Map-to-Text: Local Map Descriptor

Kanji TANAKA and Shogo HANADA

∗

Abstract : Map matching, the ability to match a local map built by a mobile robot to previously built maps, is crucial

in many robotic mapping, self-localization, and simultaneous localization and mapping (SLAM) applications. In this

paper, we propose a solution to the “map-to-text (M2T)” problem, which involves the generation of text descriptions

of local map content based on scene understanding to facilitate fast succinct text-based map matching. Unlike previous

local feature approaches that trade discriminativity for viewpoint invariance, we develop a holistic view descriptor that is

view-dependent and highly discriminative. Our approach is inspired by two independent observations: (1) The behavior

of mobile robots given a local map can often be characterized by a unique viewpoint trajectory, and (2) a holistic view

descriptor can be highly discriminative if the viewpoint is unique given the local map. Our method consists of three

distinct steps: (1) First, an informative local map of the robot’s local surroundings is built. (2) Next, a unique viewpoint

trajectory is planned in accordance with the given local map. (3) Finally, a synthetic view is described at the designated

viewpoint. Because the success of our holistic view descriptor depends on the assumption that the viewpoint is unique

given a local map, we also address the issue of viewpoint planning and present a solution that provides similar views for

similar local maps. Consequently, we also propose a practical map-matching framework that combines the advantages

of the fast succinct bag-of-words technique and the highly discriminative M2T holistic view descriptor. The results of

experiments conducted using the publicly available radish dataset verify the efficacy of our proposed approach.

KeyWords : map-to-text, map matching, scene descriptor

Members: Tanaka Kanji, Hanada Shogo, Liu Enfu, Takahashi Yoshiki

Relevant Publication:

Shogo Hanada, Kanji Tanaka
M2T: Local map descriptor
System Integration (SII), 2014 IEEE/SICE International Symposium on, 210-215
Bibtex source, Document PDF

Acknowledgements: This work is supported in part by JSPS KAKENHI Grant-in-Aid for Young Scientists (B) 23700229, and for Scientific Research (C) 26330297.

Fig. 1. Generating text description of local map content. The top row shows

four different places in the robot’s operating environment. The middle and

bottom rows respectively show two independent local maps built by the

robot at different time of the day that are warped into synthetic views by

the proposed framework. For the sake of visualization, the viewpoint are

located at the center and aligned with the uppper direction of the figure. As

can be seen, similar views are produced for similar local maps. Our idea is

to convert each view into a holistic view descriptor.

Fig. 2. Detection, extraction and description of 10-dim polestar features.

Fig. 3. Datasets used for experiments. “abuilding”, “albert”, “fr079”, “run”,

“fr101”, and “kwing” from radish dataset [10] are used as the dictionary

maps.

Fig. 4. Examples of matching relevant pairs. Green and blue points

respectively indicate query and database maps, while the red lines indicate

correspondence found by either method. For the sake of visualization, every

map in the figure is aligned by our map alignment framework.

Fig. 5. Examples of matching irrelevant pairs. Green and blue points

respectively indicate query and database maps, while the red lines indicate

correspondence found by either method. For the sake of visualization, every

map in the figure is aligned by our map alignment framework.

Table 1 Summary of ANR performance [%].

Fig. 6. ANR performance for each dataset (horizontal axis: sorted query

map ID, vertical axis: ANR in [%]). Top: BoW. Bottom: M2T.

