New features of version 3.81 (February 9, 2003)

Improvement of the precision on the date in the output files of automatic photometry (Analysis nenu). Reduction of artifacts in the non-valid zones during an interactive processing of LRGB type (command Trichromy... of Visualization menu)

New commands

WIN_WEBCAM [ X1 ] [ Y1 ] [ X2 ] [ Y2 ]
Defined coordinates of a window in the images resulting from a webcam source and acquired with the command Images acquisition of Webcam menu. Let us suppose for example that the format of the images is 320x240 pixels (Size of the images... from Webcam menu. If before launching acquisition you type in the console:

WIN_WEBCAM 100 1 120 240

then, all the acquired images (including in sequence mode of course) will have a size of 20x240 pixels, isolating in the full format image a sub-images delimited by the coordinates (100,120)-(1-240). To reset the full format you must in this example type in the console:

WIN_WEBCAM 1 1 320 240

(the effect is similar if you leave, then enter the program).

The interest of WIN_WEBCAM is a substantial saving in place on the disc if the object observed is of small size compared to the format of the image. The speed of acquisition is also increased. Another typical application is the acquisition of large number of images of a spectral line of the Sun whereas the disc of this one travels on the input slit of the spectrograph. It is in this manner possible to reconstitute a monochromatic image of the Sun (see command SCAN2PIC).

SCAN2PIC [ NAME ] [ X0 ] [NUMBER]
Select the column of coordinate [ X0 ] in the first image of a sequence of [NUMBER ] images of generic name [ NAME ]. This column becomes the first column of a new image which is built in the memory of the computer. The column of coordinate [ X0 ] in the second image of the sequence becomes the second column of the image in memory, and so on for all the images of the sequence. Finally, the image in memory, and which is displayed after the processing, has a horizontal format equal to the number of images of the sequence and a vertical format equal to the number of pixels along the axis Y in the images of the sequence.

A use of SCAN2PIC is the synthesis of a monochromatic image of the Sun while scanning its disc on the entrance slit of the spectrograph and by making a regular acquisition of images simultaneously. These images become the input sequence of SCAN2PIC. The coordinate [X0 ] is for example the core of a spectral line (the H-alpha line in the red for example) or the close continuum if one want an image standard photosphere. Click here for an illustration of this principle.

It is necessary if possible to adjust the frequency of acquisition of the images with the scanning speed if one want that the scale of the image is the same following axes X and Y. The final improvement of a different scale along the axes is possible with SCALE command which acts independently as X and Y. Command WIN_WEBCAM is useful to isolate the strictly necessary of the image during acquisition (some pixels on the right and on the left of a spectral line for example).

SMILE2 [ IN ] [OUT ] [Y0] [ RADIUS] [ NUMBER]
Same command that SMILE but applying to a sequence of image. This makes it possible to correct the distortion of the spectral lines in order to make them quite right, which is in particular significant in a command like SCAN2PIC during the synthesis of a spectroheliogramme of the Sun.

MIRRORXY2 [ IN] [OUT ] [NUMBER]
Permutation of axes X and Y in a sequence of images.