Object human observer

Objects close to us are easily perceived, but as we attempt to detect objects farther and farther away from us, the contrast between the object and the background decreases. The lowest limit of contrast for human observers is called the threshold contrast and is important because this value influences the maximum distance at which we can see various objects. 

With the best observing conditions, it is possible for the trained observer to compete with photoelectric colorimeters for detection of small color differences in samples which can be observed simultaneously. However, the human observer cannot ordinarily make accurate color comparisons over a period of time if memory of sample color is involved. This factor and others, such as variability among observers and color blindness, make it important to control or eliminate the subjective factor in color grading. In this respect, objective methods, which make use of instruments such as spectrophotometers or carefully calibrated colorimeters with conditions of observation carefully standardized, provide the most reliable means of obtaining precise color measurements. 

The subject of color, as it relates to the human eye and brain, is complex and fascinating. Overall, there are many factors that can affect the perceived color of a surface. Models like Munsell use an alphanumeric notation to identify the dimensions for a color and its location within the color space. A Munsell notation (hue, value, and chroma) depends on a subjective visual judgment made by a human observer. There are other color-order systems that specify color by objective three-dimen-... 

With this experiment, Land and McCann vividly demonstrated that the perceived color of an object does not depend on the light reflected by the object. The perceived color depends on the reflectance, which specifies how much of the incident light is reflected. The reflectance determines the color of the object. The reflected light is essentially proportional to the product of the irradiance (see Table B.l for a definition) and the reflectance of the object. A human observer is somehow able to derive the reflectances for the objects in view regardless of the illuminant used. In contrast, a digital or an analog camera can do no more than the telescopic photometer can. It only measures the reflected light. In order... 

Color is a biased human observation. A complex response to light, an object, our eyes, and subsequent analog signals that is processed by our emotional brains to form a mental interpretation called color, that is, no numbers—just simple subjective human observations or responses to a stimulation. 

Medicine is art and science. The art aspect consists of the way that the physician deals with the human aspect of the patient, expressing empathy, compassion, establishing a therapeutic relationship, and deahng with uncertainty the science is the attempts to understand disease processes, making rational treatment plans, and being objective in observations. The physician as scientist must be precise about how to elicit data and then carefully make sense of the information, using up-to-date evidence. Exercises to develop the skills of data analysis require interpretation of data in various representations, such as in tables or on graphs. 

Physical man has himself become the object of a separate science, anatomy, which in its ordinary meaning includes physiology, that science which had been retarded by a superstitious respect for the dead, profited from the general enfeeblement of prejudice and successfully undermined the support that it received from powerful men who were interested in its preservation. Its progress seems somehow to have come to a stop, and to await the discovery of improved instruments and new methods. And it now seems to be almost reduced to the study of the comparisons between the parts of animals and those of men, the organs common to different species, and the manner in which similar functions are exercised, in its search for those truths which are at the moment not open to human observation. Almost everything which the eye of the observer has been able to discover with the aid of a microscope is already unveiled. The future development of anatomy seems to depend on the possibility of experiment which has proved so useful to the progress of other sciences. But this necessary means of improvement has been denied to anatomy by the very nature of its subject. 

The mathematical color system is the CIE Color System based on mathematical descriptions of light sources, objects, and a standard observer. Light sources are specified by their relative energy distributions, objects are specified by their reflectance (or transmission) spectra, and the observer is specified by the CIE standard human observer tables. For color analysis, the light reflected (or transmitted) from (or through) an object is measured with a spectrophotometer. The... 

For small distances DLVO theory predicts that the van der Waals attraction always dominates. Please remember, the van der Waals force between identical media is always attractive irrespective of the medium in the gap. Thus thermodynamically, or after long periods of time, we expect all dispersions to precipitate. Precipitation might, however, be so slow that it exceeds the life span of any human observer. Once in contact, particles should not separate again, unless they are strongly hit by a third object and gain a lot of energy. 

For nineteenth-century scientists, the obvious way to account for the laws of black-body radiation was to use classical physics to derive its characteristics. However, much to their dismay, they found that the characteristics they deduced did not match their observations. Worst of all was the ultraviolet catastrophe classical physics predicted that any hot body should emit intense ultraviolet radiation and even x-rays and y-rays According to classical physics, a hot object would devastate the countryside with high-frequency radiation. Even a human body at 37°C would glow in the dark. There would, in fact, be no darkness. 

---