1 1150 1640 1 1289 1550 1 909 1640 2 909 1500 3 1100 1740 3 2050 1750 3 1050 1629 5 919 1479 7 11801550 7 1169 1479 7 1059 1609 7 909 1679 7 1160 1479 7 989 1450 9 4329 1690 14 1119 1740 14 919 169016 1350 1550 16 919 1609 17 1000 1450 19 1100 1629 19 1010 1550 19 909 1520 19 1000 1550 21 909 1659 224370 1640 23 989 1500 28 919 1700 31 1029 1500 32 1360 1550 33 919 1590 33 909 1440 5 020 1600 35909 1670 35 909 1540 36 1239 1550 37 919 1459 38 919 1470 38 1270 1550 41 1260 1550 42 1050 1740 421020 1740 42 1010 1740 42 989 1750 42 1229 1550 43 1040 1740 43 1000 1740 44 1130 1740 44 1090 150045 919 1570 47 909 1559 47 1160 1550 48 1150 1740 48 919 1720 50 919 1709 51 909 1550 51 919 1579 521360 1740 56 1139 1740 61 1090 1490 61 1150 1550 62 1090 1509 63 1239 1740 7 1090 1470 111 1130 1550114 1119 1509 114 1130 1520 135 1100 1529 139 1090 1479 141 919 1490 141 1189 1550 145 1220 1550 1601160 1740 160 1490 1720 160 950 1750 162 909 1509 163 1090 1529 168 1339 1550 168 1470 1720 168 11001490 170 919 1620 170 919 1600 170 909 1529 170 1389 1740 170 1090 1550 170 1029 1740 170 1320 1559170 1279 1550 170 1090 1740 170 1250 1550 170 909 1650 171 1300 1550 171 1110 1550 171 1100 1550171 1000 1740 171 1110 1729 172 979 1750 174 1090 1459 175 1220 1740 175 1169 1550 180 1139 1550 1811450 1559 182 1169 1529 186 1229 1740 190 1450 1709 190 1260 1740 190 1250 1740 192 1169 1740 199 11001520 224 1370 1550 234 1119 1550 257 1189 1740 258 1310 1550 259 1200 1750 260 1329 1550 262 10901440 262 1080 1450 263 919 1500 275 909 1409 291 1090 1540 291 1200 1559 296 970 750 299 1440 1729 304959 1750 314 1450 1720 320 1180 1750 322 1529 1729 322 1529 1720 326 1200 1550 327 1100 1540 366 11001509 370 1479 1729 376 909 1759 418 1520 1720 422 1090 1509 423 1409 1729 423 1409 1720 425 1300 1750426 1189 1750 426 909 1750 426 1279 1740 426 1210 1550 426 919 1759 427 1189 1559 427 1279 1750 4271300 1740 428 970 1759 430 1329 1740 431 1270 1740 442 350 1740 442 1339 1729 448 940 1750 450 13101740 451 1420 1720 459 1310 1750 467 1389 1550 469 1500 1729 480 940 1759 496 919 1729 504 909 1729 504909 1740 506 1329 1729 509 1339 1740 509 1379 1740 512 4420 1880 512 4310 1400 512 1690 1759 512 26801750 512 3780 1529 512 3780 3110 512 3430 1750 513 2540 1759 515 1000 1400 515 909 1389 516 3219 1750516 3150 1750 516 2209 1550 16 140 1540 518 2380 1750 519 919 1389 520 4239 1990 523 1490 1559 5262739 1540 528 4030 1690 528 4030 1740 528 4420 1759 530 1479 1559 530 989 1400 532 4429 1529 536 42791830 537 4250 1930 538 4420 1640 539 4420 1709 540 4370 1529 541 4420 1590 544 3850 1740 544 38501790 544 1679 1540 546 909 1629 549 2019 1550 553 2140 1759 553 2140 1770 554 1890 1550 555 2200 1750556 1720 1550 60 2240 1759 563 4289 1609 571 4329 1570 574 4370 1579 592 2600 1529 600 4289 1890 6004250 1880 601 4310 1869 613 2009 1759 616 1819 1550 634 4300 1659 639 4320 1629 645 2450 1759 645 24501779 651 1090 1420 652 1950 1550 658 2650 1550 665 4270 1770 666 1420 1570 669 4270 1709 669 4289 1779673 1930 1550 674 1400 1570 674 1969 1559 677 1429 1720 679 1400 1720 682 1969 1779 683 429 1729 683909 1420 687 1059 1740 698 4289 1720 699 1389 1729 704 2630 1540 708 2800 1579 729 1540 1570 731 14291570 736 930 1759 746 1370 1740 748 2040 1770 783 1090 1429 787 2290 1759 792 1809 1770 796 1869 1770806 1969 1770 808 1779 1550 808 1869 1759 825 2100 1759 836 1790 1550 840 2800 1550 840 1800 1750 8581400 1729 871 909 1429 876 2080 1759 882 1289 1750 901 1520 1729 04 2800 1559 904 1809 1759 906 15091729 908 1800 1759 928 1180 1740 930 2280 1770 930 2280 1750 931 1289 1740 931 1320 1750 934 1969 1759935 1409 1570 937 1389 1550 938 1069 1740 938 930 1750 938 1320 1740 938 1210 1750 939 1200 1740 944950 1759 944 1819 1759 959 1080 1740 966 1210 1740 968 1809 1779 970 1500 1720 978 1509 1559 979 14001559 997 1520 1570 1010 959 1759 1020 1379 1550 1023 919 1629

