Ensuring that your you have collected quality data while you are in the field will make all the difference in your final outputs. Detecting these issues before leaving the field could save you a trip back to the field to re-fly. There are many scenarios where the flight environment, hardware, or software will cause issues in your source data that makes it all or partially unusable.
Missed triggers in certain sections of the field- Caused by hardware or software
Images come off the drone to dark or light- Insufficient camera settings used
Vignetting is present in your source images- Caused by environment or time of day
To analyze your data in the field you will need to bring a laptop computer to the location. Make sure to install PrecisionViewer to this computer for analyzing the data. Below we will go step by step through the process of backing up and verifying your data in field right after your flight.
For information on in field data verification in video format check out or Managing your Data in the Field video.
Verification of Data Quality
Before checking the data quality of your source images be sure to copy all the files from the SD card after the flight. You should always keep source images for each flight backed up on the laptop computer you bring to the field. Clear the SD card once you have backed up the data so you do not get data from two different flights mixed up.
1. In your source data folder turn on "Large Icons" in the file viewer and skim through images looking for light changes, blurriness, vignetting, or any other artifacts. For more information on recognizing these effects in your source imagery see Guidelines of a Quality Orthomosaic section of our knowledge base.
2. If you find only a small number of these problem images you can delete them and try to work with the data anyways. If you see that a huge portion of your images have issues this may be a good reason for a re flight of the field. When in doubt during this process it is always safer to refly and collect more than enough data.
3. Now we open the data in PrecisionViewer to analyze the trigger locations and flight track across the field. To start open PrecisionViewer and click "Add Survey"
4. "Choose Image" by navigating to your desktop backup folder and selecting all images from this survey. Once added to the table scroll through paying attention to any warning symbols or major altitude changes.
5. Usually your camera parameters will feed through automatically. If not choose the corresponding camera model and sensor group- Importance of labeling your folders with this information
6. Your survey will appear as an icon once properly added to PrecisionViewer. To view the triggering map of your flight click the Eye Ball icon on the surveys thumbnail. This will give you a rough layout of images across your area of interest. Each white tick mark on the screen shows a trigger of the drones camera. This map will illustrate to you any missed triggers or coverage on your area of interest.
Examples of Bad Source Data
Incorrect camera settings-
The image below has over contrast present in the source images. This is caused by incorrect camera settings used during flight. A re flight with different camera settings would be suggested if this is experienced.
Cloud passed over area of interest mid survey. This causes changes in lighting throughout the source images that will cause issues in processing. A re flight under constant lighting conditions is suggested if this is experienced.
Vignetting seen in south eastern section of the image below. Notice the bright circular pattern in one section of the image. This is seen in the same area of the image throughout the source data. To avoid vignetting fly outside of the solar noon time frame at your location. For more information on vignetting see our Guidelines of a Quality Orthomosaic article.
One of the most difficult issues to pick out in your source images is blur. On the bottom right side of the image below you will notice a blurriness to the features of the image. If you experience blurriness in your source images you may consider re flying your area of interest with a higher altitude or lower flight speed.