使用触发器的Ximea Python脚本导致空白图像

Question

我正在尝试写一个Python (2.7.12)和OpenCV (3.2.0)脚本，它将打开一个左右两侧的相机Ximea xiQ相机，设置一些参数，开始采集，每秒从每个相机拍摄一张照片，将它们写入文件，然后重复直到KeyboardInterrupt。一切似乎都正常，但当我查看.png图像时，它们是空白的(或者在预览中显示为黑色，但它们都大约为2.5MB，所以不是空的)。

我刚接触OpenCV和这些相机/应用编程接口，对Python语言还不是很流利(但我可以应付)。你们能不能看一下我的脚本，让我知道你们认为问题可能是什么？下面是我正在尝试的代码(这只是所包含的Python示例的一个更精细的版本：

from ximea import xiapi
import cv2

increment_val = 0
##which_camera = 'Left\\'

save_location = 'C:\\Users\\mah_usernames\\Desktop\\camera_test\\'
image_file_name = 'image' 
image_file_type = '.png'
##saved_image_full_path = save_location + which_camera + image_file_name + image_file_type
saved_image_full_path = save_location + image_file_name + image_file_type

#create instance for first connected camera
left_cam = xiapi.Camera(dev_id=0)
right_cam = xiapi.Camera(dev_id=1)

#start communication
#to open specific device, use:
#cam.open_device_by_SN('41305651')
#(open by serial number)
print('Opening left side camera...')
left_cam.open_device()

print('Opening right side camera...')
right_cam.open_device()

#settings

##left_cam.enable_aeag() #enable auto exposure, auto gain
##right_cam.enable_aeag()
##left_cam.set_acq_timing_mode('XI_ACQ_TIMING_MODE_FREE_RUN')
##right_cam.set_acq_timing_mode('XI_ACQ_TIMING_MODE_FREE_RUN')

left_cam.set_led_selector('XI_LED_SEL3') #choose bottom LED
left_cam.set_led_mode('XI_LED_ON') #always on, power indicator
left_cam.set_led_selector('XI_LED_SEL2') #choose middle LED
left_cam.set_led_mode('XI_LED_FRAME_ACTIVE') #blinks when frame is active
left_cam.set_led_selector('XI_LED_SEL1') #choose top LED
left_cam.set_led_mode('XI_LED_ACQUISITION') #blinks when data is transferred
##
right_cam.set_led_selector('XI_LED_SEL3') #choose bottom LED
right_cam.set_led_mode('XI_LED_ON') #always on, power indicator
right_cam.set_led_selector('XI_LED_SEL2') #choose middle LED
right_cam.set_led_mode('XI_LED_FRAME_ACTIVE') #blinks when frame is active
right_cam.set_led_selector('XI_LED_SEL1') #choose top LED
right_cam.set_led_mode('XI_LED_ACQUISITION') #blinks when data is transferred

left_cam.set_trigger_source('XI_TRG_EDGE_RISING')
right_cam.set_trigger_source('XI_TRG_EDGE_RISING')
left_cam.set_trigger_selector('XI_TRG_SEL_EXPOSURE_ACTIVE')
right_cam.set_trigger_selector('XI_TRG_SEL_EXPOSURE_ACTIVE')

left_cam.set_gpi_mode('XI_GPI_TRIGGER')
right_cam.set_gpi_mode('XI_GPI_TRIGGER')
left_cam.set_exposure(5000)
right_cam.set_exposure(5000)
print('Left Camera exposure was set to %i us' %left_cam.get_exposure())
print('Right Camera exposure was set to %i us' %right_cam.get_exposure())
left_cam.set_imgdataformat('XI_RGB32')
right_cam.set_imgdataformat('XI_RGB32')

#create instance of Image to store image data and metadata
##img = xiapi.Image()
img_left = xiapi.Image()
img_right = xiapi.Image()

#start data acquisition
print('Starting data acquisition...')
left_cam.start_acquisition()
right_cam.start_acquisition()

try:
    while True:
        print str(increment_val)
        #get data and pass them from camera to img
        ##    left_cam.get_image(img_left)
        ##    right_cam.get_image(img_right)
        left_cam.get_image(img_left)
        right_cam.get_image(img_right)

        #get raw data from camera
        #for Python2.x function returns string
        #for Python3.x function returns bytes
        left_cam_data = img_left.get_image_data_numpy()
        right_cam_data = img_right.get_image_data_numpy()

        ##    #transform data to list
        ##    data = list(data_raw)
        ##
        ##    #print image data and metadata
        ##    print('Image number: ' + str(i))
        ##    print('Image width (pixels):  ' + str(img_left.width))
        ##    print('Image height (pixels): ' + str(img_left.height))
        ##    print('First 10 pixels: ' + str(left_cam_data[:10]))
        ##    print('\n')

