# Revision history [back]

### Transformation from log-polar to Cartesian

I have one simple (and perhaps stupid) question. I am using OpenCV 2.1.

• I transform the original image (320 x 240) to a log-polar image of resolution (200 x 200) by using CvLogPolar function with the magnitude parameter 40, and center of the image set as the center of transformation.
• I perform some processing, and obtain a single point (centroid of the blob) in the log polar coordinates. My question?
• How to get a coordinate values in Cartesian frame, i.e. original image? (I just want to transform the computed values, not the whole image)?

Thanks.

### Transformation from log-polar to Cartesian

I have one simple (and perhaps stupid) question. I am using OpenCV 2.1.

• I transform the original image (320 x 240) to a log-polar image of resolution (200 x 200) by using CvLogPolar function with the magnitude parameter 40, and center of the image set as the center of transformation.
• I perform some processing, and obtain a single point (centroid of the blob) in the log polar coordinates. My question?coordinates.

-My question: How to get a coordinate values in Cartesian frame, i.e. original image? (I just want to transform the computed values, not the whole image)?

Thanks.

### Transformation from log-polar to Cartesian

I have one simple (and perhaps stupid) question. I am using OpenCV 2.1.

• I transform the original image (320 x 240) to a log-polar image of resolution (200 x 200) by using CvLogPolar function with the magnitude parameter 40, and center of the image set as the center of transformation.
• I perform some processing, and obtain a single point (centroid of the blob) in the log polar coordinates.

-My question: How to get transform a coordinate values in of the point from log-polar to Cartesian frame, i.e. to the coordinates of the original image? (I just want need to transform the computed values, not the whole image)?

Thanks.

### Transformation from log-polar to Cartesian

I have one simple (and perhaps stupid) question. I am using OpenCV 2.1.

• I transform the original image (320 x 240) to a log-polar image of resolution (200 x 200) by using CvLogPolar function with the magnitude parameter 40, and center of the image set as the center of transformation.
• I perform some processing, and obtain a single point (centroid of the blob) in the log polar coordinates.

-My question: How to transform a coordinate values of the point from log-polar to Cartesian frame, i.e. to the coordinates of the original image? (I just need to transform the computed values, not the whole image)?

Thanks.