How to show the distance between two points?

I have a matrix containing x-y-coordinates of two points. The points are centers of circles I found in my image. 1st & 2nd columns represent the first piont, whereas 3rd & 4th columns represent the other one:

   points =

427.4762  968.9869  436.1298  939.4800
410.3451  531.7527  415.7316  504.8123
289.3263  833.7752  315.2286  847.8880
 32.8322  467.8996   15.9475  456.3964
184.0949  927.8066  187.6726  898.4243
167.1554  801.0665  161.9174  801.4695
 70.6457  803.9617   50.3906  793.8978
187.0649  600.8996  190.2172  559.2566
100.6608  741.2848  113.0292  723.1275
107.4194  407.3231  110.2720  349.0485
145.1516  342.2777  139.1603  349.0192
207.9099  505.1574  210.9875  474.2046
 35.5727  686.9287   25.5995  677.6045
 66.5224  412.8655   60.7199  370.5793
 56.2066  637.5961   44.8846  634.1563
199.3653  466.6608  193.0445  465.6853
218.6190  452.8426  210.9875  474.2046
 81.8380  569.2056   81.4730  564.7555
218.9364  124.3950  213.2326   75.4309
105.9599  779.3439  114.1407  780.7945
 53.9224  524.8930   65.8658  510.9172
 73.6517  658.9759   57.3831  664.3180
 19.9922  548.0229   12.7127  541.9428
231.3526  810.2561  230.0475  834.9254
 68.1422  556.0996   60.2532  567.7775
  9.4267  564.2696   12.7127  541.9428
 10.4302  649.0322   25.3083  632.5705
 13.6125  858.7830   40.8027  860.6428
 50.4056  800.7158   50.3906  793.8978
187.6887  654.8640  159.9689  623.4049
 29.0610  484.5180   57.1913  478.6240
 41.7510  919.2462   65.8827  900.7444
109.4590  842.2688  114.1407  780.7945
 21.4602  223.1551   20.3139  173.5782
 50.5669  770.8235   50.3906  793.8978
 54.4706  598.9854   52.4174  593.4113
 27.5837  323.1575   41.3871  355.3593

Now I'd like to show the distances between the two points of a row in my image. Is it possible to draw a line or an arrow ?

Answer 1

[Matt J]

distances=sqrt( sum( (points(1:2)-points(3:4)).^2 ,2 )  );

Answer 2

[Matt J]

Use the QUIVER command

[Alexander Esser]

the command shows me an arrow on a seperate plot. i want to show ON my image. how?

[Matt J]

Use the HOLD command to freeze the image and then superimpose the quiver plot on top of it.

Answer 3

[Azzi Abdelmalek]

n=size(points,1)
x=points(:,[1 3]);
y=points(:,[2 4]);
hold on;arrayfun(@(t) plot(x(t,:),y(t,:)),1:n)

Answer 4

[Chien Duong]

The plot function work like this x= [1,2]; y=[3,5]. Matlab will plot the point 1,3 with 2,5. So in order to draw the line between two point You can try this:

x = [3,5];
y = [7,2]; 
c=x;
x(1,2)=y(1,1);
y(1,1)=c(1,2);
plot(x,y)