Analysis Functions

Command which its parameter includes a region in a viewer (selected or predefined hardware region) can also use region selection.

List of Commands

• average_pixel
• hot_pixel
• noise

average_pixel

Calculates the average pixel value for the region.

Syntax:

    average_pixel box_id viewer_id region

Parameters:

box_id

    Type: String
    Description: Where to display the result.

viewer_id

    Type: String
    Description: Which viewer to analyze.

region

    Type: Region
    Description: The region of interest.

Example Usage:

    average_pixel box1 viewer2 (rect 1000 100 50 1000)
    average_pixel box1 viewer2 sel

hot_pixel

Marks the pixels above the specified threshold within the specified region.

Syntax:

hot_pixel viewer_id threshold region

Parameters:

viewer_id

    Type: String
    Description: Which viewer to analyze.

threshold

    Type: Number
    Description: The threshold for the pixel to be considered 'hot'.

region

    Type: Region
    Description: The region to analyze.

Example Usage:

    hot_pixel viewer1 150 (rect 1000 100 50 1000)

Remarks:

• At this time, only 500 pixel locations are displayed. Displaying thousands of hot pixels made debugging difficult.
• The viewer draws a DS9 "point" (actually a small circle) at each hot pixel location. Performance (but not visual clarity) is acceptable when there are thousands of hot pixels.

noise

Display the pixel noise (square root of the second moment) for the region.

Syntax:

    noise box_id viewer_id region

Parameters:

box_id

    Type: String
    Description: Where to display the result.

viewer_id

    Type: String
    Description: Which viewer to analyze.

region

    Type: Region
    Description: The region of interest.

Example Usage:

    noise box1 viewer2 (rect 1000 100 50 1000)