89 results about "Perspective distortion" patented technology

Arrangements are detailed to aid a user in positioning a camera-equipped device (e.g., a smartphone) at a particular viewing position relative to an object being imaged. Other embodiments discern the device's viewing position, and then undertake image or other processing that is dependent on such viewpoint. A great number of other features and arrangements are also detailed.

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.

A method and an apparatus for identifying motor vehicles for monitoring traffic. The identification is carried out by image-evaluation and includes determining the size ratios of a license-plate contour in a perspectively distorted image on the basis of stored standardized license-plate formats, determining the size of the perspective distortion of the license-plate contour on the basis of the associated standardized license-plate format, establishing a calculation rule for the perspective rectification on the basis of the ascertained distortion of the license-plate contour with respect to the associated license-plate format, rectifying the extracted license-plate-containing motor-vehicle view, and comparing the rectified image with reference images of front views of motor vehicles stored in a database in order to assign the image with greatest correspondence to a group of classified motor vehicles.

An electronic imaging system for capturing an image of a scene includes an optical system for producing an optical image of the scene, an imaging sensor having a surface in optical communication with the optical system, and a plurality of imaging elements distributed on the surface of the imaging sensor according to a distribution representable by a nonlinear function in which the relative density of the distributed imaging elements is greater toward the center of the sensor. Such a distribution provides physical coordinates for the imaging elements corresponding to a projection of the scene onto a non-planar surface, thereby compensating for perspective distortion of the scene onto the non-planar surface and alleviating the need to perform geometric warping of the images after they have been captured.

The invention discloses a water level gauge positioning and water level measuring method based on image processing, wherein the water level gauge positioning method comprises the following steps: calculating the longitudinal inclination angle of a mark rod main body of a pre-extracted water level gauge image; obtaining a water level gauge main body image after inclination correction by adopting arotation correction technology according to the longitudinal inclination angle of the mark rod main body; correcting perspective distortion by using a calibration point technology for the main image of the water level gauge after inclination correction; using a projection method to carry out adjacent pixel repair on a missing value part in the distortion-corrected image; carrying out accurate target clipping on the repaired image according to the coordinate equation of the left and right dividing lines; the starting position of the water level gauge and the position of the boundary line with the water surface are identified and the main body position of the water level gauge is cut according to the starting position and the position of the boundary line with the water surface. According tothe water level gauge positioning and water level measuring method based on image processing, the distortion correction is carried out on the water level gauge image after the inclination correction,the distortion problem caused by the non-parallel lateral boundary of the target caused by the viewpoint selection angle of the image is solved, and the precision of target extraction is improved.

The invention discloses a metal plate strip product label information identification method based on computer vision. the position of a product label area is obtained through segmentation of a lightweight network; the coordinate information of the product label is obtained through an image processing means; correction to enabline see-through transformer is realized, the VGG16 is used for identifying the rotating text; character rotation small-angle registration is carried out by using a variance method; the text position detection precision and the text recognition precision are effectively improved; YOLOv3 and ENet are adopted, so that text correction and position acquisition are faster and more accurate; the loss of the computer and the requirement on the performance of the computer areeffectively reduced; the detection of the text with the uncertain length is realized by utilizing the characteristics of the LSTM in the CRNN; The detection performance is effectively improved, the good recognition performance is achieved in natural scenes such as non-uniform illumination, complex backgrounds, multi-language mixing, text complex formats, product label picture rotation, affine distortion and perspective distortion, and convenience is provided for inputting of label information of metal plate strips.

The invention discloses a tool setting method of a mechanical arm feeding type laser etching system, belongs to the field of non-traditional machining, and relates to a tool setting method of a mechanical arm feeding type laser etching system based on a machine vision technology. The laser etching system is optimized and improved; a vision sensor and an active projection indication laser are added; and an interactive information obtaining function between heterogeneous space non-cooperative electromechanical equipment in the system is added. The problems of non-front-view perspective distortion and vision sensor imaging distortion introduced by an inclined vision measurement configuration are considered; and an inverse perspective transformation geometric correction and camera distortion compensation technology is adopted to correct image information. The precise alignment between a laser etching focusing plane and a part initial characteristic point to be machined in a working space is realized by combining multi-frame sequence image dynamic transformation and multi-axis driving feeding device space shape and position characteristic information. The method solves the precise positioning tool setting problem in the laser etching machining initial phase, and improves the machining precision of target workpieces and the finished product quality.

