IAES Inter national J our nal of Articial Intelligence (IJ-AI) V ol. 13, No. 4, December 2024, pp. 4722 ∼ 4735 ISSN: 2252-8938, DOI: 10.11591/ijai.v13.i4.pp4722-4735 ❒ 4722 Image classication in cultural heritage Muath Sabha 1 , Muhammed Saffarini 1,2 , Rami Y ousef 2 1 Department of Multimedia T echnology , F aculty of Information T echnology , Arab American Uni v ersity , Jenin, P alestine 2 Department of Computer Systems Engineering, F aculty of Engineering and T echnology , P alestine T echnical Uni v ersity—Kadoorie, T ulkarm, P alestine Article Inf o Article history: Recei v ed Jan 28, 2024 Re vised May 29, 2024 Accepted Jun 3, 2024 K eyw ords: Con v olutional neural netw ork Cultural heritage Image classication Image se gmentation K-nearest neighbors ABSTRA CT In this paper , an automated supervised image classication technique, speci- cally for classifying images in the cultural heritage domain, is de v eloped. The de v eloped technique classies images according to a particular date, culture, people and historical age. The proposed technique consists of tw o stages, fea- ture e xtraction us ing the unsupervised se gmentation technique, and the classi- cation stage using supervised classication techniques. Common features are e xtracted, and their histograms are applied t o three classiers: k-nearest neigh- bor (KNN), logi stic re gression (LR), and decision tree (DT). When our tech- nique w as applied to a repository of images from cultural heritage, it sho wed reduced comple xity and impro v ed classication accurac y . DT has achie v ed a higher weighted a v erage recall. This is also represented by the weighted a v- erage f-measure where DT has obtained 0.81. DT has outperformed the other classiers in terms of classifying heritage images. This is an open access article under the CC BY -SA license . Corresponding A uthor: Muath Sabha Department of Multimedia T echnology , F aculty of Information T echnology , Arab American Uni v ersity Jenin, P alestine Email: muath.sabha@aaup.edu 1. INTR ODUCTION There are tw o main cate gories of image classication algorithms: unsupervised and supervised. In unsupervised classication, the system analyzes the images without the need of pro viding an y sample. While the supervised learning is based on selecting samples and putting labels for images by the user and applying the training using training set (group of images that ha v e labels). After that, the system predicts the class that an image belongs to. F or humans, the classication method consists of man y stages, starting with image se gmentation, e xtracting features from the image, and then recognition and classication of the image, that is, assigning t he testing i mage to the right cate gory . In machine learning, it depicts the human w ay of classication. In general, the supervised image classication consists of the follo wing stages: – Building the training set: the input will be N images; each image is labeled with one of the K distinguished classes. – Learning: using the dataset to identify the characteristics of each class. This step is called training the classier or learning. – Ev aluation: estimating the quality of the classier by pro viding prediction labels from the data set for a ne w set of images that it has ne v er seen before. The true labels of these images are compared to the ones predicted by the classier . Man y of the image classications are used for kno wn and semi-visible objects and shapes. This research is to classify images related to a particular date, culture, peoples, and historical ages by e xtracting the J ournal homepage: http://ijai.iaescor e .com Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Artif Intell ISSN: 2252-8938 ❒ 4723 common features (clothes, tools, and b uildings) of the image and then classify the fea tures for which culture it belongs to. The problem is that each culture is dened by man y symbols and each age is identied by dif ferent colors and shapes. Since there are man y cultures that ha v e things in common, and also often cultural images ha v e dif ferent object sizes, the process of object identication needs more time. In the follo wing sections, we re vie w some of the related techniques from the literature in section 2. W e then describe our methodology in an e xtensi v e w ay at section 3. W e also e xplain the algorithms tha t we use in our technique and the reasons behind using these algorithms. The results are sho wn and discussed in section 4. Finally the conclusions and future w ork are discussed in section 5. 