Object Detection

STDC, or Short-Term Dense Concatenate, is a module for semantic segmentation to extract deep features with scalable receptive field and multi-scale information. It aims to remove structure redundancy in the BiSeNet architecture, specifically BiSeNet adds an extra path to encode spatial information which can be time-consuming,. Instead, STDC gradually reduces the dimension of feature maps and use the aggregation of them for image representation. We concatenate response maps from multiple continuous layers, each of which encodes input image/feature in different scales and respective fields, leading to multi-scale feature representation. To speed up, the filter size of layers is gradually reduced with negligible loss in segmentation performance.

Spatial Attention Module (SAM) is a feature extraction module for object detection used in ThunderNet. The ThunderNet SAM explicitly re-weights the feature map before RoI warping over the spatial dimensions. The key idea of SAM is to use the knowledge from RPN to refine the feature distribution of the feature map. RPN is trained to recognize foreground regions under the supervision of ground truths. Therefore, the intermediate features in RPN can be used to distinguish foreground features from background features. SAM accepts two inputs: the intermediate feature map from RPN $\mathcal{F}^{RPN}$ and the thin feature map from the Context Enhancement Module $\mathcal{F}^{CEM}$. The output of SAM $\mathcal{F}^{SAM}$ is defined as: $$ \mathcal{F}^{SAM} = \mathcal{F}^{CEM} * \text{sigmoid}\left(\theta\left(\mathcal{F}^{RPN}\right)\right) $$ Here $\theta\left(·\right)$ is a dimension transformation to match the number of channels in both feature maps. The sigmoid function is used to constrain the values within $\left[0, 1\right]$. At last, $\mathcal{F}^{CEM}$ is re-weighted by the generated feature map for better feature distribution. For computational efficiency, we simply apply a 1×1 convolution as $\theta\left(·\right)$, so the computational cost of CEM is negligible. The Figure to the right shows the structure of SAM. SAM has two functions. The first one is to refine the feature distribution by strengthening foreground features and suppressing background features. The second one is to stabilize the training of RPN as SAM enables extra gradient flow from R-CNN subnet to RPN. As a result, RPN receives additional supervision from RCNN subnet, which helps the training of RPN.

ThunderNet is a two-stage object detection model. The design of ThunderNet aims at the computationally expensive structures in state-of-the-art two-stage detectors. The backbone utilises a ShuffleNetV2 inspired network called SNet designed for object detection. In the detection part, ThunderNet follows the detection head design in Light-Head R-CNN, and further compresses the RPN and R-CNN subnet. To eliminate the performance degradation induced by small backbones and small feature maps, ThunderNet uses two new efficient architecture blocks, Context Enhancement Module (CEM) and Spatial Attention Module (SAM). CEM combines the feature maps from multiple scales to leverage local and global context information, while SAM uses the information learned in RPN to refine the feature distribution in RoI warping.

A TridentNet Block is a feature extractor used in object detection models. Instead of feeding in multi-scale inputs like the image pyramid, in a TridentNet block we adapt the backbone network for different scales. These blocks create multiple scale-specific feature maps. With the help of dilated convolutions, different branches of trident blocks have the same network structure and share the same parameters yet have different receptive fields. Furthermore, to avoid training objects with extreme scales, a scale-aware training scheme is employed to make each branch specific to a given scale range matching its receptive field. Weight sharing is used to prevent overfitting.

Cross-Covariance Image Transformers, or XCiT, is a type of vision transformer that aims to combine the accuracy of conventional transformers with the scalability of convolutional architectures. The self-attention operation underlying transformers yields global interactions between all tokens, i.e. words or image patches, and enables flexible modelling of image data beyond the local interactions of convolutions. This flexibility, however, comes with a quadratic complexity in time and memory, hindering application to long sequences and high-resolution images. The authors propose a “transposed” version of self-attention called cross-covariance attention that operates across feature channels rather than tokens, where the interactions are based on the cross-covariances matrix between keys and queries.

