Error on initial Processing

We are using DJI Phantom 4 pro UAV and  captured data with 85% overlap.The project area has a river and bridge, while processing that data it returned with results like :

1.) Uncalibrated images exactly over bridge

2.)Gaps exactly over the bridge and river

I enclosed the screenshot How to solve this problem.

 

Hi,

In the images, you provided we can see that the lake/bridge part of point cloud/orthomosaic is not properly reconstructed. The reason behind uncalibrated images is that water surfaces have almost no visual content due to large uniform areas. Sun reflection on the water and waves cannot be used for visual matching. Since the images that contain only water do not get calibrated, they do not contribute at all to the processing and can not be used to give color to the orthomosaic. Therefore, there might be holes (lack of information) in the orthomosaic on water surface areas. To reconstruct water surfaces such as rivers or lakes, each image needs to have land features. Flying higher may help to include more land features. It is suggested to take images that contain water with some land (30% of the land minimum).

Regards!