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| 5 | <title>square2quadrilateral.pro (SAXO Documentation Assistant)</title> |
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| 45 | <table border="0" cellpadding="0" cellspacing="0" width="98%" bgcolor="#F0F0FF" valign="bottom"> |
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| 46 | <tr> |
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| 47 | <td width="10%"> |
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| 48 | <a href="spl_keep_mean.html"><img src="./../prev.gif" border="0" alt="Previous"></a></td> |
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| 49 | <td width="80%" align="center" valign="center"> |
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| 50 | <font size=-1><i>SAXO Documentation Assistant</i>: <a href="./../home.html">Overview</a></font></td> |
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| 51 | <td width="10%" align="right"> |
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| 52 | <a href=""><img src="./../next.gif" border="0" alt="Next"></a></td> |
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| 53 | </tr> |
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| 54 | </table> |
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| 55 | |
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| 56 | |
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| 57 | <h1><font size="-2">Interpolation/</font></h1> |
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| 58 | <h2>square2quadrilateral.pro</h2> |
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| 59 | |
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| 60 | <dl> |
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| 61 | </dl> |
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| 62 | |
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| 63 | |
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| 64 | warm (or map) a unit square onto an arbitrary quadrilateral |
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| 65 | according to the 4-point correspondences: |
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| 66 | - (0,0) -> (x0,y0) |
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| 67 | - (1,0) -> (x1,y1) |
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| 68 | - (1,1) -> (x2,y2) |
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| 69 | - (0,1) -> (x3,y3) |
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| 70 | |
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| 71 | The mapping is done using perspective transformation which preserve |
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| 72 | lines in all orientations and permit quadrilateral to quadrilateral |
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| 73 | mappings. see ref. below. |
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| 74 | |
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| 75 | |
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| 76 | |
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| 77 | |
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| 78 | |
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| 79 | <a name="#_square2quadrilateral"></a> |
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| 80 | |
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| 81 | <h2>square2quadrilateral <font size="-1" color="#006633"> |
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| 82 | Picture, Grid |
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| 83 | </font></h2> |
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| 84 | |
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| 85 | <p><font face="Courier"><i>result = </i>square2quadrilateral(<i><a href="#_square2quadrilateral_keyword_x0in">x0in</a>, <a href="#_square2quadrilateral_keyword_y0in">y0in</a>, <a href="#_square2quadrilateral_keyword_x1in">x1in</a>, <a href="#_square2quadrilateral_keyword_y1in">y1in</a>, <a href="#_square2quadrilateral_keyword_x2in">x2in</a>, <a href="#_square2quadrilateral_keyword_y2in">y2in</a>, <a href="#_square2quadrilateral_keyword_x3in">x3in</a>, <a href="#_square2quadrilateral_keyword_y3in">y3in</a>[, <a href="#_square2quadrilateral_keyword_xxin">xxin</a>][, <a href="#_square2quadrilateral_keyword_yyin">yyin</a>]</i>, <a href="#_square2quadrilateral_keyword_DOUBLE">DOUBLE</a>=<i>salar 0 or 1</i>)</font></p> |
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| 86 | |
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| 87 | |
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| 88 | |
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| 89 | |
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| 90 | <h3>Return value</h3> |
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| 91 | (2,n) array: the new coordinates (xout,yout) of the (xin,yin) |
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| 92 | point(s) after mapping. |
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| 93 | If xin is a scalar, then n is equal to the number of elements of |
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| 94 | x0. If xin is an array , then n is equal to the number of |
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| 95 | elements of xin. |
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| 96 | If xin and yin are omitted, <a href="..//Interpolation/square2quadrilateral.html">square2quadrilateral</a> returns the |
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| 97 | matrix A which is used for the inverse transformation. |
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| 98 | |
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| 99 | |
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| 100 | |
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| 101 | <h3>Parameters</h3> |
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| 102 | |
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| 103 | |
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| 104 | <a name="#_square2quadrilateral_keyword_x0in"></a> |
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| 105 | <h4>x0in |
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| 106 | <font size="-1" color="#006633">in</font> |
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| 107 | |
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| 108 | |
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| 109 | <font size="-1" color="#006633">required</font> |
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| 110 | |
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| 111 | |
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| 112 | |
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| 113 | |
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| 114 | </h4> |
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| 115 | |
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| 116 | |
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| 117 | |
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| 118 | |
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| 119 | <a name="#_square2quadrilateral_keyword_y0in"></a> |
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| 120 | <h4>y0in |
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| 121 | <font size="-1" color="#006633">in</font> |
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| 122 | |
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| 123 | |
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| 124 | <font size="-1" color="#006633">required</font> |
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| 125 | |
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| 126 | |