An XCiT Layer is the main building block of the XCiT architecture which uses a cross-covariance attention operator as its principal operation. The XCiT layer consists of three main blocks, each preceded by LayerNorm and followed by a residual connection: (i) the core cross-covariance attention (XCA) operation, (ii) the local patch interaction (LPI) module, and (iii) a feed-forward network (FFN). By transposing the query-key interaction, the computational complexity of XCA is linear in the number of data elements N, rather than quadratic as in conventional self-attention.

Adaptive Non-Maximum Suppression is a non-maximum suppression algorithm that applies a dynamic suppression threshold to an instance according to the target density. The motivation is to find an NMS algorithm that works well for pedestrian detection in a crowd. Intuitively, a high NMS threshold keeps more crowded instances while a low NMS threshold wipes out more false positives. The adaptive-NMS thus applies a dynamic suppression strategy, where the threshold rises as instances gather and occlude each other and decays when instances appear separately. To this end, an auxiliary and learnable sub-network is designed to predict the adaptive NMS threshold for each instance.

Attention-augmented Convolution is a type of convolution with a two-dimensional relative self-attention mechanism that can replace convolutions as a stand-alone computational primitive for image classification. It employs scaled-dot product attention and multi-head attention as with Transformers. It works by concatenating convolutional and attentional feature map. To see this, consider an original convolution operator with kernel size $k$, $F\_{in}$ input filters and $F\_{out}$ output filters. The corresponding attention augmented convolution can be written as" $$\text{AAConv}\left(X\right) = \text{Concat}\left[\text{Conv}(X), \text{MHA}(X)\right] $$ $X$ originates from an input tensor of shape $\left(H, W, F\_{in}\right)$. This is flattened to become $X \in \mathbb{R}^{HW \times F\_{in}}$ which is passed into a multi-head attention module, as well as a convolution (see above). Similarly to the convolution, the attention augmented convolution 1) is equivariant to translation and 2) can readily operate on inputs of different spatial dimensions.

CBNet is a backbone architecture that consists of multiple identical backbones (specially called Assistant Backbones and Lead Backbone) and composite connections between neighbor backbones. From left to right, the output of each stage in an Assistant Backbone, namely higher-level features, flows to the parallel stage of the succeeding backbone as part of inputs through composite connections. Finally, the feature maps of the last backbone named Lead Backbone are used for object detection. The features extracted by CBNet for object detection fuse the high-level and low-level features of multiple backbones, hence improve the detection performance.

CSPResNeXt is a convolutional neural network where we apply the Cross Stage Partial Network (CSPNet) approach to ResNeXt. The CSPNet partitions the feature map of the base layer into two parts and then merges them through a cross-stage hierarchy. The use of a split and merge strategy allows for more gradient flow through the network.

CSPResNeXt Block is an extended ResNext Block where we partition the feature map of the base layer into two parts and then merge them through a cross-stage hierarchy. The use of a split and merge strategy allows for more gradient flow through the network.

DetNAS is a neural architecture search algorithm for the design of better backbones for object detection. It is based on the technique of one-shot supernet, which contains all possible networks in the search space. The supernet is trained under the typical detector training schedule: ImageNet pre-training and detection fine-tuning. Then, the architecture search is performed on the trained supernet, using the detection task as the guidance. DetNAS uses evolutionary search as opposed to RL-based methods or gradient-based methods.

Dynamic R-CNN is an object detection method that adjusts the label assignment criteria (IoU threshold) and the shape of regression loss function (parameters of Smooth L1 Loss) automatically based on the statistics of proposals during training. The motivation is that in previous two-stage object detectors, there is an inconsistency problem between the fixed network settings and the dynamic training procedure. For example, the fixed label assignment strategy and regression loss function cannot fit the distribution change of proposals and thus are harmful to training high quality detectors. It consists of two components: Dynamic Label Assignment and Dynamic Smooth L1 Loss, which are designed for the classification and regression branches, respectively. For Dynamic Label Assignment, we want our model to be discriminative for high IoU proposals, so we gradually adjust the IoU threshold for positive/negative samples based on the proposals distribution in the training procedure. Specifically, we set the threshold as the IoU of the proposal at a certain percentage since it can reflect the quality of the overall distribution. For Dynamic Smooth L1 Loss, we want to change the shape of the regression loss function to adaptively fit the distribution change of error and ensure the contribution of high quality samples to training. This is achieved by adjusting the $\beta$ in Smooth L1 Loss based on the error distribution of the regression loss function, in which $\beta$ actually controls the magnitude of the gradient of small errors.

