Canon Kabushiki Kaisha

Kieran Gerard Larkin

Peter Alleine Fletcher

Stephen James Hardy

Matthew Raphael Arnison

David Peter Morgan-Mar

Michael Alexander Oldfield

Donald James Bone

Ian Richard Gibson

Tuan Quang Pham

Ben Yip

Takeshi Yazawa

Dominic Yip

Peter William Mitchell Ilbery

Scott Alexander Rudkin

Christine Anne Deller

Richard James Zillman

Steven Parker

A technique determines a depth measurement associated with a scene captured by an image capture device. The technique receives at least first and second images of the scene, in which the first image is captured using at least one different camera parameter than that of the second image. At least first and second image patches are selected from the first and second images, respectively, the selected patches corresponding to a common part of the scene. The selected image patches are used to determine which of the selected image patches provides a more focused representation of the common part. At least one value is calculated based on a combination of data in the first and second image patches, the combination being dependent on the more focused image patch. The depth measurement of the common part of the scene is determined from the at least one calculated value.

Determining a depth map from images of a scene

Methods for determining a depth measurement of a scene which involve capturing at least two images of the scene with different camera parameters, and selecting corresponding image patches in each scene. A first approach calculates a plurality of complex responses for each image patch using a plurality of different quadrature filters, each complex response having a magnitude and a phase, assigns, for each quadrature filter, a weighting to the complex responses in the corresponding image patches, the weighting being determined by a relationship of the phases of the complex responses, and determines the depth measurement of the scene from a combination of the weighted complex responses.

A method determines at least one image value of a corresponding desired output position of an output image from an input image. An orientation of an edge passing through the output position is determined in a localised region of the input image. A frequency spectrum for the region of the input image is extended. A main frequency band of the edge is aligned in the extended frequency spectrum parallel to a first sampling axis of a grid based on the orientation of the edge. The grid is selected from a set of the input and output grids. The aligned main frequency band is filtered along a second sampling axis of the grid, orthogonal to the first sampling axis, the filter removing frequencies associated with replica bands and maintaining the main frequency band. The image value is determined from the filtered edge at the desired output position.

Image resampling by frequency unwrapping

A method of modifying the blur in at least a part of an image of a scene captures at least two images of the scene with different camera parameters to produce a different amount of blur in each image. A corresponding patch in each of the captured images is selected each having an initial amount of blur is used to calculate a set of frequency domain pixel values from a function of transforms of the patches. Each of the pixel values in the set are raised to a predetermined power, forming an amplified set of frequency domain pixel values. The amplified set of frequency domain pixel values is combined with the pixels of the patch in one of the captured images to produce an output image patch with blur modified relative to the initial amount of blur in the image patch.

Bokeh amplification

A method () is described of determining characteristic of an ink jet printer (). A chart containing multiple regions or patches is printed () on a print medium () using the ink jet print (). The chart includes at least a first region printed using a first set of nozzles, and at least a second region printed using a second set of nozzles. The first and second sets of nozzles are a predetermined distance apart in the printer head of the printer (). The printing of the first and second regions is also separated by a print medium advance operation equal to the predetermined distance. This causes the first and second regions to be aligned in the direction of the print medium advance operation. The chart is then imaged using scanner () chart to form a chart image. The positions of the regions appearing in the chart image are next determined (). The spatial alignment characteristic of the printer is calculated from the distance, in the medium advance direction, between said first and second regions.

Method of measuring printer characteristics

Disclosed is a method of determining at least one three-dimensional (3D) geometric parameter of an imaging device. A two-dimensional (2D) target image is provided having a plurality of alignment patterns. The target image is imaged with an imaging device to form a captured image. At least one pattern of the captured image is compared with a corresponding pattern of the target image. From the comparison, the geometric parameter of the imaging device is then determined. The alignment patterns include at least one of (i) one or more patterns comprising a 2D scale and rotation invariant basis function, (ii) one or more patterns comprising a 1D scale invariant basis function, and (iii) one or more patterns having a plurality of grey levels and comprising a plurality of superimposed sinusoidal patterns, the plurality of sinusoidal patterns having a plurality of predetermined discrete orientations. Also disclosed is a two-dimensional test chart for use in testing an imaging device, the test chart comprising a plurality of alignment patterns, at least one of said alignment patterns including one of those patterns mentioned above.

