Three-dimensional shape measurement of a transparent object using a rangefinding approach

This paper describes a non-contact optical measuring approach by which to measure the three-dimensional (3D) shape of a transparent object such as a glass panel or an acrylic plate. In conventional approaches to obtain the 3D shape of a transparent object, contact-type sensors have been widely used. However, the measurement accuracy of contact-type sensors is susceptible to the influence of various factors. In this paper, we propose a novel triangulation-based rangefinding approach that can be applied to the 3D shape of a transparent object or to an opaque object. The rangefinder is based on the fact that the light projected onto the surface of a transparent object is in part reflected by the surface, though the majority of the projected light is transmitted through the surface. From the experimental results, the proposed rangefinding approach has the advantage that it can easily measure the 3D-shape of an object if the object reflects or transmits light, depending on its location. As a result, we conclude that the proposed approach has great potential for a wide range of industrial applications.</p

A new method for 3-D shape measurement and surface reflectance of an object with rangefinder

An object for computer graphics application requires the following two information: the three dimensional (3D) shape and surface reflectance property of the object. We proposed a 3D shape and surface reflectance measurement system using the new sensor, which can detect the incidence position and the angle of the light simultaneously. Experimental results successfully demonstrate the efficacy of the method.</p

Causes and Prevention of Intestinal Adhesions Part 1. Surve of the Literature

1) Seven types of irritation causing intestinal adhesions are recognized in the literature : namely, a) mechanical injury; b) chemical injury; c) thermal injury; d) bacterial infection; e) foreign body; f) blood; and g) exsiccation. Certain minor differences of opinion exist among investigators, according to the experimental methods and the experimental animals used, and blood is not universally accepted as a cause of adhesions. The author believes, however, that the above list includes all of the etiological factors so far recognized in the literature. 2) The mechanism of intestinal adhesions is similar to that of wound healing. The problem of fibre synthesis is still unsolved, despite many advances in electlon microscopy, histochemistory and X-ray analysis. In recent years it has been accepted that fibres are synthesized in extra-cellular space from cytoplasmic materials derived from either mesenchymal cells or fibroblasts, and from polysaccharides in ground substances, althoughth eexact kind of polysaccharides which plays an important role in this process is still unknown. 3) Many papers are recognized with the prevention and treament of adhesions. These may be devided into six groups according to the method suggested: a) limitation of the original peritoneal injury; b) prevention of the coagulation of the exudate; c) avoidance of prolonged contact between the injured surfaces; d) removal of the fibrin after its formation; e) stopping or slowing down of the proliferation of fibroblasts; f) prevention of further obstruction by means of controlling the area of damaged intestine in stepladder fashion, the so-called the plication method. 1. It is the common practice of surgeons to limit the original peritoneal lllJury by laparotomy. Experimental studies have demonstrated that peritonealization of an area denuded of serosa often results in more extensive adhesions. 2. To prevent coagulation of the exudate, Lehman and Boys and other investigators used heparin and dicumarol. The role of heparin in the prevention of adhesions may be summarized as follow: there is a short time interval separating the production of the exudate and its subsequent coagulation with the deposition of fibrin on injured serosal surfaces. Anticoagulants of various types should be effective in preventing this fibrin formation if it is assumed that the coagulation mechanism of both exudate and blood is the same. Though the use of heparin and dicumarol has demonstrated a preventive effect on adhesion formation in experimental animals, many surgeons believe that the risk of hemorrhage from heparin and dicumarol outweighs their possible benefit in the prevention of adhesions. 3. To prevent prolonged contact between injured surfaces, amnion, omental and mesothelial graft, and so on, have been used without success. The stimulation of peristalsis by means of prostigmin and early feeding, however, appears to be effective in the prevention of adhesions, although its use in clinical cases has not been reported. 4. The experimental data indicates that streptokinase alone has no preventive effect on the formation of adhesions, because fibrinolysis is facilitated only by the existence of activated human plasmin. Concernig the use of hyaluronidase, this is an enzyme with the property of hydrolyzing hyaluronic acid, one of the polysaccharides that constitutes the intercellular ground substances. Experimental studies on the use of this material indicate, in summary, that topically administered hyaluronidase reduces the number of adhesions and particularly their density. The reason why hyaluronidase is effective in the prevention of adhesions is still unknown. 5. The use of corticoids and ACTH, according to all available experimental data, appears to delay the formation of adhesions and to prevent talc-induced adhesions, possibly by increasing the absorption of talc. In administrating corticoids, however, their tendency to delay wound healing, to perforate the intestinal wall, and to induce hemorrhage must be taken into account. 6. Experimental study and clinical USe of the plication method demonstrate that in patients with severe recurrent adhesions, or in those for whom the afore-mentio ned methods have been ineffective, this procedure is probably the most effective therapy available

Causes and Prevention of Intestinal Adhesions Part 3. Experimental Study of Prevention of Intestinal Adhesions

