ImageDecimation filter
This page applies to Harlequin v13.1r0 and later; both Harlequin Core and Harlequin MultiRIP.
Many jobs with large images can benefit from a decimating image filter. This filter reduces the size of the input image by a fixed amount. Reducing an image by a linear factor of two results in three-quarters of the image data being discarded, which can speed up all areas of job processing, at the cost of a reduction in quality. This is of particular benefit on resource-limited embedded devices.
This is implemented using the front-end image filtering system. The ImageDecimation filter reduces images by a fixed factor of two. This is controlled by a system parameter and is disabled by default.
Only 8-bit contone images can be decimated.
All controls are within a subdirectory in userparams called ImageDecimation. The controls are:
Enabled | boolean (required) | Specifies the minimum number of pixels in an image before image decimation is used (default: |
MinimumArea | positive integer (optional) | Specifies the minimum number of pixels in an image before image decimation is used (default: |
MinimumResolutionPercentage | positive integer (optional) | Specifies the minimum percentage of device resolution an image must be before decimation is used (default: 50) |
The ImageDecimation userparam accepts null values in addition to the dictionary values. The null value is a shorthand way of setting the Enabled dictionary key to false. The value is null by default.
The default settings disable decimation. When Enabled is true, the default settings mean that any image with an area greater than 100 x 100 pixels, at greater than 50% of device resolution are decimated.