Abstract: The horizontal and vertical offset for the M×N DCT block boundaries are determined for a decompressed image originally produced by a DCT-based compression system, regardless of the amount of compression and/or cropping that had been applied to the image.

Abstract: In the method, correlated achromatic single-plane images are subjected to a plurality of operations for segmenting them into uniform components on the basis of different criteria. The results of the various segmentation operations for each of the processed correlated images are analyzed in order to generate cores constituted by zones presenting high certainty as to the existence of objects. The resulting cores are compared and those zones which correspond to more than some determined threshold of the various cores are conserved as indicating the presence of an object. The previously processed images are subjected to a weighted summing operation in order to obtain a first result image containing the uniform component cores. The first result image is then subjected to coloring followed by binarization in order to obtain a second result image containing the uniform components, and the individualized objects are extracted from the image.

Abstract: A text detection technique comprises local ramp detection, identification of intensity troughs (candidate text strokes), determination of stroke width, preliminary detection of text based on contrast and stroke width, and a consistency check.

Abstract: An apparatus is disclosed that includes a memory storage unit to store an electronic version of a page and a processor coupled to the memory storage unit. The processor is configured to receive data associated with a handwritten notation applied to a printed page and an electronic image of an area of the printed version of the page near the notation, to identify a corresponding passage in the electronic version of the page and to create an electronic notation based on the received data and associated with the corresponding passage.

Abstract: Perspective distortion is estimated in a digital document image by detecting perspective pencils in two directions, one being parallel to text lines, and the other being parallel to the boundaries of formatted text columns. The pencils are detected by analyzing directional statistical characteristics of the image. To detect a pencil, a first statistical line transform is applied to transform the image into line space, and a second statistical score transform is applied to transform the image into pencil space. A dominant peak in pencil space identifies the perspective pencil. In addition, a computationally efficient line summing technique is used for effecting sums of pixels along inclined target lines (or curves) through an image. The technique includes pre-generating partial sums, and summing along step segments of a target line using the partial sums.

Abstract: Unsupervised learning of object category from images is carried out by using an automatic image recognition system. A plurality of training images are automatically analyzed using an interest operator which produces an indication of features. Those features are clustered using a vector quantizer. The model is learned from the features using expectation maximization to assess a joint probability of which features are most relevant.

Abstract: The present invention provides an automatic identification system, capable of discriminating species based on non-apparent differences in wing morphology. An input image to be classified or identified is input and stored. An image pose normalizer is used to image pose normalize the input image to produce an image pose normalized input image. The image pose normalized input image is compared to each of a plurality of sample image pose normalized images in a stored training set comprising the plurality of sample image posed normalized images. At least one of the plurality of sample images which most closely corresponds to the input image may then be displayed. The system of the present invention is ideally suited for a group of insects with apparent, but subtle wing differences, and thus is capable of overcoming the taxonomic impediment hindering the inventorying and monitoring of biodiversity.

Abstract: This disclosure provides a system for classifying images, used in image detection, image recognition, or other computer vision. The system processes directory images to obtain eigenvectors and eigenvalues, and selects a set of “smooth” basis vectors formed by linear combinations of these eigenvectors to be applied against a target image. Contrary to conventional wisdom, however, a group of the eigenvectors having the weakest eigenvalues are used to select the basis vectors. A second process is then performed on this group of “weakest” eigenvectors to identify a set of candidate vectors, ordered in terms of “smoothness.” The set of basis vectors (preferably 3-9) is then chosen from the candidate vectors in order of smoothness, which are then applied in an image detection or image recognition process.

Abstract: Embodiments of the present invention provide for compressing an image matrix by partitioning the image into overlapping sub-blocks, weighting each sub-block, and performing a decomposition of the weighted sub-blocks into a weighted sum of vector outer products, such as a singular value decomposition. Compression is provided by representing the image matrix by a subset of the scalar weights and associated vectors used in the decomposition. Embodiments of the present invention provide for synthesizing an image matrix by performing weighted sums of vector outer products based upon the subsets of scalar weights and associated vectors obtained during compression to provide synthesized sub-blocks, and overlaying and summing the synthesized sub-blocks to provide the synthesized image matrix.