2. LITERA TURE REVIEW Image clas sication could be cate gorized in tw o major research areas, computer vision and deep lea rn- ing. In computer vision, image processing is used to se gment the image and then to automatically describe by using other AI techniques. Deep learning is using multilayer decision making algorithms in art icial intelli- gence to understand the image. It is part of machine learning. This section tackles these tw o elds. 2.1. Segmentation In image se gmentation, P aschos [1] compare the performance of three color spaces (Lab, HSV , and RGB). Because RGB data are clearly ready as the e xplicitly data pro vided by the camera, the RGB color space is practically uni v ersally recognized by the image processing research society for displaying images. Ho we v er , there are more re gular cogniti v e spaces, such as Lab and Luv , where the dif ference in hue is quantied in analogy to ho w a human percei v es such a dif ference. In the research done by Delignon et al. [2], a comparison of dif ferent color spaces is made. The Lab color space has the potential to sho w results in a more natural style to human vision. W ang and Suter [3] proposed a ne w color image se gmentation method that incorporates both global and local homogeneity . In the hue and density subspace of HSV , the method applied the a v erage shift algorithm. The suggested technique additionally tak es into account the color component’ s c yclic characteristic. Experiments with natural-color photographs ha v e yielded interesting results. Ohashi et al. [4] uses the hill-climbing algorithm for image se g- mentation. It does se gmentation by rst determining the histogram for the image’ s three layers , then calculating the local maxim um v alues in the hi stogram for the three-layer H, S, and V in the image, then the algorithm connects image pix els with their respecti v e local maximum v alues. Ho we v er , there are se v eral disadv antages to t his method, including a at part of the search space in which all surrounding states ha v e the same v alue and the necessity for a lar ge jump to establish a ne w section. Most thresholding approaches in v olv e establishing boundaries based on gray v alues or pix el density of the image [5]. The color thresholding procedure is carried out based on acclimation and minor changes to the gre y-scale thresholding approaches. The RGB data from the surrounding area and another item ha v e been coupled to multile v el thresholding. The object w as able to be separated from the background using image fragmentation technology . Man y researches mak e use of machine learning techniques to se gments the images lik e [6], where the K-Means algorithm is applied to 2, 3 and k-cluster colored images for (k¿3). Silhouette analysis helps to assign the peaks for set k-cluster . Ho we v er , there are some dra wbacks, such as the dif culty in selecting the optimal number of clusters and the f act that the selection of the initial centroids is random. More techniques depend on the te xture lik e [7]–[9]. According to V adi v el et al. [10], images are analyzed and se gmented using the HSV color space. In this technique, features are e xtracted by choosing either the hue or the density as the dominating characteristic, which is determined by the pix el’ s saturation v alue. Image se gmentation is done using statistical re gion mer ging (SRM) [11]. The algorithm looks at the statistical underpinnings of a process that is frequently described in computer vision. The algorithm is used to estimate the v alues in the re gional e xtension and classify them together based on a smaller list standard. JSEG used color quantication to re p r esent numerous classes that can be used to dif ferentiate sections in the image. Color class labels are used to e xchange pix el colors, forming a class-map of the image [12]. Singh and Khare [13] creates an autonomous threshold-based information parameter for image se gmentation using a genetic algorithm to nd the best number of se gmentation areas. Only gray-scale photos are used in this technique. According to Sun et al. [14], multilayer thresholding is used to re visit gray-scale Ima g e classication in cultur al herita g e (Muath Sabha) Evaluation Warning : The document was created with Spire.PDF for Python.
4724 ❒ ISSN: 2252-8938 image se gmentation. The authors used nature-inspired a lgorithms to try to solv e the challenge of multilayer thresholding (N As). T o produce f acial picture histograms, a 256-le v el histogram must rst be created, and then e v ery eight contiguous le v els are represented as one v alue to simplify computations and comparisons, as well as to speed up image processing without sacricing image quality . Instead of 256 pins, there will be just 32 pins after this process [15]. This algorithm is commonly used in f acial recognition, b ut we will adapt it and apply it to our method. Man y techniques are pro vided in [16], [17] based on the scale-in v ariant features transform (SIFT). Another algorithm di vides the operation into tw o steps: recognition and se gment ation, using a top-do wn technique for recognition and a bottom-up approach for se gmentation. The rst is the h ypothesis and the second is the v erication of the h ypothesis, which results in the creation of a set of h ypotheses such as object location and ground mask. It computes the list of probable se gments created by the h ypothesis step in the v erication step [18]. 