histat

This program computes statistics about the HiRISE image and it's associated ancillary data including the calibration image, dark reference pixels, and buffer pixels. There are ten sets of statistics that will be produced using:

• IMAGE_POSTRAMP
  • Lines postramp
  • The first 30 lines of image data
• IMAGE
  • Remaining lines of image data after the postramp.
  • If the input image is 30 lines or less, then all statistics will be zero
• IMAGE_DARK
  • Image dark reference pixels
  • 16 pixels per line
• IMAGE_BUFFER
  • Image buffer pixels
  • 12 pixels per line
• CAL_REVERSE
  • Calibration image reverse lines
  • First 20 lines of calibration image
• CAL_MASK
  • Calibration masked lines
  • From 5 - 20 lines after reverse depending on TDI
• CAL_RAMP
  • Calibration ramp
  • Remaining lines after masked lines
• CAL_DARK
  • Calibration image dark reference pixels
  • 16 pixels per line
• CAL_DARK_RAMP
• CAL_BUFFER
  • The calibration image buffer pixels
  • 12 pixels per line

The following statistics for each data set will be produced:

• Average
• Standard deviation
• Variance
• Minimum
• Maximum
• Total pixels
• Valid pixels
• Null pixels
• Low instrument saturation pixels
• Low representation saturation pixels
• High instrument saturation pixels
• High representation saturation pixels

The statistics will be output to the print file and additionally, if the user specifies, a file using the TO parameter, the statistics will be written to the file in a standard PVL format which can then be read using the getkey program. Because the very edges of several parts of the image are often inaccurate, histat also has the ability to disregard some pixels. The first and last line of the calibration image is not regarded, nor are the first and last samples of any line in the calibration image. For this reason, an image with a calibration image of 62 lines by 512 samples will be broken down as follows:

Last 19 lines of the reverse readout pixels (all but the first)
All 6 (in this case) lines of the masked pixels
First 33 lines of the ramp pixels (all but the last)
Since the first and last samples of each of these lines is disregarded automatically, the user is left statistics for the three sections of a 60 line by 510 sample calbration image.

The user is given much more flexibility in excluding samples from the calibration and dark reference areas of the actual (not calibration) image. The specific parameters used are described in the "Parameters" section.

Gathering statistics including all buffer and dark pixel values.

histat from=histatExample.cub to=histatExampleStats.log useoffsets=false

histat Gui

Example Gui Screenshot of GUI with parameters set to gather stats without offsets.

Input image

HiRISE input image for histat Parameter Name: FROM This is the input image for which we will gather statistics.

Output from histats without offsets	This is the output file from running histats without any offsets.