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The Hough transform [3] can be used to detect lines and the output is a parametric description of the lines in an image, for example ρ = r cos(θ) + c sin(θ). [1] If there is a line in a row and column based image space, it can be defined ρ, the distance from the origin to the line along a perpendicular to the line, and θ, the angle of the perpendicular projection from the origin to the ...
The minimum required resolution according to Johnson's criteria are expressed in terms of line pairs of image resolution across a target, in terms of several tasks: [3] Detection, an object is present (1.0 +/− 0.25 line pairs) Orientation, symmetrical, asymmetric, horizontal, or vertical (1.4 +/− 0.35 line pairs)
Use of the Hough transform on noisy images is a very delicate matter and generally, a denoising stage must be used before. In the case where the image is corrupted by speckle, as is the case in radar images, the Radon transform is sometimes preferred to detect lines, because it attenuates the noise through summation.
The grid structure of a chessboard naturally defines two sets of parallel lines in an image of it. Therefore, one expects that line detection algorithms should successfully detect these lines in practice. Indeed, the following figure demonstrates Hough transform-based line detection applied to a perspective-transformed chessboard image. Clearly ...
With these line-scan cameras, the spatial dimension is collected through platform movement or scanning. This requires stabilized mounts or accurate pointing information to 'reconstruct' the image. Nonetheless, line-scan systems are particularly common in remote sensing, where it is sensible to use mobile platforms. Line-scan systems are also ...
A line-scan camera is a system for producing two-dimensional images using a single sensor element. They normally consist of a rapidly rotating mirror or prism placed in front of the sensor to provide scanning in one direction while the movement of the recording material, often photographic film , provides scanning in the second direction.
Object recognition – technology in the field of computer vision for finding and identifying objects in an image or video sequence. Humans recognize a multitude of objects in images with little effort, despite the fact that the image of the objects may vary somewhat in different view points, in many different sizes and scales or even when they are translated or rotated.
A micrograph of the corner of the photosensor array of a webcam digital camera Image sensor (upper left) on the motherboard of a Nikon Coolpix L2 6 MP. The two main types of digital image sensors are the charge-coupled device (CCD) and the active-pixel sensor (CMOS sensor), fabricated in complementary MOS (CMOS) or N-type MOS (NMOS or Live MOS) technologies.