8-th viewpoint

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1 1110 1750 7 1020 1500 7 1250 1629 7 1090 1500 7 1180 1559 7 1130 1750 14 1160 1559 15 1169 1500 151160 1490 15 1150 1620 23 1020 1550 23 1059 1590 24 2080 1770 30 1169 1509 31 1200 1629 32 919 1620 341490 1729 34 959 1759 35 1090 1490 38 1270 1559 40 1040 1750 40 1160 1750 40 1479 1729 42 1069 175042 1050 1750 42 1010 1750 42 1020 1750 43 1000 1750 45 909 1700 45 1260 1559 46 130 559 46 989 175947 1229 1559 47 1239 1559 58 970 1759 60 919 1709 60 1150 1559 60 1139 1559 60 1260 1750 60 1270 175060 1150 1750 63 1100 1609 82 1790 1800 110 1119 1559 112 1350 1559 126 1370 1750 128 909 1550 128 9401759 131 919 1740 132 2030 1759 135 909 1690 136 1409 1579 138 1110 1559 139 909 1679 143 1220 1559160 1360 1559 161 1110 1520 162 1180 1750 162 919 1609 162 1429 579 163 2059 1770 167 1239 1750 1671289 1750 168 1169 1750 168 1470 1729 168 919 1629 170 1279 1559 170 1279 1750 170 1029 1750 1701250 1750 170 1090 1750 170 1119 1750 170 1139 1750 171 1000 1750 172 1379 1750 172 1329 1559 173979 1759 175 1169 1559 184 1339 1559 189 1350 1750 190 919 1720 191 1250 1559 222 1389 1750 234 9501759 251 1360 1750 251 1090 1550 256 909 1650 257 909 1670 257 1540 1729 259 1289 1559 262 1389 1570 263 1310 1559 270 1200 1570 273 1420 1579 287 1200 1559 298 919 1750 298 1320 1550 326 1100 1529 3441370 1559 355 1409 1729 365 1090 1559 384 1200 1750 384 1400 1570 384 1200 1759 385 1220 1740 385 12201750 388 1379 1570 390 1389 1559 391 1310 1750 398 1090 1509 398 1100 1500 406 1090 1520 414 1339 1750414 1329 1740 416 1429 1729 418 909 1659 420 1800 1779 422 1100 1520 424 450 1729 424 1459 1729 4241379 1559 424 1450 1720 426 1440 1740 426 930 1759 426 1229 1750 426 1300 1750 426 1189 1750 4271310 1759 427 1310 1570 431 1210 1559 431 1189 1559 431 1329 1750 431 1189 1570 442 1090 1540 4431100 1559 447 1459 1570 449 1420 1729 478 1389 1740 482 1090 1529 487 1409 1740 490 1420 1740 496 14401729 507 919 1659 512 4360 1440 512 3950 1550 512 3950 540 13 3500 1770 513 3410 1750 516 2169 1559520 4520 1540 520 4410 1869 520 2639 1759 520 2800 1559 521 2040 1559 523 2369 1770 524 2100 1559 5284470 1409 528 4310 1930 528 2650 1759 528 4520 1420 529 2530 1770 530 4329 1690 536 4360 1900 536 27391550 536 2700 1770 537 4329 1579 537 4320 1640 538 4529 1709 539 4379 1559 540 4529 1600 541 44291690 542 4470 1640 542 4479 1700 542 520 1650 542 4420 1629 544 3669 1770 544 3710 1759 544 45101880 552 4470 1869 554 1100 1750 555 1869 1770 560 2480 1770 561 4370 1670 563 1840 1559 570 1890 1559571 4370 1620 572 4429 1579 573 2119 1809 574 4479 1579 574 1470 1570 596 1859 1759 596 1859 1770 6081509 1570 608 1509 1579 618 1759 1559 623 1479 1570 640 4019 1740 640 1679 1770 640 1659 1770 643 22801759 643 2290 759 649 1950 1559 650 2259 1759 656 1819 1779 679 1550 1579 679 1400 1729 682 15291729 682 909 1579 682 909 1520 682 909 1559 683 1300 1559 690 2130 1759 699 1500 1729 703 1059 1750718 1540 1579 736 1830 1770 736 1830 1759 740 1790 1759 746 2140 1759 751 2109 1770 758 1440 1579 767909 1529 768 4030 1740 768 3139 1759 768 3130 1770 774 1520 1729 775 1320 1759 776 2800 1550 777 7001559 782 1320 1559 784 2789 1559 784 1940 1559 792 2430 1759 803 1709 1559 803 909 1570 803 1800 1559808 919 1650 809 2440 1770 810 1400 1740 810 1210 1750 810 1210 1759 810 1320 1750 829 1969 1779 8291959 1770 831 919 1759 831 2190 1770 851 1790 1550 864 1819 1770 875 2180 1770 895 1100 1750 896 40301720 912 1809 1770 929 1930 1559 932 1790 1770 938 909 1759 938 1509 1729 40 909 1590 948 2009 1770952 2019 1779 955 1520 1579 958 919 1600 969 2019 1759 1010 2000 1770 1022 919 1640 1023 1080 1750