2.2. Cultural heritage image classication using deep lear ning Image classication in cultural heritage is an important task in the process of digitalization. It can be particularly challenging due to the lar ge number of dif ferent image cate gories, the v aria b i lity of the character - istics, and t h e need for high reliability . Deep learning techniques ha v e been emplo yed for architectural heritage images classication using pre-trained con v olutional neural netw orks (CNN). Deep learning algorithms ha v e demonstrated remarkable performance in image classication tasks. Deep learning is a subdiscipline of the area of articial intelligence that e v olv ed from classical ma- chine learning. T o create a learning model, deep learning approaches mimic the natural processing capability of the human brain [19]. T o comprehend deep learning, it is required to rst dene neural netw ork, which is one of the machine learning strate gies gi v en for creating a self-learning learning model. Support v ector machine (SVM), na ¨ ıv e Bayes (NB), decision tree (DT), k-nearest neighbor (KNN), and other machine learning tech- niques are e xamples. In terms of cl assication, neural netw ork has performed admirably . Dif ferent adaptations of articial neural netw orks (ANN), such as perceptron, multilayer perceptron, and backpropag ation, ha v e been presented; ho we v er , there is a serious dra wback still obstructs the precise learning process. Classic ANN has a high le v el of ability to learn and classify a certain dataset e xact itude (i.e. 99%). When the ANN is tested on a ne w dataset, ho we v er , it does not reach the same precision [20]. Ov ertting or v anishing ingredients are terms used to describe this problem. When an ANN learns the characteristics and features of certain data in such a w ay that an y change in the data af fects the ANN’ s capacity to nd signicant patterns, a problem arises. Deep learning algorithms are one of the neural netw ork architectures that mak e use of se v eral hidden layers [21]. Figure 1 sho ws the basic architecture for deep learning netw orks. Figure 1. Basic architecture of a deep neural netw ork Recurrent neural netw ork, long short-term memory (LSTM), deep belief netw ork (DBN), and CNN are e xamples of deep learning architectures [22]. The sub-sections that follo w will go through these archi- Int J Artif Intell, V ol. 13, No. 4, December 2024: 4722–4735 Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Artif Intell ISSN: 2252-8938 ❒ 4725 tectures in greater depth. The CNN for image clas sication w as used by [23] to classify architectural history images using a deep learning neural netw ork. The results demonstrate a le v el of precision of up to 90%. De- spite the f act that man y researchers are tackling the problem of properly classifying and annotating the digital heritage, Belhi et al. [24] use a specic type of deep learning classier , each of which is assigned the task of classifying a combination of asset classes. According to Kam bau et al. [25] to classify images, audio, video, and te xt, the authors use the CNN and recurrent neural netw orks approaches. The y ha v e applied this by propos- ing a cro wdsourcing platform to acquire data from the Indian Digital Heritage Space (IDHS) monuments, and designing a transfer learning-based image classier . K ulkarni et al. [26] perform image classication and query-based image label retrie v al. Using t h e pre-trained MobileNet V2 architecture and the ImageNet dataset, the proposed transfer learning technique achie v es an inference accurac y of 98.75%. Jank o vi ´ c [27] consider image classication in terms of cultural heritage as one of the most essential jobs in the digital era. It is crucial to b uild classication methods that are accurate; thus, their research com- pares four classication algorithms with a CNN. The y use: i) the multilayer perception, ii) a v eraged depen- dence estimators, ii i) forest by penalizing attrib utes, and i v) the KNN rough sets and analogy-based reasoning. Belhi et al. [28] tackle the challenge of automatically classifying and annotating cultural heritage assets using their visual features as well as the metadata a v ailable at hand by using multitask neural netw ork, where a CNN is designed for visual feature learning, and a re gular neural netw ork is used for te xtual feature learning. According to A w ad et al. [29], an older classication frame w ork w as presented. It depends on ho w the image is annotated and ho w human feedback is recei v ed. The classier will use these truth-ground annotations as a training set once the human gi v es a li st of image annotations. The classier is presented with a ne w test image and is ask ed to predict the annotations on it. F or each ne w image added to the training set, a human pro vides additional input. The