Abstract: The present invention provides an image decoding apparatus that realizes speed-up processing of taking out an MR (macroblock remainder) from a fixed length unit that consists of a first DCT block and the MR, without increasing cost. A Setup processor 3 outputs one out of a plurality of fixed length units that constitute an SB (synchronized block). First, calculation is performed for a length from a beginning of the fixed length unit to a EOB (end of block) that is included in the fixed length unit. The calculated length is then used as an offset in taking out the MR. Then an end portion of a second DCT block that is included in the MR is combined with a corresponding beginning portion of the second DCT block, in order to obtain the complete second DCT block. The complete second DCT block is outputted to a variable length code decoder 13.

Abstract: A region of interest coding method based on the SPIHT algorithm, in which more bits are allocated with respect to a region of interest to quickly compress and restore an image, is provided. The region of interest coding method is applied to a multiple resolution coding operation. In the coding method, an image is coded using the SPIHT algorithm before a region of interest is set. When a region of interest is defined based on a region of interest mask and a parent mask, coefficients are coded with respect to a bit plane defined by a user, and a compensation coding operation is performed with respect to coefficients not related with the region of interest. The coding operation is performed based on the SPIHT algorithm by the amount of bits permitted in the bit plane of the remaining coefficients. Therefore, it is possible to implement compression and restoration of various images.

Abstract: An imaging apparatus receives a stream of image data compressed according to a token based compression algorithm. The token dictionary is decompressed and processed according to desired standards such as optimizing for a particular image output device. After revision, the revised tokens are stored in a revised dictionary which is accessed upon decompression of image content. When the image content is decompressed the locations in the compressed or coded input data stream refer to locations in the revised dictionary which are extracted and output either to hard copy or for further processing.

Abstract: An apparatus and method of intraframe encoding of digital frequency-domain data. The data comprises a plurality of slices each having a plurality of blocks. Each block has a DC component and a plurality of AC components. A first DC component value of each slice is encoded. Each subsequent DC component value of each slice is represented as the difference between it and the DC component value preceeding it. For lossless encoding, the initial DC component value of each slice and the differences are encoding using Golomb-Rice.

Abstract: An apparatus and a method of changing a bit rate of a compressed image bit stream by changing a codeword so as to easily change the bit rate and reduce a changing loss. The apparatus for changing a bit rate, in which an input bit stream generated by an image compression encoding method is changed into an output bit stream having a desired bit rate, includes a changing codeword determiner which selects codewords to replace the codewords of the input bit stream, and a codeword changer which changes the codewords of the input bit stream into the codewords selected by the changing codeword determiner. The method and the apparatus can be applied to image services provided through the Internet and receiving apparatuses supporting the Personal Video Recorder (PVR) function. Particularly, the method of changing the bit rate of a compressed image bit stream changes the codewords of input transform coefficients so as to easily change the bit rate and reduce the changing loss.

Abstract: A method and system for processing an image based on noise appearance in the image, includes the steps of and means for: forming a noise table representing noise magnitude vs. intensity of the image; providing a plurality of potential image processing paths, each path having at least one image transform; modifying the noise table according to the image transform(s) in the at least one image processing path to produce an output noise table; generating a noise metric from the output noise table, said noise metric representing the noise appearance of the image processed by the at least one image processing path; selecting one of the plurality of potential image processing paths based on the noise metric; and applying the selected image processing path to the image.

Abstract: The present invention provides a data de-noising system utilizing processors and wavelet denoising techniques. Data is read and displayed in different formats. The data is partitioned into regions and the regions are distributed onto the processors. Communication requirements are determined among the processors according to the wavelet denoising technique and the partitioning of the data. The data is transforming onto different multiresolution levels with the wavelet transform according to the wavelet denoising technique, the communication requirements, and the transformed data containing wavelet coefficients. The denoised data is then transformed into its original reading and displaying data format.

Abstract: The present invention is a method of processing a digital image that is initially represented by digital data indexed to represent positions on a display. The digital data is indicative of an intensity value Ii(x,y) for each position (x,y) in each i-th spectral band.

Abstract: Provided is a method and apparatus of processing an image using filters. The method and apparatus receives an input pixel and a pixel window associated with the input pixel from the image, classifies the input pixel using the pixel window into a range of classes identifying pixels suitable for various degrees of smoothing and sharpening operations, receives parameter independently set for sharpening and smoothing the image, and selects a filter for processing the input pixel based upon the pixel classification and the parameter settings for sharpness and smoothness.