378-th viewpoint

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1 1150 1640 1 1289 1550 1 909 1640 2 909 1500 3 1100 1740 3 2050 1750 3 1050 1629 5 919 1479 7 1180 15507 1169 1479 7 1059 1609 7 909 1679 7 1160 1479 7 989 1450 9 4329 1690 14 1119 1740 14 919 1690 16 13501550 16 919 1609 17 1000 1450 19 1100 1629 19 1010 1550 19 909 1520 19 1000 1550 21 909 1659 22 43701640 23 989 1500 28 919 1700 31 1029 1500 32 1360 1550 33 919 1590 33 909 1440 5 20 1600 35 909 167035 909 1540 36 1239 1550 37 919 1459 38 919 1470 38 1270 1550 41 1260 1550 42 1050 1740 42 1020 1740 421010 1740 42 989 1750 42 1229 1550 43 1040 1740 43 1000 1740 44 1130 1740 44 1090 1500 45 919 1570 47909 1559 47 1160 1550 48 1150 1740 48 919 1720 50 919 1709 51 909 1550 51 919 1579 52 1360 1740 56 11391740 61 1090 1490 61 1150 1550 62 1090 1509 63 1239 1740 7 090 1470 111 1130 1550 114 1119 1509 1141130 1520 135 1100 1529 139 1090 1479 141 919 1490 141 1189 1550 145 1220 1550 160 1160 1740 160 14901720 160 950 1750 162 909 1509 163 1090 1529 168 1339 1550 168 1470 1720 168 1100 1490 170 919 1620170 919 1600 170 909 1529 170 1389 1740 170 1090 1550 170 1029 1740 170 1320 1559 170 1279 1550 1701090 1740 170 1250 1550 170 909 1650 171 300 1550 171 1110 1550 171 1100 1550 171 1000 1740 171 11101729 172 979 1750 174 1090 1459 175 1220 1740 175 1169 1550 180 1139 1550 181 1450 1559 182 1169 1529186 1229 1740 190 1450 1709 190 1260 1740 190 1250 1740 192 1169 1740 199 1100 1520 224 1370 1550 2341119 1550 257 1189 1740 258 1310 1550 259 1200 1750 260 1329 1550 262 1090 1440 262 1080 1450 263 9191500 275 909 1409 91 1090 1540 291 1200 1559 296 970 1750 299 1440 1729 304 959 1750 314 1450 1720 3201180 1750 322 1529 1729 322 1529 1720 326 1200 1550 327 1100 1540 366 1100 1509 370 1479 1729 376 9091759 418 1520 1720 422 1090 1509 423 1409 1729 423 1409 1720 425 1300 1750 426 1189 1750 426 909 1750426 1279 1740 426 1210 1550 426 919 1759 427 1189 1559 427 1279 1750 427 1300 