Clinton   Campbell
EGGN512

Goal:   Match   drill   points   to   image   in
CNC   coordinates

Find   drill   centers
 Assume   CAM   file   has   no   noise
 We   want   white   blobs   under   a   certain   size
 Find   the   centroids of   the   blobs

The   Platform
 1   inch   circles   with   centers   spaced   at   8   inches
 Allows   to   find   object   relative   to   origin
 Allows   to   calculate   distance   per   pixel

The   Camera   setup
 The   camera   is   mounted   on   the   Z   axis   (it   moves   with   the   tool)
 3   pictures   were   taken
 1   at   the   origin   at   full   height
 1   at   center   at   full   height
 1   at   center   at   bottom

Calibration   images
 First   and   second   image   calibrate   the   conversion   factors
 Third   image   finds   the   origin   and   calculates   the   transformation

Matching   the   Images
 Interpretation   tree
 Match   lines   by   size   against   other    lines,    and   compare   the   angle   and   distance   between   centers
 Match   chains   of   3
 Use    a   Hough   voting   pattern   for    each   set   of   matches
7
2
4
6
8
9
3
5
1
11
10 29
22
7 17
14
8
32
16
18

5
13
38
20
1
34
7
4
22
30
3637
14 2
12
28
6 16
4
19 2
5
17
3
7
9
18
1
11
Found   Lines
7
2
1
4
6
3
5
7
4
1 6
2
3
5
Correspondence   =
17      11
9       4
13      28
7       6
13      28
7       6
19      13
Angle   =    7.13
degrees
True   =    6.8
degrees
Translation   =   (250,267)
True   =   (238,   267)

Using   blobs   for   more   accuracy
 Rotate   Cam   file   and   close   the   image   and   reduce   noise
 Look   for   blobs   of   a   certain   size,   while   ignoring   the   platform   markers
1
1

Use   the   Blob   information
 The   blob   centroids and   bounding   box   corner   coordinates   add   information   to   the   translation
 Overlaying   the   images   confirms   correct   matching

Pruning   Our   Tree
 We   check   that   the   lines    fall   within   a   range   of   the   most   common   angle
 Check   that   the   blob   bounding   box    dimensions   match
 Check   that   the   translations   of   lines    falls   within   a   range   of   blob   translation

H

Match   the   Drill   Points




 cos sin
0

 sin cos
0


Tx
Ty
1




 Rotate   and   translate   the   drill   points
 Visually   Confirm   match   and   send   to   CNC

Demonstration

Motors   Moving

Things   That   Need   Work
 Compensating   for   backlash   on   lead   screws   on
CNC
 Optimizing   traversal   of   points
 Further   optimizing   of   thresholds   and   line   selecting   parameters
 Using   a   copper   circuit   board