Eastman-kodak Company

Philip G Powell

Richard A Sharman

Jennifer C Loveridge

Image processing method for the removal of spot defects and apparatus

Image processing method and apparatus using moving one-dimensional

Image processing apparatus including a partitioned low pass channel

Image gradient detectors operating in a partitioned low-pass channel

An image processing method is provided for reducing noise in a sampled image, particularly for reducing noise in an image divided into blocks of sampled image elements that are transformed by a linear procedure, such as the Walsh-Hadamard transform, and improved regarding visible noise by non-linear thresholding of the transform coefficients. By operating the process in a hierarchy of stages, each stage employing a block operating on image signals derived from a preceding stage, and by overlapping the blocks processed in each stage, the processed signal from each image element is the linear combination of many transform coefficients from each stage and from each overlapped block within each stage. Such a large number of contributions making up each processed image element assures that the processed image is generated without a characteristic block-like structure due to block transform processing while the wanted components of the image are rendered with minimal image loss or distortion.

Image processing method using a block overlap transformation procedure

An electronic image processing system, using image dissection by solid state devices or by scanning and sampling, applies a signal representing a succession of signal values on an array of picture elements to complementary high and low pass electronic filters to produce an output signal in which a desired image feature is enhanced and noise is suppressed. The high pass filter, e.g. FIG. 1, comprises at least one matched pair of signal weighting gradient detectors, e.g. FIGS. 3 and 5, arranged back-to-back to detect a brightness transition 10, as shown in FIGS. 4 and 6, and having their outputs cored independently. Each pair will be sensitive to gradients in a particular direction in the array, e.g. horizontal, vertical or diagonal. The system is applicable to two-dimensional spatial arrays, three dimensional spatial arrays, and also to the temporal dimension, e.g. succession of moving pictures.

Electronic image processing

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Pinner, United Kingdom

Philip G Powell