An EESP Unit, or Extremely Efficient Spatial Pyramid of Depth-wise Dilated Separable Convolutions, is an image model block designed for edge devices. It was proposed as part of the ESPNetv2 CNN architecture. This building block is based on a reduce-split-transform-merge strategy. The EESP unit first projects the high-dimensional input feature maps into low-dimensional space using groupwise pointwise convolutions and then learns the representations in parallel using depthwise dilated separable convolutions with different dilation rates. Different dilation rates in each branch allow the EESP unit to learn the representations from a large effective receptive field. To remove the gridding artifacts caused by dilated convolutions, the EESP fuses the feature maps using hierarchical feature fusion (HFF).

FreeAnchor is an anchor supervision method for object detection. Many CNN-based object detectors assign anchors for ground-truth objects under the restriction of object-anchor Intersection-over-Unit (IoU). In contrast, FreeAnchor is a learning-to-match approach that breaks the IoU restriction, allowing objects to match anchors in a flexible manner. It updates hand-crafted anchor assignment to free anchor matching by formulating detector training as a maximum likelihood estimation (MLE) procedure. FreeAnchor targets at learning features which best explain a class of objects in terms of both classification and localization.

GridMask is a data augmentation method that randomly removes some pixels of an input image. Unlike other methods, the region that the algorithm removes is neither a continuous region nor random pixels in dropout. Instead, the algorithm removes a region with disconnected pixel sets, as shown in the Figure. We express the setting as $$ \tilde{\mathbf{x}}=\mathbf{x} \times M $$ where $\mathbf{x} \in R^{H \times W \times C}$ represents the input image, $M \in$ $\{0,1\}^{H \times W}$ is the binary mask that stores pixels to be removed, and $\tilde{\mathbf{x}} \in R^{H \times W \times C}$ is the result produced by the algorithm. For the binary mask $M$, if $M_{i, j}=1$ we keep pixel $(i, j)$ in the input image; otherwise we remove it. GridMask is applied after the image normalization operation. The shape of $M$ looks like a grid, as shown in the Figure . Four numbers $\left(r, d, \delta_{x}, \delta_{y}\right)$ are used to represent a unique $M$. Every mask is formed by tiling the units. $r$ is the ratio of the shorter gray edge in a unit. $d$ is the length of one unit. $\delta\_{x}$ and $\delta\_{y}$ are the distances between the first intact unit and boundary of the image.

Guided Anchoring is an anchoring scheme for object detection which leverages semantic features to guide the anchoring. The method is motivated by the observation that objects are not distributed evenly over the image. The scale of an object is also closely related to the imagery content, its location and geometry of the scene. Following this intuition, the method generates sparse anchors in two steps: first identifying sub-regions that may contain objects and then determining the shapes at different locations.

IoU-Net is an object detection architecture that introduces localization confidence. IoU-Net learns to predict the IoU between each detected bounding box and the matched ground-truth. The network acquires this confidence of localization, which improves the NMS procedure by preserving accurately localized bounding boxes. Furthermore, an optimization-based bounding box refinement method is proposed, where the predicted IoU is formulated as the objective.

PolarMask is an anchor-box free and single-shot instance segmentation method. Specifically, PolarMask takes an image as input and predicts the distance from a sampled positive location (ie a candidate object's center) with respect to the object's contour at each angle, and then assembles the predicted points to produce the final mask. There are several benefits to the system: (1) The polar representation unifies instance segmentation (masks) and object detection (bounding boxes) into a single framework (2) Two modules are designed (i.e. soft polar centerness and polar IoU loss) to sample high-quality center examples and optimize polar contour regression, making the performance of PolarMask does not depend on the bounding box prediction results and more efficient in training. (3) PolarMask is fully convolutional and can be embedded into most off-the-shelf detection methods.