block diagram of image classication is sho wn in Figure 2. Figure 2. Block diagram for image classication 3. METHODOLOGY In this research, RGB and Lab are tested in the e xpression of their performance in the ideal i mage processing function, such as the se gmentation of images. There has been an only restricted act on the color sides of te xtured images. Our methodology is summarized in Figure 3. W e rst con v ert the image color space from RGB to CIELab . In Lab color space, there are tw o color channels; the rst channel is blue to w ard yello w (opponents) and the second is green to w ards red channel, which is almost closer to ho w humans percei v e images. In addition to that, we ha v e the lightness L. Using ab from Lab , we can e xtract the lightness from the image to reduce the ef fect of shado ws, darkness, and lightness inside the images. W e intend to use pure color and to use the mix ed colors inside each layer of the image to mimic the human visual system, which may produce more accurate se gmentation. Moreo v er , the Lab g amut is lar ger than RGB g amut, which separates colors by dif ferent absolute relati v e distances than it in the RGB space [30]. Ima g e classication in cultur al herita g e (Muath Sabha) Evaluation Warning : The document was created with Spire.PDF for Python.
4726 ❒ ISSN: 2252-8938 There are man y algorithms for image se gmentation and there are also man y algorithms for image clas- sication. In this paper , some of these se gmentation and classication algorithms are discussed and the results of the proposed algori thm are compared with the results of the most well-kno wn algorithms. W e will st art with se gmentation and we will discuss three main algorithms which are gray thresholding, color thresholding, and max v alue thresholding. Figure 3. Our methodology steps 3.1. Segmentation In this step, we se gment the images and tak e the common features inside them, and then calculate the histogram for each Lab channel of the image. The Lab color space has three layers L , a , and b . The range v alues for L are [0 to 100], the range v alues for a are [-86.185 to 98.254] and the range v alues for b are [-107.863 to 94.482]. Each v alue in one layer may ha v e a set of v alues in other layers. F or e xample, we may ha v e 30 pix els that ha v e the v alue 10 on the b channel b ut dif ferent v alues in the a channel. W e assumed that we ha v e 201 dif ferent sampled v alues in the a channel, which are the inte ger v alues in the range of the a channel mentioned earlier . This is to reduce the number of histogram columns. After this step, we mer ge e v ery 3 adjacent columns for e v ery layer , which reduces the number of columns in each channel. That will reduce the time needed to recognize the features as sho wn in the ne xt stage from N × M to a constant v alue. W e repeat the mer ging step until we reach the total number of columns of 29 columns for each layer . These 29 v alues in calculation do not tak e too much processing time. The mer ging process is performed by taking the a v erage of adjacent columns. After that, we create a v ector of 29 v alues, which results in a ne w histogram of 29 columns. This will reduce the time comple xity in the ne xt step as these v ectors will be the ne w representation for each layer instead of the pre vious histogram for the a and b layers. After that, we enter these ne w v ectors (the ne w histogram) into equations that calculate the local minimum and maximum v alues in these histograms by nding the centers of the pre vious histograms to con v ert the columns to groups of points. That means, rst we con v ert the histogram fr om the columns to the linear chart that contains continuous v alues, then we apply the loca l min-max v alue so that we can calculate the local min-max v alues. The aim of calculating the local min-max v alues is to see when the color inside Lab layers changes from one color to another . After calculating the min-max v alues, we store these v alues in v ectors, thus producing these v ectors of points, and we call them clusters ( C ) . The y consist of local min-max v alues for three layers in the Lab color histogram of the image. W e assume that e v ery cluster will ha v e the v alues between e v ery contiguous local min and max v al ues in the histogram. At this stage, we found that the time for computation will be short and constant, with time comple xity O ( C ) . W e apply the equation of mer ging columns that gi v e 20 columns, (not for all the columns in the rst histogram,) then the number of the local min-max v alues equals the number of clusters that we will use to se gment the images, into se gments to use these se gments for recognition and classication as we will see in the ne xt steps. After nding min-max v ectors, we use these v ectors as the clusters by applying these v ectors into k-means clustering (an unsupervised technique for clustering images without the user