## compute rotation angle of binary shape image without having primary image(image before rotation)

I have some binary image of letters.I need to rotate these letters shapes X degree, then compute the degree of rotation (X) without having the first letters shapes image (Not-Rotated shapes).

I tested several ways. I used RegionProps.Rotation(RP.R), but had little accuracy.

For example if RP.R is 90 degree, after 5 degree rotation with imrotate method, it will be 80 degree instead 85 degree.

Also I used minimum bounding box;before and after rotating the shapes, I measure the angle between square diagonal and x-axis, or on side of square and x-axis. In this way,for some shapes of letters, measure specified angle after rotating the shape and it was inaccurate and in some cases after X degree rotation(X = 2,3, or 5 degree),the specified angle was unchanged (figure1).

<</matlabcentral/answers/uploaded_files/106773/Figure2.png>>

I want to familiar me with a solution for this problem with these constraints:

-we don’t have the ascii code.

-we couldn’t used OCR for letter detection

-for angle calculation,we don’t have the primary image shape.

thank you.I have some binary image of letters.I need to rotate these letters shapes X degree, then compute the degree of rotation (X) without having the first letters shapes image (Not-Rotated shapes).

I tested several ways. I used RegionProps.Rotation(RP.R), but had little accuracy.

For example if RP.R is 90 degree, after 5 degree rotation with imrotate method, it will be 80 degree instead 85 degree.

Also I used minimum bounding box;before and after rotating the shapes, I measure the angle between square diagonal and x-axis, or on side of square and x-axis. In this way,for some shapes of letters, measure specified angle after rotating the shape and it was inaccurate and in some cases after X degree rotation(X = 2,3, or 5 degree),the specified angle was unchanged (figure1).

<</matlabcentral/answers/uploaded_files/106773/Figure2.png>>

I want to familiar me with a solution for this problem with these constraints:

-we don’t have the ascii code.

-we couldn’t used OCR for letter detection

-for angle calculation,we don’t have the primary image shape.

thank you. I have some binary image of letters.I need to rotate these letters shapes X degree, then compute the degree of rotation (X) without having the first letters shapes image (Not-Rotated shapes).

I tested several ways. I used RegionProps.Rotation(RP.R), but had little accuracy.

For example if RP.R is 90 degree, after 5 degree rotation with imrotate method, it will be 80 degree instead 85 degree.

Also I used minimum bounding box;before and after rotating the shapes, I measure the angle between square diagonal and x-axis, or on side of square and x-axis. In this way,for some shapes of letters, measure specified angle after rotating the shape and it was inaccurate and in some cases after X degree rotation(X = 2,3, or 5 degree),the specified angle was unchanged (figure1).

<</matlabcentral/answers/uploaded_files/106773/Figure2.png>>

I want to familiar me with a solution for this problem with these constraints:

-we don’t have the ascii code.

-we couldn’t used OCR for letter detection

-for angle calculation,we don’t have the primary image shape.

thank you. text image processing, text image rotation, image processing MATLAB Answers — New Questions