V. P. Kosykh

Construction of a multichannel filter for detecting point targets in the image formed by a matrix photodetector

A new approach is proposed to construct a multichannel filter for detecting small-size targets in images recorded by a matrix photodetector. For estimating the pulse response of each channel of the filter, the set of experimentally obtained images of targets having different locations with respect to photodetector cells is divided into several subsets, which are used as reference elements in calculating the pulse response of the filter. Experimental data are presented, which demonstrate appreciable reduction of the probability of missing the targets in images subjected to processing with a filter constructed by the proposed method.

Formation of a high-resolution image from a series of mutually shifted images using optimal linear prediction

A high-resolution image is constructed by joint interpolation of a series of low-resolution images differing in mutual shifts which are not multiples of the sampling interval. Interpolation coefficients are determined by using correlations between the readings of the initial images. Results of experiments showing the efficiency of the proposed approach are given.

Algorithm of detection of moving small-scale objects in a sequence of images

An algorithm is proposed for detection, in a sequence of images, of small-scale objects moving with a known velocity vector, the initial positions of the objects being unknown. Random noise is suppressed by four-channel filtration based on estimating subpixel coordinates of the objects in the sequence of images. Results of numerical experiments are presented as a dependence of the detection probability on the false alarm level for different object sizes and input noise levels.

Suppression of a quasi-stationary background in a sequence of images by means of interframe processing

Various methods of background compensation in a sequence of images are analyzed under conditions where the main change in the background is its spatial shift. Methods of estimating the background in a current frame by means of interpolation of data contained in the previous frames are considered. Analytical estimates of the compensation error are given as functions of the spectral properties of images and interpolation methods. Results of numerical experiments are reported, which confirm these analytical estimates and show that the use of local interpolating filters allows extremely low errors of compensation.

Fast algorithms of image construction with a high sampling frequency

Some modifications of the algorithm of image construction with a high sampling frequency are proposed. These modifications multiply reduce the computational costs with an almost unchanged quality of the result. Software implementation of the proposed modifications of the algorithm allows the latter to be used in video surveillance systems for real-time formation of high-quality image fragments.

Estimation of the Scanning Speed of Random Texture by a Multirow Focal Plane Array

Scanning devises based on a set of mutually shifted focal plane arrays to increase the sampling rate in a direction orthogonal to the scanning direction require a high degree of stabilization of the scanning speed in order to obtain high-quality images. A new method for estimating the scanning speed is proposed based on the analysis of shifts of arbitrary random texture images generated by subarrays during scanning. The dependence of the accuracy of various methods of estimating the scanning speed based on the statistical characteristics of the texture is studied by simulation modeling. It is shown that even at a sufficiently high random noise level (SNR = 10) in images with texture satisfying the Nyquist criterion for each subarray, scanning speed estimation errors do not exceed 0.1% of the nominal value.

Estimation of the Alignment Parameters of a Scanning Device with a Multirow Focal Plane Array

Scanning devices based on multirow focal plane arrays providing increased resolution impose much more stringent requirements on alignment than single-row arrays. This paper presents a new method for measuring and estimating the scanning speed and the angle of orientation of a multirow focal plane array relative to the scanning direction — the parameters that determine the quality of the discrete image formed. The method is based on an analysis of the image of a simple test object — an optical slit. An algorithm for estimating these parameters is proposed which provides high-accuracy estimates under fairly weak requirements for the image quality of the test object. The estimation accuracy was calculated analytically and confirmed by simulation modeling.

Detection of suspicious objects on the basis of analysis of human X-ray images

A new approach is proposed for detection of suspicious objects in X-ray images for security assurance. The approach is based on using the statistical model of the image for detecting anomalies. The model is designed with the use of the “bag-of-words” with context definition of the word coordinates in the image during statistical pattern formation. It is experimentally demonstrated that this approach ensures adequate approximation of the result of detection of suspicious objects by humans.

Specific features of detecting point objects in images formed by a detector array

The efficiency of detecting point objects in images obtained by a photodetector array is analyzed. It is shown that the detection efficiency depends both on the image processing method and on the relationship between the sizes of the array elements, the gaps between these elements, and the point spread function of the optical system forming the image. Results of a computational experiment are given, which confirm the existence of an optimal relationship between these parameters.

Optimal Linear Prediction in Interelement Interpolation Problems of Discrete Signals and Images

Optimal linear prediction (OLP) as applied to form oversampled signals from undersampled signals is considered. The OLP-based algorithm for aliasing suppression and sampling frequency enhancement of an image that accumulates a series of geometrically distorted undersampled images is proposed. Results of numerical experiments showing the significant quality improvement for images constructed by OLP are given.