The experiments were designed (1) to investigate the effects of various types of injury to the peritoneum on the formation of adhesions, and (2) to study the hitological changes of the intestinal wall when injured artificially with 5 % iodine tincture. The experimental animals used were Wistar adult male rats with a weight range of 90 to 120 grams. A total of 170 rats were used. Experiment 1. The experimental animals were divided into 10 groups, each group consisting of 10 to 20 rats. Group A. The caecal serosa was injured with 2 % iodine tincture. Group B. The caecal seroSa was injured with 5 % iodine tincture. Group C. The caecal serosa was abraded with gauze until subserosal petechies were produced. Additional trauma to this area waS inflicted with 2 % iodine tincture. Group D. The caecal serosa was injured as in group C, but 5 % iodine tincture was used. Group E. The caecal serosa waS injured with 2 % aqueous mercurochrome solution. Group F. The caecal serosa was rubbed with gauze until subserosaI petechies were produced. Additional trauma to this area was inflicted with 2 % aqueous mercurochrome solution. Group G. The caecal wall was rubbed with gauze 100 times, injuring the subserosa. Group R. The anterior wall of the stomach and caecum was traumatized with a toothbrush and 2 ml of aqueous talcum solution were instilled into the peritoneal cavity. Group I. Excisions of the parietal peritoneum were performed with a surgical knife over areas of varying sizes at both sides of the operation wound. Group J. Adjacent loop of the intestines with normal serosa were connected to one another by No.2 black silk suture at two or three points. In five cases of this group, contacting surfaces of the intestines were injured with 5 % iodine tincture. The results obtained were as follows : (1) Local administration of 2 % iodine tincture and 2 % aqueous mercurochrome solution would not produce adhesions unless mechanical injury, such as rubbing with gauze was also present. (2) When the serosa was slightly injured with gauze, fibrinous adhesions were separated or torn apart by bowel movements. (3) Local administration of 5 % iodine tincture produced in all members of group B. The adhesions were moderate, not extensive in degree. Additional mechanical trauma aggravated the adhesions caused by bacterial contamination. (4) Intraperitoneal instillation of 10 % aqueous talcum solution produced extensive adhesions. The favorite sites of occurrence of the adhesions were the greater omentum and the small intestine. (5) Excision of the parietal peritoneum over areas of vareous sizes caused no adhesion. (6) Even prolonged contact between the intestinal wall and normal serosa did not result in the formation of adhesions. However, firm adhesions resulted from prolonged contact between injured serosal surfaces regardless of the type of injury. (7) The author would like to emphasize that large peritoneal defects should be left untreated, because attempts at peritonealization result in additional injury to the subserosa and often in more extensive adhesions. Experiment 2. (1) Edema and an infiltration of leucocytes occurred in the early stages of the inflammation. These histological changes were seen not only in the subserosa, the muscular layer, and the submucosa, but also in the mucosa. Lesions in the mucosa slowly developed into necroses or ulcers. The intensity of the adhesions varied with the severity of the lesions in the mucosa. (2) Twenty-four hours after injury to the peritoneum, P. A. S. positive substances began to appear in the submucosa, disappearing fourth post-operative day. (3) The process of the formation of the adhesions may be outlined as follow: a) After injury to the peritoneal surface, an exudate is formed. b) Thise xudate coagulates to form fibrin, which causes adiacent surfaces to cohere. c) Dunng organization, fibroblasts or fibrocytes migrate into this area. e) Whth the aid of mucopolysacchrides in ground substances, collagen is deposited and grdually a firm adhesion is formed. In some cases, however, this area becomes membraneous or strand-like in form during the completion of the process of adhesions, and is eventually torn apart

A new sensor system for simultaneously detecting the position and incident angle of a light spot

The present paper describes a newly devised sensor, which has the ability to detect the two-dimensional position and the one-dimensional angle of a light spot simultaneously. Ordinary laser-based measurement systems utilize CCD or PSD sensors. These conventional sensors can detect only a light spot's position. When the sensor can detect the incident angle of a light spot as well as the position, the sensor has a wide range of applicability. The sensor consists of two linear array-type sensors whose depth positions are slightly different. We have designed and built a prototype sensor system. We experimentally verified the practicable accuracy of the present sensor system. We also applied the present sensor system to two typical laser-based measurement systems: 2-D position measurement, and 3-D shape measurement for specular objects. Experimental results show that the sensor system was applicable to a laser-based measurement system. </p

A Statistical and Clinical Study of Postoperative Intestinal Adhesions

The author studied 36 cases of postoperative intestinal adhesions treated in this insitute during the past ten years. The results obtained were as follow. 1) The sex ratio was 21 (male) to 15 (female). 2) Fifty-three percent of the cases ranged from 20 to 40 years in age. 3) The initial operations which supposedly caused the adhesions were appendectomies. 4) Of the primary causative disease of the acute intetinal obstruction group, appendicitis accounted for 62% and gastrointestinal diseases for 15.4%. The primary causative disease of the chronic intestinal obstruction group was found to be appendicitis in about 70% of the cases. 5) The chief complaints made by patients were of vomiting and generalized Severe pain of the abdomen. 6) The most frequent sites of occurrence of the adhesions were the greater omentum, the small intestine and the sutured part of the peritoneum. 7) As regards the final therapeutic approach, in the largest number of cases (36.% of the total) lysis of the adhesion was performed. In most other cases, however, distress was relieved by enterostomy, resection of the bowel, and so on. Finally, the four most recent cases, all of whom suffered from recurrent intestinal obstrution, were relieved of the major portion of their abdominal complaints by a new method, an improvement of the original technique advocated by Noble in 1937. The details of this new technique will be reported in the next issue

A new method of measuring the 3-D shape and surface reflectance of an object using a laser rangefinder

The present paper describes a newly proposed method for simultaneously measuring 3D shape and surface reflectance of an object using a laser rangefinder. The original work of this method lies in the advantage that the proposed method measures the surface reflectance using the object itself that is used for the 3D shape measurement. Experimental results show that the proposed method was applicable to noncontact industrial inspection, robot vision in automatic assembly, and reverse engineering.</p

A new laser-based position sensor with the ability of detecting the incident angle of a light

This paper describes a new sensor with the ability of simultaneously detecting the position and the incident angle of a light. The basic principle is to detect the difference in the peak positions between two image sensors. We have designed and build three kinds of prototype of the proposed sensor. We experimentally verified the practicable accuracy of the proposed position sensors.</p