264 
Fishery Bulletin 114(3) 
Table 1 
Summary of environmental data and measurements of sea scallops (Placopecten magellanicus) derived from photographs 
taken with an underwater camera within an autonomous underwater vehicle (AUV) during surveys within the Long Island 
(LI) and New York Bight (NYB) areas. 
AUV 
survey 
site 
Latitude 
(°) 
Longitude 
n 
Bottom 
Water water Survey 
depth temperature distance 
(m) (“O (m) 
Survey 
area 
(m^) 
Number 
of bottom 
images 
Number 
of 
scallops 
Scallop 
density 
scallops/m^) 
Mean 
shell 
height 
(mm) 
Mean 
meat 
weight 
(g/scallop) 
Long Island 
LIl 
40.5529 
-72.5899 
41.9 
8.8 
15,904 
26,834 
14,742 
2,172 
0.081 
121.1 
37.0 
area 
LI2 
40.5503 
-72.5872 
43.5 
8.8 
3,015 
5,280 
2,387 
894 
0.169 
119.6 
35.2 
LI3 
40.4712 
-72.5294 
45.4 
8.5 
10,337 
18,135 
8,065 
3,706 
0.204 
103.7 
23.7 
LI4 
40.3449 
-72.8817 
45.8 
8.6 
12,280 
21,689 
9,992 
1,365 
0.063 
101.4 
21.8 
LI5 
40.3111 
-73.0825 
42.1 
8.9 
10,773 
19,085 
8,338 
1,850 
0.097 
102.8 
23.6 
LI6 
40.3961 
-73.3818 
31.7 
11.9 
14,211 
23,473 
11,329 
422 
0.018 
100.0 
25.3 
LI7 
40.3551 
-73.3483 
33.7 
10.8 
12,271 
20,384 
10,163 
227 
0.011 
112.6 
33.5 
LIS 
40.3213 
-73.2749 
35.3 
9.8 
12,154 
21,328 
9,780 
1,403 
0.066 
104.2 
26.5 
Mean 
Mean 
Total 
Total 
Total 
Total 
Mean 
Mean 
Mean 
Summary 
39.3 
9.6 
90,945 
156,208 
74,796 
12,039 
0.077 
107.7 
27.3 
New York 
Bight area 
NYBl 
40.2368 
-73.7828 
35.5 
11.0 
10,398 
17,684 
9,141 
82 
0.005 
106.4 
28.4 
NYB2 
40.0279 
-73.8078 
27.7 
11.5 
12,511 
21,000 
9,523 
16 
0.001 
112.5 
37.0 
NYB3 
39.5942 
-73.5386 
41.5 
8.4 
11,691 
19,079 
9,544 
508 
0.027 
116.4 
35.5 
NYB4 
39.8873 
-73.6105 
32.8 
9.1 
12,181 
19,069 
9,479 
212 
0.011 
130.2 
51.4 
NYB5 
39.9019 
-73.5318 
36.9 
9.2 
11,752 
20,440 
9,425 
801 
0.039 
117.2 
36.7 
NYB6 
39.9793 
-73.6383 
37.9 
9.4 
12,133 
20,036 
9,281 
331 
0.017 
119.7 
37.7 
NYB7 
39.2332 
-73.6423 
46.6 
8.0 
12,196 
18,228 
12,068 
506 
0.028 
121.0 
35.9 
NYB8 
39.3621 
-73.5099 
50.7 
8.2 
12,149 
20,006 
9,572 
140 
0.007 
120.6 
37.2 
NYB9 
39.3266 
-73.7925 
40.0 
9.5 
13,086 
21,704 
10,950 
523 
0.024 
128.9 
45.8 
NYBIO 
39.1000 
-74.4470 
21.9 
11.6 
11,791 
19,740 
9,170 
3 
<0.001 
92.2 
23.3 
NYBll 
39.1431 
-74.0397 
38.7 
10.0 
13,499 
23,559 
7,050 
1 
<0.001 
86.8 
14.0 
NYB12 
39.1431 
-74.0397 
28.2 
11.6 
12,207 
20,700 
7,345 
0 
0 
- 
- 
NYB13 
39.4200 
-74.0267 
20.1 
12.7 
8,292 
13,494 
6,285 
0 
0 
- 
- 
NYB14 
39.0950 
-73.984 
42.0 
9.2 
12,331 
21,334 
9,437 
90 
0.004 
126.7 
43.6 
Mean 
Mean 
Total 
Total 
Total 
Total 
Mean 
Mean 
Mean 
Summary 
36.2 
9.9 
166,218 
276,073 
128,270 
3,213 
0.012 
120.8 
38.9 
from a set of images taken within a test tank described 
below show that scale distortions in relation to the im- 
age center were less than 2 pixels over 65% of the full 
frame (Fig. 2). Each image had a metadata header that 
contained navigation (i.e. latitude, longitude, altitude, 
depth, etc.) and near seafloor environmental conditions 
corresponding to the capture time of the photo from the 
sensors of the AUV. 
Calibration of the camera system was conducted 
with photos gathered with the AUV camera system in 
a saltwater tank. The calibration process entailed a se- 
quence of images of a standard planar checkerboard 
pattern viewed from multiple angles and processed by 
using the Camera Calibration Toolbox for Matlab de- 
veloped by Bouguet (2011) and based on the models 
of Zhang (2000) and Heikkila and Silven (1997). The 
analysis (Fig. 2) provided a direct quantitative measure 
of the camera field of view (FOV) and showed that min- 
imal radial and tangential lens distortion affected the 
camera. These results agreed closely with previously 
published results from the same AUV and camera sys- 
tems (Gudmundsson, 2012; Singh et al. 2013; Singh et 
ah, 2014 ) and were further confirmed by independent 
analysis of the images (Rzhanov'^). 
The camera calibration (Fig. 2) showed the spatial 
pattern as that of the AUV camera, namely the impact 
of spherical and tangential lens distortion at each pix- 
el point within the full image frame. Most of the area 
within each image (65%) exhibits distortion of less than 
2 pixels (~5 mm in ground distance), except for the up- 
per and lower left corners, which have 7 or more pixels 
of displacement (~16 mm in on the ground distance), 
representing a maximum error of <1% of total pixel 
width. These distortions will have generally less than 
1% impact on the estimation of scallop shell height be- 
cause the average distortion of 1-2 pixels translates to 
^ Rzhanov, Y. 2015. Personal commun. Center for Coastal 
and Ocean Mapping, Univ. New Hampshire, Durham, NH 
03824. 
