Calibration – Generate Cal File

To calibrate images in Hoku, you first generate a calibration file for the folder of images, with Statistics. Then you read the images with calibration turned on; see Read Calibrated Images.

1. Read the images. Use ReadStack to read all the images in the folder that you want to calibrate. Typically, these are images that contain a calibration target. Do not check the “calibration” flag in ReadStack.

2. Mark the target. Display one of the images, and draw a window on the white calibration target; see Window Arguments.

3. Set up Statistics. Enter the window into Statistics, and check its “calibration” and “verbose” flags.

4. Run the job. A window shows the statistics and asks whether you want to write out the calibration file. Say yes.

The calibration file is written in the same folder as the images. Its name is the folder's name followed by .cal. Any calibration file already there is overwritten. Calibration works only with single-band images.