The present technology relates to methods, systems and computer program products for detecting objects in images captured by a camera of a mobile device. The detection of objects (such as barcodes, QR codes, and text) in images can be based at least in part on image gradients of the image. The image can be divided into a plurality of regions, each having a dominant gradient direction. Based at least in part on the dominant gradient directions of the regions satisfying orientation thresholds, the regions can be identified as candidate or non-candidate regions for corresponding to a predetermined object. The candidate regions can be merged if they satisfy a connecting criterion. The merged regions can then be analyzed to determine if the merged regions satisfy a geometric property of the predetermined object, such as having a rectangular shape substantially similar to that of a barcode.