A flexible optical measuring device is laser rangefinder with flexible ranging direction which includes a TOF (time of flight) laser rangefinder, an optical fiber adapter and a dual branch flexible light guide. The TOF laser rangefinder includes a laser diode source, an optical receiver and a computing unit. The dual branch flexible light guide is disposed and connected the TOF laser rangefinder. Due to the flexibility of dual branch flexible light guide, the laser ranging direction can also achieve ranging in any direction. Its ranging curve line equation is highly linearity. The cofficient of determination (R2) is moer than 0.9. Therefore, this design has been presented to meet with requirement for measuring distance indeeds for many applications.
A 2D detector array is used popularly to acquire image in spatial and spectral dimension simultaneously for
hyperspectral imager. The detector array will be malfunctioned gradually and partially after long-term operations.
These defective CCDs will cause vertical stripes in images. But it's not cost effective to replace the detector due to a few
of defects. In this article, we propose an algorithm including two parts for hyperspectral image restoration. One is the
CCDs defect parts detection according to their radiance deviation, and another is the image restoration based on
inter-band radiance interpolation using Lagrange polynomial.
The detection process of finding CCDs defect parts for an imager must be conducted periodically to update the CCDs
health status. HOPE images with simulated defective CCDs of various performance decay level are applied for
validation. We found the accuracy for images with homogeneous ground feature is higher than the ones with
non-homogeneous feature. And defect CCDs with performance decay of 10% still can be designated precisely.
Restoration accuracy of pixel radiance is presented for various spectral bands using proposed algorithm. We also
perform the image reconstruction using interpolation of spatial neighboring pixels. Radiance deviation for restored
pixels is compared between both methods. Proposed algorithm can handle the images taken by hyperspectral imager
with adjoining defective CCDs both in spatial and spectral. However, the method using interpolation of neighboring
pixels can't. Applying the purposed algorithm on hyperspectral images, the imager can continue operating like a good
one though there are a few of defects in detector.