Abstract: A smoothing method extracts an evaluation window including a target pixel of a multi-value image data in which tone is represented by a multi-value in units of pixels, and judges black and white of the target pixel according to a predetermined rule, and binarizes pixel data within the evaluation window. Further, the smoothing method generates a correction value based on collating binarized pixel data within the evaluation window and a look-up table which stores patterns in vicinities of the target pixel, and outputs a multi-value correction signal in which the correction value is converted into a multi-value.

Abstract: An optimizing video processing method and system selects algorithms for best obtainable video quality for the available computation resources. A video processing module, which processes an input of a video stream, architectural parameters for identifying an order of cascaded video functions and determining a bit precision between data of any consecutive cascaded functions according to an associated complexity level which correlates with a value of available computational resources. An optimizer module optimizes processing of the video stream and includes a plurality of optimization engines each having an associated complexity level. The optimizer module selects an optimization engine according a complexity level which correlates with the value of available computational resources. An Object Image Quality (OIQ) evaluator module evaluates an image quality of an output of the video stream from the video processing module.

Abstract: The conversion into a progressive format of digital images organized in half-frames or fields with interlaced lines or rows envisages selecting successive lines in one or more of said fields and reconstructing by pixels an image line set between the interlaced lines selected. The reconstruction operation obtains the image by creating a set of candidate patterns associated to the work window by selecting the patterns to be considered within the window. Next, applying to the patterns of the aforesaid set a first cost function which is representative of the correlations between pairs of pixels. Applying to the patterns of the aforesaid set a second cost function which is representative of the non-correlations between pairs of pixels. Selecting, for each candidate pattern, respective internal correlations and external non-correlations, calculating corresponding scores for the candidate patterns using the aforesaid first cost function.

Abstract: In one embodiment the present invention provides a device for monitoring a cable, comprising an imaging device having a field of view; a target, distinguishable within the field of view of the imaging device, associated with a cable; and a computer processor connected to the imaging device for analyzing images of the target produced by the imaging device to determine a position of the cable. In another embodiment, the present invention provides a method for monitoring a cable, comprising calibrating a first image of a predetermined field of view showing a portion of a cable to be monitored; capturing a second image of the predetermined field of view; correlating the first image with the second image to determine a position of the portion of the cable within the second image; and reporting said position.

Abstract: The display of images comprising animated microstructures can be used to create beautiful information and publicity sites attracting the attention of clients. Especially for clients visiting Web sites, images with animated microstructures are capable of forwarding a message incorporated into the animated microstructure (e.g. an advertisement).

Abstract: A system and method for extracting and manipulating image data is provided. A pixel panel is rotated so as to increase a resolution of a projected image. The rotation may be calculated so as to achieve a desired resolution. A portion of the image is retrieved from a memory and an address is calculated for either the portion or discrete bits in order to determine where the bits should appear on the pixel panel. The manipulated bits are transferred to a buffer, which may be a line or frame buffer, and from the buffer to the pixel panel. One or more shift registers may be used to shift the bits into the buffer.

Abstract: A pattern generating and adjustment apparatus and method for generating and adjusting patterns on a display includes a first pattern generator generating a first signal on the display as a first pattern and a second pattern generator generating a second signal on the display as a second pattern. A characteristic of the first pattern is different from a characteristic of the second pattern and when properly adjusted, the first and second patterns form an aggregate pattern having a recognizable shape. The recognizable shape may be, for example, an aggregate cross shape combining two differently shaped patterns. The first and second patterns on the display may be properly adjusted by manually or automatically aligning the first and second patterns into the recognizable shape. When properly adjusted, there is no overlap of the first and second patterns, making a manual adjustment, for example a convergence adjustment, easier and faster.

Abstract: A workstation-user interface for evaluating computer assisted diagnosis (CAD) methods for digital mammography is disclosed. Implementation of such an interface enables multiple, large-size images to be handled at high speeds. Furthermore, controls such as contrast, pan, and zoom, and tools such as reporting forms, case information, and analysis of results are included. The software and hardware used to develop such a workstation and interface were based on Sun platforms and the Unix operating system. The software is user friendly, and comparable to standard mammography film reading in terms of display layout and speed. The software, as designed, will work on entry-level workstations as well as high-end workstations with specialized hardware, thus being usable in an educational, training, or clinical environment for annotation purposes using CAD techniques as well as primary diagnosis.