Arrangements are detailed to aid a user in positioning a camera-equipped device (e.g., a smartphone) at a particular viewing position relative to an object being imaged. Other embodiments discern the device's viewing position, and then undertake image or other processing that is dependent on such viewpoint. A great number of other features and arrangements are also detailed.

The invention discloses a self-adaptive receptive field crowd density estimation method based on cavity convolution, which belongs to the field of computer vision, and comprises the following steps: segmenting an original data set image and a crowd density map to obtain image blocks and crowd density map blocks; constructing and training an adaptive receptive field population density estimation network, wherein the model comprises a cavity convolution module and a classification module, the classification module is used for classifying the segmented image blocks, the cavity convolution moduleadaptively selects a cavity convolution sub-network corresponding to the receptive field according to the image block category output by the classification module, and performs feature extraction on the segmented image blocks to obtain a crowd density map; and inputting the picture to be predicted into the trained adaptive receptive field crowd density estimation model to obtain a crowd density estimation result. According to the method, the cavity convolution sub-network corresponding to the receptive field can be adaptively selected for crowd density estimation, and the problem of perspective distortion is solved, so that the accuracy of crowd density estimation is improved.

For keystone correction of the perspective distortion of an image (18) projected onto a projection surface (12), an image existing in electronic form is processed by a processing device to reverse the perspective distortion. For this purpose, the processing device, respectively rotates and shifts exactly one image line (36) at a time, respectively, while the orientation of the other image lines (40,42,46) is maintained fixed. In addition or alternately, the image lines (36,40,42,46) of the original electronic image comprise a plurality of partial sections of equal lengths which are differently stretched and / or compressed by the processing device. Subsequently, the image is newly computed under consideration of all of the image lines (36,40,42,46) and is projected onto a projection surface (12) by a projector.

The invention discloses a curved surface image restoration method, device and equipment and a readable storage medium, and the method comprises the steps: carrying out the preprocessing of a first curved surface two-dimensional code image after the first curved surface two-dimensional code image is obtained, and obtaining a second curved surface two-dimensional code image; carrying out plane perspective correction operation on the second curved surface two-dimensional code image to obtain a third curved surface two-dimensional code image; and performing curved surface restoration operation onthe third curved surface two-dimensional code image to obtain a planar two-dimensional code image corresponding to the first curved surface two-dimensional code image. According to the invention, theshot curved-surface two-dimensional code image caused by perspective distortion is restored into the planar two-dimensional code image through the planar perspective correction operation and the curved-surface restoration operation.

A fisheye correction with perspective distortion reduction method used for saving memory space and reducing perspective distortion includes a coordinate transformation function, a fisheye distorted image and a fisheye corrected image, the fisheye corrected image includes a plurality of pixels, for each pixel of the plurality of pixels, orderly calculating a coordinate value in the fisheye distorted image, and according to the coordinate value, calculating a pixel value of the fisheye corrected image via an interpolation method, wherein the coordinate transformation function includes a fisheye correction coordinate transformation, a perspective distortion reduction coordinate transformation and an image crop and scale coordinate transformation.

A method of acquiring images of an object arranged on a supporting surface includes providing at least one optical image acquisition apparatus of the object provided with an optical axis; in a work step of the optical apparatus an acquired image is processed to correct a possible perspective distortion of the image and at least one feature of the object is extracted from the processed image. The method further includes associating a known reference plane with the object and, in a configuration step of the optical apparatus preceding the work step, obtaining a corresponding inclination between the reference plane and the optical axis; processing the acquired image in fact comprises identifying a processing mode determined as a function of the corresponding inclination and applying this preset processing mode to correct the possible perspective distortion.