eatSift('PeakThresh',11);
</precode>

<p>
Let's generate a test image.
</p>

<precode type="matlab">
ellBlobs = datasets.helpers.genEllipticBlobs();
ellBlobsPath = fullfile('data','ellBlobs.png');
imwrite(ellBlobs,ellBlobsPath);
</precode>

<p> To extract features from an image, each feature extractor implements
method <code>frames = detObj.extractFeatures(imgPath)</code>. </p>

<precode type="matlab">
siftFrames = sift.extractFeatures(ellBlobsPath);
bigScaleSiftFrames = bigScaleSift.extractFeatures(ellBlob