Process options

If you are a user of DPlngScan (by David Pilling) the process options available here will be familiar to you - the options use the same code library. If you are not sure how or when some of these options would be useful, and you have DPlngScan, then use it with some test images to see the possibilities.

Rotate/flip

If this option is ticked, each image will be transformed by rotation or flipping before type conversion and saving. The current setting for transform type is shown to the right, and may be changed by clicking on the popup menu button and selecting a new setting from the menu that appears.

The options available are

• rotate left 90°
• rotate 180°
• rotate right 90°
• flip horizontal
• flip vertical

Note that there is no 'Auto-rotate' option - only some types of file can store orientation information, and even with those files, it is optional. If you wish to 'auto-rotate' jpeg images from e.g. a digital camera, then use my other application !TransJPEG (available from my web site) to do this.

Resize

If this option is ticked, each image will be transformed by resizing before type conversion and saving. The current setting for resizing method is shown to the right, and may be changed by clicking on the popup menu button. A dialogue box will be opened.

There are currently four options for resizing.

Resize by

This will rescale the image by the percentage shown in the field to the right.

Resize X to

This will scale the images to the width (in pixels) entered in the field to the right. The aspect ratio of the image will be preserved.

Resize Y to

This will scale the images to the height (in pixels) entered in the field to the right. The aspect ratio of the image will be preserved.

Fit within

This will resize the images such that they fit within the height and width values specified. If the button Ignore aspect is not ticked then the aspect ratio will be preserved. If it is ticked then the image will be stretched in one of the directions to completely fill the specified size.

If the option 'Allow scale up' is ticked, then the images will be scaled up if necessary to fit the size, otherwise images smaller than the set dimensions will be left as is. This setting applies only to the last three options. If the 'Resize by' value is greater than 100%, then this will always be honoured.

The SET button should be clicked to apply the new settings.

Histogram

If this option is ticked, the range of pixel intensities in the image will be expanded to cover the full range from black to white.

The current setting for histogram expanding is shown to the right, and may be changed by clicking on the popup menu button. A dialogue box will be opened.

This allows the setting of

• the number of intensity levels used in the calculation, currently 32 to 256, the maximum
• the intensity threshold (as a percentage of the maximum intensity in the image) used when searching the histogram for levels to discard at each end

The SET button should be clicked to apply the new settings.

A fuller description of this option may be found here.

Filter

If this option is ticked, each image will have a filter applied before type conversion and saving. The filter that will be applied is shown to the right, and may be changed by clicking on the popup menu button. The current options are:

Various levels of sharpening or blurring are available. The option 'Slight sharpen' is probably the one to use to reduce the softness of digital camera images.

Colour

If this option is ticked, each image will have colour processing applied. The type of processing to be applied is set by clicking on the menu button to the right of this field, and follows closely the operation of similar features in DPScan. The dialogue that opens is shown below.

You can select the type of colour processing by selecting one of the radio icons non-linear or balance.

Non-linear allows the gamma to be changed. Values of gamma less than unity will brighten the mid-tones of the image, while values greater than unity will darken the mid-tones of the image. It is possible to operate on all three colour channels at the same time (the default) or on one or two colour channels, using Select and/or Adjust accordingly. Levels changes the number of straight line segments used to approximate a gamma curve.

Balance allows the brightness and contrast of the image to be modified. It operates in the same way as DPScan - values greater than 0 will increase brightness or contrast, values less than zero will decrease them.

The SET button should be clicked to apply the new settings.

Convert to greyscale

This will convert the image to a greyscale image. There are no additional settings for this option.

Invert image colours

This option will invert all the colours in the image, and is probably of most use for black and white line art images. Some users have found it useful when scanning diagrams as TIFF files, which then come out as 'negative' in some software.

There are no additional settings for this option.

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Processing order

For versions of ConvImgs up to version 1.12 the transformations were always carried out in the order hardwired in to the code. From version 1.13 it is now possible to choose the order in which the transformations selected are carried out. The next section of the control window allows this.

There are two radio buttons. If Default is selected, then the transformations are still carried out in the previous hardwired order. If Custom is selected, then the transformations are carried out in a chosen order. This order can be set by clicking on the Menu button to the right of the Custom radio button. This opens a window listing (from top to bottom) the current custom set order.

To the right of each field is a menu button. Clicking this will open a menu listing the processes.

Clicking on one of the entries will insert that transform into the field to the left of the menu button that was clicked. You can set up the various transforms in any order you require. If a field is left blank then it will simply be ignored. Remember - the transform must also be selected in the control window for it to be carried out. The program will allow you to insert the same transform more than once in the list, although it would be a very strange requirement, if this were necessary. It is possible to clear fields using the menu, but that is not really necessary, since transforms will be ignored if not selected in the main control window. The final option in the menu is to reload the process order that has been saved previously (see below).

At the foot of the window are three action buttons.

Set

Clicking Set will apply the order to any subsequent processing as long as the Custom radio button is selected.

Set and Save

Clicking Set and Save will apply the order to any subsequent processing as long as the Custom radio button is selected, and will also save this order which will be reloaded when ConvImgs is next run.

Cancel

Cancel will close the window and any changes made since the last Set or Set and Save will be forgotten.