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| 127 | |
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| 128 | |
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| 129 | </h4> |
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| 130 | |
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| 131 | |
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| 132 | |
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| 133 | |
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| 134 | <a name="#_square2quadrilateral_keyword_x1in"></a> |
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| 135 | <h4>x1in |
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| 136 | <font size="-1" color="#006633">in</font> |
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| 137 | |
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| 138 | |
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| 139 | <font size="-1" color="#006633">required</font> |
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| 140 | |
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| 141 | |
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| 142 | |
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| 143 | |
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| 144 | </h4> |
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| 145 | |
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| 146 | |
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| 147 | |
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| 148 | |
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| 149 | <a name="#_square2quadrilateral_keyword_y1in"></a> |
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| 150 | <h4>y1in |
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| 151 | <font size="-1" color="#006633">in</font> |
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| 152 | |
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| 153 | |
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| 154 | <font size="-1" color="#006633">required</font> |
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| 155 | |
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| 156 | |
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| 157 | |
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| 158 | |
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| 159 | </h4> |
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| 160 | |
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| 161 | |
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| 162 | |
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| 163 | |
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| 164 | <a name="#_square2quadrilateral_keyword_x2in"></a> |
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| 165 | <h4>x2in |
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| 166 | <font size="-1" color="#006633">in</font> |
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| 167 | |
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| 168 | |
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| 169 | <font size="-1" color="#006633">required</font> |
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| 170 | |
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| 171 | |
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| 172 | |
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| 173 | |
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| 174 | </h4> |
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| 175 | |
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| 176 | |
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| 177 | |
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| 178 | |
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| 179 | <a name="#_square2quadrilateral_keyword_y2in"></a> |
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| 180 | <h4>y2in |
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| 181 | <font size="-1" color="#006633">in</font> |
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| 182 | |
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| 183 | |
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| 184 | <font size="-1" color="#006633">required</font> |
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| 185 | |
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| 186 | |
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| 187 | |
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| 188 | |
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| 189 | </h4> |
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| 190 | |
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| 191 | |
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| 192 | |
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| 193 | |
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| 194 | <a name="#_square2quadrilateral_keyword_x3in"></a> |
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| 195 | <h4>x3in |
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| 196 | <font size="-1" color="#006633">in</font> |
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| 197 | |
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| 198 | |
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| 199 | <font size="-1" color="#006633">required</font> |
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| 200 | |
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| 201 | |
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| 202 | |
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| 203 | |
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| 204 | </h4> |
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| 205 | |
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| 206 | |
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| 207 | |
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| 208 | |
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| 209 | <a name="#_square2quadrilateral_keyword_y3in"></a> |
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| 210 | <h4>y3in |
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| 211 | <font size="-1" color="#006633">in</font> |
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| 212 | |
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| 213 | |
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| 214 | <font size="-1" color="#006633">required</font> |
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| 215 | |
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| 216 | |
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| 217 | |
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| 218 | |
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| 219 | </h4> |
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| 220 | |
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| 221 | |
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| 222 | the coordinates of the quadrilateral (see above for correspondence with the |
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| 223 | unit square). |
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| 224 | Can be scalar or array. |
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| 225 | (x0,y0), (x1,y1), (x2,y2) and (x3,y3) are given in the anticlockwise order. |
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| 226 | |
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| 227 | |
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| 228 | |
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| 229 | <a name="#_square2quadrilateral_keyword_xxin"></a> |
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| 230 | <h4>xxin |
