SCM

[#315607] Benq 5250C: saned scans only 1/4 of the image

View Trackers | Bugs | Export CSV

Date:
2017-01-24 20:32
Priority:
3
State:
Open
Submitted by:
Boris Lytochkin (lytboris-guest)
Assigned to:
Oliver Schwartz (oliver-guest)
Category:
backends (drivers)
Group:
None
Resolution:
None
Summary:
Benq 5250C: saned scans only 1/4 of the image

Detailed description
With 1.0.25 and no patches saned (snapscan backend) scans exactly 1/4 of the image.

If I patch snapscan-options.c doubling ranges for this scanner:
=============
>diff -u snapscan-options.c~ snapscan-options.c
--- snapscan-options.c~ 2015-09-01 03:31:54.000000000 +0300
+++ snapscan-options.c 2017-01-24 23:12:03.724027000 +0300
@@ -119,11 +119,11 @@
/* ranges */
static const SANE_Range x_range_fb =
{
- SANE_FIX (0.0), SANE_FIX (216.0), 0
+ SANE_FIX (0.0), SANE_FIX (432.0), 0
}; /* mm */
static const SANE_Range y_range_fb =
{
- SANE_FIX (0.0), SANE_FIX (297.0), 0
+ SANE_FIX (0.0), SANE_FIX (594.0), 0
}; /* mm */

/* default TPO range (shortest y_range
=============
most of the image is scanned (white is only rightmost 1/4 of the image) but 3/4 has color broken.

Any ideas how to fix this?

Followups: Sort comments antichronologically

Message
Date: 2017-01-29 12:24
Sender: Olaf Meeuwissen

Looks like this is in the backend but it'd be nice to know whether you also see this when scanning over USB.
Date: 2017-01-29 19:41
Sender: Boris Lytochkin

Yeah, scanning though scanimage gives the same thing.
I just noticed that the image with patched snapscan is scanned completely, but right half of the image has colors broken in two different ways.
Date: 2017-01-29 20:14
Sender: Boris Lytochkin

And grayscale is even more broken (still patched backend to scan whole image)
Date: 2017-01-30 08:17
Sender: Oliver Schwartz

Is the scan range wrong for all resolutions? A better place to adjust the scan area is snapscan_scsi.c, around line 977, where the scan area is calculated from the physical dimensions. You could try to adjust pos_factor there and see if that delivers better results.
Date: 2017-02-04 15:31
Sender: Boris Lytochkin

--- snapscan-scsi.c~ 2017-01-29 22:58:31.000000000 +0300
+++ snapscan-scsi.c 2017-02-04 18:04:05.355844000 +0300
@@ -974,7 +974,7 @@
case PRISA5000:
case PRISA5000E:
case PRISA5150:
- pos_factor = (pss->res > 600) ? 1200 : 600;
+ pos_factor = 1200; //(pss->res > 600) ? 1200 : 600;
break;
case PERFECTION1270:
case PERFECTION1670:

does the same trick - image is scanned 100% but colors are still broken and gray mode has broken line alignment.

If I scan Gray and 1200dpi - image itself is not distorted but is seen as if you take 5250c-fullpage.png and make it gray-scale.

halftone with patched snapscan-scsi.c is even more broken (150 dpi attached, 300 and 1200 are the same but the angle of color stripes is different).

Attached Files:

Attachments:
Size Name Date By Download
1.46 MiB5250c-fullpage.png2017-01-24 20:32lytboris-guest5250c-fullpage.png
1.22 MiBout-gray.png2017-01-29 20:14lytboris-guestout-gray.png
6.4 MiB150-ht.tiff2017-02-04 15:31lytboris-guest150-ht.tiff

Changes:

Field Old Value Date By
File Added7345: 150-ht.tiff2017-02-04 15:31lytboris-guest
File Added7335: out-gray.png2017-01-29 20:14lytboris-guest
assigned_tonone2017-01-29 12:24olaf-guest
File Added7334: 5250c-fullpage.png2017-01-24 20:32lytboris-guest
Powered By FusionForge