Open source print quality software

2.  Commercial systems dedicated to assess print quality already
exist. They usually implement the ISO 13660 standard with a
focus on character and line attributes (raggedness, line
width, darkness, character, contrast, fill, extraneous marks,
character field, background haze, character field)
 However, they are expensive, lack of flexibility and the access
to their algorithms is not possible.
 Fiji/ImageJ and its environment enables to develop an open
source program dedicated to print quality assessment
› free license
› Interface based
› Development using Java language and pre-coded functions
› Enhance collaboration

3. Print target
design
Choice of Printing System model
relevant features
Image
Printing sequences Printing parameters
(drop speed,…) acquisition
Features
Substrate High resolution &
low field of view extraction
Ink vs low resolution
Lines Statistical
& high field of
Printing
view analysis
configuration Dot
Lighting Text Intra-samples
Dithering conditions
techniques Registration mark Inter-
samples
Fiji

4.  Fiji is an image processing package. It can be
described as a distribution of ImageJ together
with Java, Java 3D and a lot of plugins.
 User interface
 Macro/plugings editor

5. Individual ‘bricks’
-Color conversion Software development
-Binary analysis Macro
-Illumination correction Java based program
-…
Increase productivity
Automation
Shorter development time
Proprietary routines and
development of standard

6.  Image creation to design test charts
 Dithering techniques
 Dots and satellites
 Line width/raggedness
 Series of parallel lines

7.  By example, test of optical density regularity
along the swathe
› Periodic pattern
› Random pattern

8.  Comparison and impact of different
dithering techniques
 Implementation of algorithms specific to
greyscale printhead

9. Particles extraction
Particles counting
Background subtraction
RGB – one layer
Binarization

10. Individual object’s properties
Histogram for a given
parameter

11. › Edges extraction + angular correction +
average and standard deviation on both
sides of the line

12.  Idea The centre of each line is
computed to obtain the The histogram is then
Original image distance between two plotted
successive lines
Histogram
%
di
di
REFERENCE

13.  implementation
The red circles represent
the middle of the line
Average and standard
deviation are then calculated

14.  Colour deconvolution
 Results tolerance
 Text recognition and limit of
“readability”

15.  Objective: to quantify colour variations caused by
due to undesirable drops overlap,...
Placement
accuracy
% of
coverage
Printing
Colour Colour
direction
clustering split
in RGB Dithering
space techniques

16.  Objective: to evaluate the interval of confidence for
results like dot diameter, (x,y) positioning, roundness,…
Pixel size: 2 µm Distribution of error centred of the
Dot diameter: 60 µm theoretical dot area
Algorithm based
on dot permutation

17.  Image analysis is an approach, but not
the end of the story
 PQ can be described along several others
physical dimensions (Optical density,
colour gamut, full tone uniformity…)
 Some levels of overlapping exist between
them

18.  If you:
› want to know more about ImageJ / Fiji
› are interested in developing an ISO13660
open source software
› have a specific need regarding print quality
assessment, beyond image analysis
 I would be please to heard from you.