49 research outputs found
Du capteur à l'image couleur
This chapter deals with the acquisition of colour images by mono-CCD colour cameras. These devices acquire only one colour component at each pixel through the CFA (Colour Filter Array) that covers the CCD sensor. A procedure - called demosaicing - is necessary to estimate the other two missing colour components at each pixel to obtain a colour image. A mathematical formalization for demosaicing is proposed, before we present some of the methods in the demosaicing literature, as well as the post-processing algorithms to correct the estimated images. We then present objective criteria for the quality evaluation of colour images, and apply them to estimated images to draw up conclusions about the selection of a demosaicing method. At last, we examine why and how white balancing is required and implemented to provide images faithfull to the observed scene under varying illumination conditions
Risk Categorization Using New American College of Cardiology/American Heart Association Guidelines for Cholesterol Management and Its Relation to Alirocumab Treatment Following Acute Coronary Syndromes
BACKGROUND: The 2018 US cholesterol management guidelines recommend
additional lipid-lowering therapies for secondary prevention in patients with lowdensity lipoprotein cholesterol ≥70 mg/dL or non−high-density lipoprotein cholesterol
≥100 mg/dL despite maximum tolerated statin therapy. Such patients are considered
at very high risk (VHR) based on a history of >1 major atherosclerotic cardiovascular
disease (ASCVD) event or a single ASCVD event and multiple high-risk conditions.
We investigated the association of US guideline-defined risk categories with the
occurrence of ischemic events after acute coronary syndrome and reduction of
those events by alirocumab, a PCSK9 (proprotein convertase subtilisin/kexin type 9)
inhibitor.
METHODS: In the ODYSSEY OUTCOMES trial (Evaluation of Cardiovascular
Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab),
patients with recent acute coronary syndrome and residual dyslipidemia despite
optimal statin therapy were randomly assigned to alirocumab or placebo. The primary
trial outcome (major adverse cardiovascular events, ie, coronary heart disease death,
nonfatal myocardial infarction, is
From the Sensor to Color Images
International audienceThis chapter deals with the acquisition of colour images by mono-CCD colour cameras. These devices acquire only one colour component at each pixel through the CFA (Colour Filter Array) that covers the CCD sensor. A procedure - called demosaicing - is necessary to estimate the other two missing colour components at each pixel to obtain a colour image. A mathematical formalization for demosaicing is proposed, before we present some of the methods in the demosaicing literature, as well as the post-processing algorithms to correct the estimated images. We then present objective criteria for the quality evaluation of colour images, and apply them to estimated images to draw up conclusions about the selection of a demosaicing method. At last, we examine why and how white balancing is required and implemented to provide images faithfull to the observed scene under varying illumination conditions