pro viding sample classes or labels, and uses an equation to get results such that Euclidean distance). After that, we apply the k-means to the whole original image, which is a tw o-dimensional array . W e then tak e the number of local min-max v alues that will be the number of groups and the number of se gments in the image which we w ant to apply this Int J Artif Intell, V ol. 13, No. 4, December 2024: 4722–4735 Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Artif Intell ISSN: 2252-8938 ❒ 4727 algorithm on, and the v alues for the v ectors that are the outcomes of local min-max v alues as initial v alues for centroid in each cluster . W e nally produce indices for clusters, which will enhance the nal outcomes of the k-means that will represent the se gments in the image we are w orking on. The L 2 norm is used in the k-means algorithm to group the Lab colors, considering the Lab as a Euclidean space. d ( p 1 , p 2 ) = p ( x 1 − x 2 ) 2 + ( y 1 − y 2 ) 2 W e nd the distance from e v ery color to e v ery centroid to get the minimum distance, and so to wh i ch cluster this color is related. If the color distance is shorter to another centroid, this means that this color does not belong to this centroid. This color is transferred to the cluster that has the minimum distance from its centroid. After that, we check if there is an y ne w pix el to be transferred to another cluster , update the centers of clusters (as the rst steps), and see if there are no transfers between pix els from an y cluster to another . The result will be the v ector containing the cluster indices that will r epresent the se gments in the image on which we apply this algorithm. That means, this step will produce a ne w image with a group of se gments where each se gment is represented inside the image with a limited number of colors where each color represents the se gment from the original image. As sho wn in Figure 4, the ne w image will ha v e a limited number of colors as labels, each color represents a se gment inside the image. These se gments will be used in the recognition and classication steps. Then we trim the background area adjacent to this object by trimming the area of the same color (so that the image contains a nite number of colors to represent each color se gment). W e apply the trimming process in the original image in the Lab color space by comparing each area of the ne w image (containing a nite number of colors) with the original image containing all colors. Then we get all pix els that ha v e a color with v alue C that found in the inde x ( i s , j s ) and get all pix els from the original image with the same indices, b ut there will be a group of colors found within the inde x es ( i s , j s ) in the original image. This operation will be applied for all three layers L , a and b in the ( i s , j s ) re gions. Figure 4. The result from applying K-means and taking local min-max v alues as the clusters The se gmented re gions of the k-means output are transferred to the original image in the same pla ce for all layers. The areas that were trimmed in the pre vious stages will be used as images and the transfer of these ne w images to the recognition and classication of calls in the ne xt stage. After se gmenting the images, each se gment is tak en separately (these se gments should represent a meaningful se gment; otherwis e, it will be rejected). 3.2. Recognition step At this stage, the se gments e xtracted from the original image must be recognized as sho wn in the pre vious stage. As discussed in the pre vious sections, all se gments will be treated as a ne w image. The Luminance histogram of this se gment is calculated using a v ector of 256 columns. Ev ery 3 adjacent columns are mer ged by taking the a v erage for these three column v alues, as sho wn in Figure 5. The resulting 86 columns are mer ged ag ain (each 3 columns) to produce 29 columns. This operation will be applied to all images in the data set. Ev ery image will be represented by a v ector of 29 columns, which means a v ector of 29 v alues instead of se gments of N × M pix els. W e just need a v ector of limited size of 29 v alues. The operation of this se gment will con v ert from comple xity of O ( N × M ) to O ( C ) . This means con v erting from the quadratic system to the constant system, which will increase the speed and the performance and mak e it more po werful. This v ector will be used in the classication step instead of the original se gment. Ima g e classication in cultur al herita g e (Muath Sabha) Evaluation Warning : The document was created with Spire.PDF for Python.
