Is it always necessary to convert image to double type before further execution?

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Krishna 2013-10-2

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关闭： MATLAB Answer Bot 2021-8-20

Hi,

I want to threshold an image. I can read the image and it is a byte type (UINT 8). I want to pass this image to another function as it is but it asks me to convert to double before I can pass to another function where threshold is performed via MEX MATLAB. How can I pass the image as the same data type? Thanks in advance.

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Walter Roberson 2013-10-2

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We don't know. You will need to tell us which function you are trying to pass it to.

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Krishna 2013-10-4

Thanks.

Image Analyst 2013-10-2

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Well apparently you can't. It said so. It said it wanted double and rejected your call when you tried to pass in uint8(). I don't know why, but that's the way it is. It seems like it could just cast it to double internally, but, for whatever reason, it doesn't. So I guess you have to live with it. Either use double() if it can take whatever range you have, or use im2double() if it wants it in the 0-1 range.

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Jan 2013-10-8

编辑：Jan 2013-10-8

@Krishna: This is not Matlab. We do not know: getData_Image function, type and size of "image", value or "rows" and "cols", size and type of "matlab_image" and why you use 1-based indexing here. So currently there is no chance to guess, what you are doing.

Krishna 2013-10-8

编辑：Krishna 2013-10-8

Sorry that it was not clear. Actually 'image' variable is byte-array type defined in my header file along with that 'getData_Image' function.1-based indexing is for the matlab arrays as compared to C which is 0-based since I want to transfer pixel values to corresponding places. If all these are unclear, can you please let me know how to access each value of image (which is obviously a matrix) we read in matlab and pass to a C type multidimensional array.

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