Image processing

AxZaHeCa

Hi everybody, I want to use the QImage class as opencv form to access the pixels and manipulate it as the function image.at<uchar>(i, j) because opencv android is useless in QT android, someone knows the way to access the pixels properly???

mrjj

Hi and welcome to the forums
You mean something like
https://doc.qt.io/qt-5/qimage.html#bits
?

Pablo J. Rogina

@AxZaHeCa said in Image processing:

opencv android is useless in QT android,

Are you sure? I'm able to run a sample app on Android with Qt 5.12 + OpenCV 4.0 for Android pre-built with no issues.

You may want to look at this blog post just in case.

AxZaHeCa

@mrjj how can you use this function?? because i saw that returns a pointer to the first pixel data but i don't see how can you get the pixel value in the (i,j) position

mrjj

@AxZaHeCa
Hi
well its actually ScanLine you will use as seen here
https://forum.qt.io/topic/73504/qimage-read-pixels-and-copy-them-with-scanline-method
this might also be of interrest
https://doc.qt.io/qt-5/qimage.html#pixel-manipulation

AxZaHeCa

@mrjj ok ,I don't know if Qrgb is a qreal value, because want to create a histogram from a grayscale image and create a binary image using Otsu method

AxZaHeCa

@Pablo-J.-Rogina I had problems with the lopencv_core.a it show that this static library has some extra characters

mrjj

@AxZaHeCa
well docs
says
typedef QRgb
An ARGB quadruplet on the format #AARRGGBB, equivalent to an unsigned int.