Abstract: An electronic database for image interpolation is generated by a computer. The computer generates a low-resolution image from a training image, a plurality of representative vectors from the low-resolution image, and a plurality of interpolation filters corresponding to each of the representative vectors. The interpolation filters and the representative vectors are generated off-line and can be used to perform image interpolation on an image other than the training image. The database can be stored in a device such as computer or a printer.

Abstract: Software System, referred to as Image Transport Engine, for processing a sequence of images by deploying Image Processing Functions onto a multiprocessor system called Platform, which generates input image data in order to provide processed output image data. The Software System comprises a software data partitioning model, referred to as Communication Pattern, which partitions the images of the sequence using time-stamped data packets, the transfer of which may overlap the execution of said image processing functions. The Communication Pattern is formed of Software Modules linked by oriented Connections associated to the Modules through Ports. Each Module activates one Image Processing Function attached to it and manages data transfers and synchronization. The source Module partitions the Input Data into data packets that are Image Strips, formed of consecutive image lines. The Image Strips may overlap other Image Strips.

Abstract: A system and method generate a read only memory (ROM) image for a ROM. The ROM image generator operates with a data image builder. The ROM image generator processes an input file to identify data images for a build. The image identifier generates tokens for building each data image. A data image builder uses the tokens as an input to build each data image. A ROM image builder builds the ROM image using each data image build and generates a data image build validating signature for each data image build, such as a checksum.

Abstract: A method for data entry, includes receiving a plurality of images and sorting the images into an order responsive to a measure of similarity between the images, so as to group similar images together in the order. A first image among the images in the order is presented to an operator, and an input is received from the operator specifying a code to be assigned to the first image. A second image, subsequent to the first image among the images in the order, is then presented to the operator, along with the code specified by the operator for assignment to the first image. The code is assigned to the second image responsive to a single input action by the operator, indicating that the second image is to be assigned the same code as the first image.

Abstract: A push-on pull-off and screw-on screw-off closure assembly 20 is provided comprising a spout 30 adapted to be attached to a container 10, the spout 30 having a wall 36 defining a flow path and having an outer surface 40 having a spiral-shaped spout thread 44 thereon. The assembly also comprises a cap 50 having a base 52 with an outer annular wall 54 extending from the base 52 having an inner surface 58. The inner surface 58 having a cap thread 60 thereon, wherein the cap thread 60 substantially engages the spout thread 44 and the cap 50 and spout 30 are adapted to close the flow path when the cap 50 is pushed onto the spout 30.

Abstract: An angular contact ball bearing includes an outer ring having an outer ring race formed on an inner surface thereof, an inner ring having an inner ring race provided on the outer surface thereof, a plurality of rolling elements provided between the outer ring and the inner ring, an annular cage for retaining the rolling elements, and seals provided on openings between the respective ends of the inner and outer rings. The cage is made of a synthetic resin material and is supported through the guide of the rolling elements. The cage includes a plurality of cylindrical pockets arranged peripherally for retaining the rolling elements and a reduced diameter portion formed at ends of the pocket for regulating the radial movement of the cage while being in contact with the rolling element.

Abstract: In a bearing apparatus which are composed of two bearings each including a crown-shaped retainer and also in which a lubricant is filled into raceways formed in the two bearings, not only a preload is applied from the retainer pocket opening side end face of an inner ring but also a preload is applied from the retainer pocket counter-opening side end face of an outer ring.

Abstract: Mounted in a suspension upright for land vehicles, there is provided an arrangement comprising a constant velocity joint, a hub and two wheel bearings with provision for preload adjustment, wherein the CV joint's outer race proper is the inboard wheel bearing's inner race. The bearing raceway formed on the exterior surface of the CV joint's outer race proper is located so as to be in the general area occupied by the driven plane in line with the CV joint's flexural center, providing full end support to the CV joint itself, and concurrently bring about increased axial spacing between the inboard and outboard bearings. Having the CV joint's outer race proper thus integrated to the inboard wheel bearing, a robust hub assembly is provided, wherein the CV joint's flexural center can be placed more closely to the wheel center plane than is normally possible, making negative scrub radius with low kingpin inclination easily achievable.

