A Modified 2-D Logarithmic Search Technique for Video Coding

A Modified 2-D logarithmic reckon Technique for flick secret writing With Reduced face Points Tahmina Akhtar, Rahima Akter, Chhalma Sultana Chhaya , Ashfaqur Rahman army Institute of Science and Tech no.ogy/Dept of CSE, Dhaka, Bangladesh, underlying Queensland University/Centre for Intelligent and Networked Systems, QLD, Australia email&clxprotected com, email&160protected com, email&160protected com, a. email&160protected edu. au outline depiction cryptograph is a impact for representing pic epochs in a backpack manner.A significant tincture in impression coding is faceing for connatural segments in forward designs and use only the disagreement information for reconstruction thusly reduce space requirement. Different calculate proficiencys including near seem and 2-D logarithmic attend etcetera ar utilise in the on-line(prenominal) literature. exuberant reckon restricts its application because of its computational load. 2D logarithmic seek is co mputation intactlyy less(prenominal) costly although there be nigh spaces for gain. In this paper we rede a new inquisition proficiency by modifying the 2-D logarithmic seek that requires less count tiptops with peanut mischief in visual smell.Experimental heads demonst swan the effectualness of the proposed technique. Keywords impression coding, 2-D logarithmic bet. i. INTRODUCTION Video is a epoch of still images representing scenes in gesture. A television system is created by capturing a metrical composition of still images in a shortly date interval. When these still images are displayed precise quickly, it represents the motion of the object in the images. Video represent the huge amount of info. In order to transfer photograph data from unrivaled practice to another efficiently it is ask to compress the size of it of motion picture data.One way to compress the size of video data is video coding 1 2 . The oral sex goal in the design of a vi deo-coding system is to reduce the transmission rate subject to roughly picture quality constraint. In transmission side, the first under puke (normally called the reference exactlyt on) is transmitted as it is and the rest hurtles are sent as a function of the reference skeletal system. The frame to be sent is separate into a progeny of blocks and the best tally for the block is looked for in the depend window of the reference frame. This process is called the hunting technique in video coding literature.There last a human body of video coding techniques including MPEG-1/2/4 2 7 , H. 26X 8 etc. uses hunting techniques like spacious essay 1 , 2-D logarithmic inquisition 3 , Coarse-Fine-Three-Step front 4 , Conjugate Direction calculate 5 , and profit anticipate 6 . Each of these take care techniques has merits and demerits in their favor. bounteous pursuit breaks the best receive for a block as it appeares all the candidate positions in the ta ke care window. liberal seem however is computationally expensive and renders difficulty for real time implementation. few variants exist that applies few heuristics to reduce the candidate chase draws and reduce the computational complexity although compromise the image quality a bit. 2-D logarithmic anticipate is one such search technique that reduces the search points to a subset of the search window (to be detailed in literature review) and finds the near-optimal best contradict with trim computational complexity. Although computationally inexpensive it contains some redundancy in the search space. We manoeuvre to reduce this redundancy and aim to find a modified 2-D logarithmic search technique with even reduced computational load.Experimental results demonstrate that the proposed technique reduces the act of search points and thus reduces search time with insignificant sacrifice of image quality. The paper is organize as follows. In Section II we elaborate some re lated kit and boodle. In Section III we present our proposed search approach. Some experimental results to demonstrate the effective of the proposed approach is presented in Section IV. in conclusion Section V concludes the paper. II. Related works In this section we present teeming search technique and the logarithmic search technique.In both cases the frame to be coded is divided into a number of non-overlapping pertain size blocks of size p? q. The best match is looked for in a search window of size (2d+1)? (2d+1) in the reference frame . form 1 Block unified process in video coding that uses search techniques. * A. wide Search In Full search 1 finds the best match by inspecting all the (2d+1)? (2d+1) candidate positions deep down the search window. Full search turn is brute force in nature. The service of Full Search is that it delivers good true statement in searching for the best match.The damage is that it involves a large amount of computation. * B. 2-D logarit hmic Search Jain and Jain 3 substantial a 2-D logarithmic search technique that successively reduces the search electron orbit, thus trim the computational burden. The first pure tone computes the similitude for cinque points in the search window. These tail fin points are as follows the central point of the search window and the four points touch it, with all(prenominal) being a substance surrounded by the central point and one of the four boundaries of the window. Among these five points, the one correspondent to the sink limit discordantity is picked as the winner.In the close step, surrounding this winner, another set of five points are ap waded in a similar fashion to that in the first step, with the distances between the five points remaining