Semantic segmentation aims to provide pixel-wise accurate predictions for images. Semi-supervised semantic segmentation aims to learn a semantic segmentation model using a limited number of labeled images and a large fraction of unlabeled images. Existing methods primarily focus on introducing additional models or complex training procedures but overlook the model itself and such complex strategies tend to discard many usable pixels, exacerbating the class imbalance problem . In this paper, we propose DAM for semi-supervised semantic segmentation, a simple yet effective method that mainly focuses on the inputs and outputs of the model itself. For the input component, we posit that diverse data augmentations can provide more semantic information . Therefore, we propose a method called Random Diversity Augmentations. Given an unlabeled image, we apply different triple-level data augmentations to provide more semantic information. For the output component, our approach is inspired by the fact that many unreliable predictions are confused only among the top classes rather than all classes, so we contend that fuzzy pixels can still provide valuable guidance to the model. Specifically, we select fuzzy pixels based on confidence and assign multi-fuzzy labels to these pixels for training the model, which allows us to leverage the information more effectively. Our straightforward DAM achieves new state-of-the-art performance on SSS different benchmarks. Code is available at https://github.com/Wang-zhenyan/DAM .

Facial sketch synthesis (FSS) has advanced significantly in recent years, but challenges remain in few-shot settings. Some few-shot learning methods can convert photos (source domain) into sketches of a specified style (target sketch domain). However, they overlook the available samples of other sketch styles (non-target sketch domains). We argue that the information in these samples can help the model enhance its mapping ability from the source domain to the target domain. This paper proposes a progressive domain gap reduction (PDGR) method for few-shot facial sketch synthesis, which consists of three stages: teacher training, knowledge distillation, and intra-domain few-shot adaptation. In the first stage, we adapt a pretrained StyleGAN to a non-target sketch domain with more available samples than the target sketch domain. To generate diverse and high-quality sketches, we employ a dual-discriminator adversarial mechanism to guide the model in focusing on the overall structure and style, as well as multi-scale details and textures. In the second stage, the knowledge from StyleGAN is transferred to a U-Net for more efficient image translation. In the third stage, we adapt the output of the U-Net from the non-target sketch domain to the target sketch domain in few-shot settings. To alleviate overfitting, preserve individual characteristics, and enhance detail representation, we leverage the FFHQ dataset to construct dual training paths and design a domain-directional triple loss. Experiments show that PDGR significantly outperforms previous few-shot learning methods and even outperforms the state-of-the-art FSS methods trained on the full dataset.

It is a typical problem in the field of object detection to simultaneously detect objects with large scale variation in one image. Recently proposed state-of-the-art object detectors generally learn pyramidal feature representation to deal with the scale variation, which has been proved effective via various feature pyramid networks. However, the majority of the feature pyramid networks based on heuristic feature fusion strategies may be suboptimal, as excess human guidance will restrict the self-learning of deep neural networks. An adaptive feature pyramid is bound to provide a significant performance boost. In this paper, we propose a novel feature pyramid network named CATFPN that consists of Scale-Wise Feature Concatenation (SWFC) module and Global Context (GC) block. The SWFC module evenly distributes semantic features for each feature layer and the GC block introduces a self-attention mechanism. As a feature pyramid network, the CATFPN can be applied to any detector based on multi-scale features. We adopt the CATFPN in typical RetinaNet and Faster R-CNN detector models, without bells and whistles, achieving 1.1% AP and 0.7% AP improvements over FPN on the MS COCO benchmark, respectively. Our competitive performance reported on the test-dev subset of COCO achieves 42.3% AP.

Although high-accuracy networks have been applied to semantic segmentation at present, their inference speeds remain slow. A trade-off between accuracy and speed is demanded for real-time applications. To approach this problem, we propose Multi-Feature Fusion Network (MFNet) with real-time efficient prediction capacity. MFNet adopts three branches (attention, semantic and spatial information) to capture low-level and high-level features. Additionally, MFNet exerts asymmetric factorized (AF) blocks to extract local and long-range features. As a result, without any pre-training or post-processing, MFNet using only 1.34 M parameters, achieves 72.1% mean intersection over union (mIoU) on the Cityscapes test set at a speed of 116 frames per second (FPS), with$512\times 1024$high resolution on a single Titan Xp graphics card. Our network’s performance stands out from other state-of-the-art networks on four datasets (Cityscapes, CamVid, KITTI, and Gatech).

In this paper, we investigate BER performances of hybrid carrier (HC) framework based on weighted-type fractional Fourier transform (WFRFT) precoding with transmitter (TX) in-phase/quadrature (IQ) imbalance. Orthogonal frequency division multiplexing (OFDM) and single carrier (SC) systems with IQ imbalance are unified in proposed HC framework. Considering IQ imbalance as interference, the signal-to-interference-plus-noise ratio (SINR) of HC scheme is calculated, and then theoretical BER expressions over fading channels with zero forcing (ZF) and minimum mean square error (MMSE) equalizers are derived. Since a performance gain is involved in SC scheme with IQ imbalance interference, SC BER is theoretically given as a special case. Furthermore, we also put forward an IQ imbalance compensation method for HC framework through removing IQ imbalance interference at the cost of enlarged noise. The postcompensation noise of HC scheme is calculated and used to derive analytical BER expressions. The compensation performances of HC with ZF and MMSE receivers are verified through theoretical and simulated results.

