Fig. 1. Applications of straight line segment detection. (a) Remote sensing image analysis^{[<xref ref-type="bibr" rid="b13">13</xref>-<xref ref-type="bibr" rid="b15">15</xref>]}; (b) image matching^{[<xref ref-type="bibr" rid="b16">16</xref>]}; (c) vanishing point detection^{[<xref ref-type="bibr" rid="b17">17</xref>]}; (d) object detection<sup>[<xref ref-type="bibr" rid="b18">18</

Fig. 2. Problem of direct straight line segment detection on gray-value images. (a) Test image; (b) detection result of CannyLines algorithm^{[<xref ref-type="bibr" rid="b20">20</xref>]} (no straight line segment is detected); (c) detection result of proposed algorithm

Fig. 3. Flow chart of straight line segment detection algorithm for color images

Fig. 4. Detection results of different algorithms on the 25th image of York City Straight Line Database.(a) Image # P1020867 (640&#x000D7;480); (b) ground truth;(c) ours; (d) CannyLines^{[<xref ref-type="bibr" rid="b20">20</xref>]}; (e) EDLines^{[<xref ref-type="bibr" rid="b6">6</xref>]}; (f) ELSDc^{[<xref ref-type="bibr" rid="b22">22</xref>]}; (g) Linelet<sup>[<xref ref-type="bibr" rid="b11">

Fig. 5. Detection results of different algorithms on the 42th image of the York City Straight Line Database. (a) Image # P1040814 (640&#x000D7;480); (b) ground truth; (c) ours; (d) CannyLines^{[<xref ref-type="bibr" rid="b20">20</xref>]}; (e) EDLines^{[<xref ref-type="bibr" rid="b6">6</xref>]}; (f) ELSDc^{[<xref ref-type="bibr" rid="b22">22</xref>]}; (g) Linelet<sup>[<xref ref-type="bibr" rid="b1

Table 1. Objective evaluation results of different algorithms on YorkUrbanDB database