[argyllcms] Scanner profiling, it8.7/2
- From: Simon Burrell <sirgadabout1@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Thu, 25 Aug 2011 18:11:36 +0100
Hi,
OS X 10.6.8, Epson Stylus SX525WD, ColorAid R1 target, Argyll 1.3.3.
I've just attempted to create a scanner profile using the above, and
received the following result:
Profile check complete, peak err = 23.656901, avg err = 3.248197
That seems pretty poor. The R1 target is brand-new, and I used it with the
white-backing .txt file on the CD (because my scanner has a white backing)
and the Argyll-provided .CHT file. The target was scanned at 300dpi to a
TIF file. Here is the output from the SCANIN tool:
About to allocate scanrd_ object
Verbosity = 2, flags = 0x40000
About to read input tiff file and discover groups
adivval = 1.000000
About to calculate edge lines
682 useful edges out of 2130
About to calculate rotation
Mean angle = -0.570682
Standard deviation = 4.094583
Robust mean angle = -0.114407 from 656 lines
About to calculate feature information
About to read reference feature information
Read of chart reference file succeeded
About to match features
Checking xx
Checking yy
Checking xy
Checking yx
Checking xix
Checking yiy
Checking xiy
Checking yix
Axis matches for each possible orientation:
0: xx = 0.670086, yy = 0.627941, xx.sc = 0.334199, yy.sc = 0.331459
90: xiy = 0.197707, yx = 0.503140, xiy.sc = 0.662976, yx.sc =
0.332411
180: xix = 0.548814, yiy = 0.522990, xix.sc = 0.334015, yiy.sc =
0.331470
270: xy = 0.192080, yix = 0.472476, xy.sc = 0.661090, yix.sc =
0.332357
r0 = 0.910799, r90 = 0.271048, r180 = 0.752324, r270 = 0.256412
There are 2 candidate rotations:
cc = 0.910799, irot = -0.114407, xoff = 30.905212, yoff = 27.488833,
xscale = 2.992227, yscale = 3.016961
cc = 0.752324, irot = 179.885593, xoff = -1880.348447, yoff =
-1268.426914, xscale = 2.993875, yscale = 3.016860
About to compute match transform for rotation -0.114407 deg.
About to setup value scanrdg boxes
About to read raster values
About to compute expected value correlation
About to compute match transform for rotation 179.885593 deg.
About to setup value scanrdg boxes
About to read raster values
About to compute expected value correlation
Expected value distance values are:
0, rot -0.114407: 264.632392
1, rot 179.885593: 2965.435616
Chosen rotation -0.114407 deg. as best
About to compute final match transform
Improve match
About to setup value scanrdg boxes
About to read raster values
About to write diag file
Writing output values to file
The first thing that stands out is the line, "682 useful edges out of 2130"
- does this suggest an error in my .tif file? There also seems to be a lot
of rotation work - would re-scanning my target and attempting to get it
straighter benefit?
This is just my every-day scanner, I'm practising on it before engaging with
my Epson Perfection 4990 Photo, so any advice to help improve my results
would be much appreciated.
Regards,
S.
Other related posts:
