21 Jan
2008
21 Jan
'08
12:13 p.m.
See the attached patch, Sara Kolster and I use it in our workshops. Original by Ben Bogart, posted to the list when we had similar questions a few years ago.
best, d.
matteo sisti sette wrote:
I have to perform some very very simple computer-vision tasks (such as motion detection) on image data captured by a camera, and I was considering/evaluating the possibility of using GEM to do that.
--
derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
---Oblique Strategy # 58:
"Do we need holes?"
#N canvas 574 31 1163 721 10;
#X obj 277 131 pix_grey;
#X msg 302 159 reset;
#X obj 277 188 pix_background;
#X msg 370 167 $1 $1 $1;
#X msg 370 132 0.5;
#X floatatom 370 151 5 0 0 0 - - -;
#N canvas 486 104 585 607 cursor 0;
#X obj 19 36 inlet;
#X obj 231 32 inlet;
#X obj 151 346 translateXYZ;
#X text 62 150 0.64;
#X text 34 151 1;
#X obj 20 63 t f f;
#X obj 34 176 -;
#X text 59 177 X-Range;
#X text 280 176 Y-Range;
#X obj 53 215 expr (8/$f1);
#X obj 20 215 -;
#X obj 38 241 *;
#X obj 26 95 max 0;
#X obj 68 95 min 10;
#X obj 58 131 f;
#X obj 30 131 f;
#X obj 39 267 - 4;
#X text 278 148 0.64;
#X text 250 147 1;
#X obj 232 60 t f f;
#X obj 250 172 -;
#X obj 267 215 expr (8/$f1);
#X obj 233 215 -;
#X obj 251 241 *;
#X obj 238 92 max 0;
#X obj 280 92 min 10;
#X obj 272 128 f;
#X obj 246 127 f;
#X obj 221 268 expr (-1*$f1)+4;
#X obj 436 30 inlet;
#X obj 437 61 * 10;
#X obj 150 323 gemhead 15;
#X obj 357 496 circle 0.1;
#X obj 33 410 separator;
#X obj 204 410 separator;
#X obj 205 496 rectangle 0.2 0.01;
#X obj 357 410 separator;
#X msg 367 454 draw line;
#X obj 367 433 loadbang;
#X obj 152 371 colorRGB 1 0 0 1;
#X obj 32 495 rectangle 0.01 0.2;
#X msg 438 454 width $1;
#X obj 437 398 int;
#X obj 438 425 + 1;
#X text 433 10 size;
#X text 20 13 X-coordinate;
#X text 221 11 Y-coordinate;
#X text 278 370 color red;
#X connect 0 0 5 0;
#X connect 1 0 19 0;
#X connect 2 0 39 0;
#X connect 5 0 10 0;
#X connect 5 0 12 0;
#X connect 5 1 13 0;
#X connect 6 0 9 0;
#X connect 9 0 11 1;
#X connect 10 0 11 0;
#X connect 11 0 16 0;
#X connect 12 0 15 0;
#X connect 13 0 14 0;
#X connect 14 0 6 1;
#X connect 14 0 10 1;
#X connect 14 0 13 1;
#X connect 15 0 6 0;
#X connect 15 0 12 1;
#X connect 16 0 2 1;
#X connect 19 0 22 0;
#X connect 19 0 24 0;
#X connect 19 1 25 0;
#X connect 20 0 21 0;
#X connect 21 0 23 1;
#X connect 22 0 23 0;
#X connect 23 0 28 0;
#X connect 24 0 27 0;
#X connect 25 0 26 0;
#X connect 26 0 20 1;
#X connect 26 0 22 1;
#X connect 26 0 25 1;
#X connect 27 0 20 0;
#X connect 27 0 24 1;
#X connect 28 0 2 2;
#X connect 29 0 30 0;
#X connect 30 0 32 1;
#X connect 30 0 42 0;
#X connect 31 0 2 0;
#X connect 33 0 40 0;
#X connect 34 0 35 0;
#X connect 36 0 32 0;
#X connect 37 0 32 0;
#X connect 38 0 37 0;
#X connect 39 0 33 0;
#X connect 39 0 34 0;
#X connect 39 0 36 0;
#X connect 41 0 32 0;
#X connect 42 0 43 0;
#X connect 43 0 41 0;
#X restore 282 510 pd cursor;
#X obj 612 110 separator;
#X obj 612 131 pix_texture;
#X obj 612 152 square 4;
#X obj 62 264 pix_texture;
#X obj 62 244 alpha;
#X obj 62 224 colourRGB 1 1 1 0.65;
#X obj 62 284 translateXYZ -2.4 -2.4 0;
#X obj 427 49 gemhead 10;
#X obj 62 205 spigot;
#X obj 99 160 tgl 20 0 empty empty empty 0 -6 0 8 -262144 -1 -1 1 1
;
#X obj 427 70 pix_video;
#X obj 16 114 gemwin 30;
#X msg 24 47 create;
#X msg 25 71 destroy;
#X obj 19 18 tgl 15 0 empty empty empty 0 -6 0 8 -262144 -1 -1 1 1
;
#X text 335 440 size;
#X text 315 440 Y;
#X text 289 439 X;
#X text 859 10 by Ben Bogart (ben@ekran.org);
#X obj 62 304 square 1.5;
#X obj 277 106 separator;
#X obj 278 423 pix_blob;
#X obj 205 15 loadbang;
#X msg 202 34 0;
#X obj 426 15 tgl 15 0 empty empty empty 0 -6 0 8 -262144 -1 -1 1 1
;
#X msg 33 92 dimen 300 300;
#X text 48 16 gem window;
#X text 449 13 live input camera [firewire/usb];
#X text 610 224 [pix_background] 'removes' the background of an image
by comparing a static image in memory to an incoming video stream.
all values withing a given range are turned black. for best effect
, place a camera on a static scene like a blank wall and hit 'reset'.
then set the range control to cover any variance in the background.
when a new object enters the scene it will be the only thing draw against
a black background. use pix_chroma_key or pix_compare to add in images
in place of the black.;
#X text 611 199 --------------;
#X text 607 85 image of the camera;
#X text 608 93 --------------------;
#X text 610 392 Inlet 2: float: range (<f> == <f> <f> <f>);
#X text 609 341 Inlet 2: list: range ; in RGBA mode this is <+-red>
<+-green> <+-blue> ; in YUV-mode this is <+-luma> <+-Cb> <+-Cr> ;
in Gray-mode only the first value is important <+-gray>;
#X text 612 211 Description: separate an object from background;
#X text 215 80 motion tracking;
#X text 216 88 ---------------;
#X text 34 167 --------;
#X text 440 171 threshold;
#X text 605 446 [pix_blob] will calculate the "center-of-gravity" of
a certain (combination of) channel(s).;
#X text 604 434 --------------;
#X text 607 476 You can choose the combination of channels used for
the calculation by changing the <mode>. Valid modes are: 0(gray)(default)
, 1(red) , 2(green) , 3(blue) , 4(alpha);
#X text 608 520 pE: selecting "red" (1) will weight position of each
pixel with its red-value. Pixels with "more" red will be weighted stronger
, thus moving the "center of gravity" -- the blob position -- nearer
to themself. The total amount of "red" in the image defines the size
of the blob.;
#X text 608 587 You can specify a custom combination of channels with
<color-weights>. pE: "1 0 2" will give more weight to the blue-channel
than to the red-channel , green- and alpha-values will be ignored.
;
#X text 608 642 Specifing only one single color-weight <w> , is the
same as "<w> <w> <w> 0";
#X text 387 190 ------------------------------- PIX_BACKGROUND;
#X text 380 424 ------------------------------- PIX_BLOB;
#X text 858 23 changed by Sara Kolster;
#X text 857 36 [text from GEM help patches];
#X msg 304 373 <mode>;
#X msg 329 395 <color-weights>;
#X text 273 529 representation of the 'movement';
#X text 274 541 by a cursor. Click on pd cursor;
#X text 273 553 to open the subpatch;
#X text 37 441 outlet 1: gemlist;
#X text 37 482 outlet 4: size;
#X text 37 468 outlet 3: Y coordinate;
#X text 37 454 outlet 2: X coordinate;
#X text 35 496 [upper left corner is 1 , 1;
#X text 36 509 down right corner is 0 , 0];
#X text 35 430 ----------------;
#X text 37 421 OUTPUT PIX_BLOB ---------------;
#X text 34 159 preview;
#X obj 319 668 send tracking;
#X obj 372 594 change;
#X text 317 686 send coordinates to soundpatch;
#X text 856 66 1] make gemwindow;
#X text 856 79 2] turn on rendering;
#X text 856 92 3] set the background;
#X text 857 116 5] move object and receive information;
#X text 856 104 4] turn on live input camera;
#X msg 372 615 s $1;
#X msg 331 615 y $1;
#X msg 292 615 x $1;
#X msg 110 571 send x $1;
#X msg 153 595 send y $1;
#X msg 178 618 send s $1;
#X msg 51 685 connect localhost 3000;
#X obj 124 643 netsend;
#X connect 0 0 2 0;
#X connect 1 0 2 0;
#X connect 2 0 15 0;
#X connect 2 0 28 0;
#X connect 3 0 2 1;
#X connect 4 0 5 0;
#X connect 5 0 3 0;
#X connect 7 0 8 0;
#X connect 8 0 9 0;
#X connect 10 0 13 0;
#X connect 11 0 10 0;
#X connect 12 0 11 0;
#X connect 13 0 26 0;
#X connect 14 0 17 0;
#X connect 15 0 12 0;
#X connect 16 0 15 1;
#X connect 17 0 7 0;
#X connect 17 0 27 0;
#X connect 19 0 18 0;
#X connect 20 0 18 0;
#X connect 21 0 18 0;
#X connect 27 0 0 0;
#X connect 28 1 6 0;
#X connect 28 1 80 0;
#X connect 28 1 81 0;
#X connect 28 2 6 1;
#X connect 28 2 79 0;
#X connect 28 2 82 0;
#X connect 28 3 6 2;
#X connect 28 3 71 0;
#X connect 28 3 83 0;
#X connect 29 0 30 0;
#X connect 30 0 14 0;
#X connect 31 0 14 0;
#X connect 32 0 18 0;
#X connect 56 0 28 1;
#X connect 57 0 28 2;
#X connect 71 0 78 0;
#X connect 78 0 70 0;
#X connect 79 0 70 0;
#X connect 80 0 70 0;
#X connect 81 0 85 0;
#X connect 82 0 85 0;
#X connect 83 0 85 0;
#X connect 84 0 85 0;