Abstract: An apparatus and associated method for modulating the propagation constant of a region of modulating propagation constant in an optical waveguide. The method comprising positioning an electrode of a prescribed electrode shape proximate the waveguide. The region of modulating propagation constant is projected into the waveguides that correspond, in shape, to the prescribed electrode shape by applying a voltage to the shaped electrode. The propagation constant of the region of modulating propagation constant is controlled by varying the voltage.

Abstract: An apparatus and associated method for altering the propagation constant of a region of changable propagation constant in an optical waveguide. The method comprising positioning an electrode of a prescribed electrode shape proximate the waveguide. An altered region of changable propagation constant is projected into the waveguides that correspond, in shape, to the prescribed electrode shape by applying a voltage to the shaped electrode. The propagation constant of the region of changable propagation constant is controlled by varying the voltage.

Abstract: A self-aligned optical modulator that modulates an input optical signal in order to generate a modulated output optical signal includes an optical modulator device including a waveguide, a first modulating electrode, a second modulating electrode, and a two-dimensional electron (hole) gas (2DEG) proximate the first modulating electrode, the waveguide includes an input port wherein the input optical signal is introduced into the waveguide, an output port wherein the modulated output optical signal exits the waveguide, and a region of modulating propagation constant disposed along a first length of the waveguide and between the input port and the output port, wherein the input optical signal is guided by total internal reflection in the waveguide, and the waveguide is formed at least in part from an active semiconductor. The first modulating electrode is positioned proximate a first surface of the region of modulating propagation constant and electrically separated from an active semiconductor.

Abstract: The present invention provides a wavelength-tunable optical device structure which monolithically integrates both active and passive device components on a single substrate. Monolithically-integrated active and passive optical device components may be fabricated by growing high-quality active optical devices, such as optical emitters and optical detectors, on a single substrate and using electro-optical crystalline oxide materials to tune optical devices, such as directional couplers, to transmit radiation having selected wavelengths. In this manner, cost-effective, monolithically-integrated, tunable wavelength multiplexers and/or demultiplexers may be formed.

Abstract: A giga-bit interface converter (GBIC) includes a die cast metal housing forming integral grounding tabs for adding stability and increasing ESD grounding path. The grounding tabs are provided on opposite sides of SCA-2 connector of the GBIC for electrically engaging grounding terminal of a matable female SCA-2 connector. Furthermore, grounding pads are formed on a circuit board of the GBIC for direct engagement with the conductive housing to complete a grounding path to electronics of the circuit board.

Abstract: The invention provides a device having a light transmission device wherein a light-emitting element, a driving circuit for driving this light-emitting element, a light-receiving element (light-detecting element), a light-guiding path (wave-guiding path) for guiding light from the light-emitting element to the light-receiving element, an amplifying circuit, wiring and a circuit are successively provided on a substrate. The light from the light-emitting element passes through the light-guiding path and is received at the light-receiving element, transferring photoelectricity. The electric signals from the light-receiving element are amplified at the amplifying circuit and are input to the circuit through the wiring. The circuit operates based on these electric signals.

Abstract: A planar waveguide Mach-Zehnder interferometer (MZ) has improved performance as a variable optical attenuator as well as a thermo-optic switch (TOS) with reduced polarization dependent loss (PDL) in high attenuation states. The PDL was reduced by correcting for the increased birefringence that occurs on heating one waveguide arm by making the two waveguides inherently asymmetric, such that when one of the waveguides is heated, the differential birefringence of the two arms becomes zero. This asymmetry can be realized simply by changing the width of one of the waveguides. The modified device allows for very small PDL in the high attenuation state of a VOA and for theoretically perfect contrast in a TOS in the off state, with only a small penalty in PDL of the on state.

Abstract: A wavelength-dispersive device for processing a multi-channel optic signal, the device including an optic chip defining first and second diffraction gratings coupled via a first free propagation region, the second diffraction grating coupled at its output end to an array of light-receiving elements via a second free propagation region, each light-receiving element positioned to selectively receive a respective channel of the multi-channel signal, and wherein the first free propagation region includes a spatial filter defined by selective doping of the optic chip so as to preferentially transmit a selected portion of the output from the first diffraction grating to the second diffraction grating and thereby reduce cross-talk at the array of light-receiving elements.

