Rank: 360 based on 233 downloads (last 30 days) and 15 files submitted

Tristan Ursell

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Company/University: Stanford University

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Professional Interests:: physics, biophysics, genetic algorithms

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Files Posted by Tristan					View all 1 - 5 of 15
Updated		File	Tags	Downloads (last 30 days)	Comments	Rating
12 Feb 2013		Adaptive Colormap Function Creates a Colormap Specific to Data Easily design and fit a colormap to the values in your data! Author: Tristan Ursell	color, red, blue, green, colormap, map	14	1
16 Nov 2012		Image Noise Reduction by Local Statistics Reduce image noise by measuring local pixel statistics and remapping intensities. Author: Tristan Ursell	relative, deviation, statistics, image processing, reduction, processing	57	1
09 Nov 2012		Active Figure Zoom for Selecting Points Select points at a user-specified zoom level that moves around the image as you click. Author: Tristan Ursell	points, ginput, getrect, figure, line, zoom	6	0
30 Aug 2012		Connected Component Analysis on an Undirected Graph Connected component analysis on undirected graphs, with thresholding and connectivity constraints. Author: Tristan Ursell	graph, theory, undirected, connected, connection, component	13	0
04 Apr 2012		Create a Simulated Image of Diffraction Limited Spots with Noise Create images with diffraction-limited spots of varying size and intensity, with noise. Author: Tristan Ursell	image, create, creation, spot, region, centroid	9	0

Comments and Ratings by Tristan		View all 1 - 5 of 11
Updated	File	Comments	Rating
14 Dec 2012	Adaptive Colormap Function Creates a Colormap Specific to Data Easily design and fit a colormap to the values in your data! Author: Tristan Ursell	I'll fix the typos in the description soon.
15 Nov 2012	Image Noise Reduction by Local Statistics Reduce image noise by measuring local pixel statistics and remapping intensities. Author: Tristan Ursell	if you like this function, please consider rating it! (if you don't, please tell me why)
23 Mar 2012	Copy Files in Batches using Search Terms Copy files matching search terms, from sub-directories matching search terms into a new directory. Author: Tristan Ursell	@Jan, thanks. I 'char'-ed it just to be safe :)
15 Mar 2012	Connect Randomly Ordered 2D Points into a Minimal Nearest-Neighbor Closed Contour Connects randomly ordered 2D points into a minimal nearest neighbor contour. Author: Tristan Ursell	Here's a partial fix of the problem you mention Catherine. There is no general solution to your problem without solving the TSP -- which is NP hard :) There is however another level of fix that would require time to write, where you sample N-points ahead in the contour and search exhaustively for the shortest local N-path. That would likely get rid of most crossings and
13 Mar 2012	Connect Randomly Ordered 2D Points into a Minimal Nearest-Neighbor Closed Contour Connects randomly ordered 2D points into a minimal nearest neighbor contour. Author: Tristan Ursell	Hi Catherine -- I'll be away for a few days, but yes, I was going to add a feature like that, and will try to get to it this week. Interesting that you bring up shorelines, which are fractals, and fractals, having no absolute scale do not have a definitely shortest contour. I realize that for your example its discrete and hence there is some shortest path, but it's still really hard to connect such structures because they tend to have this scale free property.