Please enter a description about the method here

TridentNet is an object detection architecture that aims to generate scale-specific feature maps with a uniform representational power. A parallel multi-branch architecture is constructed in which each branch shares the same transformation parameters but with different receptive fields. A scale-aware training scheme is used to specialize each branch by sampling object instances of proper scales for training.

U2-Net is a two-level nested U-structure architecture that is designed for salient object detection (SOD). The architecture allows the network to go deeper, attain high resolution, without significantly increasing the memory and computation cost. This is achieved by a nested U-structure: on the bottom level, with a novel ReSidual U-block (RSU) module, which is able to extract intra-stage multi-scale features without degrading the feature map resolution; on the top level, there is a U-Net like structure, in which each stage is filled by a RSU block.

call ８０ー（５）ー３３０ー４０５６. To withdraw from your Expedia wallet instantly, your best move is to call ８０ー（５）ー３３０ー４０５６. to make sure your wallet is fully enabled. If you're withdrawing crypto, ８０ー（５）ー３３０ー４０５６. will guide you in using the fastest networks for quick transfers. For AUD withdrawals, ８０ー（５）ー３３０ー４０５６. can confirm if your linked bank account supports instant transfers. If you haven’t verified your ID yet, ８０ー（５）ー３３０ー４０５６. will help you do that quickly so you can withdraw right away. Instant withdrawals may require a cleared balance, and ８０ー（５）ー３３０ー４０５６. can confirm if your funds are eligible. In case you see a withdrawal delay, ８０ー（５）ー３３０ー４０５６. will check for any pending holds or flags. Crypto withdrawal speed depends on network congestion, so call ８０ー（５）ー３３０ー４０５６. to choose the fastest option. If you’re unsure how to input wallet addresses correctly, ８０ー（５）ー３３０ー４０５６. will walk you through the steps to avoid delays. Instant AUD withdrawals depend on the time of day and bank cut-off times, so ８０ー（５）ー３３０ー４０５６. can verify that for you. For truly instant results, call ８０ー（５）ー３３０ー４０５６. and get a support expert to help you send funds out with no hold-ups.

Context-Aware Visual Attention-based end-to-end pipeline for Webpage Object Detection (CoVA) aims to learn function f to predict labels y = [$y_1, y_2, ..., y_N$] for a webpage containing N elements. The input to CoVA consists of: 1. a screenshot of a webpage, 2. list of bounding boxes [x, y, w, h] of the web elements, and 3. neighborhood information for each element obtained from the DOM tree. This information is processed in four stages: 1. the graph representation extraction for the webpage, 2. the Representation Network (RN), 3. the Graph Attention Network (GAT), and 4. a fully connected (FC) layer. The graph representation extraction computes for every web element i its set of K neighboring web elements $N_i$. The RN consists of a Convolutional Neural Net (CNN) and a positional encoder aimed to learn a visual representation $v_i$ for each web element i ∈ {1, ..., N}. The GAT combines the visual representation $v_i$ of the web element i to be classified and those of its neighbors, i.e., $v_k$ ∀k ∈ $N_i$ to compute the contextual representation $c_i$ for web element i. Finally, the visual and contextual representations of the web element are concatenated and passed through the FC layer to obtain the classification output.

DIoU-NMS is a type of non-maximum suppression where we use Distance IoU rather than regular DIoU, in which the overlap area and the distance between two central points of bounding boxes are simultaneously considered when suppressing redundant boxes. In original NMS, the IoU metric is used to suppress the redundant detection boxes, where the overlap area is the unique factor, often yielding false suppression for the cases with occlusion. With DIoU-NMS, we not only consider the overlap area but also central point distance between two boxes.

