97 results about "Low spatial frequency" patented technology

A camera acquires a 4D light field of a scene. The camera includes a lens and sensor. A mask is arranged in a straight optical path between the lens and the sensor. The mask including an attenuation pattern to spatially modulate the 4D light field acquired of the scene by the sensor. The pattern has a low spatial frequency when the mask is arranged near the lens, and a high spatial frequency when the mask is arranged near the sensor.

Scatter correction of the projection images used to reconstruct volume CT images is a computationally intensive process that cannot at present be done in real time. We note, however, that although scatter is non-uniform, it varies smoothly - i.e. with a low spatial frequency. Existing Monte-Carlo estimation methods need to run over a large number of iterations in order to eliminate the mainly high-frequency artefacts that are present initially, but this process can be cut short and a low-pass filter applied instead thereby substantially reducing the computational load. By applying the same principle in the spatial domain and interpolating some scatter images from adjacent and surrounding scatter images, the computational load can be reduced still further. Applying these techniques in an iterative process on graphics-processor-quality computational hardware enables real-time scatter correction and reconstruction of CT volume images.

An image processing device for processing an original image divided into a plurality of blocks that are made up of a plurality of picture elements from encoded image-data which is obtained by encoding a spatial-frequency component of the block as a plurality of spatial-frequency coefficients, and producing reduced encoded image-data which is encoded data on a reduced image that is obtained by reducing the original image to a given reduction rate. If the block in the encoded image-data of the original image is in an area where the value of the function is small due to gentle change in brightness or color of the image, for example, only the direct-current component coefficient of is used for the block. On the other hand, if the block is in a area where the value of the function is large because the area is a boundary area, for example, such as an outline in the image, limited number of lower spatial frequency-coefficients are used for the block. The number is based on the reduction rate of the image.

An image processing system, comprising a scanning device having at least first and second light sources for illuminating an object to be scanned, the second light source configured to emit light at a different frequency spectrum than the first light source, a scanned image of the object generated using light emitted by the first and second light sources, the system further comprising a processor, wherein image data representing at least two images of the object respectively generated using light from the first and second light sources is processed by the processor in order to decompose the images into component data representing respective higher and lower spatial frequency components, and wherein component data relating to at least the lower spatial frequency components for the first and second images is transformed in order to generate transformed data for the low spatial frequency components, and method.

CT scanner is disclosed for providing an image of a region comprising: at least one X-ray cone beam for illuminating mthe region with X-rays; a plurality of rows of X-ray detectors that generate signals responsive to line attenuation of X-rays from the at least one controller that controls providing an image of a region comprising: at least one X-ray cone beam for illuminating the region with X-rays; a plurality of rows of X-ray detectors that generate signals responsive to line attenuation of X-rays from the at least one X-ray source that pass through the region; a controller that controls the at least one X-ray cone beam to acquire line attenuation data for the region for different view angles of the region; and a processor that receives the signals and: a) determines low spatial frequency components of the image from the data; b) generates a first spatial image of the region from the low high spatial frequency components of the image from the data; d) generates a second spatial image of the region from the high frequency components; and e) combines the first and second images to generate the CT image.

The time required for capturing an image in synchronization with cyclic body movement information relating to an examinee having a cyclic body movement can be reduced while maintaining a desired image contrast. In a synchronous measurement of an echo signal synchronized with trigger information detected from the cyclic body movement information relating to the examinee, a first period is providedbefore the measurement period of the echo signal or a second period is provided after the measurement period of the echo signal. A K-space is divided into a plurality of partial regions. At least oneof the first period and the second period is made different between the echo signal measurement corresponding to the partial region of the low spatial frequency side and the echo signal measurement corresponding to the partial region of the high spatial frequency side.