An image of a target (11) is produced by illumination of the target (11) with overlapping fields (18, 20) of wave energy, such as coherent light, producing an interference pattern (22) moving across the target. At least one pair (12) of sources (14, 16) wave energy provide the moving interference pattern (22). The scattered illumination reflected from the target is detected by a non-imaging receiver (24); a two dimensional spatial frequency map is recorded (30, 62), based upon the amplitude, frequency and phase of the illumination received; and a two dimensional image of the target is formed (32, 72) by applying a Fourier transform to the two dimensional frequency map.
A method and apparatus for forming a synthesized optical image with all of the desired objects in focus. A prescribed number of optical images of the same scene are provided by recording an optical image at a respective focal distance and changing the focal distance for each additional optical image as recorded. The optical images are subjected to wavelet transformation to form a multi-resolution representation. The coefficients of the various multi-resolution representations are compared at the same position to detect the maximum spectral amplitudes. Based on the detected maximum spectral amplitudes, another multi-resolution representation is obtained. Then, an inverse wavelet transformation is performed to obtain the synthesized optical image.
A method for depth-resolved optical detection of a specimen comprises the steps of providing a scanning movement over the specimen or at least a part of the specimen of an illumination light distribution of at least one wavelength which is generated on or in the specimen, providing detection particularly of the light which is influenced based on interaction with the specimen, especially fluorescent light and/or reflected light and/or luminescent light and/or scattered and/or transmitted light, the illumination light having a modulation in at least one spatial direction, and carrying out the scanning movement and detection associated with the scanning with the scanning movement at least in a first and a second different phase position of the modulation and/or first and second frequency of the periodicity of the modulation and calculating at least one optical section image through the specimen or through part of the specimen. Other methods and arrangements are disclosed.
A force is produced within an object by two intersecting ultrasonic beams. The frequency of this force is equal to the beat frequency of the two intersecting beams when their frequencies are made different, or the force may vary as a function of a baseband audio signal f(t) that is used to modulate one of the two beams. The sonic waves produced at the intersection of the two beams can be used to detect the presence of objects or to image objects based on their mechanical properties, or to regenerate desired audio signals at the intersection.
An apparatus for, and method of, improving the resolution of a conventional imaging system by effectively increasing the bandwidth of an imaging system's transfer function. An object is first illuminated with periodic illumination. The phase of the periodic illumination is varied while the periodic illumination is used to scan the object. A plurality of images are received by an imaging system whereby the images received correspond to variations in the phase of the periodic illumination. These images are subsequently processed to extract information in phase with the periodic illumination and information 90 degrees out of phase with the periodic illumination. In an optical microscope system, the periodic illumination also provides automatic focusing and three-dimensional imaging capabilities.
A method of determining a feature-forming variant, such as focus or exposure, for a lithographic system or the like includes Fourier processing that extracts a figure of merit. In a preferred embodiment, the lithographic system fabricates a series of formations of a single pattern. An optical image of each exposure is formed. A Fourier power spectrum is determined for each optical image. An angular power function is extracted from each power spectrum by quantifying optical power along lines originating at various angles from an origin of the power spectrum. With regard to axes of maximum power, the distribution of on-axes and off-axes power is quantified for each angular power function. An optimum for the lithographic system is determined based upon the data extracted from the angular power functions. Preferably, the extraction of an angular power function from the associated Fourier power spectrum is an averaging of the optical power along selected portions of the lines originating from the origin, thereby improving the signal-to-noise ratio.
