Tobii-Eyetracker with python，无法打印凝视数据

Question

我正在从事一个项目，需要在屏幕上的用户的眼睛的位置。我遵循了tobii-sdk文档，它帮助创建了一个非常基本的程序，可以从我的眼球跟踪器打印凝视数据。然而，当我运行代码时，凝视数据没有打印出来，我不确定为什么。

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import time
import tobii_research as tr

found_eyetrackers = tr.find_all_eyetrackers()

my_eyetracker = found_eyetrackers[0]
print("Address: " + my_eyetracker.address)
print("Model: " + my_eyetracker.model)
print("Name (It's OK if this is empty): " + my_eyetracker.device_name)
print("Serial number: " + my_eyetracker.serial_number)

def gaze_data_callback(gaze_data):
    # Print gaze points of left and right eye
    print("Left eye: ({gaze_left_eye}) \t Right eye: ({gaze_right_eye})".format(
        gaze_left_eye=gaze_data['left_gaze_point_on_display_area'],
        gaze_right_eye=gaze_data['right_gaze_point_on_display_area']))

my_eyetracker.subscribe_to(tr.EYETRACKER_GAZE_DATA, gaze_data_callback, as_dictionary=True)
time.sleep(5)
my_eyetracker.unsubscribe_from(tr.EYETRACKER_GAZE_DATA, gaze_data_callback)

​

我得到的输出是：

​

Address: MY-ADDRESS
Model: IS4_Large_Peripheral
Name (It's OK if this is empty):
Serial number: MY-SERIAL NUMBER

​

Answer 1

当我使用这个回调函数时：

def gazeDataCallback(self,startGazeData):
    print(startGazeData)

我得到以下格式的输出：

{'device_time_stamp': 1623291632673972, 'system_time_stamp': 34428318423, 
'left_gaze_point_on_display_area': (nan, nan), 
'left_gaze_point_in_user_coordinate_system': (nan, nan, nan), 
'left_gaze_point_validity': 0, 'left_pupil_diameter': nan,    
'left_pupil_validity': 0, 
'left_gaze_origin_in_user_coordinate_system': (nan, nan, nan), 
'left_gaze_origin_in_trackbox_coordinate_system': (nan, nan, nan), 
'left_gaze_origin_validity': 0, 
'right_gaze_point_on_display_area': (nan, nan), 
'right_gaze_point_in_user_coordinate_system': (nan, nan, nan), 
'right_gaze_point_validity': 0, 
'right_pupil_diameter': nan, 
'right_pupil_validity': 0, 
'right_gaze_origin_in_user_coordinate_system': (nan, nan, nan), 
'right_gaze_origin_in_trackbox_coordinate_system': (nan, nan, nan), 
'right_gaze_origin_validity': 0}

我怀疑你需要做的是用正确的键查询字典--即

print(gaze_data['left_gaze_point_on_display_area'])

而不是

print({gaze_left_eye})