4728 ❒ ISSN: 2252-8938 Figure 5. Mer ging each 3 columns of the histogram by taking their a v erage 3.3. K-near est neighbor calculations The KNN algorithm will be used to classify these se gments to determine to which class each se gment belongs, of which cultural heritage is stored in the datas et. The v ector that is produced in the pre vious step will be considered and all the v ectors that are stored inside the dataset that hold labels to see which of these v ectors that are nearest to the ne w v ector by using this formula: d 1 ( I 1 , I 2 ) = P P | I p 1 − I p 2 | Where P is the cell number or the inde x inside the v ector , I 1 , 2 represents the ima g e s or se gments, and d is the result that has the label of specic cultural heritage that the ne w image belongs to. W e subtract the v ector from the 29 v alues that represent the se gment produced in the last step with some v ectors from a set of v ectors in the complete data set. 3.4. Classication After that, the last step produces a group of v alues, each v alue representing the sum of all 29 v alues produced from the subtracting operation. Finding the m inimum v alue of these v alues and looking at the image that will get the min v alue from these operations is ne xt. This image will hold the goal cultural heritage for this se gment b ut not the whole original image because the whole original image has man y se gments, some of them not cultural features. Instead of applying the KNN algorithm and subtracting the entire image of size ( x × y × 3) (three layers), we only need to subtract 29 v alues, then the time comple xity will be O(C) instead of O ( N × M ) as mentioned earlier , which has a signicant ef fect for a lar ge number of pix els that will be calculated. Ev ery culture has common characteristics, and the classication is to tak e e v ery se gment of the image tested and nd its match from the v ectors. It is labeled accordingly and then decided that this se gment belongs to a group that represents a certain cultural heritage. The image is added to the data set, and the data set is gro wn by one. After lling in the v ector , determine to which cultural heritage group the image belongs. Ho we v er , the time comple xity will be O ( K × N ) where K is the number of se gments in each image in data set and N is the number of images in data set. It will be huge for huge data sets. F or e xample, if we ha v e 100 , 000 images in the data set a n d each image has 50 se gments, then the number of iterations will be 100 , 000 × 50 that will produce 5 , 000 , 000 which is huge in real time system. T o o v ercome this problem, we use another methodology to store data which is a binary search tree. This means that each se gment inside specic cultural heritage images will be stored in a binary search tree that represents this cultural heritage. The aim of using the binary search tree is to apply its concept that the v alue of the root is lar ger than the left child and less than the right child that gi v es e xibility for our search, Int J Artif Intell, V ol. 13, No. 4, December 2024: 4722–4735 Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Artif Intell ISSN: 2252-8938 ❒ 4729 instead of taking O ( k ) by us ing linear search, or using search item by item where the comple xity is O ( Log ( k )) then it will tak e l og ( K ) for the iteration, instead of K iterations. This means that we do not need to test the whole tree, just l og ( k ) of elements from this tree (that the binary search tree is just testing the left or right branch). Then, the test will be by calculating the dif ference between the v ector and the v ectors in the data set, getting the summation, and testing it with the tree. That will help to mak e the decision to go to the left or right or to stop i f the v alue is lar ger than the pre vious le v el. Ev ery time we go deep in the left branches, the v alue should be lo wer than pre vious left le v el and vice v ersa for the right side; then in e v ery test we will discard half of the v ectors from v ectors inside the tree that represent specic image; then its v alue of search will be smaller than the le v el that stands in it before. W e als o applied three classiers including KNN, logistic re gression (LR), and DT . The splitting rate of training and testing has been set to %75 and %25 respecti v ely . The e v aluation of classication results will be based on the common information retrie v al metrics including precision, recall, and f-measure. 4. RESUL TS AND DISCUSSION After around 150 e xperiment s on 3200 images of cultural heritage from the Pinterest data set of 20 cultures, it is noticed that the se gmentation step has se v eral attrib utes to consider , such as the dependence on the color dif ference within the image. Another thing is that se gmentation depends on image r esolution, where higher resolution results in better classication. There is another attrib ute that determines the resol ution of the color -space se gmentation which is the channels created by the color space in the laboratory , which made the selection of the section more accurate and solv ed the problem created by the lightness. F or se gmenting certain re gions, as sho wn in our methodology , we se gment the images by taking the closed re gions. As sho