needing help in algorithm
-
I know this way but it is a lot of noise in image and the plus isn't like this : ------------o-------- -----------ooo------- ------------o-------- it is like this : -----------------------o----------- -----------------------o----------- -----------------------o----------- ---------------o o o o O --- o o o o ---------------------o------------ ----------------------o----------- ----------------------o----------- ----------------------o----------- and the most important is that it may rotate . and i dont want to rotate it in a ( for ) I want it to be a speedy algorithm . and i also want to use the long tail of plus , I mean it isn't one pixel . thanks -- modified at 10:19 Thursday 11th May, 2006
To find something like that I recommed correlation. When you find your first red pixel, you sum the multiplication of all of the pixels in your defined "plus" with the ones in the appropriate location in the image. Since your image is noisy your defined "plus" needs to be thicker than a single pixel width. Once you get a total sum that exceeds a specified threshold, you declare that a "plus" has been found. Since you have to deal with rotations, the appropriate locations for the multiplies will have to be computed taking different rotations into account. This will increase your processing time significantly. To reduce the number of iterations, once you find the first pixel you know that all other pixels will be right or down from there, assuming the origin is in the top left corner. -- modified at 10:29 Thursday 11th May, 2006
-
I know this way but it is a lot of noise in image and the plus isn't like this : ------------o-------- -----------ooo------- ------------o-------- it is like this : -----------------------o----------- -----------------------o----------- -----------------------o----------- ---------------o o o o O --- o o o o ---------------------o------------ ----------------------o----------- ----------------------o----------- ----------------------o----------- and the most important is that it may rotate . and i dont want to rotate it in a ( for ) I want it to be a speedy algorithm . and i also want to use the long tail of plus , I mean it isn't one pixel . thanks -- modified at 10:19 Thursday 11th May, 2006
You can use 2D-fft (or 2D convolution/correlation). It will work also if there is a rotation on the plus (i.e. there is only a phase rotation) or if there is a scale factor (i.e. the ratio between frequency amplitudes remains constant),..... but they aren't
V_shr wrote:
speedy algorithm
If you want a good and fast way ,probally, your work will be very hard! Try also something using some pre-processing operation, like noise filters and/or colors thresholds(-> RED plus) Hope it helps
-
hello all I need to find a red " + " in a image and i want a good algorithm . thank you -- modified at 9:48 Thursday 11th May, 2006
-
-
hello all I need to find a red " + " in a image and i want a good algorithm . thank you -- modified at 9:48 Thursday 11th May, 2006
Good luck; you'll need it. That's a sophisticated algorithm you're after. I suggest you get a good book on digital processing and don't expect results too quickly. Steve
-
You can use 2D-fft (or 2D convolution/correlation). It will work also if there is a rotation on the plus (i.e. there is only a phase rotation) or if there is a scale factor (i.e. the ratio between frequency amplitudes remains constant),..... but they aren't
V_shr wrote:
speedy algorithm
If you want a good and fast way ,probally, your work will be very hard! Try also something using some pre-processing operation, like noise filters and/or colors thresholds(-> RED plus) Hope it helps
_Russell_ wrote:
Try also something using some pre-processing operation, like noise filters and/or colors thresholds(-> RED plus)
Good!
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers, Alok Gupta VC Forum Q&A :- I/ IV
-
-
Humm...
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers, Alok Gupta VC Forum Q&A :- I/ IV
ThatsAlok wrote:
Humm...
pardon dear ? what's up ?
TOXCCT >>> GEII power
[VisualCalc 3.0 updated ][Flags Beginner's Guide new! ]
-
ThatsAlok wrote:
Humm...
pardon dear ? what's up ?
TOXCCT >>> GEII power
[VisualCalc 3.0 updated ][Flags Beginner's Guide new! ]
-
toxcct wrote:
pardon dear ?what's up ?
oops sorry! wrong person :)
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers, Alok Gupta VC Forum Q&A :- I/ IV