Background and Objectives: Depth perception of the human visual system in three-dimensional (3D) space plays an important role in human–computer interaction and artificial intelligence (AI) areas. It mainly employs binocular disparity and motion parallax cues. This study aims to systemically summarize the related studies about depth perception specified by these two cues. Materials and Methods: We conducted a literature investigation on related studies and summarized them from aspects like motivations, research trends, mechanisms, and interaction models of depth perception specified by these two cues. Results: Development trends show that depth perception research has gradually evolved from early studies based on a single cue to quantitative studies based on the interaction between these two cues. Mechanisms of these two cues reveal that depth perception specified by the binocular disparity cue is mainly influenced by factors like spatial variation in disparity, viewing distance, the position of visual field (or retinal image) used, and interaction with other cues; whereas that specified by the motion parallax cue is affected by head movement and retinal image motion, interaction with other cues, and the observer’s age. By integrating these two cues, several types of models for depth perception are summarized: the weak fusion (WF) model, the modified weak fusion (MWF) model, the strong fusion (SF) model, and the intrinsic constraint (IC) model. The merits and limitations of each model are analyzed and compared. Conclusions: Based on this review, a clear picture of the study on depth perception specified by binocular disparity and motion parallax cues can be seen. Open research challenges and future directions are presented. In the future, it is necessary to explore methods for easier manipulating of depth cue signals in stereoscopic images and adopting deep learning-related methods to construct models and predict depths, to meet the increasing demand of human–computer interaction in complex 3D scenarios.

Spectral irradiance scale in the wavelength range from 250 nm to 2500 nm was realized at National Institute of Metrology on the basis of a large area tungsten carbide–carbon (WC–C) high temperature fixed point blackbody, which is composed of a 14 mm diameter WC–C fixed point cell and a variable temperature blackbody BB3500MP as a furnace. A series of 1000 W FEL tungsten halogen lamps were used as transfer standards. The new spectral irradiance scale was compared with the scale based on a variable-temperature blackbody BB3500M, and the divergence between these two methods varied from −0.66% to 0.79% from 280 nm to 2100 nm. The measurement uncertainty of spectral irradiance scale based on fixed-point blackbody was analyzed, and the expanded uncertainty was estimated as 3.9% at 250 nm, 1.4% at 280 nm, 0.43% at 400 nm, 0.27% at 800 nm, 0.25% at 1000 nm, 0.62% at 1500 nm, 0.76% at 2000 nm, and 2.4% at 2500 nm respectively. In the range from 300 nm to 1000 nm the fixed-point scale was improved obviously: the uncertainty decreased by more than 25% compared to the uncertainty based on the variable temperature blackbody. Below 300 nm, the uncertainty became higher because the signal to noise ratio was poor. Above 1100 nm, the contribution of temperature measurement to the uncertainty of spectral irradiance decreases, therefore the uncertainties of two methods are almost at the same level. The fixed-point blackbody was also used to realize the correlated colour temperature and distribution temperature of a tungsten filament lamp, the deviation from the variable temperature blackbody method was −0.5 K and −2.9 K, respectively.

Accurately simulating the asymmetric spectral profiles of blue LEDs is crucial for photobiological research, yet it remains a challenge for traditional symmetric models. This study proposes a novel spectral simulation model that effectively captures these asymmetries. The proposed model structure is partly motivated by known broadening and dispersion mechanisms observed in real LED spectra; it employs a ‘base model + correction’ framework, where an Exponentially Modified Gaussian (EMG) function captures the primary spectral shape and falling edge and an Asymmetric Pseudo-Voigt (APV) function corrects the deviations on the rising edge. Requiring only the central wavelength and bandwidth as user inputs, the simulation results exhibit a high degree of agreement with the experimental data spectra. The model provides a rapid and robust tool for pre-evaluating light sources against regulatory criteria (e.g., >99% of the spectral intensity is in the 400–500 nm band), thereby enhancing the efficiency of experimental design in blue light protection studies.

Measuring the emissivity of an infrared radiant sample with high accuracy is important. Previous studies reported on the multi- or two-temperature calibration methods, which used a reference blackbody (or blackbodies) to eliminate the background radiation, and assumed that the background radiation was independent of temperature. However, in practical measurements, this assumption does not hold. To solve the above problems, this study proposes a modified two-temperature calibration method and facility. The two temperature points are set in a certain small interval based on the proposed calculation method; based on the indication of the approximation that the emissivities of the sample and the background radiations remain the same at these two temperatures, the emissivities can be calculated with measurement signals at these two temperatures, and a reference blackbody is not needed. An experimental facility was built up and three samples with emissivities around 0.100, 0.500, and 0.900 were measured in (8~14) μm. The relative expanded uncertainties were 9.6%, 4.0%, and 1.5% at 60 °C, respectively, and 8.8%, 5.8%, and 1.2% at 85 °C (k = 2), respectively. The experimental results showed consistency with the results obtained using other methods, indicating the effectiveness of the developed method. The developed method might be suitable for samples whose emissivities are temperature insensitive.

Ultraviolet (UV) total spectral radiant flux has been realized by a gonioradiometer-based method using double grating monochromators for the first time. The measurement based on the gonioradiometer method contains three facilities. The first facility measures the UV total spectral radiant flux of deuterium lamps in the wavelength range from 200 nm to 450 nm, where the double grating monochromators are used to reduce the stray light effect. The second one is the facility for UV total spectral radiant flux measurement of UV LEDs, also based on double grating monochromators. The third facility measures the UV total radiant flux of the UV germicidal lamp, which is the low pressure mercury lamp with the peak wavelength of 253.7 nm. All the facilities are realized based on gonioradiometer method. The measurement not only obtain the total spectral radiant flux of these lamps, but also obtain the spatial distribution of these lamps in the whole space. Furthermore, the reliability and accuracy of the systems were further assessed through consistency checks: for the three lamps, the deviations obtained using different facilities were -1.84%, -0.88% and 0.77%, respectively, demonstrating good consistency under the common gonioradiometer-based method.

A novel correction method was demonstrated for measuring spectral irradiance of light sources with a narrow bandwidth. Using the correction method based on differential quadrature method, an estimate of the true value was achieved with measured values of seven adjacent points. The formula of this correction method was derived. Numerical simulations and experimental validation of this correction method were also performed, respectively. This correction method could be used in radiometry, photometry, colorimetry, and other spectrometry fields, especially in the spectrum measurement of LED lamp.