        ##    #show acquired image
        ##    print('Drawing image...')
        ##    cv2.imshow('Left side camera', left_cam_data)
        ##    cv2.imshow('Right side camera', right_cam_data)
        ##    cv2.waitKey(0)
        ##    cv2.destroyAllWindows()

        #save acquired image
        print('Saving image...')
        cv2.imwrite((save_location + 'Left\\' + image_file_name + str(increment_val) + image_file_type), left_cam_data) 
        cv2.imwrite((save_location + 'Right\\' + image_file_name + str(increment_val) + image_file_type), right_cam_data)
        increment_val += 1
        print str(increment_val)

except:
    KeyboardInterrupt
    #stop data acquisition
    print ('Stopping acquisition...')
    left_cam.stop_acquisition()
    right_cam.stop_acquisition()

    #stop communication
    left_cam.close_device()
    right_cam.close_device()

    print ('All finished!')

在此之前，我一直在使用修改较少的预制示例版本……

from ximea import xiapi
import cv2

##increment_val = 0
##which_camera = 'Left\\'

save_location = 'C:\\Users\\mah_usernames\\Desktop\\camera_test\\'
image_file_name = 'image' 
image_file_type = '.png'
##saved_image_full_path = save_location + which_camera + image_file_name + image_file_type
saved_image_full_path = save_location + image_file_name + image_file_type

#create instance for first connected camera
left_cam = xiapi.Camera(dev_id=0)
right_cam = xiapi.Camera(dev_id=1)

#start communication
#to open specific device, use:
#cam.open_device_by_SN('41305651')
#(open by serial number)
print('Opening left side camera...')
left_cam.open_device()

print('Opening right side camera...')
right_cam.open_device()

#settings
left_cam.set_exposure(10000)
right_cam.set_exposure(8000)
print('Left Camera exposure was set to %i us' %left_cam.get_exposure())
print('Right Camera exposure was set to %i us' %right_cam.get_exposure())
left_cam.set_imgdataformat('XI_RGB24')
right_cam.set_imgdataformat('XI_RGB24')

#create instance of Image to store image data and metadata
##img = xiapi.Image()
img_left = xiapi.Image()
img_right = xiapi.Image()

#start data acquisition
print('Starting data acquisition...')
left_cam.start_acquisition()
right_cam.start_acquisition()


for i in range(10):
    increment_val = i
    print str(increment_val)
    #get data and pass them from camera to img
##    left_cam.get_image(img_left)
##    right_cam.get_image(img_right)
    left_cam.get_image(img_left)
    right_cam.get_image(img_right)

    #get raw data from camera
    #for Python2.x function returns string
    #for Python3.x function returns bytes
    left_cam_data = img_left.get_image_data_numpy()
    right_cam_data = img_right.get_image_data_numpy()

##    #transform data to list
##    data = list(data_raw)
##
##    #print image data and metadata
##    print('Image number: ' + str(i))
##    print('Image width (pixels):  ' + str(img_left.width))
##    print('Image height (pixels): ' + str(img_left.height))
##    print('First 10 pixels: ' + str(left_cam_data[:10]))
##    print('\n')

##    #show acquired image
##    print('Drawing image...')
##    cv2.imshow('Left side camera', left_cam_data)
##    cv2.imshow('Right side camera', right_cam_data)
##    cv2.waitKey(0)
##    cv2.destroyAllWindows()

    #save acquired image
    print('Saving image...')
    cv2.imwrite((save_location + 'Left\\' + image_file_name + str(increment_val) + image_file_type), left_cam_data) 
##    which_camera = 'Right\\'
    cv2.imwrite((save_location + 'Right\\' + image_file_name + str(increment_val) + image_file_type), right_cam_data) 

#stop data acquisition
print('Stopping acquisition...')
left_cam.stop_acquisition()
right_cam.stop_acquisition()

#stop communication
left_cam.close_device()
right_cam.close_device()

print('Done.')

...and认为其中一种工作正常，即从每个摄像头拍摄一张图像，并且所有图像都正确显示。所以，我认为这与我触发设置的方式有关。仅供参考，我使用来自GPS接收器的1pps信号作为GPI引脚的触发器输入。

无论如何，如果您对这个问题或重构脚本有任何建议，请让我知道，以便更好地使用OpenCV应用程序接口。

谢谢!

Answer 1

我在上面的第一条评论中提出的解决方案是一个可行的答案，因此足以结束这一点。我将继续研究为什么我看不到RGBA文件，但我认为这更多地与Windows处理该文件类型的方式有关，而不是Python/Open CV脚本的问题。

我将把这篇文章留给那些需要一个触发的，两个Ximea摄像头的Python和OpenCV解决方案的人，因为Ximea的文档是缺乏的。

祝好运!