1740 428 970 759 301329 1740 431 1270 1740 442 1350 1740 442 1339 1729 448 940 1750 450 1310 1740 451 1420 1720 459 13101750 467 1389 1550 469 1500 1729 480 940 1759 496 919 1729 504 909 1729 504 909 1740 506 1329 1729 5091339 1740 509 1379 1740 512 4420 1880 512 4310 1400 512 1690 1759 512 2680 1750 512 3780 1529 512 37803110 512 3430 1750 513 2540 1759 515 1000 1400 515 909 1389 516 3219 750 16 3150 1750 516 2209 1550516 2140 1540 518 2380 1750 519 919 1389 520 4239 1990 523 1490 1559 526 2739 1540 528 4030 1690 5284030 1740 528 4420 1759 530 1479 1559 530 989 1400 532 4429 1529 536 4279 1830 537 4250 1930 538 44201640 539 4420 1709 540 4370 1529 541 4420 1590 544 3850 1740 544 3850 1790 544 1679 1540 546 909 1629549 2019 1550 553 2140 1759 553 2140 1770 554 1890 550 555 2200 1750 556 1720 1550 560 2240 1759 5634289 1609 571 4329 1570 574 4370 1579 592 2600 1529 600 4289 1890 600 4250 1880 601 4310 1869 613 20091759 616 1819 1550 634 4300 1659 639 4320 1629 645 2450 1759 645 2450 1779 651 1090 1420 652 1950 1550658 2650 1550 665 4270 1770 666 1420 1570 669 4270 1709 669 4289 1779 673 1930 1550 674 1400 1570 6741969 1559 677 1429 1720 79 1400 1720 682 1969 1779 683 1429 1729 683 909 1420 687 1059 1740 698 42891720 699 1389 1729 704 2630 1540 708 2800 1579 729 1540 1570 731 1429 1570 736 930 1759 746 1370 1740748 2040 1770 783 1090 1429 787 2290 1759 792 1809 1770 796 1869 1770 806 1969 1770 808 1779 1550 8081869 1759 825 2100 1759 836 1790 1550 840 2800 1550 840 1800 1750 858 1400 1729 871 909 1429 876 20801759 882 1289 1750 901 1520 1729 904 2800 1559 904 1809 1759 906 1509 1729 908 1800 1759 928 1180 1740930 2280 1770 930 2280 1750 931 1289 1740 931 1320 1750 934 1969 1759 935 1409 1570 937 1389 1550 9381069 1740 938 930 1750 938 1320 1740 938 1210 1750 939 1200 1740 944 950 1759 944 1819 1759 959 10801740 966 1210 1740 968 1809 1779 970 1500 1720 978 1509 1559 979 1400 559 997 1520 1570 1010 959 17591020 1379 1550 1023 919 1629

