Statistics Oriented Preprocessing of Document Image

Old printed documents represent an important part of our cultural heritage. Their digitalization plays an important role in creating data and metadata. The paper proposed an algorithm for estimation of the global text skew. First, document image is binarized reducing the impact of noise and uneven illumination. The binary image is statistically analyzed and processed. Accordingly, redundant data have been excluded. Furthermore, the convex hulls are established encircling each text object. They are joined establishing connected components. Then, the connected components in complementary image are enlarged with morphological dilation. At the end, the biggest connected component is extracted. Its orientation is similar to the global orientation of text document which is calculated by the moments. Efficiency and correctness of the algorithm are verified by testing on a custom dataset

Estimation of the Text Skew in the Old Printed Documents

Old printed documents represent the significant part of our heritage. In order to preserve them, the digitalization is indispensable. The paper proposed a robust skew estimation method for old printed document. It is based on the connected components made by filled convex hulls around text element. The connected components are enlarged by oriented morphological operation. Then, the longest connected component is extracted. The global orientation of the document is detected by its orientation. Accordingly, document image was globally de-skewed. The algorithm is tested on synthetic and real datasets. Obtained results proved the algorithmscorrectness

TWO STEP CURRENT INCREASES IN GLOW DISCHARGE DEVELOPMENT IN NEON FILLED DIODE AT 4 mbar

Abstract. The results are presented of investigating temporal and spatial development of electrical glow discharge in a neo

THE GLOW DURATION TIME INFLUENCE ON THE IONIZATION RATE DETECTED IN THE DIODES FILLED WITH NOBLE GASES ON mbar PRESSURES UDC 537.52; 533.9

Abstract. The results of the glow current duration time (glowing-time) influence on the ionization rate detected in the gas filled diodes are presented. The electrical breakdown was detected as the minimal current impulse. After that diode glow from the minimal glowing-time (10-3 s), up to the maximal 10 3 s, which overlap the time of the stationary regime formation in the gas diode tube. The diodes were with volumes of 300 cm 3, but with a diode gap volume of about 1 cm 3 and filled with helium, neon, argon or krypton, at the pressures of the order of mbar. The ionization rates were detected as the residual ionization after the glowing was interrupted, using the electrical breakdown time delay measuring method. The influence of the gap distance, stationary current values and the relaxation period were also investigated. The result shows that the stationary regime in such a gas diode is established after the glowing time of 1-3 s, although the breakdown formative times were smaller then 1 ms. Key words: gas discharges,ionization rate, time delay 1

An Approach to Skew Detection of Printed Documents

In this paper, we propose an approach to estimate the text skew for printed documents. This is an important step to prevent errors in further stages of an automatic document processing system (as text segmentation). Our approach is based on the statistical analysis of the height of the connected components. In a nutshell, our algorithm is comprised of four steps: (i) removal of redundant data; (ii) establishment of the connected components, which represent filled convex hulls around each text element; (iii) enlargement of these components using morphological erosion; (iv) removal of the largest connected component to identify the first estimation of text skew. According to it, the connected components are enlarged by oriented morphological erosion and the longest of them is extracted. Statistical moments are applied to this longest component to evaluate its orientation and the global text skew of the document is identified. At the end of this process, the original document is rotated back based on the calculated angle. The performance of the proposed algorithm is examined by testing on a custom dataset. The results support the robustness of our approach

An Approach to Skew Detection of Printed Documents

In this paper, we propose an approach to estimate the text skew for printed documents. This is an important step to prevent errors in further stages of an automatic document processing system (as text segmentation). Our approach is based on the statistical analysis of the height of the connected components. In a nutshell, our algorithm is comprised of four steps: (i) removal of redundant data; (ii) establishment of the connected components, which represent filled convex hulls around each text element; (iii) enlargement of these components using morphological erosion; (iv) removal of the largest connected component to identify the first estimation of text skew. According to it, the connected components are enlarged by oriented morphological erosion and the longest of them is extracted. Statistical moments are applied to this longest component to evaluate its orientation and the global text skew of the document is identified. At the end of this process, the original document is rotated back based on the calculated angle. The performance of the proposed algorithm is examined by testing on a custom dataset. The results support the robustness of our approach

TWO STEP CURRENT INCREASES IN GLOW DISCHARGE DEVELOPMENT IN NEON FILLED DIODE AT 4 mbar UDC 537.52; 533.9

Abstract. The results are presented of investigating temporal and spatial development of electrical glow discharge in a neon filled tube under 4mbar pressure. Linear increasing voltage (at 5 V/s increasing voltage rate) is applied to the gas diode. Time dependence of 585.2 nm line light emitted from negative glow is observed from various positions in the diode during formation of electrical discharge. The results show that the development of glow discharge starts in the gap, and propagates to the cathode and in the space around and behind the cathode. An unexpected two-step current rise is found. In the stationary regime, most of the emitted light occupied the cathode carrier rod. This indicates the position where the secondary electron emission is intensive. It corresponds to the second step in the current increase app. 3 ms after the breakdown has already taken place. It is assumed that this step originates from different surface characteristics of the rode material. The analysis of time dependencies of the current and light from the negative glow, from different positions in the gas diode, suggests that the observation of deexcitation processes in gas can be used for determination of early discharge formative processes, as well as processes that lead to the stationary regime in the gas diode tube