1. Test overview.

In the diagnosis tests there are tests that call upon a Automatic Crosses Detection (ACD).
The purpose of this help is to briefly explain how this ACD work, and especially how to react when facing this event.

2. Affected test.

Here the list of the tests which call upon this ACD :

• 135 Cal Pre-V-Offset
• 135 Ratio RGB-IR
• 135 Sharpness-CoeffG
• 135 Cal H-Offset
• APS Ratio RGB-IR
• APS Sharpness-CoeffG
• 120 Ratio RGB-IR
• 120 Sharpness-CoeffG
• Slide Ratio RGB-IR

3. Comportment.

A cross is made of a vertical line and a horizontal line. Each one of these 2 lines makes approximately 4 or 5 pixels in width.
According to whether the image is either scanned in IR or RGB, the cross will be white on a dark background or dark on a white darkground.
The calibration films with the required crosses are made by KIS, therefore the approximate position of the required cross is known.
An algo can determine, in a pre-determined zone of search , the place where white switches to dark (and vice versa) and this in the horizontal and vertical direction. The intersection of the two will allow to find out the centre of the cross.
When this centre is known, check that it is indeed the centre of a cross. For that, verify that the 4 angles of the square formed by the cross are of an opposite colour to that of the cross.
In the last analysis, the software is capable of detecting the intersection between an horizontal line and a vertical line, and is able to confirm that it found is the correct centre of a cross.

4. Comportement.

In all the tests quoted above, the ACD can be used to find out the centre of cross position, and thus to calculate sizes, positions...
Here are 2 distinct cases of behaviour of the ACD :

1. The crosses have all correctly been detected : In this case, the DAC will completely be transparent for the user, it will directly reach to the test result.
2. Certain crosses were not found : In this case, the user will have to act: a window containing the scanned image will be displayed. The title of this screen is the searched cross (Top cross, bottom cross..) By zooming on the cross in question, a small blue cross will appear. The software has detected the centre of the cross, but the result is not conclusing so here, 2 cases can come up :
1. The detected cross corresponds exactly to the searched centre of the cross : In this case, click on OK to confirm to the software that the cross which it found is at the right place. It will link up either on the search for another cross, or on the final result.
2. 2. The detected cross does not correspond to the centre of the required cross : In this case, it is necessary to manually specify the true position of the cross. For that, click on the button " cross " which is below the image. Zoom on the cross in question and click approximately on the centre of this cross (not need to be precise). A green cross will appear indicating the position which has been just indicated. Click on OK so that the software sets out again in search starting from the new indicated position.

5. Informations.

The theoritical position of the required crosses can be found in a file which the software will read. If this position is correct, ACD should work smoothly. On the other hand, if it does not correspond to the true position of the searched cross, ACD will not work and the software will require the intervention of the user.
If the user is brought to reposition the cross, this new position will automatically be saved in the file, and it will become the position of search for the following ACD.
By using this procedure it is possible that the first ACD of a test requires the intervention of the user, on the other hand, the following operations should automatically work.

6. Trouble shooting.

If the intervention of the user is required, but that the detected cross is found at the centre of the required cross : this case is possible owing to the fact that all the films are different. Some may seem more or less dense, and that can influence on the check of the shape of the cross. In this case, just click on OK to confirm.

the intervention of the user is required, although the true position of the cross is indicted, the software still does not find it : it could be that a piece of image (white block for example) near to the cross disturbs the search . In this case, try to not position the green cross on the exact centre of the cross, but by slightly moving away from this little disrusptive piece of image.