Automated rolling shutter calibration with an LED panel.

Cameras with rolling shutters (RSs) dominate consumer markets but are subject to distortions when capturing motion. Many methods have been proposed to mitigate RS distortions for applications such as vision-aided odometry and three-dimensional (3D) reconstruction. They usually need known line delay d between successive image rows. To calibrate d, several methods have been proposed that often involve complex procedures. This Letter proposes an easy RS calibration method by using an off-the-shelf light-emitting diode (LED) panel, using the fact that the RS causes the blinking LED columns to appear slanted in images by a static camera. The calibration starts with extracting the LED lights and then rectifies the images to remove the lens distortion and misalignment between the camera and the LED panel. Next, blocks of slanted bright LEDs are recognized and their inclination leads to the line delay estimate. Our method needs not to move the camera, adjust the ambient light, or calibrate camera intrinsic parameters beforehand, and it can usually estimate the line delay given two LED panel images in one second. Extensive tests with industrial cameras and consumer cameras of wide-angle and fish-eye lenses validate its competitive accuracy relative to the established methods.

Mitochondrial enzymes in schizophrenia.

The responses of brain metabolism and blood flow to stimulation are diminished in the dorsolateral prefrontal cortexes (DLPFCs) of schizophrenic patients. Reductions in mitochondrial enzymes underlie diminished metabolism in several neurodegenerative diseases. Thus, we tested whether reductions in selected mitochondrial enzymes could underlie the changes in schizophrenia. The activities of the pyruvate dehydrogenase complex (PDHC), aconitase, isocitrate dehydrogenase (ICDH), and the alpha-ketoglutarate dehydrogenase complex (KGDHC) were determined on DLPFCs from patients with schizophrenia (n=26) and normal nonpsychiatric disease controls (n=13). The enzyme activities (mU/mg protein; mean +/- SEM) were similar (values for controls and schizophrenic patients, respectively) for PDHC (11.36 +/-1.5, 10.33 +/- 0.8), aconitase (1.06 +/- 0.1, 1.35 +/- 0.2), ICDH (31.70 +/- 2.7, 32.00 +/- 2.6), and KGDHC (2.62 +/- 0.4, 3.09 +/- 0.3). Separate analyses of the patients matched for age or postmortem interval gave similar conclusions. Cognitive dementia rating scores correlated poorly with activities of PDHC, aconitase, ICDH, and KGDHC. In one schizophrenic patient, activity of aconitase was undetectable, and in two others KGDHC activity was very low. Both had low activities of ICDH. A reduced activity of these enzymes in a subgroup is consistent with other data, suggesting that some patients with schizophrenia have abnormalities in brain mitochondria. However, in schizophrenia, unlike a number of neurodegenerative diseases, reductions in the activities of the key mitochondrial enzymes KGDHC and PDHC are not frequent.