unchanged. The exception takes place when either a central point of a set of five points or a boundary point of the search window gives a negligible dissimilarity. In these circumstances, the distances between the five p oints need to be reduced. The procedure continues until the final step, in which a set of candidate points are situated in a 3&2153 2-D grid.The locomote in a 2-D logarithmic search technique are presented in fig 2. soma 2 The 2-D logarithmic search technique. The circle numbered n is searched at the n-th step. The arrows indicate the points selected as the nerve center of the search for the coterminous obviate. The 2-D logarithmic search hits a maximum of 18 points and a negligible of 13 search points. The advantage of this technique is that it successively reduces the search area, thus trim down the computational burden. One of the disadvantages is that some points are searched more than once thus start out some space for improvement.Moreover, it follows a penurious approach by selecting the minimum dissimilar point at each step thus posing a flagellum to follow a local minimum trend. Considering these facts we propose to modify the 2-D logarithmic search to overcome the local minimum line and also press out the redundant figuring as described in the succeeding(a) section. iii. proposed search technique We mainly modified the 2-D logarithmic search technique to eliminate the redundancy and local minimum task associated with it. The search technique is elaborated next under the light of 2-D logarithmic search technique.Our proposed search technique starts with the five points in the search window where the one is at the center and other four surrounds center point ( pattern 3(a)). Unlike 2-D logarithmic search, our proposed technique selects two points min1 and min2 ( frame 3(b)) that has dissimilarity scores lower than the other triple points. We then select a point as the center of search for the next pass that lies on the line in between min1 and min2. This alternative reduces the local minimum effect as it simply does not follow the minimum point.Moreover, the five points selected in the next pass does not match with any of the previo us points thus eliminates the redundancy that exists in 2-D logarithmic search. Centered at the point selected at the next pass the search continues ( chassis 3(d)- flesh 3(f)). The steps of the search are portrayed in figure of speech 3. Following are some of the merits of our proposed technique * Successively reduces the search area with no point searched twice * supreme search points are 12 and minimum search points are 5 an improvement over 2-D logarithmic search. iv. Results and DiscussionWe have conducted a comparative analysis of Full Search, 2-D logarithmic Search and our proposed search technique as presented next. All the experiments were conducted on MPEG sequences utilize MATLAB. We used sequences like garden, Akiyo, hold over Tennis, auto, and coastguard. Full search, 2-D logarithmic search and our proposed technique applied in these standard MPEG file and we computed the ASNR (Average Signal to interference Ratio) and Computational load (i. e. number of search p oints). The results on divers(prenominal) sequences are presented next. Akiyo rate Each frame of the Akiyo sequence is of 352? 88 pixels, recorded at 25 frames per sulfur and there are a total of 398 video frames. Fig 4 shows the theorize twentieth frame of Akiyo sequence coded apply Full search, 2D-logarithmic search and proposed search technique. In this video only face portion is moving. Search point comparison for these three search techniques is presented in Fig 5 and ASNR is reported in Fig 6. ASNR achieved utilise the proposed search technique is close to equal 2D logarithmic search unless at reduced number of search points (Fig 5). Number of search points remains almost similar over the different frames.ASNR valuate shown in prorogue 1. (a) (b) (c) (d) (e) (f) Fig 3 The different steps of our proposed 2-D logarithmic search technique. (a) five points of search window, (b) the direction of the search in between the direction offered by the two points min1 and min2. (c) Search at step 2, (d) min1 and min2 at step 2, (e) Search points at step 3, and (f) Search ends at the no-good point. (a) (b) (c) Fig 4 reconstruct twentieth frame of the Akiyo sequence employ (a) Full search, (b) 2-D logarithmic search, and (c) Our proposed search technique.Fig 5 affinity of of search points for Akiyo sequence. Fig 6 comparison of ASNR for Akiyo sequence. skirt 1 ASNR value of different search for Akiyo sequence sort No Full Search 2D logarithmic Search Proposed Search inaugural 25. 86188 25. 55678 25. 46245375 fifth 24. 84504 23. 77938883 23. 57562323 tenth 24. 37532 23. 01043038 22. 67351877 15th 24. 38495 22. 98908004 22. 5831958 twentieth 24. 4424 22. 90227928 22. 56886825 twenty-fifth 24. 44956 23. 03416597 22. 51615637 cable car ecological succession Each frame of the Car sequence is of 320? 240 pixels and ecorded at 25 frames per second and there are a total of 398 video frames. The reconstructed twentieth frame of Car sequence using the three search techniques is presented in Fig 7. In this video sequence the gondola moves but background is still. here each repeated two times. Average no of search point is almost 10. 46 for repeated frames and 11. 