Showing papers on "Image conversion published in 1982"

Hybrid optical processor for pattern recognition and classification using a generalized set of pattern functions.

Abstract: A pattern recognition and classification system has been studied which computes the inner products of an input pattern with a generalized set of pattern functions. The system utilizes a filter whose impulse response consists of an amplitude superposition of a set of generalized pattern functions in phase-coded form and has a space–bandwidth product the same as that of a matched filter for one pattern function. Each pattern function in the general set may correspond to a different variation (e.g., scale or rotation) of the object to be detected. Because the amplitude superposition of the phase-coded pattern functions takes place in the digital computer, and the filter is created as a computer-generated hologram, the biasing problem of conventional, multiple exposure (intensity superposition) holograms is significantly reduced. This makes it possible to encode many more pattern functions than was previously possible using multiple exposure techniques. Furthermore, the use of computer-generated holograms eliminates the need to generate a transparency for each pattern function and complex phase code. To facilitate real-time operation a hybrid system was constructed consisting of a liquid crystal light valve for incoherent-to-coherent image conversion, a TV camera and image digitizer for image analysis, and a laser scanner to produce the computer-generated holograms. Both the TV camera/digitizer and the laser scanner systems were interfaced to a digital computer for automatic operation. Experimental results using the hybrid system are presented for pattern recognition of rotated and scaled objects and pattern classification. In the second half of the paper we provide an analysis on the SNR of the processor employing the coded-phase technique, on the diffraction efficiencies of computer-generated filters (amplitude superposition) vs conventional filters (intensity superposition), and on the number of pattern functions required for a certain recognition task.

Radiation image conversion

Abstract: PURPOSE: To form an image with a good conversion efficiency by exciting with near-IR rays and allowing to emit in near UV rays with the high luminance, by using a particular accumulative phosphor in the radiation image conversion utilizing a stimulative phosphor. CONSTITUTION: By irradiating an object 12 with light from a radiation source 11, a latent image is formed on a radiation image conversion panel 13. Then the fluorescence corresponding to said latent image is produced by light emitted from a light source 14 and displayed through a filter 18, a photoelectric convertor 15, and an image regenerator 16 on an image display device 17. In said method, an accumulative phosphor contg. an Eu 2+ -activated compound halide phosphor of the formula (wherein X, X' are each Cl, Br; x, a are each 0W2) (e.g., BaFBr.10 -3 NaBr:10 -3 Eu 2+ ) is used and the latent image formed is excited by light of 450W1,100nm in wavelength. COPYRIGHT: (C)1984,JPO&Japio

Optical fourier transform device

Abstract: PURPOSE:To execute Fourier transform with a real time by optically Fourier- transforming the optical information converted into coherent light. CONSTITUTION:A image formation lens 7 and an image conversion element 15 closely locate a dichroic mirror 16 which reflects only regenerative light He-Ne laser beam on the left side of the element 15. By performing this action, image reproduction becomes reflecting type reading. Then, this means that polarizers are mutually located in parallel and the reproduced image becomes a positive image. A Fourier transform lens 13 collimates a semiconductor laser light source 18 which emits red-near infrared light to be used as a reproducing light source, and irradiates to the element 15 to Fourier-transform the reflected regenerating light. A image sensor 19 converts the obtained Fourier transform pattern into an electric signal.

Transmitting and receiving system for ultrasonic wave

Abstract: PURPOSE:To obtain clear-cut images with a simple device by carrying out successively beam scanning with different depths at which beams converge and adopting only information that is useful for displaying a tomographic image for each scanning and storing the information in memory. CONSTITUTION:An echo signal 200 received by a probe 10 becomes a tomographic image information 300 at an image information conversion section 16 through a receiving and transmitting section 14, and the information 300 is stored in a frame memory 20, and its output is inputted into a display device 22. The gate signal 500 of a ultra- sonic wave repetition gate circuit 24 controls the receiving and transmitting section 14 and the frame memory 20. The receiving and transmitting section makes delayed control of each vibrator of the probe 10, and thereby electronic scanning is applied to the ultra-sonic beam, and the far section and near section of conversion is changed over. An image conversion information section 16 has a STC circuit in which the amplification factor is controlled by time, and it is synchronized with the change-over of the far and near sections of the converting section. If the conversion is at the near (far) section, the signal from the far (near) section is given a fixed bias so that the signal becomes a black level. In this arrangement only the signal at a desired depth is taken out and the image is clear.