8-th viewpoint

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1 1420 1239 3 1590 830 3 1540 830 3 1490 839 4 970 800 8 1450 1220 10 970 1389 15 1420 720 22 1440 91923 1440 850 27 940 1270 28 970 1000 31 1020 729 31 1429 729 32 1470 1220 32 940 1300 33 1119 729 33 970900 33 959 850 33 970 1360 33 959 1090 34 970 1370 34 1590 909 34 1520 919 35 1040 729 35 970 1139 41970 1409 42 1509 919 42 970 1150 42 959 979 42 959 839 42 970 1239 42 970 909 42 180 729 42 1000 729 421150 729 42 1130 729 43 1260 729 43 1409 1239 44 959 880 44 970 1119 45 1010 729 46 959 869 46 1389 123946 940 1260 46 959 1110 48 1210 1180 48 959 770 49 970 1229 49 940 1279 50 970 1400 52 959 989 53 12501180 53 1000 729 58 1160 729 60 1379 1239 62 1289 770 63 1400 729 67 970 1020 80 970 1329 82 1229 118086 1370 760 96 959 760 99 1459 739 107 1360 1239 111 270 29 126 1289 760 127 1300 729 128 959 1069 128970 1160 128 970 919 129 1189 729 130 979 720 136 959 750 146 970 779 160 1529 750 160 1169 729 160 9401310 160 970 1500 162 1029 729 162 1500 919 163 1450 739 163 1350 1239 166 1360 750 167 1400 1239 168959 1000 168 959 1329 168 1220 1180 168 970 1350 169 959 970 170 1239 1180 170 1429 1239 170 1339 1239170 1110 729 170 1090 729 170 970 1130 170 959 1100 170 959 1080 170 970 1010 170 959 860 170 959 889170 979 1479 171 970 810 172 970 789 172 970 1379 174 1289 729 174 1139 729 176 1459 1220 177 1379 729178 1289 1220 179 1250 729 180 1260 1200 185 1389 729 186 1270 1220 186 1239 729 186 1329 720 186 13701239 186 1310 720 191 1409 729 192 940 1320 206 1350 729 208 1479 1220 217 1339 750 225 1550 930 2251520 750 234 1339 729 235 1370 729 238 1279 729 238 1360 729 256 959 1050 256 59 1189 256 959 940 256970 940 256 970 1040 258 959 959 259 959 810 260 1440 1239 262 1210 729 280 1229 729 289 1540 739 298959 739 299 959 819 311 1440 739 357 1329 1250 368 1320 720 370 1279 1220 371 1579 739 373 1260 1189378 1270 1210 382 1360 760 396 1329 1229 396 1329 1239 404 1320 1229 412 1479 739 416 970 1470 416 9591180 418 1310 1220 418 970 1189 420 1310 1229 421 970 429 424 970 1169 426 970 1050 426 1479 750 426970 930 426 970 950 426 1470 739 426 959 950 427 1200 720 434 1320 1220 447 959 729 481 1509 750 490 9591440 490 1540 729 496 1329 729 498 1300 1220 507 950 1320 512 1160 1189 537 1339 979 538 1310 930 5431389 950 554 1150 1189 567 1389 869 571 1360 889 606 1279 760 640 959 1200 658 1520 1189 681 1500 750682 1470 919 682 1529 919 682 260 1180 682 970 1029 682 1450 1229 686 1429 720 686 1220 729 686 11891189 687 970 1520 687 1450 919 688 1540 1189 735 940 1289 744 1509 1220 744 1500 1200 767 959 830 768970 1059 770 1210 720 775 1459 919 777 1550 739 793 1490 750 802 1579 909 806 1220 720 808 1490 739 810959 1059 865 1529 1189 872 959 1450 894 1069 729 895 970 729 898 1180 1189 898 1570 909 911 1559 739916 970 450 933 1550 909 935 1479 919 937 1059 729 938 1069 739 938 1559 909 938 1540 919 938 979 1459938 1200 1189 938 1490 919 939 1570 739 939 1169 1189 948 1500 739 952 1490 1220 959 959 1220 978 15091189 988 1550 729 991 959 1210 1000 1509 1210 1002 970 1420 1008 1500 1220 1019 970 1180 1019 1050 7291022 959 1339 1023 1100 729 1023 1080 729

360-th viewpoint

b-4

Fig. 7. Examples of matching M2T local map descriptors. (a) The local maps and the viewpoint trajectories. The top panel shows a collection of local

maps (blue dots), the viewpoint trajectory (purple points), as well as the “unique” viewpoints planned by our framework (blue points). The bottom panel

shows the sequence of planned viewpoints in the xyt space (t: viewpoint ID). (b) Matching M2T descriptors between a relevant map pair (first and second

columns) and between an irrelevant map pair (third and fourth columns). The relevant and irrelevant pairs are also indicated by purple line segments in

Fig. 7a. For each column, the matched visual words are highlighted in red. Each row shows from top to bottom, appearance word wa, pose words wx;wy,

and the text description fhwx;wy;waig.