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| 231 | <font size="-1" color="#006633">in</font> |
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| 232 | |
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| 233 | <font size="-1" color="#006633">optional</font> |
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| 234 | |
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| 235 | |
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| 236 | |
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| 237 | |
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| 238 | |
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| 239 | </h4> |
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| 240 | |
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| 241 | |
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| 242 | first coordinates of the point(s) for which we want to do the mapping. |
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| 243 | |
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| 244 | |
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| 245 | <a name="#_square2quadrilateral_keyword_yyin"></a> |
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| 246 | <h4>yyin |
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| 247 | <font size="-1" color="#006633">in</font> |
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| 248 | |
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| 249 | <font size="-1" color="#006633">optional</font> |
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| 250 | |
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| 251 | |
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| 252 | |
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| 253 | |
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| 254 | |
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| 255 | </h4> |
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| 256 | |
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| 257 | |
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| 258 | second coordinates of the point(s) for which we want to do the mapping. |
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| 259 | |
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| 260 | |
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| 261 | |
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| 262 | |
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| 263 | |
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| 264 | <h3>Keywords</h3> |
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| 265 | |
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| 266 | |
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| 267 | <a name="#_square2quadrilateral_keyword_DOUBLE"></a> |
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| 268 | <h4>DOUBLE |
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| 269 | |
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| 270 | |
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| 271 | |
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| 272 | |
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| 273 | |
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| 274 | <font size="-1" color="#006633">type:</font> <font size="-1" color="#006633"><i>salar 0 or 1</i></font> |
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| 275 | <font size="-1" color="#006633">default:</font> <font size="-1" color="#006633"><i>0</i></font> |
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| 276 | |
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| 277 | </h4> |
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| 278 | |
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| 279 | |
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| 280 | activate to perform double precision computation |
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| 281 | |
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| 282 | |
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| 283 | |
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| 284 | |
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| 285 | <h3>Examples</h3><pre> |
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| 286 | |
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| 287 | IDL> splot,[0,5],[0,3],/nodata,xstyle=1,ystyle=1 |
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| 288 | IDL> tracegrille, findgen(11)*.1, findgen(11)*.1,color=indgen(12)*20 |
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| 289 | IDL> xin = (findgen(11)*.1)#replicate(1, 11) |
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| 290 | IDL> yin = replicate(1, 11)#(findgen(11)*.1) |
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| 291 | IDL> out = square2quadrilateral(2,1,3,0,5,1,2,3, xin, yin) |
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| 292 | IDL> tracegrille, reform(out[0,*],11,11), reform(out[1,*],11,11),color=indgen(12)*20 |
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| 293 | |
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| 294 | </pre><h3>Version history</h3> |
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| 295 | |
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| 296 | <h4>Version</h4> |
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| 297 | $Id: square2quadrilateral.pro 372 2008-08-08 12:31:53Z pinsard $ |
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| 298 | |
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| 299 | <h4>History</h4> |
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| 300 | Sebastien Masson (smasson@lodyc.jussieu.fr) |
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| 301 | - August 2003 |
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| 302 | Based on "Digital Image Warping" by G. Wolberg |
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| 303 | IEEE Computer Society Press, Los Alamitos, California |
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| 304 | Chapter 3, see p 52-56 |
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| 305 | |
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| 306 | |
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| 307 | |
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| 308 | <h3>Known issues</h3> |
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| 309 | |
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| 310 | |
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| 311 | |
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| 312 | <h4>Restrictions</h4> |
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| 313 | I think degenerated quadrilateral (e.g. flat of twisted) is not work. |
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| 314 | This has to be tested. |
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| 315 | |
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| 323 | |
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| 324 | |
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| 325 | <font size="-3"><p> </p></font> |
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| 326 | <hr size="1" color="#CCCCCC"/> |
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| 327 | |
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| 330 | |
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| 331 | <p><font color="gray" size="-3"> Produced by IDLdoc 2.0.</font></p> |
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| 332 | |
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| 333 | </body> |
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| 334 | </html> |
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