Concealed objects detection based on FWT in active millimeter-wave images

Millimeter Wave Sensing: A Review of Application Pipelines and Building Blocks

“…and lat. R and v Undefined Radar [146] Doppler shift data (time, TX channel) [190] [63] Spectrogram (range, velocity) Radar [181] Radar image (x, z) Active imaging [191] Radar image (x, z) Active imaging [67] R, ϕ, and vr Undefined Radar [192] Radar image (x, z) Active imaging [193] Radar image (x, z) Active imaging [69] Heartbeat data (time) Radar [189] Radar image (x, z) Active imaging [72] Spectrogram (x, z) [194] [176] Radar image (x, y) Active imaging [177] Radar image (x, y) Active imaging Point cloud frame (x, y) R, vr , θ, and power Undefined [81] Spectrogram (range, velocity) [195] [83] Spectrogram (range, azimuth) Radar [84] Profile (range) Radar Range compressed down-conversion IF data [89] Point cloud frame (x, y, z) Radar [91] Spectrogram (range, velocity) Radar Point cloud frame (x, y, z) vr Undefined [97] Point cloud frame (x, y, z) Radar [99] R and θ Undefined Radar [196] Reflection intensity Undefined Radar Profile (range) Spectrogram (time, frequency) [104] Radar trace Undefined Radar [178] Spectrogram (x, y) Active imaging [105] Heartbeat data (time) [198] [112] Spectrogram (time, frequency) [199] [185] Positioning data Undefined Spatial sweeping [115] R and θ Undefined Radar [153] RSS signal (time, RX channel) Spatial sweeping Profile (range) Waterfall chart (time, range) Dynamic (time-varying) signal components Point cloud frame (x, y, z) vr Undefined Point cloud frame (x, y, z) vr and intensity Undefined [125] Spectrogram (range, velocity) Radar [131] Spectrogram (x, y) Radar…”

“…Binarization refers to the creation of a binary image from a radar image. Binary images contain black and white values assigned through use of a threshold [191]. Mathematical morphology is a term used to describe a set of matrix operations that are used to transform binary images [176], [191].…”

“…Binary images contain black and white values assigned through use of a threshold [191]. Mathematical morphology is a term used to describe a set of matrix operations that are used to transform binary images [176], [191]. These matrix operations are called erosion, dilation, opening, and closing, and involve an input image and a structuring element.…”

“…The application pipeline in [120] uses a similar approach in which points converted to camera coordinates are used to compute RGB values. Fast Wavelet Transformation (FWT) is used to transform a radar image into the wavelet domain with the intent to denoise it in the wavelet domain [191]. Greyscaling refers to converting a spectrogram consisting of magnitude values to a grayscale image [116].…”

3D Holographic Millimeter-Wave Imaging for Concealed Metallic Forging Objects Detection

“…Various imaging techniques include infrared imaging [5,6], passive millimeter-wave (MMW) imaging [7][8][9], active MMW imaging [10,11], X-ray imaging [12,13] and holographic imaging [14][15][16][17] have been investigated for concealed metallic object detection. Recent studies have demonstrated that passive MMW imaging has the most potential to become a useful tool to identify concealed MFOs under clothing [18,19], which has been investigated for various applications include security, military, surveillance and biomedical [20].…”