# Stochastic Detection of Interior Design Styles Using a Deep-Learning Model for Reference Images
## 2 Literature Review
### Deep-Learning Algorithms for Interior Design Image Recognition  
Deep learning has achieved great success in various machine learning fields, such as computer vision and natural language processing. Deep-learning mechanisms enable computational models composed of multiple processing layers to learn data representations with multiple levels of abstraction [8]. Convolutional neural networks (CNNs) are most commonly applied in computer vision applications, such as facial detection [9]. The convolutional and pooling layers in CNNs can be considered imitations of human neurons [27]. A CNN consists of a feature extractor and classifier. Before deep learning and CNNs were developed, the features of images were manually extracted by domain experts. By contrast, the feature extractor of a CNN learns to calculate the main features of images for classification. The calculated feature data are used to train a classifier consisting of neural network layers and a classification layer, such as a support vector machine or softmax activation function. In the architectural and interior design domain, some researchers have proposed CNN-based approaches for the recognition of design-related information in images. [PERSON], [PERSON], et al. (2017) constructed a large image database of outdoor and indoor locations for deep learning and provided the source code and weights for a CNN model trained on their database [28]. Their database contains approximately 10 million images representing more than 400 space categories. [PERSON], [PERSON], et al. (2019) used deep learning to explore the trends of interior design in different regions [29]. Moreover, [PERSON], [PERSON] and [PERSON], (2018) implemented auto-recognition of room usage in indoor images of apartments in South Korea as a component of an intelligent management system for interior reference images [30]. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Style** & **Description** & **Abstract Factor** \\ \hline \multirow{7}{*}{\begin{tabular}{c} Casual \\ Style \\ \end{tabular} } & Round shapes instead of straight lines or squares are implemented. Based on two to three core colors, various bright and cheerful colors are used. Checks, stripes, and geometric patterns are used frequently. Light-feeling materials (e.g., plastics and fabrics) and compositions of heterogeneous materials (e.g., metals and textiles or wood and glass) are commonly chosen. & Shapes/forms: round Colors: bright colors, two to three colors; Materials: plastic, fabric; Patterns: for example, checks and stripes. \\ \multirow{7}{*}{\begin{tabular}{c} Classic \\ Style \\ \end{tabular} } & The classic style is formal and luxurious. Most of the classic styles in Europe (including Baroque, Rocco, and Neo-classic styles) were developed long ago and are used to this day. Dark colors such as brown, dark green, and beige are frequently used. In addition, wood and tile are used for finishing, and gorgeous decorations such as patterns and large molding are implemented. & Shapes/forms: formal, gorgeous; Colors: brown, dark green; Materials: wood, gold, velvet; Patterns: traditional patterns. \\ \multirow{7}{*}{\
\begin{tabular}{c} Modern \\ Style \\ \end{tabular} } & An urban clean image with achromatic colors and intense contrast. Straightforward designs without messy decorations provide clean and simple functional beauty. & Shapes/forms: straight, simple; Colors: achromatic colors; Materials: glass, metal, leather; Patterns: solid patterns. \\ \multirow{7}{*}{
\begin{tabular}{c} Natural \\ Style \\ \end{tabular} } & The main materials used are hard and cool materials such as glass, metal, and artificial materials. Recently, simple and geometric curves have been used. A single emphasis color is used to create a sharp image. & Shapes/forms: curved, simple; Colors: colors of nature such as green, beige, and yellow; Materials: wood, fabric, stone; Patterns: plant patterns. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: General definitions of interior design styles derived from previous research studies.