linux下通过V4L2的接口调用camera，获取数据。保存成YUV和RGB文件。可以通过YUV和RGB工具查看是否获取数据正常与否。可以在ubuntu中，切换成framebuffer，申请一块内存使其显示在屏幕。-in linux,with v4l2 interface,open camera and obtain data buffer.we can save data buffer with yuv or rgb.such as rawview tools,check data buffer is ture.In ubuntu,change xll to framebuffer,we show image in framebuffer.