opencv 3.3 multicamera calibration: size of pattern

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I am trying to use the opencv multi camera calibration from http://docs.opencv.org/trunk/d2/d1c/tutorial_multi_camera_main.html.

What size of random pattern should i generate? I tried the code at bo lis page with various size of the pattern but every time the code failed with two types of errors.

1. Invalid photo due to too few matches with pattern.
2. Invalid photo due to too few inliers by Fundam./Homog. Matrix check

Is the distance between the sensor and the calibration board important to decide the size of the pattern image? I capture the images(IR) using a depth sensor with incandescent light as IR source(IR projector is closed with cardboard). The minimum distance of the board from the sensor is 40cm. So I cant go closer.