wn in Figure 6, the number of se gments is 3, representing the columns, the sk y , and the area between the columns. The rst se gme n t will recognize the column as roman culture, the other se gments will get unkno wn label, the result will be a roman cultural image depending on the labeled se gment. Figure 6. Recognition result from testing a roman culture image 4.1. T ime complexity In Figure 7, a comparison is made between the time comple xity of the proposed method compared to the def ault technique (linear binary search tree). The time comple xity is signicantly reduced in the proposed technique, where the comple xity of the proposed technique is O ( N × Log ( K )) , while it is O ( N × K ) in the linear binary tree. As sho wn in Figure 7, the g ap between the tw o curv es increases e xponentially as the x-axis progresses (number of se gments). Ima g e classication in cultur al herita g e (Muath Sabha) Evaluation Warning : The document was created with Spire.PDF for Python.
4730 ❒ ISSN: 2252-8938 0 20 40 60 80 10 0 12 0 0 2 4 6 8 10 12 Ti m e #i m a g es   *  1 0 Ti m e   C o m p l e x i t y  O   ( N  *   L o g  K ) O( N * K ) Figure 7. T ime comple xity for our method vs. the BST Figure 8 compares the time comple xity in the proposed methodology and that in the KNN algorithm. The KNN algorithm subtracts the entire image tested with images from the dataset that has N ro ws and M columns. Ho we v er , the proposed method needs only to subtract a v ector of 29 v alues that is static for all images inside the dataset. The g ap between the tw o curv es increases as the number of images increases, and this is another bonus point for the proposed methodology . 0 20 00 0 40 00 0 60 00 0 80 00 0 10 00 00 12 00 00 0 50 10 0 15 0 20 0 25 0 30 0 35 0 Ti m e #   im ag e s Ti m e   C o m p l e x i t y   f o r   s u b t r a c t i o n O( N * M ) 29  v a l u e Figure 8. T ime comple xity for our subtraction method ag ainst subtraction in KNN Figure 9 compares the accurac y of the results by using three dif ferent color spaces, CIELab, HSV , and RGB. It is clear that the curv es are almost parallel to each other , and the results are almost the same with a pri vile ge to the CIE-Lab color space. W e think that the results are close and parallel because the original images are captured in the RGB color space. The pri vile ge of Lab and HSV comes from the f act that these color spaces are closer to human perception. The CIE-Lab color space has a bigger g amut and it gi v es better results in the k-means algorithm [30]. This pro v es that our method in using tw o dimensions out of the Lab color space ( ab ) impro v ed the results. Int J Artif Intell, V ol. 13, No. 4, December 2024: 4722–4735 Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Artif Intell ISSN: 2252-8938 ❒ 4731 0% 10 % 20 % 30 % 40 % 50 % 60 % 70 % 80 % 0 20 40 60 80 10 0 12 0 14 0 16 0 Ac c u r a c y #  I m a g es Ac c u r a c y CI E   L A B   c o l o r   s p a c e HS V   c o l o r   s p a c e RG B   c o l o r   s p a c e Figure 9. Accurac y using CIELab, RGB and HSV color spaces Figure 10 compares the classication accurac y of the proposed technique with v e of the most related algorithms and techniques from pre vious research, namely hill climbing, gray multile v el thresholding (GMT), SRM, te xture features, and k-means color clustering. The classication accurac y is measured relati v e to the human classication. It is noticed that the closest algorithms are the te xture and K-means color clustering. The y depend on the number of clusters to gi v e a nite number of se gments. On the other hand, the y used the L -layer of the Lab color space in their solution, while the proposed algorithm concentrated on pure color to mimic human perception. 0% 10 % 20 % 30 % 40 % 50 % 60 % 70 % 80 % 0 20 40 60 80 10 0 12 0 14 0 16 0 Ac c u r a c y #  i m a g es Co m p a r i s o n mi n   -   m a x   w i t h   L A B hi l l   c l i m b i n g Gr a y   M u l t i l e v e l   T h r e s h o l d i n g SR M Te x t u r e   F e a t u r e s K- m e a n s   c l u s t e r   a n a l y s i s   f o r   i m a g e   s e g m e n t a t i o n Figure 10. Comparing our algorithm (min-max with Lab) to v e other well-kno wn most related algorithms Hill climbing algorithm produces less accurate results, and that is because it depends on max v a lue, where the number of clusters is small, and it remo v es too much features in the image. Therefore, the number of se gments will be less than our proposed algorithm. The number of se gments in our algorithm is about double. The gray thresholding uses one layer while our algorithm uses tw o layers from a perceptual color space, which uses more useful information. Finally , as sho wn in Figure 10, our technique gi v es the best result in cultural heritage features among all the compared techniques. Ima g e classication in cultur al herita g e (Muath Sabha) Evaluation Warning : The document was created with Spire.PDF for Python.