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    <p>Well, it mostly depends on how you'll use your matrices. If you're doing a lot of "jumping" anyways - it won't make much difference, but in 'continuous' use cases, it will matter a few dozens of percents.</p> <p>The following example (which simply shifts the matrices values) gives me an output:</p> <pre><code>image.isContinuous() = 1 roi.isContinuous() = 0 image: 0.0162504 s roi: 0.0219723 s Sanity check: OK </code></pre> <p>Which is about 30% difference. Your millage will vary depending on the hardware and actual use cases.</p> <p>Source (notice how the first loop is much simpler in that case):</p> <pre><code>#include &lt;opencv2/core/core.hpp&gt; #include &lt;iostream&gt; using namespace cv; using namespace std; int main( int argc, char** argv ) { int cols = 4096; int rows = 4096; int scale = 2; Mat image(rows, cols, CV_8UC1); Mat image_big(rows * scale, cols * scale, CV_8UC1); Mat roi = image_big(Rect(0, 0, cols, rows)); randu(image, 0, 255); image.copyTo(roi); cout &lt;&lt; "image.isContinuous() = " &lt;&lt; image.isContinuous() &lt;&lt; "\n" &lt;&lt; "roi.isContinuous() = " &lt;&lt; roi.isContinuous() &lt;&lt; endl; { cout &lt;&lt; "image: "; double start = getTickCount(); for (int i = 1; i &lt; image.total(); i++) { image.data[i - 1] = image.data[i]; } cout &lt;&lt; (getTickCount() - start)/getTickFrequency() &lt;&lt; " s" &lt;&lt; endl; } { cout &lt;&lt; "roi: "; double start = getTickCount(); for (int y = 0; y &lt; roi.cols; y++) { if (y != 0) { roi.ptr&lt;char&gt;(y-1)[roi.cols-1] = roi.ptr&lt;char&gt;(y)[0]; } for (int x = 1; x &lt; roi.rows; x++) { roi.ptr&lt;char&gt;(y)[x - 1] = roi.ptr&lt;char&gt;(y)[x]; } } cout &lt;&lt; (getTickCount() - start)/getTickFrequency() &lt;&lt; " s" &lt;&lt; endl; } cout &lt;&lt; "Sanity check: " &lt;&lt; (countNonZero(image - roi) ? "FAIL" : "OK") &lt;&lt; endl; } </code></pre>
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    1. POOpenCV : What is the real performance difference between continuous and non-continuous matrices?
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    1. USSergei Nosov
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      1. VTUpMod
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    1. COGreat answer thanks.
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      1. USpeter_gent
 

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