How to obtain the array of black pixel columnwise??

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Poornima Gokhale 2015-12-15

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评论： Poornima Gokhale 2015-12-17

here I want to get the size of the letter.For that i want the array of black pixels columnwise.I know to calculate the entire pixels of the word.But please help me with this.

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Walter Roberson 2015-12-15

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col_idx_first_black = sum(cumprod(YourImage,1)) + 1;
col_idx_last_black  = size(YourImage,1) - sum(cumprod(flipud(YourImage),1));
col_letter_size = max(0, col_idx_last_black - col_idx_first_black + 1);

Note: col_letter_size will be 0 for columns that contain no black. The first occupied row for the column will be in col_idx_first_black and the last occupied row for the column will be in col_idx_last_black (but those will have misleading values if the row has no black.)

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Walter Roberson 2015-12-17

It is visiting every column and locating the first black pixel in the column and returning the row index within the column. It also visits every column and locates the last black pixel in the column and returns the row index within the column. It also calculates the difference between the first and last index for each column in order to tell you the "size" in rows of the letter in that column -- but keep in mind that two columns that are the same "size" for the letter might have very different locations within the column.

The total number of rows in the image is size(YourImage,1)

Poornima Gokhale 2015-12-17