Comments and Ratings on Tristan's Files			View all 1 - 5 of 25
Updated	File	Comment by	Comments	Rating
10 Apr 2013	Connect Randomly Ordered 2D Points into a Minimal Nearest-Neighbor Closed Contour Connects randomly ordered 2D points into a minimal nearest neighbor contour. Author: Tristan Ursell	Cheng, Jay	Awesome work! It works on my data set while built in poly2cw does not. my x=[121 121 121 121 121 121 121 121 121 121 121 121 121 121 121 121 121 122 122 122 122 122 122 122 122 122 123 123 123 123 123 124 124 124 125 125 125 125 125 125 125 125 126 126 126 127 127 127 128 128 128 128 129 129 129 130 130 130 130 131 131 131 131 132 132 133 133 134 134 135 135 136 136 137 137 138 138 139 139 140 140 141 141 142 142 143 143 144 144 145 145 145 145 146 146 147 147 148 148 149 149 150 150 151 151 152 152 153 153 154 154 155 155 156 156 157 157 158 158 159 159 160 160 161 161 162 162 163 163 164 164 165 165 166 166 167 167 168 168 169 169 170 170 171 171 171 171 172 172 173 173 174 174 175 175 175 175 175 175 176 176 176 176 177 177 178 178 179 179 180 180 181 181 182 182 183 183 184 184 184 184 185 185 186 186 187 187 188 188 189 189 190 190 190 190 190 191 191 191 191 191 191 191 191 191 192 192 192 192 192 192 192 192 192 192 192 192 192 193 193 193 193 193 193 193 ]; y=[121 121 121 121 121 121 121 121 121 121 121 121 121 121 121 121 121 122 122 122 122 122 122 122 122 122 123 123 123 123 123 124 124 124 125 125 125 125 125 125 125 125 126 126 126 127 127 127 128 128 128 128 129 129 129 130 130 130 130 131 131 131 131 132 132 133 133 134 134 135 135 136 136 137 137 138 138 139 139 140 140 141 141 142 142 143 143 144 144 145 145 145 145 146 146 147 147 148 148 149 149 150 150 151 151 152 152 153 153 154 154 155 155 156 156 157 157 158 158 159 159 160 160 161 161 162 162 163 163 164 164 165 165 166 166 167 167 168 168 169 169 170 170 171 171 171 171 172 172 173 173 174 174 175 175 175 175 175 175 176 176 176 176 177 177 178 178 179 179 180 180 181 181 182 182 183 183 184 184 184 184 185 185 186 186 187 187 188 188 189 189 190 190 190 190 190 191 191 191 191 191 191 191 191 191 192 192 192 192 192 192 192 192 192 192 192 192 192 193 193 193 193 193 193 193 ]; Maybe I misunderstood poly2cw. But what ever, your points2contour can sort my coordinates into correct order! Many thanks!
14 Dec 2012	Adaptive Colormap Function Creates a Colormap Specific to Data Easily design and fit a colormap to the values in your data! Author: Tristan Ursell	Ursell, Tristan	I'll fix the typos in the description soon.
15 Nov 2012	Image Noise Reduction by Local Statistics Reduce image noise by measuring local pixel statistics and remapping intensities. Author: Tristan Ursell	Ursell, Tristan	if you like this function, please consider rating it! (if you don't, please tell me why)
26 Apr 2012	Generate Random Numbers from a 2D Discrete Distribution Random numbers from any 2D discrete probability distribution, at any resolution. Author: Tristan Ursell	Trönnberg, Filip	Wonderful function!!
23 Mar 2012	Copy Files in Batches using Search Terms Copy files matching search terms, from sub-directories matching search terms into a new directory. Author: Tristan Ursell	Ursell, Tristan	@Jan, thanks. I 'char'-ed it just to be safe :)

Top Tags Applied by Tristan	1 - 5 of 170
image, 2d, matrix, noise, custom

Files Tagged by Tristan					View all 1 - 5 of 15
Updated		File	Tags	Downloads (last 30 days)	Comments	Rating
12 Feb 2013		Adaptive Colormap Function Creates a Colormap Specific to Data Easily design and fit a colormap to the values in your data! Author: Tristan Ursell	color, red, blue, green, colormap, map	14	1
16 Nov 2012		Image Noise Reduction by Local Statistics Reduce image noise by measuring local pixel statistics and remapping intensities. Author: Tristan Ursell	relative, deviation, statistics, image processing, reduction, processing	57	1
09 Nov 2012		Active Figure Zoom for Selecting Points Select points at a user-specified zoom level that moves around the image as you click. Author: Tristan Ursell	points, ginput, getrect, figure, line, zoom	6	0
30 Aug 2012		Connected Component Analysis on an Undirected Graph Connected component analysis on undirected graphs, with thresholding and connectivity constraints. Author: Tristan Ursell	graph, theory, undirected, connected, connection, component	13	0
04 Apr 2012		Create a Simulated Image of Diffraction Limited Spots with Noise Create images with diffraction-limited spots of varying size and intensity, with noise. Author: Tristan Ursell	image, create, creation, spot, region, centroid	9	0