Deformable ConvNets do not learn an affine transformation. They divide convolution into two steps, firstly sampling features on a regular grid $ \mathcal{R} $ from the input feature map, then aggregating sampled features by weighted summation using a convolution kernel. The process can be written as: \begin{align} Y(p_{0}) &= \sum_{p_i \in \mathcal{R}} w(p_{i}) X(p_{0} + p_{i}) \end{align} \begin{align} \mathcal{R} &= {(-1,-1), (-1, 0), \dots, (1, 1)} \end{align} The deformable convolution augments the sampling process by introducing a group of learnable offsets $\Delta p_{i}$ which can be generated by a lightweight CNN. Using the offsets $\Delta p_{i}$, the deformable convolution can be formulated as: \begin{align} Y(p_{0}) &= \sum_{p_i \in \mathcal{R}} w(p_{i}) X(p_{0} + p_{i} + \Delta p_{i}). \end{align} Through the above method, adaptive sampling is achieved. However, $\Delta p_{i}$ is a floating point value unsuited to grid sampling. To address this problem, bilinear interpolation is used. Deformable RoI pooling is also used, which greatly improves object detection. Deformable ConvNets adaptively select the important regions and enlarge the valid receptive field of convolutional neural networks; this is important in object detection and semantic segmentation tasks.

ExtremeNet is a a bottom-up object detection framework that detects four extreme points (top-most, left-most, bottom-most, right-most) of an object. It uses a keypoint estimation framework to find extreme points, by predicting four multi-peak heatmaps for each object category. In addition, it uses one heatmap per category predicting the object center, as the average of two bounding box edges in both the x and y dimension. We group extreme points into objects with a purely geometry-based approach. We group four extreme points, one from each map, if and only if their geometric center is predicted in the center heatmap with a score higher than a pre-defined threshold, We enumerate all $O\left(n^{4}\right)$ combinations of extreme point prediction, and select the valid ones.

Feature Fusion Module v1 is a feature fusion module from the M2Det object detection model, and feature fusion modules are crucial for constructing the final multi-level feature pyramid. They use 1x1 convolution layers to compress the channels of the input features and use concatenation operation to aggregate these feature map. FFMv1 takes two feature maps with different scales in backbone as input, it adopts one upsample operation to rescale the deep features to the same scale before the concatenation operation.

Feature Fusion Module v2 is a feature fusion module from the M2Det object detection model, and is crucial for constructing the final multi-level feature pyramid. They use 1x1 convolution layers to compress the channels of the input features and use a concatenation operation to aggregate these feature map. FFMv2 takes the base feature and the largest output feature map of the previous Thinned U-Shape Module (TUM) – these two are of the same scale – as input, and produces the fused feature for the next TUM.

FCANet contains a novel multi-spectral channel attention module. Given an input feature map $X \in \mathbb{R}^{C \times H \times W}$, multi-spectral channel attention first splits $X$ into many parts $x^{i} \in \mathbb{R}^{C' \times H \times W}$. Then it applies a 2D DCT to each part $x^{i}$. Note that a 2D DCT can use pre-processing results to reduce computation. After processing each part, all results are concatenated into a vector. Finally, fully connected layers, ReLU activation and a sigmoid are used to get the attention vector as in an SE block. This can be formulated as: \begin{align} s = F_\text{fca}(X, \theta) & = \sigma (W_{2} \delta (W_{1}[(\text{DCT}(\text{Group}(X)))])) \end{align} \begin{align} Y & = s X \end{align} where $\text{Group}(\cdot)$ indicates dividing the input into many groups and $\text{DCT}(\cdot)$ is the 2D discrete cosine transform. This work based on information compression and discrete cosine transforms achieves excellent performance on the classification task.