Abstract: An optical component is disclosed. The optical component includes an array waveguide grating having a plurality of array waveguides. The optical component also includes a light distribution component configured to receive a light signal through an inlet port and distribute the light signal to a plurality of the array waveguides. The optical component further includes an output light distribution component configured to receive the light signal distributed to the array waveguides. The light distribution component is configured such that a light signal received through the inlet port with a non-periodic intensity distribution is received in the output light distribution component with a periodic intensity distribution. The period intensity distribution can have a shape that approximates a sinc function.

Abstract: In accordance with another exemplary embodiment of the present invention, an optical device includes an interleaver/deinterleaver, which includes a passive thermal compensator, wherein an optical signal which traverses the optical device undergoes substantially no temperature induced frequency drift over a desired temperature range.

Abstract: An optical device is formed by a first chip and a second chip bonded together. The first chip (4 has an optical layer of glass housing an optical circuit; the second chip has a body of semiconductor material housing integrated electronic components and coated with a bonding layer of glass fixed directly and contiguous to the optical layer of the first chip. The bonding layer delimits cavities facing corresponding cavities in the first chip in positions corresponding to the intersection points of waveguides constituting the optical circuit. The cavities are filled with a liquid having the same refractive index as the waveguides. Underneath each cavity, in the body of semiconductor material there is present a resistor, which, when traversed by current, causes formation of a bubble inside the chamber and deflection of the light beam traversing a waveguide towards a different waveguide.

Abstract: Based on the two-mode interference principle and the free-carrier plasma dispersion effect, a high carrier injection optical waveguide includes: a pair of optical waveguide elements, one functioning as an optical waveguide input and the other functioning as an optical waveguide output; a two-mode interference (TMI) region, made of semiconductor material, between the optical waveguide input and the optical waveguide output; first and second carrier injection regions; and a lateral carrier collection region, the lateral carrier collection region and the first carrier injection region being positioned on opposite sides of the TMI region with the second carrier injection region being positioned between the lateral carrier collection region and the first carrier injection region. In one implementation, the input and output waveguides are each formed as a Y-branch of two single-mode rib waveguides.

Abstract: Practical utilization of an optical signal processor configured by combining a plurality of optical components requires configurations and methods by which reflected light arising in the processor during assembly, installation, or operation thereof can be detected reliably and immediately to enable switching of optical signal paths and recovery actions (maintenance) such as replacement and repair of components, thereby improving the reliability, availability, and service ability of the processor. The present invention provides an optical switching system configured as a combination of optical components, including multistage-connected optical switching devices each having a plurality of optical reflection monitoring functions. These functions enable reliable and immediate detection and notification of reflected light arising in the optical switching system. The invention also provides a method of monitoring and reporting reflection.

Abstract: An optical switch architecture in an optical communications network. The imminent removal of a line card from a slot at the optical switch is detected to inform an associated software process/manager that manages the line card that it is going to be removed. The movement of a locking mechanism that locks the line card in its slot triggers a message to a Node Manager that the line card is about to be removed. The software process knows that it will not be able to communicate with the line card, such as to request data or transmit commands. Moreover, the software process knows to not set an alarm for a malfunctioning line card since it will not receive any responses from the removed line card. The software process also maintains information related to the line card during its removal for use when the line card is subsequently re-installed.

Abstract: A photonic switch includes an array of waveguides (optical fibers) that are rigidly mounted together and arranged as a matrix. One waveguide acts as an input for the switch, and is used to transmit a light beam into free space. The other waveguides then function individually as outputs for the switch. Operationally, a switch connection is made by moving a steering mirror to direct the light beam from the input waveguide to a selected output waveguide. For one embodiment, the mirror is flat. For this embodiment the switch incorporates a collimating lens positioned between the array and the mirror, with the mirror at the telecentric stop of the lens. In another embodiment, the mirror has a concave surface.

Abstract: Disclosed herein is a method including the steps of wavelength division multiplexing a plurality of optical signals having different wavelengths to obtain resultant WDM signal light; transmitting the WDM signal light by an optical fiber transmission line; supplying reference light having a predetermined wavelength to the optical fiber transmission line; generating four-wave mixing in the optical fiber transmission line by the interaction of the WDM signal light and the reference light; detecting the power of light generated as the result of the four-wave mixing; and controlling the power of the WDM signal light to be supplied to the optical fiber transmission line according to the power detected. According to this method, the effect of four-wave mixing can be suppressed.