how get quick grabing of Qimage from QCameraimagecapture capture()

Balaji G

by using QcameraImageCaptrue capture() method, it calls slot
cameraImageCaptured(int,QImage image){}. but timing is about 150 to 200 ms ,how to reduce this timing in qt5

SGaist

Hi and welcome to devnet,

Which exact version of Qt ?
On which OS ?
Which device ?
Which camera ?
What is your application doing ?
QtQuick ?
QtWidgets ?

Balaji G

@SGaist
sorry for late reply
I am using Qt Creator 4.8.2
Based on Qt 5.11.3 (GCC 8.3.0, 32 bit) in Raspberry pi 4 with raspi-camera imx477 ,to grab image from camera to make image process in high speed manner (qtwidget)

Pl45m4

@Balaji-G said in how get quick grabing of Qimage from QCameraimagecapture capture():

I am using Qt Creator 4.8.2
Based on Qt 5.11.3 (GCC 8.3.0, 32 bit)

That's not your Qt version, that's the Qt version your QtCreator uses.

Balaji G

@Pl45m4
QMake version 3.1
Using Qt version 5.11.3 in /usr/lib/arm-linux-gnueabihf

SGaist

What kind of high speed image processing do you want to do ?

Balaji G

@SGaist
i Have to grab image for vision project with opencv in high speed (with in 100-200 ms) for total process including image processing. by using QCameraImageCapture it grab correct frame, but method capture() for Qimage emits a signal(int,const QImage &) make delay upto 100-150ms

Pl45m4

@Balaji-G

When you use OCV, why you want to use QCamera...? OCV is more powerful when it comes to some special image processing.

Balaji G

@Pl45m4
initially started project with opencv videocapture method to grab image from raspberry camera but it gives buffer(past image ).tried to solve that issues ,atlast got some hacks to get latest(current) image but not efficient ,I also tried raspicam_cv lib but its grabing time is little high ,in Qcamera gives current and exact image but method capture() emits a signal with delay of 100-150ms

SGaist

Can you describe your exact pipeline ?
From capturing to final step.

Balaji G

@SGaist
for camera in raspberry pi Iam using v4l2 driver

SGaist

I meant the business logic from the camera to the screen.