Buildroot上的Python picamera？

Question

from picamera import PiCamera 在 buildroot 生成的 linux 映像上的 python3.7 中给出以下错误。感谢有关如何修复的建议。谢谢！

/usr/bin/python3.7: symbol 'mmal_port_pool_create': can't resolve symbol
/usr/bin/python3.7: symbol 'mmal_list_push_front': can't resolve symbol
/usr/bin/python3.7: symbol 'mmal_list_destroy': can't resolve symbol
/usr/bin/python3.7: symbol 'mmal_rational_to_fixed_16_16': can't resolve symbol
/usr/bin/python3.7: symbol 'mmal_status_to_string': can't resolve symbol
/usr/bin/python3.7: symbol 'mmal_list_push_back': can't resolve symbol
/usr/bin/python3.7: symbol 'mmal_list_create': can't resolve symbol
/usr/bin/python3.7: symbol 'mmal_list_insert': can't resolve symbol
/usr/bin/python3.7: symbol 'mmal_rational_equal': can't resolve symbol
/usr/bin/python3.7: symbol 'mmal_list_pop_front': can't resolve symbol
/usr/bin/python3.7: symbol 'mmal_port_type_to_string': can't resolve symbol
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.7/site-packages/picamera/__init__.py", line 72, in <module>
    from picamera.exc import (
  File "/usr/lib/python3.7/site-packages/picamera/exc.py", line 41, in <module>
    import picamera.mmal as mmal
  File "/usr/lib/python3.7/site-packages/picamera/mmal.py", line 49, in <module>
    _lib = ct.CDLL('libmmal.so')
  File "/usr/lib/python3.7/ctypes/__init__.py", line 356, in __init__
    self._handle = _dlopen(self._name, mode)
OSError: dlopen() error

Answer 1

您需要选择rpi-userland 包。

我假设您在 Raspberry Pi 上工作，否则 picamera 不适合您。

picamera 尝试打开 libmmal.so 共享库。 rpi-userland Buildroot 包将下载、构建和安装这个库。

如果你为python-picamera 制作了一个Buildroot 包，你应该将select BR2_PACKAGE_RPI_USERLAND 添加到它的Config.in 文件中，并复制rpi-userland 包的依赖项。在python-picamera.mk 文件中，您应该添加PYTHON_PICAMERA_DEPENDENCIES += rpi-userland。这将确保在您启用 picamera 时始终选择并构建包。

另外，如果您有一个可用的python-picamera 包，请考虑在contribution guidelines 之后将其发送到上游。

如果您没有为 python-picamera 制作 Buildroot 包，那可能是问题的根源。 PyPI 的 picamera 包与特定版本的 libmmal 链接，该版本可能与 Buildroot 中的版本不同。这可能会导致您在导入模块时看到错误。

Answer 2

FWIW 我最终只使用了 raspistill...

  raspistill_params = (' -n'
  + ' -ISO ' + str(iso)
  + ' -ss ' + str(shutter_speed)
  + ' -mm ' + meter_mode
  + ' -ex ' + exposure_mode
  + ' --ev ' + str(exposure_compensation)
  + ' -awb ' + awb_mode
  + ' -br ' + str(brightness)
  + ' -co ' + str(contrast)
  + ' -sa ' + str(saturation)
  + ' -sh ' + str(sharpness)
  + ' -drc ' + drc_strength
  + ' -rot ' + str(rotation) 
  + ' -q ' + str(quality) 
  + ' -w ' + str(width) 
  + ' -h ' + str(height) 
  + ' -ae ' + str(annotate_text_size) + ',0xff,0x808000 '
  + ' -a "' + annotate_text + '"'
  + ' -x GPS.GPSLatitudeRef=' + exif_lat_ref(latitude)  
  + ' -x GPS.GPSLatitude=' + exif_latlong(latitude)  
  + ' -x GPS.GPSLongitudeRef=' + exif_long_ref(longitude)  
  + ' -x GPS.GPSLongitude=' + exif_latlong(longitude) 
  + ' -o ' + filename
  )

  proc = subprocess.Popen("raspistill " + raspistill_params, shell=True, stdout=subprocess.PIPE)
  ret_val = proc.communicate() 

Answer 3

sudo apt-get update
sudo apt-get upgrade

sudo raspi-config

启用相机并重启