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I am trying to capture a high resolution frame (1280x720) from the camera in a pair of Google Glass using OpenCV 2.4.10 for Android. I have implemented the CameraBridgeViewBase.CvCameraViewListener2 in my Activity and try to grab the frame in the onCameraFrame method. So far everything works well, and i get a 512x288 Mat object.

My problem is that the 512x288 resolution is not high enough for what I need. So I tried to setup my project the same way as they do in Sample 3 that follows with OpenCV: http://goo.gl/iDyqQj. The problem is that it only works for resolutions below 512x288, as soon as I increase the resolution above this level it defaults back to to being 512x288 (without any notice).

I found some suggestions, http://goo.gl/X2wtM4, that OpenCV is restricting the frame size to a maximum of the screen resolution. But the Google Glass screen should have a 640x360 resolution? I tried to do as described in the answer, but when I override calculateCameraFrameSize and return a Size-object larger than 512x288, I get a distorted frame (but with the larger dimensions, see below).

Distorted image

Does anyone have a suggestion on how capture a higher captured resolution on the Google Glass using OpenCV?

Andain
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1 Answers1

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So I found a solution. It seem to be two separate problems. As I thought in my question you need to override calculateCameraFrameSize in JavaCameraView to be able to fetch higher resolutions than the device's screen in onCameraFrame. This is apparently a design choice by OpenCV and have been since version 2.4.5. So this is why I could not get a frame with higher resolution.

Even though I now can get a frame with higher resolution, it still is distorted for most preview sizes. This is a bug in the GDK that seem to have been known for quite some time (since XE10 if I understood correctly), but still is not fixed. Fortunately there is a workaround! The issue is avoided by manually setting the FPS of the preview using setPreviewFpsRange after you acquire the Camera.

Camera.Parameters params = camera.getParameters();
params.setPreviewFpsRange(30000, 30000);
camera.setParameters(params);
Andain
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