Process Tab
Process images captured by MAPIR cameras.
Analyze
To get started, press the INPUT button, and select a folder of MAPIR camera images.
We automatically select the same folder for the OUTPUT folder. We'll create a new folder named "Processed_1" in the INPUT folder to store your processed images. If you prefer, you can select a different output location. If there is already a folder named "Processed_1" we'll create "Processed_2", etc.
Now press the ANALYZE button. The program will display some feedback messages in the log window while it analyzes your input images.
When analyzing the DAQ logs it will assess which logs match up with the timestamps on the images. You can provide as many DAQ logs as you wish and it will sort them automatically for you, as you can see below.
You may be warned that the images containing our targets are over or under exposed.
Over-exposed means they are too bright. Lower the exposure. Increase N in shutter speed 1/N.
Under-exposed means they are too dark. Increase exposure. Decrease N in shutter speed 1/N.
You can proceed with calibration regardless of WARNINGS, but the results may not be as good.
Processing Settings
Clicking on the gear icon in the bottom right corner of the Process tab opens the Processing settings window with the following options:
Recalibration interval (seconds)
During the reflectance calibration process, the calibration formulas will be re-calculated when a new calibration target image equal to or greater than the interval time is found. Interval time is the number of seconds since the last calibration target image timestamp. Setting to 0 will update the calibration formulas for every target image found. This allows you to account for changing ambient light more easily. If non-target images are found prior in time to the first target image, then all images prior will be corrected with the first found target image.
Minimum calibration sample area (pixels)
When assessing the calibration target images we reject any that are too far away from the camera. We limit this distance by setting a minimum sample area for the pixels of each reflectance target. The smaller the minimum sample area the further the target can be, but the less pixels used for the average. The more pixels of each target used the better the average will be, and thus the better the results should be. This setting is useful if you are capturing multiple calibration images from various distances (such as when a drone takes off). We are sampling a square region, so the side length of the square controls the total area. Area = length x width. So an area value of 25 is a 5 x 5 pixel square minimum.
Save calibrated reference target images
Enables/disables saving the target images used for calibration. If you do not need to analyze the images with the calibration targets then not saving them will speed up processing time.
Apply PPK corrections
Post Process Kinematics (PPK) is a method of post processing that uses the exposure pulse sent by the camera when it actually captures the image to correct the GNSS (GPS) location metadata. There is a difference in time between when the camera reads the GNSS location and when the sensor is actually capturing the image. If the camera is moving while capturing, such as when on a drone, then there may be a difference of over a meter distance. By using PPK we can use the exposure pulse to more accurately update the GNSS metadata on the images, which improves the results you would see when using photogrammetry to produce a 3D model or 2D orthomosaic.
Use high-quality debayering (slower)
Debayering is the process of converting the RAW pixel data into a 3-channel image. There are many methods to debayer an image, and the better methods typically produce more accurate results and take more time to process. If this option is checked, then it will use a better method that produces far less debayering artifacts, though it does add more time to the debayering step. The amount of extra processing time that this high-quality debayer method adds will vary based on your computer's specifications. On computers that tend to take about 10 seconds to fully process a RAW to TIFF we see an increase of about 5 seconds, per image.
Processing Options
Vignette (Flat Field) Correction
By default we will select "Vignette (Flat Field) Correction" if it is supported by the input camera model(s). This is ideal to do whenever possible. It will brighten up the outer perimeter of pixels in the images, which are darker due to the lens optics.
Sensor Response Correction
Sensor response correction corrects for the sensor sensitivity differences due to the bandpass filter and lens optics used in each camera model. For RGB (Bayer CFA) sensor models the sensor response correction separates each image channel/spectrum from one another.
White Balancing
For RGB filter camera models we support white balancing the images using a "gray world" method. At this time we do not support calibrating the RGB filter models for reflectance using the target.
Reflectance Calibration
If you provided a photo of our reflectance targets then the "Reflectance Calibration / White Balance" option will be enabled. See here for more about our calibration targets.
If you have a sub-folder in your INPUT folder titled "target", we will search there only for target photos. This helps reduce the ANALYSIS time, since we search each photo for the target fiducial pattern.
"Image Format" drop-down allows you to select the type of output images you require.
Image Format Options
TIFF (16-bit)
16-bit (pixel digital number 0 - 65535) TIFF (.tif) format output.
TIFF (32-bit, Percent %)
32-bit (pixel float 0.0 - 0.1) TIFF (.tif) format output.
JPG (8-bit)
8-bit (pixel digital number 0 -255) JPG (.jpg) format output.
JPG (8-bit, Percent %)
32-bit (pixel float 0.0 - 0.1) JPG (.jpg) format output.
Depending on your inputs, certain outputs may not be enabled.
If you have a RGB-sensor camera with a single channel/band filter installed (i.e. Survey3 RE) or have a mono-sensor camera (i.e. Kernel2 M3M), the resulting output images will be single channel/band, mono, grayscale.
Percent Image Output
Our cameras can be calibrated to provide pixel level reflectance measurements. Reflectance is commonly provided as a percent value, so in addition to the typical integer pixel value output our software also provides percent pixel value output.
This means that each pixel will range from a value of 0.0 to 1.0, meaning 0% to 100%. A pixel value of 0.83 would mean 83.0%.
Percent images are large in size, so confirm you have enough storage before processing.
To begin processing, press the PROCESS button.
The log on the right side will provide feedback during processing. Processing times can be long depending on your computer's capabilities and the number of images. When processing is complete the log can be saved to a text file using the SAVE LOG button.
If you have PPK enabled, and if there were 2 cameras connected to the DAQ, then you will be asked to confirm which camera port you had each camera plugged into. For example, if you used both a Survey3W_OCN and Survey3W_RGN, the pop-up window will look like the below. If Survey3W_OCN was plugged into port 1, it's good as shown. Otherwise, press the crossed arrow button to swap them.
After processing you can analyze the photos on the Analyze Tab.
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