Wildfires have devastating consequences on ecological systems and human lives. Accurate and fast wildfire detection is crucial to reduce damage. The existing smoke detection algorithms using convolution neural network are mostly based on the classification of smoke images or patches, whereas the traditional smoke detection algorithms are often necessary to extract multiple features for integration. With the methods mentioned above, false positive is always an insurmountable problem in wildfire smoke detection. Moreover, there are few studies on the detection of wildfire smoke. Thus, to detect the wildfire smoke more intelligent, a 3D parallel fully convolutional network for wildfire smoke detection is proposed to segment the smoke regions in video sequences. Wildfire smoke detection is considered as a segmentation problem in this paper. There are more than 90 videos including various scenes used for training and test. Experiments have demonstrated that our architecture can segment smoke regions accurately and eliminate the interference of natural scenes. Smoke targets in multiple scenes can be detected accurately and quickly.

With the development of biometric recognition technology, sketch face recognition has been widely applied to assist the police to confirm the identity of the criminal suspect. Most of the present recognition methods use the image features directly, in which the key parts can’t be used sufficiently. This paper presents a sketch face recognition method based on P-HOG multi-features weighted fusion. Firstly, the global face image and the local face image which contains key components of the face are divided into patches based on spatial scale pyramid, and then the global P-HOG features and local P-HOG features are extracted, respectively. After that, the dimensions of global and local features are reduced using PCA and NLDA. Finally, the features are weighted based on sensitivity and fused. The nearest neighbor classifier is used to complete the final recognition. The experimental results on different databases show that the proposed method outperforms state-of-the-art methods.

Traffic sign detection is challenging in cases of a complex background, occlusions, distortions, and so on. To overcome the above-mentioned challenges, this paper pays close attention to channel-wise feature responses to propose an end-to-end deep learning-based saliency traffic sign detection method. Our model contains three main components: channel-wise coarse feature extraction (CCFE), channel-wise hierarchical feature refinement (CHFR), and hierarchical feature map fusion (HFMF). In addition, it is based on the squeeze-and-excitation-residual network to explicitly model the inter dependences between the channels of its convolution features at a slight computational cost. We first apply CCFE to produce coarse feature maps with much information loss. To make full use of spatial information and fine details, CHFR is executed to refine hierarchical features. After that, HFMF is used to fuse hierarchical feature maps to generate the final traffic sign saliency map. Compared with other five traffic sign detection methods, the experimental results demonstrate the efficiency (a real-time speed) and superior performance of the proposed method according to comprehensive evaluations over three benchmark data sets.

Heterogeneous face sketch-photo synthesis is an important and challenging task in computer vision, which has widely applied in law enforcement and digital entertainment. According to the different synthesis results based on different scales, this paper proposes a cascade sketch-photo synthesis method via dual-scale Markov Network. Firstly, Markov Network with larger scale is used to synthesise the initial sketches and the local vertical and horizontal neighbour search (LVHNS) method is used to search for the neighbour patches of test patches in training set. Then, the initial sketches and test photos are jointly entered into smaller scale Markov Network. Finally, the fine sketches are obtained after cascade synthesis process. Extensive experimental results on various databases demonstrate the superiority of the proposed method compared with several state-of-the-art methods.

Face sketch recognition has great practical value in the criminal detection, security and other fields. Especially, it can help the police narrow down potential suspects in criminal detection effectively. Face sketch represents the original photos in a simple and recognizable form, so sketch and photo are images of two different modes. In order to identify the corresponding sketch face image in a lot of photo face images, this paper presents an improved sketch–photo transformation algorithm, and it uses the effective characteristics of the photo image more reasonably during transforming a photo image into sketch. In this way, it can reduce the difference between the sketch and photo image to improve the matching effect, and save the recognition time. Many experiments on CUHK Face Sketch database including 188 sketch–photos prove the effectiveness of the method in this paper.

A novel method is proposed in this paper to improve the recognition accuracy of Local Binary Pattern (LBP) on low-resolution face recognition. More precise descriptors and effectively face features can be extracted by combining multi-scale blocking center symmetric local binary pattern (CS-LBP) based on Gaussian pyramids and weighted principal component analysis (PCA) on low-resolution condition. Firstly, the features statistical histograms of face images are calculated by multi-scale blocking CS-LBP operator. Secondly, the stronger classification and lower dimension features can be got by applying weighted PCA algorithm. Finally, the different classifiers are used to select the optimal classification categories of low-resolution face set and calculate the recognition rate. The results in the ORL human face databases show that recognition rate can get 89.38% when the resolution of face image drops to 12[Formula: see text]10 pixel and basically satisfy the practical requirements of recognition. The further comparison of other descriptors and experiments from videos proved that the novel algorithm can improve recognition accuracy.

Changes in light intensity and angle present a major challenge to the creation of reliable face recognition systems. The existence of bright regions and dark regions has been shown to have a serious negative impact on the performance of face recognition systems. This paper proposes a solution to this problem based on self-quotient image (SQI) processing method. In this method, bright and dark areas are processed separately without changing the essential characteristics of the image of the face. The dark and light areas are processed separately by SQI. Experimental results indicate that this Single-Light-Region and Single-Dark-Region SQI method removes the adverse effect of multi-bright and multi-dark areas better than competing methods.