minmax: Compute the minimum and maximum pixel values in an image

Package: imutil

Usage

minmax images

Parameters

images: Image template specifying the images to be examined.

force = no: Force recomputation of the minimum and maximum pixel and pixel values even if they are noted as up to date in the image header.

update = yes: Update the image header with the new values (requires write permission).

verbose = yes: Print the image name, minimum value, and maximum value of each image processed.

minval = INDEF: Set to the minimum pixel value of the last image processed. If the pixel type of the last input image was complex, this is the real part of the minimum value.

maxval = INDEF: Set to the maximum pixel value of the last image processed. If the pixel type of the last input image was complex, this is the real part of the maximum value.

iminval = INDEF: Set to the minimum imaginary part of the pixel value of the last image processed. Only used if the pixel type of the last input image was complex.

imaxval = INDEF: Set to the maximum imaginary part of the pixel value of the last image processed. Only used if the pixel type of the last input image was complex.

minpix = "": Set to the minimum pixel specification of the last image processed.

maxpix = "": Set to the maximum pixel specification of the last image processed.

Description

The minmax task computes the minimum and maximum pixel and pixel values of each of the images or image sections listed in the image template images. If the force option is set the extreme values will be recomputed by physical examination of the data, otherwise the image is examined only if the extreme values stored in the image header are flagged as invalid. The minimum and maximum pixel will be printed only if the force option is enabled or if the image minimum and maximum is out of date. If the update option is set the image header will be updated with the newly computed values. Updating is not allowed when a section is used to compute the new values.

Examples

1. Compute and print the minimum and maximum values of the images image1 and image2, updating the image header with the new values when done.

cl> minmax image1,image2

2. Force update the minimum and maximum values in the image headers of all images matching the template in the background, without printing the computed values on the terminal.

cl> minmax nite1.* force+ verbose- &

Bugs

The minimum and maximum pixel values are stored in the image header as values of type real, hence some precision may be lost for images of type long integer or double precision floating.