Geometric parameter measurement of an imaging device

Methods, apparatuses, systems and computer program products for measuring spatial characteristics of an inkjet printer are disclosed. Group of marks of a first predetermined pattern are printed on a print medium using a first group of nozzles. Groups of marks of a second predetermined pattern are printed using a second group of nozzles. A region of overlap of the printed groups of marks is formed. At least a portion of the print medium having printed groups of marks is imaged. From the region of overlap, first and second groups of marks from the first and second printed patterns are selected. For each group of marks, a position representative of that group is determined. An offset for measuring spatial characteristics of the printer between the first and second printed patterns is determined dependent upon the representative position of each of the first and second groups of marks.

Method of measuring printer spatial characteristics

A method for measuring the spatial frequency response (SFR) of an imaging system () including a display device () and an image capture device () is disclosed. The method displays a sequence of displayable test pattern images on the display device, the sequence comprising a first test pattern image and at least two subsequent test pattern images, each of the displayable test pattern images including a test pattern having at least one sinusoidal pattern at one or more spatial frequencies such that a phase shift of the sinusoidal pattern has a plurality of pre-determined values. The displayed images are captured with the image capture device to generate a corresponding sequence of captured test pattern images. The captured test pattern images are then compared with the displayable test pattern images to calculate the SFR at a plurality of image locations in the imaging system at the one or more spatial frequencies.

Measure display SFR using a camera and phase shifting

A method () of measuring performance parameters of an imaging device () is disclosed. The method () maintains a test pattern image (), the test pattern image () comprising alignment features and image analysis features. A test chart () containing a representation of the test pattern image is next imaged using the imaging device () to form a second image (). The test pattern image () and the second image () are then registered using region based matching () operating on the alignment features. Finally, the performance parameters are measured by analysing () the image analysis features.

Imaging system performance measurement

A method () of determining at least rotation and scale parameters of a transformation relating two images is disclosed. The method () starts by forming a spatial domain representation of each of the images that is invariant to translation of the images. A correlation in the log-polar domain is next performed between the representations. After detecting a magnitude peak in the correlation, the method () determines the rotation and scale parameters from the position of the magnitude peak.

Image registration method improvement

Method of measuring printing characteristics

A method of generating a matching key for an image is disclosed. The matching key is substantially invariant to rotation, scale and translation. The method starts by forming a spatial domain representation of the image that is substantially invariant to translation of the image. Rotation and/or scaling in the spatial domain representation is next transformed into translation to form a transformed image. A representation of the transformed image is then formed that is substantially invariant to translation of the transformed image. The representation of the transformed image is the matching key for the image.

Image database key generation method

A method () is disclosed for estimating an affine relation between a first image and a second image. The first and second images each have at least 4 non-parallel lines therein. The method () starts by identifying () sets of intersection points of the lines appearing in each of the images. The method () then determines () whether a relation between intersection points exists. If the relation exists then the first and second images are affine related and the affine distortion may be inverted ().

Method of estimating an affine relation between images

A method () of demodulating a real two-dimensional pattern () is disclosed. The method () estimates () a quadrature two-dimensional pattern from the real two-dimensional pattern () using a smooth phase only transform having an anti-symmetric phase, such as a spiral phase filter (). A demodulated image is created by combining () the real two-dimensional pattern () and the estimated quadrature two-dimensional pattern.

Demodulation and phase estimation of two-dimensional patterns

A method () of enhanced peak detection in a correlation signal (g(x)) is disclosed. The method () comprises identifying () in the correlation signal (g(x)) positions where the modulus value of the correlation signal is above a first predetermined value. Each of the identified positions is then processed by forming () a sub-signal from the correlation signal by isolating a region of samples, the region comprising substantially equal numbers of samples on opposite sides of the identified position. The sub-signal is then up-sampled () to a higher resolution using Fourier interpolation. The up-sampled sub-signal is searched () for a peak value, and when the peak value is greater than a second predetermined value, parameters associated with the peak value is stored ().

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Putney, Australia

Kieran Gerard Larkin