.CameraParams(xresolution=640, yresolution=512, FOV=FOV)
         self.cam1_projection = camera_projection.CameraProjection(self.cam1_params, self.elevation_model, self.terrain_source)
 
     # update the displayed map with polygon