50 for new frames. here(predicate) number of search points vary significantly compared to Akiyo sequence. Overall the proposed technique has reduced search points (Fig 8) although the ASNR is bit low (Fig 9). ASNR value of some frames shown in Table 2. a) (b) (c) Fig 7 Reconstructed 20th frame of the Car sequence using (a) Full search, (b) 2-D logarithmic search, and (c) Our proposed search technique. Fig 8 equality of of search points for Car sequence. Fig 9 Comparison of ASNR for Car sequence. Table 2 ASNR value of different search for Car sequence Frame No Full Search 2D logarithmic Search Proposed Search first 27. 13312 26. 5682 26. 08265 5th 26. 68718 25. 75123 25. 16904 10th 26. 10589 25. 12647 24. 27394 15th 26. 31185 25. 16266 24. 54981 20th 26. 28613 25. 1915 24 . 61234 25th 25. 86261 25. 02255 24. 12599 tend Sequence Each frame of the garden sequence is of 352? 240 pixels and recorded at 30 frames per second and there are a total of 59 video frames. Fig 10 represents the reconstructed 20th frame of this sequence coded using the three search techniques. In this video the motion is repayable to camera movement. Fig 11 and Fig 12 reveals that the new search technique reduces the number of search points with minor loss in ASNR. ASNR value of some frames shown in Table 3. Here Average no of search point for each frames demand almost same.In frame 20th ordinary no of search point is 11. 6053 and ASNR is 18. 22931. (a) (b) (c) Fig 10 Reconstructed 20th frame of the Garden sequence using (a) Full search, (b) 2-D logarithmic search, and (c) Our proposed search technique. Fig 11 Comparison of of search points for Garden sequence. Fig 12 Comparison of ASNR for Garden sequence. Table 3 ASNR value of different search for Garden sequence Frame No F ull Search 2Dlogarithmic Search Proposed Search 1st 24. 27663 24. 27663 23. 5971 5th 21. 6078 21. 6078 20. 49847 0th 20. 71779 20. 71779 19. 34323 15th 19. 9641 19. 9641 18. 69269 20th 19. 6754 19. 6754 18. 22931 25th 19. 39791 19. 39791 18. 05226 Coastguard Sequence Each frame of the Coastguard sequence is of 320? 240 pixels and recorded at 25 frames per second and there are a total of 378 video frames. Here the ride and the camera are moving. Fig 13 represents a reconstructed frame of this sequence coded using the three search techniques. Fig 14 represents the search point required by the three techniques. Our proposed technique shows semestral nature in terms of search points.This is due to the repetitive nature of motion in the video. Fig 15 represents a comparison of ASNR obtained using different techniques. Table 4 shown ASNR of some frames. (a) (b) (c) Fig 13 Reconstructed frame of the Coastguard sequence using (a) Full search, (b) 2-D logarithmic search, and (c) Our propos ed search technique. Fig 14 Comparison of of search points for Coastguard seq. Fig 15 Comparison of ASNR for Coastguard sequence. Table 4 ASNR value of different search for Coastguard seq. Frame No Full Search 2D logarithmic Search Proposed Search 1st 24. 8771 24. 33338 23. 61801 5th 24. 31753 23. 35416 22. 54516 10th 23. 90367 23. 03317 22. 07546 15th 24. 36529 23. 44171 22. 66604 20th 24. 38658 23. 26823 22. 50994 25th 24. 54524 23. 91583 22. 91885 Table tennis Sequence Each frame of the Table tennis sequence is of 352? 240 pixels and recorded at 30 frames per second and there are a total of 9 video frames. Here ball is moving fast. The reconstructed frames, number of search points, and ASNR of the three search techniques are presented in Fie 16, Fig 17, and Fig 18. Some ASNR of Table tennis sequence shown in table 5. a) (b) (c) Fig 16 Reconstructed frame of the Table tennis sequence using (a) Full search, (b) 2-D logarithmic search, and (c) Our proposed search technique. Fig 17 Comparison of of search points for Table tennis sequence. Overall the result of ASNR for Full Search is best in all cases but number of search point is so high. The result of ASNR for 2-D logarithmic and our proposed search is almost same but the number of search point of our proposed search is smaller than the 2-D logarithmic search and thus an improvement over the brisk technique.Fig 18 Comparison of ASNR for Table tennis sequence. Table 5 ASNR value of different search for Table tennis seq Frame No Full Search 2D logarithmicSearch ProposedSearch 1st 25. 2698 24. 56416 23. 90544 3rd 23. 60795 22. 69326 21. 81273 5th 23. 43996 22. 35007 21. 29301 7th 23. 71878 22. 71607 21. 58383 v. inference In this paper we have presented a new search technique for video coding that is a modification of the existing 2-D logarithmic search. The proposed technique reduces the search time of 2-D logarithmic search by minify the redundant search points.Although ASNR is sacrificed to some accompl ishment it had insignificant visual impact as observed from the experimental results. References 1 Shi and H. Sun, video and Video Compression for Multimedia Engineering, Fundamentals, Algorithms and Standards, second Edition. 2 P. N. Tudor, MPEG-2 Video Compression, IEEE J Langham Thomson Prize, Electronics and confabulation Engineering journal, celestial latitude 1995. 3 J. R. Jain and A. K. Jain, sack Measurement and Its Application in Interframe Image Coding, IEEE Transactions on Communications, vol. com-29, no. 12, December 1981. 4 T. Koga, K. Linuma, A. Hirano, Y. Iijima, and T.Ishiguro, Motion-compensated interframe coding for video conferencing, Proc. NTC81, G5. 3. 1-G5. 3. 5, juvenile Orleans, LA, Dec. 1981. 5 R. Srinivasan and K. R. Rao, Predictive coding based on efficient motion estimation, Proc. of ICC, 521-526, May 1984. 6 D. Tzovaras, M. G. Strintzis, and H. Sahinolou, rating of multiresolution block matching techniques for motion and disagreement estimation, Si gnal Process. Image Commun. , 6, 56-67, 1994. 7 MPEG-4, http//en. wikipedia. org/wiki/MPEG-4, last accessed in December 2008. 8 H. 264, http//en. wikipedia. org/wiki/H. 264, last accessed in December 2008. *