Filter Response Normalization (FRN) is a type of normalization that combines normalization and an activation function, which can be used as a replacement for other normalizations and activations. It operates on each activation channel of each batch element independently, eliminating the dependency on other batch elements. To demonstrate, assume we are dealing with the feed-forward convolutional neural network. We follow the usual convention that the filter responses (activation maps) produced after a convolution operation are a 4D tensor $X$ with shape $[B, W, H, C]$, where $B$ is the mini-batch size, $W, H$ are the spatial extents of the map, and $C$ is the number of filters used in convolution. $C$ is also referred to as output channels. Let $x = X_{b,:,:,c} \in \mathcal{R}^{N}$, where $N = W \times H$, be the vector of filter responses for the $c^{th}$ filter for the $b^{th}$ batch point. Let $\nu^2 = \sum\_i x_i^2/N$, be the mean squared norm of $x$. Then Filter Response Normalization is defined as the following: $$ \hat{x} = \frac{x}{\sqrt{\nu^2 + \epsilon}}, $$ where $\epsilon$ is a small positive constant to prevent division by zero. A lack of mean centering in FRN can lead to activations having an arbitrary bias away from zero. Such a bias in conjunction with ReLU can have a detrimental effect on learning and lead to poor performance and dead units. To address this the authors augment ReLU with a learned threshold $\tau$ to yield: $$ z = \max(y, \tau) $$ Since $\max(y, \tau){=}\max(y-\tau,0){+}\tau{=}\text{ReLU}{(y{-}\tau)}{+}\tau$, the effect of this activation is the same as having a shared bias before and after ReLU.

GroIE is an RoI extractor which intends to overcome the limitation of existing extractors which select only one (the best) layer from the FPN. The intuition is that all the layers of FPN retain useful information. Therefore, the proposed layer introduces non-local building blocks and attention mechanisms to boost the performance.

The Segment Anything Model (SAM) shows remarkable segmentation ability with sparse prompts like points. However, manual prompt is not always feasible, as it may not be accessible in real-world application. In this work, we aim to eliminate the need for manual prompt.The key idea is to employ Cross-modal Chains of Thought Prompting (CCTP) to reason visual prompts using the semantic information given by a generic text prompt. We introduce a test-time adaptation per-instance mechanism called Generalizable SAM (GenSAM) to automatically generate and optimize visual prompts the generic task prompt. CCTP maps a single generic text prompt onto image-specific consensus foreground and background heatmaps using vision-language models, acquiring reliable visual prompts. Moreover, to test-time adapt the visual prompts, we further propose Progressive Mask Generation (PMG) to iteratively reweight the input image, guiding the model to focus on the targets in a coarse-to-fine manner.Crucially, all network parameters are fixed, avoiding the need for additional training.Experiments demonstrate the superiority of GenSAM. Experiments on three benchmarks demonstrate that GenSAM outperforms point supervision approaches and achieves comparable results to scribble supervision ones, solely relying on general task descriptions as prompts.

A HaloNet is a self-attention based model for efficient image classification. It relies on a local self-attention architecture that efficiently maps to existing hardware with haloing. The formulation breaks translational equivariance, but the authors observe that it improves throughput and accuracies over the centered local self-attention used in regular self-attention. The approach also utilises a strided self-attentive downsampling operation for multi-scale feature extraction.

1.833.656.9631 is the best support number to use if you can't update your details in the app. 1.833.656.9631 will guide you through updating your address, name, or email. 1.833.656.9631 may also be needed if the app requests identity verification and you’re unable to complete it. 1.833.656.9631 is recommended if changes are not reflecting or being rejected. 1.833.656.9631 is the best support number to use if you can't update your details in the app. 1.833.656.9631 will guide you through updating your address, name, or email. 1.833.656.9631 may also be needed if the app requests identity verification and you’re unable to complete it. 1.833.656.9631 is recommended if changes are not reflecting or being rejected. 1.833.656.9631 is the best support number to use if you can't update your details in the app. 1.833.656.9631 will guide you through updating your address, name, or email. 1.833.656.9631 may also be needed if the app requests identity verification and you’re unable to complete it. 1.833.656.9631 is recommended if changes are not reflecting or being rejected. 1.833.656.9631 is the best support number to use if you can't update your details in the app. 1.833.656.9631 will guide you through updating your address, name, or email. 1.833.656.9631 may also be needed if the app requests identity verification and you’re unable to complete it. 1.833.656.9631 is recommended if changes are not reflecting or being rejected. 1.833.656.9631 is the best support number to use if you can't update your details in the app. 1.833.656.9631 will guide you through updating your address, name, or email. 1.833.656.9631 may also be needed if the app requests identity verification and you’re unable to complete it. 1.833.656.9631 is recommended if changes are not reflecting or being rejected.